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![Wei Liu](/assets/img/avatar_default.png)
Originally Xen PV drivers only use single-page ring to pass along information. This might limit the throughput between frontend and backend. The patch extends Xenbus driver to support multi-page ring, which in general should improve throughput if ring is the bottleneck. Changes to various frontend / backend to adapt to the new interface are also included. Affected Xen drivers: * blkfront/back * netfront/back * pcifront/back * scsifront/back * vtpmfront The interface is documented, as before, in xenbus_client.c. Signed-off-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Signed-off-by: Bob Liu <bob.liu@oracle.com> Cc: Konrad Wilk <konrad.wilk@oracle.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2126 lines
56 KiB
C
2126 lines
56 KiB
C
/*
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* blkfront.c
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*
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* XenLinux virtual block device driver.
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*
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* Copyright (c) 2003-2004, Keir Fraser & Steve Hand
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* Modifications by Mark A. Williamson are (c) Intel Research Cambridge
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* Copyright (c) 2004, Christian Limpach
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* Copyright (c) 2004, Andrew Warfield
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* Copyright (c) 2005, Christopher Clark
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* Copyright (c) 2005, XenSource Ltd
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <linux/interrupt.h>
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#include <linux/blkdev.h>
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#include <linux/hdreg.h>
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#include <linux/cdrom.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/scatterlist.h>
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#include <linux/bitmap.h>
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#include <linux/list.h>
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#include <xen/xen.h>
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#include <xen/xenbus.h>
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#include <xen/grant_table.h>
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#include <xen/events.h>
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#include <xen/page.h>
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#include <xen/platform_pci.h>
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#include <xen/interface/grant_table.h>
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#include <xen/interface/io/blkif.h>
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#include <xen/interface/io/protocols.h>
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#include <asm/xen/hypervisor.h>
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enum blkif_state {
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BLKIF_STATE_DISCONNECTED,
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BLKIF_STATE_CONNECTED,
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BLKIF_STATE_SUSPENDED,
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};
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struct grant {
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grant_ref_t gref;
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unsigned long pfn;
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struct list_head node;
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};
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struct blk_shadow {
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struct blkif_request req;
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struct request *request;
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struct grant **grants_used;
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struct grant **indirect_grants;
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struct scatterlist *sg;
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};
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struct split_bio {
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struct bio *bio;
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atomic_t pending;
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int err;
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};
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static DEFINE_MUTEX(blkfront_mutex);
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static const struct block_device_operations xlvbd_block_fops;
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/*
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* Maximum number of segments in indirect requests, the actual value used by
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* the frontend driver is the minimum of this value and the value provided
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* by the backend driver.
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*/
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static unsigned int xen_blkif_max_segments = 32;
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module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
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MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 32)");
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#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
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/*
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* We have one of these per vbd, whether ide, scsi or 'other'. They
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* hang in private_data off the gendisk structure. We may end up
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* putting all kinds of interesting stuff here :-)
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*/
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struct blkfront_info
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{
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spinlock_t io_lock;
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struct mutex mutex;
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struct xenbus_device *xbdev;
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struct gendisk *gd;
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int vdevice;
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blkif_vdev_t handle;
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enum blkif_state connected;
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int ring_ref;
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struct blkif_front_ring ring;
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unsigned int evtchn, irq;
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struct request_queue *rq;
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struct work_struct work;
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struct gnttab_free_callback callback;
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struct blk_shadow shadow[BLK_RING_SIZE];
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struct list_head grants;
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struct list_head indirect_pages;
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unsigned int persistent_gnts_c;
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unsigned long shadow_free;
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unsigned int feature_flush;
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unsigned int feature_discard:1;
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unsigned int feature_secdiscard:1;
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unsigned int discard_granularity;
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unsigned int discard_alignment;
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unsigned int feature_persistent:1;
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unsigned int max_indirect_segments;
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int is_ready;
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};
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static unsigned int nr_minors;
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static unsigned long *minors;
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static DEFINE_SPINLOCK(minor_lock);
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#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
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(BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
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#define GRANT_INVALID_REF 0
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#define PARTS_PER_DISK 16
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#define PARTS_PER_EXT_DISK 256
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#define BLKIF_MAJOR(dev) ((dev)>>8)
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#define BLKIF_MINOR(dev) ((dev) & 0xff)
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#define EXT_SHIFT 28
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#define EXTENDED (1<<EXT_SHIFT)
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#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
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#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
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#define EMULATED_HD_DISK_MINOR_OFFSET (0)
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#define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
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#define EMULATED_SD_DISK_MINOR_OFFSET (0)
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#define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
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#define DEV_NAME "xvd" /* name in /dev */
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#define SEGS_PER_INDIRECT_FRAME \
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(PAGE_SIZE/sizeof(struct blkif_request_segment))
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#define INDIRECT_GREFS(_segs) \
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((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
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static int blkfront_setup_indirect(struct blkfront_info *info);
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static int get_id_from_freelist(struct blkfront_info *info)
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{
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unsigned long free = info->shadow_free;
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BUG_ON(free >= BLK_RING_SIZE);
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info->shadow_free = info->shadow[free].req.u.rw.id;
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info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
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return free;
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}
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static int add_id_to_freelist(struct blkfront_info *info,
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unsigned long id)
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{
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if (info->shadow[id].req.u.rw.id != id)
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return -EINVAL;
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if (info->shadow[id].request == NULL)
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return -EINVAL;
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info->shadow[id].req.u.rw.id = info->shadow_free;
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info->shadow[id].request = NULL;
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info->shadow_free = id;
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return 0;
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}
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static int fill_grant_buffer(struct blkfront_info *info, int num)
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{
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struct page *granted_page;
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struct grant *gnt_list_entry, *n;
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int i = 0;
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while(i < num) {
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gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO);
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if (!gnt_list_entry)
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goto out_of_memory;
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if (info->feature_persistent) {
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granted_page = alloc_page(GFP_NOIO);
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if (!granted_page) {
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kfree(gnt_list_entry);
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goto out_of_memory;
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}
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gnt_list_entry->pfn = page_to_pfn(granted_page);
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}
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gnt_list_entry->gref = GRANT_INVALID_REF;
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list_add(&gnt_list_entry->node, &info->grants);
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i++;
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}
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return 0;
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out_of_memory:
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list_for_each_entry_safe(gnt_list_entry, n,
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&info->grants, node) {
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list_del(&gnt_list_entry->node);
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if (info->feature_persistent)
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__free_page(pfn_to_page(gnt_list_entry->pfn));
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kfree(gnt_list_entry);
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i--;
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}
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BUG_ON(i != 0);
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return -ENOMEM;
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}
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static struct grant *get_grant(grant_ref_t *gref_head,
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unsigned long pfn,
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struct blkfront_info *info)
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{
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struct grant *gnt_list_entry;
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unsigned long buffer_mfn;
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BUG_ON(list_empty(&info->grants));
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gnt_list_entry = list_first_entry(&info->grants, struct grant,
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node);
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list_del(&gnt_list_entry->node);
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if (gnt_list_entry->gref != GRANT_INVALID_REF) {
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info->persistent_gnts_c--;
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return gnt_list_entry;
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}
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/* Assign a gref to this page */
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gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
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BUG_ON(gnt_list_entry->gref == -ENOSPC);
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if (!info->feature_persistent) {
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BUG_ON(!pfn);
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gnt_list_entry->pfn = pfn;
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}
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buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
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gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
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info->xbdev->otherend_id,
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buffer_mfn, 0);
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return gnt_list_entry;
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}
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static const char *op_name(int op)
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{
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static const char *const names[] = {
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[BLKIF_OP_READ] = "read",
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[BLKIF_OP_WRITE] = "write",
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[BLKIF_OP_WRITE_BARRIER] = "barrier",
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[BLKIF_OP_FLUSH_DISKCACHE] = "flush",
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[BLKIF_OP_DISCARD] = "discard" };
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if (op < 0 || op >= ARRAY_SIZE(names))
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return "unknown";
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if (!names[op])
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return "reserved";
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return names[op];
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}
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static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
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{
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unsigned int end = minor + nr;
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int rc;
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if (end > nr_minors) {
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unsigned long *bitmap, *old;
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bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
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GFP_KERNEL);
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if (bitmap == NULL)
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return -ENOMEM;
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spin_lock(&minor_lock);
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if (end > nr_minors) {
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old = minors;
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memcpy(bitmap, minors,
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BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
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minors = bitmap;
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nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
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} else
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old = bitmap;
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spin_unlock(&minor_lock);
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kfree(old);
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}
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spin_lock(&minor_lock);
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if (find_next_bit(minors, end, minor) >= end) {
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bitmap_set(minors, minor, nr);
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rc = 0;
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} else
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rc = -EBUSY;
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spin_unlock(&minor_lock);
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return rc;
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}
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static void xlbd_release_minors(unsigned int minor, unsigned int nr)
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{
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unsigned int end = minor + nr;
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BUG_ON(end > nr_minors);
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spin_lock(&minor_lock);
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bitmap_clear(minors, minor, nr);
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spin_unlock(&minor_lock);
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}
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static void blkif_restart_queue_callback(void *arg)
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{
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struct blkfront_info *info = (struct blkfront_info *)arg;
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schedule_work(&info->work);
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}
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static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
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{
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/* We don't have real geometry info, but let's at least return
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values consistent with the size of the device */
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sector_t nsect = get_capacity(bd->bd_disk);
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sector_t cylinders = nsect;
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hg->heads = 0xff;
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hg->sectors = 0x3f;
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sector_div(cylinders, hg->heads * hg->sectors);
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hg->cylinders = cylinders;
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if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
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hg->cylinders = 0xffff;
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return 0;
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}
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static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
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unsigned command, unsigned long argument)
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{
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struct blkfront_info *info = bdev->bd_disk->private_data;
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int i;
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dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
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command, (long)argument);
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switch (command) {
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case CDROMMULTISESSION:
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dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
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for (i = 0; i < sizeof(struct cdrom_multisession); i++)
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if (put_user(0, (char __user *)(argument + i)))
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return -EFAULT;
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return 0;
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case CDROM_GET_CAPABILITY: {
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struct gendisk *gd = info->gd;
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if (gd->flags & GENHD_FL_CD)
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return 0;
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return -EINVAL;
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}
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default:
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/*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
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command);*/
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return -EINVAL; /* same return as native Linux */
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}
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return 0;
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}
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/*
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* Generate a Xen blkfront IO request from a blk layer request. Reads
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* and writes are handled as expected.
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*
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* @req: a request struct
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*/
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static int blkif_queue_request(struct request *req)
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{
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struct blkfront_info *info = req->rq_disk->private_data;
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struct blkif_request *ring_req;
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unsigned long id;
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unsigned int fsect, lsect;
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int i, ref, n;
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struct blkif_request_segment *segments = NULL;
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/*
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* Used to store if we are able to queue the request by just using
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* existing persistent grants, or if we have to get new grants,
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* as there are not sufficiently many free.
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*/
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bool new_persistent_gnts;
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grant_ref_t gref_head;
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struct grant *gnt_list_entry = NULL;
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struct scatterlist *sg;
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int nseg, max_grefs;
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if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
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return 1;
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max_grefs = req->nr_phys_segments;
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if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST)
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/*
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* If we are using indirect segments we need to account
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* for the indirect grefs used in the request.
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*/
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max_grefs += INDIRECT_GREFS(req->nr_phys_segments);
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|
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/* Check if we have enough grants to allocate a requests */
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if (info->persistent_gnts_c < max_grefs) {
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new_persistent_gnts = 1;
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if (gnttab_alloc_grant_references(
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max_grefs - info->persistent_gnts_c,
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&gref_head) < 0) {
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gnttab_request_free_callback(
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&info->callback,
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blkif_restart_queue_callback,
|
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info,
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max_grefs);
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return 1;
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}
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} else
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new_persistent_gnts = 0;
|
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|
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/* Fill out a communications ring structure. */
|
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ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
|
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id = get_id_from_freelist(info);
|
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info->shadow[id].request = req;
|
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|
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if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {
|
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ring_req->operation = BLKIF_OP_DISCARD;
|
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ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
|
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ring_req->u.discard.id = id;
|
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ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req);
|
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if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
|
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ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
|
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else
|
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ring_req->u.discard.flag = 0;
|
|
} else {
|
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BUG_ON(info->max_indirect_segments == 0 &&
|
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req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
|
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BUG_ON(info->max_indirect_segments &&
|
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req->nr_phys_segments > info->max_indirect_segments);
|
|
nseg = blk_rq_map_sg(req->q, req, info->shadow[id].sg);
|
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ring_req->u.rw.id = id;
|
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if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) {
|
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/*
|
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* The indirect operation can only be a BLKIF_OP_READ or
|
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* BLKIF_OP_WRITE
|
|
*/
|
|
BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA));
|
|
ring_req->operation = BLKIF_OP_INDIRECT;
|
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ring_req->u.indirect.indirect_op = rq_data_dir(req) ?
|
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BLKIF_OP_WRITE : BLKIF_OP_READ;
|
|
ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req);
|
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ring_req->u.indirect.handle = info->handle;
|
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ring_req->u.indirect.nr_segments = nseg;
|
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} else {
|
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ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
|
|
ring_req->u.rw.handle = info->handle;
|
|
ring_req->operation = rq_data_dir(req) ?
|
|
BLKIF_OP_WRITE : BLKIF_OP_READ;
|
|
if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
|
|
/*
|
|
* Ideally we can do an unordered flush-to-disk. In case the
|
|
* backend onlysupports barriers, use that. A barrier request
|
|
* a superset of FUA, so we can implement it the same
|
|
* way. (It's also a FLUSH+FUA, since it is
|
|
* guaranteed ordered WRT previous writes.)
|
|
*/
|
|
switch (info->feature_flush &
|
|
((REQ_FLUSH|REQ_FUA))) {
|
|
case REQ_FLUSH|REQ_FUA:
|
|
ring_req->operation =
|
|
BLKIF_OP_WRITE_BARRIER;
|
|
break;
|
|
case REQ_FLUSH:
|
|
ring_req->operation =
|
|
BLKIF_OP_FLUSH_DISKCACHE;
|
|
break;
|
|
default:
|
|
ring_req->operation = 0;
|
|
}
|
|
}
|
|
ring_req->u.rw.nr_segments = nseg;
|
|
}
|
|
for_each_sg(info->shadow[id].sg, sg, nseg, i) {
|
|
fsect = sg->offset >> 9;
|
|
lsect = fsect + (sg->length >> 9) - 1;
|
|
|
|
if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
|
|
(i % SEGS_PER_INDIRECT_FRAME == 0)) {
|
|
unsigned long uninitialized_var(pfn);
|
|
|
|
if (segments)
|
|
kunmap_atomic(segments);
|
|
|
|
n = i / SEGS_PER_INDIRECT_FRAME;
|
|
if (!info->feature_persistent) {
|
|
struct page *indirect_page;
|
|
|
|
/* Fetch a pre-allocated page to use for indirect grefs */
|
|
BUG_ON(list_empty(&info->indirect_pages));
|
|
indirect_page = list_first_entry(&info->indirect_pages,
|
|
struct page, lru);
|
|
list_del(&indirect_page->lru);
|
|
pfn = page_to_pfn(indirect_page);
|
|
}
|
|
gnt_list_entry = get_grant(&gref_head, pfn, info);
|
|
info->shadow[id].indirect_grants[n] = gnt_list_entry;
|
|
segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
|
|
ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
|
|
}
|
|
|
|
gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info);
|
|
ref = gnt_list_entry->gref;
|
|
|
|
info->shadow[id].grants_used[i] = gnt_list_entry;
|
|
|
|
if (rq_data_dir(req) && info->feature_persistent) {
|
|
char *bvec_data;
|
|
void *shared_data;
|
|
|
|
BUG_ON(sg->offset + sg->length > PAGE_SIZE);
|
|
|
|
shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
|
|
bvec_data = kmap_atomic(sg_page(sg));
|
|
|
|
/*
|
|
* this does not wipe data stored outside the
|
|
* range sg->offset..sg->offset+sg->length.
|
|
* Therefore, blkback *could* see data from
|
|
* previous requests. This is OK as long as
|
|
* persistent grants are shared with just one
|
|
* domain. It may need refactoring if this
|
|
* changes
|
|
*/
|
|
memcpy(shared_data + sg->offset,
|
|
bvec_data + sg->offset,
|
|
sg->length);
|
|
|
|
kunmap_atomic(bvec_data);
|
|
kunmap_atomic(shared_data);
|
|
}
|
|
if (ring_req->operation != BLKIF_OP_INDIRECT) {
|
|
ring_req->u.rw.seg[i] =
|
|
(struct blkif_request_segment) {
|
|
.gref = ref,
|
|
.first_sect = fsect,
|
|
.last_sect = lsect };
|
|
} else {
|
|
n = i % SEGS_PER_INDIRECT_FRAME;
|
|
segments[n] =
|
|
(struct blkif_request_segment) {
|
|
.gref = ref,
|
|
.first_sect = fsect,
|
|
.last_sect = lsect };
|
|
}
|
|
}
|
|
if (segments)
|
|
kunmap_atomic(segments);
|
|
}
|
|
|
|
info->ring.req_prod_pvt++;
|
|
|
|
/* Keep a private copy so we can reissue requests when recovering. */
|
|
info->shadow[id].req = *ring_req;
|
|
|
|
if (new_persistent_gnts)
|
|
gnttab_free_grant_references(gref_head);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static inline void flush_requests(struct blkfront_info *info)
|
|
{
|
|
int notify;
|
|
|
|
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&info->ring, notify);
|
|
|
|
if (notify)
|
|
notify_remote_via_irq(info->irq);
|
|
}
|
|
|
|
static inline bool blkif_request_flush_invalid(struct request *req,
|
|
struct blkfront_info *info)
|
|
{
|
|
return ((req->cmd_type != REQ_TYPE_FS) ||
|
|
((req->cmd_flags & REQ_FLUSH) &&
|
|
!(info->feature_flush & REQ_FLUSH)) ||
|
|
((req->cmd_flags & REQ_FUA) &&
|
|
!(info->feature_flush & REQ_FUA)));
|
|
}
|
|
|
|
/*
|
|
* do_blkif_request
|
|
* read a block; request is in a request queue
|
|
*/
|
|
static void do_blkif_request(struct request_queue *rq)
|
|
{
|
|
struct blkfront_info *info = NULL;
|
|
struct request *req;
|
|
int queued;
|
|
|
|
pr_debug("Entered do_blkif_request\n");
|
|
|
|
queued = 0;
|
|
|
|
while ((req = blk_peek_request(rq)) != NULL) {
|
|
info = req->rq_disk->private_data;
|
|
|
|
if (RING_FULL(&info->ring))
|
|
goto wait;
|
|
|
|
blk_start_request(req);
|
|
|
|
if (blkif_request_flush_invalid(req, info)) {
|
|
__blk_end_request_all(req, -EOPNOTSUPP);
|
|
continue;
|
|
}
|
|
|
|
pr_debug("do_blk_req %p: cmd %p, sec %lx, "
|
|
"(%u/%u) [%s]\n",
|
|
req, req->cmd, (unsigned long)blk_rq_pos(req),
|
|
blk_rq_cur_sectors(req), blk_rq_sectors(req),
|
|
rq_data_dir(req) ? "write" : "read");
|
|
|
|
if (blkif_queue_request(req)) {
|
|
blk_requeue_request(rq, req);
|
|
wait:
|
|
/* Avoid pointless unplugs. */
|
|
blk_stop_queue(rq);
|
|
break;
|
|
}
|
|
|
|
queued++;
|
|
}
|
|
|
|
if (queued != 0)
|
|
flush_requests(info);
|
|
}
|
|
|
|
static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
|
|
unsigned int physical_sector_size,
|
|
unsigned int segments)
|
|
{
|
|
struct request_queue *rq;
|
|
struct blkfront_info *info = gd->private_data;
|
|
|
|
rq = blk_init_queue(do_blkif_request, &info->io_lock);
|
|
if (rq == NULL)
|
|
return -1;
|
|
|
|
queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
|
|
|
|
if (info->feature_discard) {
|
|
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
|
|
blk_queue_max_discard_sectors(rq, get_capacity(gd));
|
|
rq->limits.discard_granularity = info->discard_granularity;
|
|
rq->limits.discard_alignment = info->discard_alignment;
|
|
if (info->feature_secdiscard)
|
|
queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
|
|
}
|
|
|
|
/* Hard sector size and max sectors impersonate the equiv. hardware. */
|
|
blk_queue_logical_block_size(rq, sector_size);
|
|
blk_queue_physical_block_size(rq, physical_sector_size);
|
|
blk_queue_max_hw_sectors(rq, (segments * PAGE_SIZE) / 512);
|
|
|
|
/* Each segment in a request is up to an aligned page in size. */
|
|
blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
|
|
blk_queue_max_segment_size(rq, PAGE_SIZE);
|
|
|
|
/* Ensure a merged request will fit in a single I/O ring slot. */
|
|
blk_queue_max_segments(rq, segments);
|
|
|
|
/* Make sure buffer addresses are sector-aligned. */
|
|
blk_queue_dma_alignment(rq, 511);
|
|
|
|
/* Make sure we don't use bounce buffers. */
|
|
blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
|
|
|
|
gd->queue = rq;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const char *flush_info(unsigned int feature_flush)
|
|
{
|
|
switch (feature_flush & ((REQ_FLUSH | REQ_FUA))) {
|
|
case REQ_FLUSH|REQ_FUA:
|
|
return "barrier: enabled;";
|
|
case REQ_FLUSH:
|
|
return "flush diskcache: enabled;";
|
|
default:
|
|
return "barrier or flush: disabled;";
|
|
}
|
|
}
|
|
|
|
static void xlvbd_flush(struct blkfront_info *info)
|
|
{
|
|
blk_queue_flush(info->rq, info->feature_flush);
|
|
pr_info("blkfront: %s: %s %s %s %s %s\n",
|
|
info->gd->disk_name, flush_info(info->feature_flush),
|
|
"persistent grants:", info->feature_persistent ?
|
|
"enabled;" : "disabled;", "indirect descriptors:",
|
|
info->max_indirect_segments ? "enabled;" : "disabled;");
|
|
}
|
|
|
|
static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
|
|
{
|
|
int major;
|
|
major = BLKIF_MAJOR(vdevice);
|
|
*minor = BLKIF_MINOR(vdevice);
|
|
switch (major) {
|
|
case XEN_IDE0_MAJOR:
|
|
*offset = (*minor / 64) + EMULATED_HD_DISK_NAME_OFFSET;
|
|
*minor = ((*minor / 64) * PARTS_PER_DISK) +
|
|
EMULATED_HD_DISK_MINOR_OFFSET;
|
|
break;
|
|
case XEN_IDE1_MAJOR:
|
|
*offset = (*minor / 64) + 2 + EMULATED_HD_DISK_NAME_OFFSET;
|
|
*minor = (((*minor / 64) + 2) * PARTS_PER_DISK) +
|
|
EMULATED_HD_DISK_MINOR_OFFSET;
|
|
break;
|
|
case XEN_SCSI_DISK0_MAJOR:
|
|
*offset = (*minor / PARTS_PER_DISK) + EMULATED_SD_DISK_NAME_OFFSET;
|
|
*minor = *minor + EMULATED_SD_DISK_MINOR_OFFSET;
|
|
break;
|
|
case XEN_SCSI_DISK1_MAJOR:
|
|
case XEN_SCSI_DISK2_MAJOR:
|
|
case XEN_SCSI_DISK3_MAJOR:
|
|
case XEN_SCSI_DISK4_MAJOR:
|
|
case XEN_SCSI_DISK5_MAJOR:
|
|
case XEN_SCSI_DISK6_MAJOR:
|
|
case XEN_SCSI_DISK7_MAJOR:
|
|
*offset = (*minor / PARTS_PER_DISK) +
|
|
((major - XEN_SCSI_DISK1_MAJOR + 1) * 16) +
|
|
EMULATED_SD_DISK_NAME_OFFSET;
|
|
*minor = *minor +
|
|
((major - XEN_SCSI_DISK1_MAJOR + 1) * 16 * PARTS_PER_DISK) +
|
|
EMULATED_SD_DISK_MINOR_OFFSET;
|
|
break;
|
|
case XEN_SCSI_DISK8_MAJOR:
|
|
case XEN_SCSI_DISK9_MAJOR:
|
|
case XEN_SCSI_DISK10_MAJOR:
|
|
case XEN_SCSI_DISK11_MAJOR:
|
|
case XEN_SCSI_DISK12_MAJOR:
|
|
case XEN_SCSI_DISK13_MAJOR:
|
|
case XEN_SCSI_DISK14_MAJOR:
|
|
case XEN_SCSI_DISK15_MAJOR:
|
|
*offset = (*minor / PARTS_PER_DISK) +
|
|
((major - XEN_SCSI_DISK8_MAJOR + 8) * 16) +
|
|
EMULATED_SD_DISK_NAME_OFFSET;
|
|
*minor = *minor +
|
|
((major - XEN_SCSI_DISK8_MAJOR + 8) * 16 * PARTS_PER_DISK) +
|
|
EMULATED_SD_DISK_MINOR_OFFSET;
|
|
break;
|
|
case XENVBD_MAJOR:
|
|
*offset = *minor / PARTS_PER_DISK;
|
|
break;
|
|
default:
|
|
printk(KERN_WARNING "blkfront: your disk configuration is "
|
|
"incorrect, please use an xvd device instead\n");
|
|
return -ENODEV;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static char *encode_disk_name(char *ptr, unsigned int n)
|
|
{
|
|
if (n >= 26)
|
|
ptr = encode_disk_name(ptr, n / 26 - 1);
|
|
*ptr = 'a' + n % 26;
|
|
return ptr + 1;
|
|
}
|
|
|
|
static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
|
|
struct blkfront_info *info,
|
|
u16 vdisk_info, u16 sector_size,
|
|
unsigned int physical_sector_size)
|
|
{
|
|
struct gendisk *gd;
|
|
int nr_minors = 1;
|
|
int err;
|
|
unsigned int offset;
|
|
int minor;
|
|
int nr_parts;
|
|
char *ptr;
|
|
|
|
BUG_ON(info->gd != NULL);
|
|
BUG_ON(info->rq != NULL);
|
|
|
|
if ((info->vdevice>>EXT_SHIFT) > 1) {
|
|
/* this is above the extended range; something is wrong */
|
|
printk(KERN_WARNING "blkfront: vdevice 0x%x is above the extended range; ignoring\n", info->vdevice);
|
|
return -ENODEV;
|
|
}
|
|
|
|
if (!VDEV_IS_EXTENDED(info->vdevice)) {
|
|
err = xen_translate_vdev(info->vdevice, &minor, &offset);
|
|
if (err)
|
|
return err;
|
|
nr_parts = PARTS_PER_DISK;
|
|
} else {
|
|
minor = BLKIF_MINOR_EXT(info->vdevice);
|
|
nr_parts = PARTS_PER_EXT_DISK;
|
|
offset = minor / nr_parts;
|
|
if (xen_hvm_domain() && offset < EMULATED_HD_DISK_NAME_OFFSET + 4)
|
|
printk(KERN_WARNING "blkfront: vdevice 0x%x might conflict with "
|
|
"emulated IDE disks,\n\t choose an xvd device name"
|
|
"from xvde on\n", info->vdevice);
|
|
}
|
|
if (minor >> MINORBITS) {
|
|
pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n",
|
|
info->vdevice, minor);
|
|
return -ENODEV;
|
|
}
|
|
|
|
if ((minor % nr_parts) == 0)
|
|
nr_minors = nr_parts;
|
|
|
|
err = xlbd_reserve_minors(minor, nr_minors);
|
|
if (err)
|
|
goto out;
|
|
err = -ENODEV;
|
|
|
|
gd = alloc_disk(nr_minors);
|
|
if (gd == NULL)
|
|
goto release;
|
|
|
|
strcpy(gd->disk_name, DEV_NAME);
|
|
ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset);
|
|
BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN);
|
|
if (nr_minors > 1)
|
|
*ptr = 0;
|
|
else
|
|
snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr,
|
|
"%d", minor & (nr_parts - 1));
|
|
|
|
gd->major = XENVBD_MAJOR;
|
|
gd->first_minor = minor;
|
|
gd->fops = &xlvbd_block_fops;
|
|
gd->private_data = info;
|
|
gd->driverfs_dev = &(info->xbdev->dev);
|
|
set_capacity(gd, capacity);
|
|
|
|
if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size,
|
|
info->max_indirect_segments ? :
|
|
BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
|
|
del_gendisk(gd);
|
|
goto release;
|
|
}
|
|
|
|
info->rq = gd->queue;
|
|
info->gd = gd;
|
|
|
|
xlvbd_flush(info);
|
|
|
|
if (vdisk_info & VDISK_READONLY)
|
|
set_disk_ro(gd, 1);
|
|
|
|
if (vdisk_info & VDISK_REMOVABLE)
|
|
gd->flags |= GENHD_FL_REMOVABLE;
|
|
|
|
if (vdisk_info & VDISK_CDROM)
|
|
gd->flags |= GENHD_FL_CD;
|
|
|
|
return 0;
|
|
|
|
release:
|
|
xlbd_release_minors(minor, nr_minors);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
static void xlvbd_release_gendisk(struct blkfront_info *info)
|
|
{
|
|
unsigned int minor, nr_minors;
|
|
unsigned long flags;
|
|
|
|
if (info->rq == NULL)
|
|
return;
|
|
|
|
spin_lock_irqsave(&info->io_lock, flags);
|
|
|
|
/* No more blkif_request(). */
|
|
blk_stop_queue(info->rq);
|
|
|
|
/* No more gnttab callback work. */
|
|
gnttab_cancel_free_callback(&info->callback);
|
|
spin_unlock_irqrestore(&info->io_lock, flags);
|
|
|
|
/* Flush gnttab callback work. Must be done with no locks held. */
|
|
flush_work(&info->work);
|
|
|
|
del_gendisk(info->gd);
|
|
|
|
minor = info->gd->first_minor;
|
|
nr_minors = info->gd->minors;
|
|
xlbd_release_minors(minor, nr_minors);
|
|
|
|
blk_cleanup_queue(info->rq);
|
|
info->rq = NULL;
|
|
|
|
put_disk(info->gd);
|
|
info->gd = NULL;
|
|
}
|
|
|
|
static void kick_pending_request_queues(struct blkfront_info *info)
|
|
{
|
|
if (!RING_FULL(&info->ring)) {
|
|
/* Re-enable calldowns. */
|
|
blk_start_queue(info->rq);
|
|
/* Kick things off immediately. */
|
|
do_blkif_request(info->rq);
|
|
}
|
|
}
|
|
|
|
static void blkif_restart_queue(struct work_struct *work)
|
|
{
|
|
struct blkfront_info *info = container_of(work, struct blkfront_info, work);
|
|
|
|
spin_lock_irq(&info->io_lock);
|
|
if (info->connected == BLKIF_STATE_CONNECTED)
|
|
kick_pending_request_queues(info);
|
|
spin_unlock_irq(&info->io_lock);
|
|
}
|
|
|
|
static void blkif_free(struct blkfront_info *info, int suspend)
|
|
{
|
|
struct grant *persistent_gnt;
|
|
struct grant *n;
|
|
int i, j, segs;
|
|
|
|
/* Prevent new requests being issued until we fix things up. */
|
|
spin_lock_irq(&info->io_lock);
|
|
info->connected = suspend ?
|
|
BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
|
|
/* No more blkif_request(). */
|
|
if (info->rq)
|
|
blk_stop_queue(info->rq);
|
|
|
|
/* Remove all persistent grants */
|
|
if (!list_empty(&info->grants)) {
|
|
list_for_each_entry_safe(persistent_gnt, n,
|
|
&info->grants, node) {
|
|
list_del(&persistent_gnt->node);
|
|
if (persistent_gnt->gref != GRANT_INVALID_REF) {
|
|
gnttab_end_foreign_access(persistent_gnt->gref,
|
|
0, 0UL);
|
|
info->persistent_gnts_c--;
|
|
}
|
|
if (info->feature_persistent)
|
|
__free_page(pfn_to_page(persistent_gnt->pfn));
|
|
kfree(persistent_gnt);
|
|
}
|
|
}
|
|
BUG_ON(info->persistent_gnts_c != 0);
|
|
|
|
/*
|
|
* Remove indirect pages, this only happens when using indirect
|
|
* descriptors but not persistent grants
|
|
*/
|
|
if (!list_empty(&info->indirect_pages)) {
|
|
struct page *indirect_page, *n;
|
|
|
|
BUG_ON(info->feature_persistent);
|
|
list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
|
|
list_del(&indirect_page->lru);
|
|
__free_page(indirect_page);
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < BLK_RING_SIZE; i++) {
|
|
/*
|
|
* Clear persistent grants present in requests already
|
|
* on the shared ring
|
|
*/
|
|
if (!info->shadow[i].request)
|
|
goto free_shadow;
|
|
|
|
segs = info->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
|
|
info->shadow[i].req.u.indirect.nr_segments :
|
|
info->shadow[i].req.u.rw.nr_segments;
|
|
for (j = 0; j < segs; j++) {
|
|
persistent_gnt = info->shadow[i].grants_used[j];
|
|
gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
|
|
if (info->feature_persistent)
|
|
__free_page(pfn_to_page(persistent_gnt->pfn));
|
|
kfree(persistent_gnt);
|
|
}
|
|
|
|
if (info->shadow[i].req.operation != BLKIF_OP_INDIRECT)
|
|
/*
|
|
* If this is not an indirect operation don't try to
|
|
* free indirect segments
|
|
*/
|
|
goto free_shadow;
|
|
|
|
for (j = 0; j < INDIRECT_GREFS(segs); j++) {
|
|
persistent_gnt = info->shadow[i].indirect_grants[j];
|
|
gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
|
|
__free_page(pfn_to_page(persistent_gnt->pfn));
|
|
kfree(persistent_gnt);
|
|
}
|
|
|
|
free_shadow:
|
|
kfree(info->shadow[i].grants_used);
|
|
info->shadow[i].grants_used = NULL;
|
|
kfree(info->shadow[i].indirect_grants);
|
|
info->shadow[i].indirect_grants = NULL;
|
|
kfree(info->shadow[i].sg);
|
|
info->shadow[i].sg = NULL;
|
|
}
|
|
|
|
/* No more gnttab callback work. */
|
|
gnttab_cancel_free_callback(&info->callback);
|
|
spin_unlock_irq(&info->io_lock);
|
|
|
|
/* Flush gnttab callback work. Must be done with no locks held. */
|
|
flush_work(&info->work);
|
|
|
|
/* Free resources associated with old device channel. */
|
|
if (info->ring_ref != GRANT_INVALID_REF) {
|
|
gnttab_end_foreign_access(info->ring_ref, 0,
|
|
(unsigned long)info->ring.sring);
|
|
info->ring_ref = GRANT_INVALID_REF;
|
|
info->ring.sring = NULL;
|
|
}
|
|
if (info->irq)
|
|
unbind_from_irqhandler(info->irq, info);
|
|
info->evtchn = info->irq = 0;
|
|
|
|
}
|
|
|
|
static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
|
|
struct blkif_response *bret)
|
|
{
|
|
int i = 0;
|
|
struct scatterlist *sg;
|
|
char *bvec_data;
|
|
void *shared_data;
|
|
int nseg;
|
|
|
|
nseg = s->req.operation == BLKIF_OP_INDIRECT ?
|
|
s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
|
|
|
|
if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
|
|
/*
|
|
* Copy the data received from the backend into the bvec.
|
|
* Since bv_offset can be different than 0, and bv_len different
|
|
* than PAGE_SIZE, we have to keep track of the current offset,
|
|
* to be sure we are copying the data from the right shared page.
|
|
*/
|
|
for_each_sg(s->sg, sg, nseg, i) {
|
|
BUG_ON(sg->offset + sg->length > PAGE_SIZE);
|
|
shared_data = kmap_atomic(
|
|
pfn_to_page(s->grants_used[i]->pfn));
|
|
bvec_data = kmap_atomic(sg_page(sg));
|
|
memcpy(bvec_data + sg->offset,
|
|
shared_data + sg->offset,
|
|
sg->length);
|
|
kunmap_atomic(bvec_data);
|
|
kunmap_atomic(shared_data);
|
|
}
|
|
}
|
|
/* Add the persistent grant into the list of free grants */
|
|
for (i = 0; i < nseg; i++) {
|
|
if (gnttab_query_foreign_access(s->grants_used[i]->gref)) {
|
|
/*
|
|
* If the grant is still mapped by the backend (the
|
|
* backend has chosen to make this grant persistent)
|
|
* we add it at the head of the list, so it will be
|
|
* reused first.
|
|
*/
|
|
if (!info->feature_persistent)
|
|
pr_alert_ratelimited("backed has not unmapped grant: %u\n",
|
|
s->grants_used[i]->gref);
|
|
list_add(&s->grants_used[i]->node, &info->grants);
|
|
info->persistent_gnts_c++;
|
|
} else {
|
|
/*
|
|
* If the grant is not mapped by the backend we end the
|
|
* foreign access and add it to the tail of the list,
|
|
* so it will not be picked again unless we run out of
|
|
* persistent grants.
|
|
*/
|
|
gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL);
|
|
s->grants_used[i]->gref = GRANT_INVALID_REF;
|
|
list_add_tail(&s->grants_used[i]->node, &info->grants);
|
|
}
|
|
}
|
|
if (s->req.operation == BLKIF_OP_INDIRECT) {
|
|
for (i = 0; i < INDIRECT_GREFS(nseg); i++) {
|
|
if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) {
|
|
if (!info->feature_persistent)
|
|
pr_alert_ratelimited("backed has not unmapped grant: %u\n",
|
|
s->indirect_grants[i]->gref);
|
|
list_add(&s->indirect_grants[i]->node, &info->grants);
|
|
info->persistent_gnts_c++;
|
|
} else {
|
|
struct page *indirect_page;
|
|
|
|
gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL);
|
|
/*
|
|
* Add the used indirect page back to the list of
|
|
* available pages for indirect grefs.
|
|
*/
|
|
indirect_page = pfn_to_page(s->indirect_grants[i]->pfn);
|
|
list_add(&indirect_page->lru, &info->indirect_pages);
|
|
s->indirect_grants[i]->gref = GRANT_INVALID_REF;
|
|
list_add_tail(&s->indirect_grants[i]->node, &info->grants);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static irqreturn_t blkif_interrupt(int irq, void *dev_id)
|
|
{
|
|
struct request *req;
|
|
struct blkif_response *bret;
|
|
RING_IDX i, rp;
|
|
unsigned long flags;
|
|
struct blkfront_info *info = (struct blkfront_info *)dev_id;
|
|
int error;
|
|
|
|
spin_lock_irqsave(&info->io_lock, flags);
|
|
|
|
if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
|
|
spin_unlock_irqrestore(&info->io_lock, flags);
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
again:
|
|
rp = info->ring.sring->rsp_prod;
|
|
rmb(); /* Ensure we see queued responses up to 'rp'. */
|
|
|
|
for (i = info->ring.rsp_cons; i != rp; i++) {
|
|
unsigned long id;
|
|
|
|
bret = RING_GET_RESPONSE(&info->ring, i);
|
|
id = bret->id;
|
|
/*
|
|
* The backend has messed up and given us an id that we would
|
|
* never have given to it (we stamp it up to BLK_RING_SIZE -
|
|
* look in get_id_from_freelist.
|
|
*/
|
|
if (id >= BLK_RING_SIZE) {
|
|
WARN(1, "%s: response to %s has incorrect id (%ld)\n",
|
|
info->gd->disk_name, op_name(bret->operation), id);
|
|
/* We can't safely get the 'struct request' as
|
|
* the id is busted. */
|
|
continue;
|
|
}
|
|
req = info->shadow[id].request;
|
|
|
|
if (bret->operation != BLKIF_OP_DISCARD)
|
|
blkif_completion(&info->shadow[id], info, bret);
|
|
|
|
if (add_id_to_freelist(info, id)) {
|
|
WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
|
|
info->gd->disk_name, op_name(bret->operation), id);
|
|
continue;
|
|
}
|
|
|
|
error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
|
|
switch (bret->operation) {
|
|
case BLKIF_OP_DISCARD:
|
|
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
|
|
struct request_queue *rq = info->rq;
|
|
printk(KERN_WARNING "blkfront: %s: %s op failed\n",
|
|
info->gd->disk_name, op_name(bret->operation));
|
|
error = -EOPNOTSUPP;
|
|
info->feature_discard = 0;
|
|
info->feature_secdiscard = 0;
|
|
queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
|
|
queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
|
|
}
|
|
__blk_end_request_all(req, error);
|
|
break;
|
|
case BLKIF_OP_FLUSH_DISKCACHE:
|
|
case BLKIF_OP_WRITE_BARRIER:
|
|
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
|
|
printk(KERN_WARNING "blkfront: %s: %s op failed\n",
|
|
info->gd->disk_name, op_name(bret->operation));
|
|
error = -EOPNOTSUPP;
|
|
}
|
|
if (unlikely(bret->status == BLKIF_RSP_ERROR &&
|
|
info->shadow[id].req.u.rw.nr_segments == 0)) {
|
|
printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
|
|
info->gd->disk_name, op_name(bret->operation));
|
|
error = -EOPNOTSUPP;
|
|
}
|
|
if (unlikely(error)) {
|
|
if (error == -EOPNOTSUPP)
|
|
error = 0;
|
|
info->feature_flush = 0;
|
|
xlvbd_flush(info);
|
|
}
|
|
/* fall through */
|
|
case BLKIF_OP_READ:
|
|
case BLKIF_OP_WRITE:
|
|
if (unlikely(bret->status != BLKIF_RSP_OKAY))
|
|
dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
|
|
"request: %x\n", bret->status);
|
|
|
|
__blk_end_request_all(req, error);
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
info->ring.rsp_cons = i;
|
|
|
|
if (i != info->ring.req_prod_pvt) {
|
|
int more_to_do;
|
|
RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
|
|
if (more_to_do)
|
|
goto again;
|
|
} else
|
|
info->ring.sring->rsp_event = i + 1;
|
|
|
|
kick_pending_request_queues(info);
|
|
|
|
spin_unlock_irqrestore(&info->io_lock, flags);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
|
|
static int setup_blkring(struct xenbus_device *dev,
|
|
struct blkfront_info *info)
|
|
{
|
|
struct blkif_sring *sring;
|
|
grant_ref_t gref;
|
|
int err;
|
|
|
|
info->ring_ref = GRANT_INVALID_REF;
|
|
|
|
sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
|
|
if (!sring) {
|
|
xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
|
|
return -ENOMEM;
|
|
}
|
|
SHARED_RING_INIT(sring);
|
|
FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
|
|
|
|
err = xenbus_grant_ring(dev, info->ring.sring, 1, &gref);
|
|
if (err < 0) {
|
|
free_page((unsigned long)sring);
|
|
info->ring.sring = NULL;
|
|
goto fail;
|
|
}
|
|
info->ring_ref = gref;
|
|
|
|
err = xenbus_alloc_evtchn(dev, &info->evtchn);
|
|
if (err)
|
|
goto fail;
|
|
|
|
err = bind_evtchn_to_irqhandler(info->evtchn, blkif_interrupt, 0,
|
|
"blkif", info);
|
|
if (err <= 0) {
|
|
xenbus_dev_fatal(dev, err,
|
|
"bind_evtchn_to_irqhandler failed");
|
|
goto fail;
|
|
}
|
|
info->irq = err;
|
|
|
|
return 0;
|
|
fail:
|
|
blkif_free(info, 0);
|
|
return err;
|
|
}
|
|
|
|
|
|
/* Common code used when first setting up, and when resuming. */
|
|
static int talk_to_blkback(struct xenbus_device *dev,
|
|
struct blkfront_info *info)
|
|
{
|
|
const char *message = NULL;
|
|
struct xenbus_transaction xbt;
|
|
int err;
|
|
|
|
/* Create shared ring, alloc event channel. */
|
|
err = setup_blkring(dev, info);
|
|
if (err)
|
|
goto out;
|
|
|
|
again:
|
|
err = xenbus_transaction_start(&xbt);
|
|
if (err) {
|
|
xenbus_dev_fatal(dev, err, "starting transaction");
|
|
goto destroy_blkring;
|
|
}
|
|
|
|
err = xenbus_printf(xbt, dev->nodename,
|
|
"ring-ref", "%u", info->ring_ref);
|
|
if (err) {
|
|
message = "writing ring-ref";
|
|
goto abort_transaction;
|
|
}
|
|
err = xenbus_printf(xbt, dev->nodename,
|
|
"event-channel", "%u", info->evtchn);
|
|
if (err) {
|
|
message = "writing event-channel";
|
|
goto abort_transaction;
|
|
}
|
|
err = xenbus_printf(xbt, dev->nodename, "protocol", "%s",
|
|
XEN_IO_PROTO_ABI_NATIVE);
|
|
if (err) {
|
|
message = "writing protocol";
|
|
goto abort_transaction;
|
|
}
|
|
err = xenbus_printf(xbt, dev->nodename,
|
|
"feature-persistent", "%u", 1);
|
|
if (err)
|
|
dev_warn(&dev->dev,
|
|
"writing persistent grants feature to xenbus");
|
|
|
|
err = xenbus_transaction_end(xbt, 0);
|
|
if (err) {
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
xenbus_dev_fatal(dev, err, "completing transaction");
|
|
goto destroy_blkring;
|
|
}
|
|
|
|
xenbus_switch_state(dev, XenbusStateInitialised);
|
|
|
|
return 0;
|
|
|
|
abort_transaction:
|
|
xenbus_transaction_end(xbt, 1);
|
|
if (message)
|
|
xenbus_dev_fatal(dev, err, "%s", message);
|
|
destroy_blkring:
|
|
blkif_free(info, 0);
|
|
out:
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* Entry point to this code when a new device is created. Allocate the basic
|
|
* structures and the ring buffer for communication with the backend, and
|
|
* inform the backend of the appropriate details for those. Switch to
|
|
* Initialised state.
|
|
*/
|
|
static int blkfront_probe(struct xenbus_device *dev,
|
|
const struct xenbus_device_id *id)
|
|
{
|
|
int err, vdevice, i;
|
|
struct blkfront_info *info;
|
|
|
|
/* FIXME: Use dynamic device id if this is not set. */
|
|
err = xenbus_scanf(XBT_NIL, dev->nodename,
|
|
"virtual-device", "%i", &vdevice);
|
|
if (err != 1) {
|
|
/* go looking in the extended area instead */
|
|
err = xenbus_scanf(XBT_NIL, dev->nodename, "virtual-device-ext",
|
|
"%i", &vdevice);
|
|
if (err != 1) {
|
|
xenbus_dev_fatal(dev, err, "reading virtual-device");
|
|
return err;
|
|
}
|
|
}
|
|
|
|
if (xen_hvm_domain()) {
|
|
char *type;
|
|
int len;
|
|
/* no unplug has been done: do not hook devices != xen vbds */
|
|
if (xen_has_pv_and_legacy_disk_devices()) {
|
|
int major;
|
|
|
|
if (!VDEV_IS_EXTENDED(vdevice))
|
|
major = BLKIF_MAJOR(vdevice);
|
|
else
|
|
major = XENVBD_MAJOR;
|
|
|
|
if (major != XENVBD_MAJOR) {
|
|
printk(KERN_INFO
|
|
"%s: HVM does not support vbd %d as xen block device\n",
|
|
__func__, vdevice);
|
|
return -ENODEV;
|
|
}
|
|
}
|
|
/* do not create a PV cdrom device if we are an HVM guest */
|
|
type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
|
|
if (IS_ERR(type))
|
|
return -ENODEV;
|
|
if (strncmp(type, "cdrom", 5) == 0) {
|
|
kfree(type);
|
|
return -ENODEV;
|
|
}
|
|
kfree(type);
|
|
}
|
|
info = kzalloc(sizeof(*info), GFP_KERNEL);
|
|
if (!info) {
|
|
xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
mutex_init(&info->mutex);
|
|
spin_lock_init(&info->io_lock);
|
|
info->xbdev = dev;
|
|
info->vdevice = vdevice;
|
|
INIT_LIST_HEAD(&info->grants);
|
|
INIT_LIST_HEAD(&info->indirect_pages);
|
|
info->persistent_gnts_c = 0;
|
|
info->connected = BLKIF_STATE_DISCONNECTED;
|
|
INIT_WORK(&info->work, blkif_restart_queue);
|
|
|
|
for (i = 0; i < BLK_RING_SIZE; i++)
|
|
info->shadow[i].req.u.rw.id = i+1;
|
|
info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
|
|
|
|
/* Front end dir is a number, which is used as the id. */
|
|
info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
|
|
dev_set_drvdata(&dev->dev, info);
|
|
|
|
err = talk_to_blkback(dev, info);
|
|
if (err) {
|
|
kfree(info);
|
|
dev_set_drvdata(&dev->dev, NULL);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void split_bio_end(struct bio *bio, int error)
|
|
{
|
|
struct split_bio *split_bio = bio->bi_private;
|
|
|
|
if (error)
|
|
split_bio->err = error;
|
|
|
|
if (atomic_dec_and_test(&split_bio->pending)) {
|
|
split_bio->bio->bi_phys_segments = 0;
|
|
bio_endio(split_bio->bio, split_bio->err);
|
|
kfree(split_bio);
|
|
}
|
|
bio_put(bio);
|
|
}
|
|
|
|
static int blkif_recover(struct blkfront_info *info)
|
|
{
|
|
int i;
|
|
struct request *req, *n;
|
|
struct blk_shadow *copy;
|
|
int rc;
|
|
struct bio *bio, *cloned_bio;
|
|
struct bio_list bio_list, merge_bio;
|
|
unsigned int segs, offset;
|
|
int pending, size;
|
|
struct split_bio *split_bio;
|
|
struct list_head requests;
|
|
|
|
/* Stage 1: Make a safe copy of the shadow state. */
|
|
copy = kmemdup(info->shadow, sizeof(info->shadow),
|
|
GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
|
|
if (!copy)
|
|
return -ENOMEM;
|
|
|
|
/* Stage 2: Set up free list. */
|
|
memset(&info->shadow, 0, sizeof(info->shadow));
|
|
for (i = 0; i < BLK_RING_SIZE; i++)
|
|
info->shadow[i].req.u.rw.id = i+1;
|
|
info->shadow_free = info->ring.req_prod_pvt;
|
|
info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
|
|
|
|
rc = blkfront_setup_indirect(info);
|
|
if (rc) {
|
|
kfree(copy);
|
|
return rc;
|
|
}
|
|
|
|
segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
blk_queue_max_segments(info->rq, segs);
|
|
bio_list_init(&bio_list);
|
|
INIT_LIST_HEAD(&requests);
|
|
for (i = 0; i < BLK_RING_SIZE; i++) {
|
|
/* Not in use? */
|
|
if (!copy[i].request)
|
|
continue;
|
|
|
|
/*
|
|
* Get the bios in the request so we can re-queue them.
|
|
*/
|
|
if (copy[i].request->cmd_flags &
|
|
(REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
|
|
/*
|
|
* Flush operations don't contain bios, so
|
|
* we need to requeue the whole request
|
|
*/
|
|
list_add(©[i].request->queuelist, &requests);
|
|
continue;
|
|
}
|
|
merge_bio.head = copy[i].request->bio;
|
|
merge_bio.tail = copy[i].request->biotail;
|
|
bio_list_merge(&bio_list, &merge_bio);
|
|
copy[i].request->bio = NULL;
|
|
blk_end_request_all(copy[i].request, 0);
|
|
}
|
|
|
|
kfree(copy);
|
|
|
|
/*
|
|
* Empty the queue, this is important because we might have
|
|
* requests in the queue with more segments than what we
|
|
* can handle now.
|
|
*/
|
|
spin_lock_irq(&info->io_lock);
|
|
while ((req = blk_fetch_request(info->rq)) != NULL) {
|
|
if (req->cmd_flags &
|
|
(REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
|
|
list_add(&req->queuelist, &requests);
|
|
continue;
|
|
}
|
|
merge_bio.head = req->bio;
|
|
merge_bio.tail = req->biotail;
|
|
bio_list_merge(&bio_list, &merge_bio);
|
|
req->bio = NULL;
|
|
if (req->cmd_flags & (REQ_FLUSH | REQ_FUA))
|
|
pr_alert("diskcache flush request found!\n");
|
|
__blk_end_request_all(req, 0);
|
|
}
|
|
spin_unlock_irq(&info->io_lock);
|
|
|
|
xenbus_switch_state(info->xbdev, XenbusStateConnected);
|
|
|
|
spin_lock_irq(&info->io_lock);
|
|
|
|
/* Now safe for us to use the shared ring */
|
|
info->connected = BLKIF_STATE_CONNECTED;
|
|
|
|
/* Kick any other new requests queued since we resumed */
|
|
kick_pending_request_queues(info);
|
|
|
|
list_for_each_entry_safe(req, n, &requests, queuelist) {
|
|
/* Requeue pending requests (flush or discard) */
|
|
list_del_init(&req->queuelist);
|
|
BUG_ON(req->nr_phys_segments > segs);
|
|
blk_requeue_request(info->rq, req);
|
|
}
|
|
spin_unlock_irq(&info->io_lock);
|
|
|
|
while ((bio = bio_list_pop(&bio_list)) != NULL) {
|
|
/* Traverse the list of pending bios and re-queue them */
|
|
if (bio_segments(bio) > segs) {
|
|
/*
|
|
* This bio has more segments than what we can
|
|
* handle, we have to split it.
|
|
*/
|
|
pending = (bio_segments(bio) + segs - 1) / segs;
|
|
split_bio = kzalloc(sizeof(*split_bio), GFP_NOIO);
|
|
BUG_ON(split_bio == NULL);
|
|
atomic_set(&split_bio->pending, pending);
|
|
split_bio->bio = bio;
|
|
for (i = 0; i < pending; i++) {
|
|
offset = (i * segs * PAGE_SIZE) >> 9;
|
|
size = min((unsigned int)(segs * PAGE_SIZE) >> 9,
|
|
(unsigned int)bio_sectors(bio) - offset);
|
|
cloned_bio = bio_clone(bio, GFP_NOIO);
|
|
BUG_ON(cloned_bio == NULL);
|
|
bio_trim(cloned_bio, offset, size);
|
|
cloned_bio->bi_private = split_bio;
|
|
cloned_bio->bi_end_io = split_bio_end;
|
|
submit_bio(cloned_bio->bi_rw, cloned_bio);
|
|
}
|
|
/*
|
|
* Now we have to wait for all those smaller bios to
|
|
* end, so we can also end the "parent" bio.
|
|
*/
|
|
continue;
|
|
}
|
|
/* We don't need to split this bio */
|
|
submit_bio(bio->bi_rw, bio);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* We are reconnecting to the backend, due to a suspend/resume, or a backend
|
|
* driver restart. We tear down our blkif structure and recreate it, but
|
|
* leave the device-layer structures intact so that this is transparent to the
|
|
* rest of the kernel.
|
|
*/
|
|
static int blkfront_resume(struct xenbus_device *dev)
|
|
{
|
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
|
|
int err;
|
|
|
|
dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
|
|
|
|
blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
|
|
|
|
err = talk_to_blkback(dev, info);
|
|
|
|
/*
|
|
* We have to wait for the backend to switch to
|
|
* connected state, since we want to read which
|
|
* features it supports.
|
|
*/
|
|
|
|
return err;
|
|
}
|
|
|
|
static void
|
|
blkfront_closing(struct blkfront_info *info)
|
|
{
|
|
struct xenbus_device *xbdev = info->xbdev;
|
|
struct block_device *bdev = NULL;
|
|
|
|
mutex_lock(&info->mutex);
|
|
|
|
if (xbdev->state == XenbusStateClosing) {
|
|
mutex_unlock(&info->mutex);
|
|
return;
|
|
}
|
|
|
|
if (info->gd)
|
|
bdev = bdget_disk(info->gd, 0);
|
|
|
|
mutex_unlock(&info->mutex);
|
|
|
|
if (!bdev) {
|
|
xenbus_frontend_closed(xbdev);
|
|
return;
|
|
}
|
|
|
|
mutex_lock(&bdev->bd_mutex);
|
|
|
|
if (bdev->bd_openers) {
|
|
xenbus_dev_error(xbdev, -EBUSY,
|
|
"Device in use; refusing to close");
|
|
xenbus_switch_state(xbdev, XenbusStateClosing);
|
|
} else {
|
|
xlvbd_release_gendisk(info);
|
|
xenbus_frontend_closed(xbdev);
|
|
}
|
|
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
bdput(bdev);
|
|
}
|
|
|
|
static void blkfront_setup_discard(struct blkfront_info *info)
|
|
{
|
|
int err;
|
|
unsigned int discard_granularity;
|
|
unsigned int discard_alignment;
|
|
unsigned int discard_secure;
|
|
|
|
info->feature_discard = 1;
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"discard-granularity", "%u", &discard_granularity,
|
|
"discard-alignment", "%u", &discard_alignment,
|
|
NULL);
|
|
if (!err) {
|
|
info->discard_granularity = discard_granularity;
|
|
info->discard_alignment = discard_alignment;
|
|
}
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"discard-secure", "%d", &discard_secure,
|
|
NULL);
|
|
if (!err)
|
|
info->feature_secdiscard = !!discard_secure;
|
|
}
|
|
|
|
static int blkfront_setup_indirect(struct blkfront_info *info)
|
|
{
|
|
unsigned int indirect_segments, segs;
|
|
int err, i;
|
|
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"feature-max-indirect-segments", "%u", &indirect_segments,
|
|
NULL);
|
|
if (err) {
|
|
info->max_indirect_segments = 0;
|
|
segs = BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
} else {
|
|
info->max_indirect_segments = min(indirect_segments,
|
|
xen_blkif_max_segments);
|
|
segs = info->max_indirect_segments;
|
|
}
|
|
|
|
err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE);
|
|
if (err)
|
|
goto out_of_memory;
|
|
|
|
if (!info->feature_persistent && info->max_indirect_segments) {
|
|
/*
|
|
* We are using indirect descriptors but not persistent
|
|
* grants, we need to allocate a set of pages that can be
|
|
* used for mapping indirect grefs
|
|
*/
|
|
int num = INDIRECT_GREFS(segs) * BLK_RING_SIZE;
|
|
|
|
BUG_ON(!list_empty(&info->indirect_pages));
|
|
for (i = 0; i < num; i++) {
|
|
struct page *indirect_page = alloc_page(GFP_NOIO);
|
|
if (!indirect_page)
|
|
goto out_of_memory;
|
|
list_add(&indirect_page->lru, &info->indirect_pages);
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < BLK_RING_SIZE; i++) {
|
|
info->shadow[i].grants_used = kzalloc(
|
|
sizeof(info->shadow[i].grants_used[0]) * segs,
|
|
GFP_NOIO);
|
|
info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * segs, GFP_NOIO);
|
|
if (info->max_indirect_segments)
|
|
info->shadow[i].indirect_grants = kzalloc(
|
|
sizeof(info->shadow[i].indirect_grants[0]) *
|
|
INDIRECT_GREFS(segs),
|
|
GFP_NOIO);
|
|
if ((info->shadow[i].grants_used == NULL) ||
|
|
(info->shadow[i].sg == NULL) ||
|
|
(info->max_indirect_segments &&
|
|
(info->shadow[i].indirect_grants == NULL)))
|
|
goto out_of_memory;
|
|
sg_init_table(info->shadow[i].sg, segs);
|
|
}
|
|
|
|
|
|
return 0;
|
|
|
|
out_of_memory:
|
|
for (i = 0; i < BLK_RING_SIZE; i++) {
|
|
kfree(info->shadow[i].grants_used);
|
|
info->shadow[i].grants_used = NULL;
|
|
kfree(info->shadow[i].sg);
|
|
info->shadow[i].sg = NULL;
|
|
kfree(info->shadow[i].indirect_grants);
|
|
info->shadow[i].indirect_grants = NULL;
|
|
}
|
|
if (!list_empty(&info->indirect_pages)) {
|
|
struct page *indirect_page, *n;
|
|
list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
|
|
list_del(&indirect_page->lru);
|
|
__free_page(indirect_page);
|
|
}
|
|
}
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Invoked when the backend is finally 'ready' (and has told produced
|
|
* the details about the physical device - #sectors, size, etc).
|
|
*/
|
|
static void blkfront_connect(struct blkfront_info *info)
|
|
{
|
|
unsigned long long sectors;
|
|
unsigned long sector_size;
|
|
unsigned int physical_sector_size;
|
|
unsigned int binfo;
|
|
int err;
|
|
int barrier, flush, discard, persistent;
|
|
|
|
switch (info->connected) {
|
|
case BLKIF_STATE_CONNECTED:
|
|
/*
|
|
* Potentially, the back-end may be signalling
|
|
* a capacity change; update the capacity.
|
|
*/
|
|
err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
|
|
"sectors", "%Lu", §ors);
|
|
if (XENBUS_EXIST_ERR(err))
|
|
return;
|
|
printk(KERN_INFO "Setting capacity to %Lu\n",
|
|
sectors);
|
|
set_capacity(info->gd, sectors);
|
|
revalidate_disk(info->gd);
|
|
|
|
return;
|
|
case BLKIF_STATE_SUSPENDED:
|
|
/*
|
|
* If we are recovering from suspension, we need to wait
|
|
* for the backend to announce it's features before
|
|
* reconnecting, at least we need to know if the backend
|
|
* supports indirect descriptors, and how many.
|
|
*/
|
|
blkif_recover(info);
|
|
return;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
dev_dbg(&info->xbdev->dev, "%s:%s.\n",
|
|
__func__, info->xbdev->otherend);
|
|
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"sectors", "%llu", §ors,
|
|
"info", "%u", &binfo,
|
|
"sector-size", "%lu", §or_size,
|
|
NULL);
|
|
if (err) {
|
|
xenbus_dev_fatal(info->xbdev, err,
|
|
"reading backend fields at %s",
|
|
info->xbdev->otherend);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* physcial-sector-size is a newer field, so old backends may not
|
|
* provide this. Assume physical sector size to be the same as
|
|
* sector_size in that case.
|
|
*/
|
|
err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
|
|
"physical-sector-size", "%u", &physical_sector_size);
|
|
if (err != 1)
|
|
physical_sector_size = sector_size;
|
|
|
|
info->feature_flush = 0;
|
|
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"feature-barrier", "%d", &barrier,
|
|
NULL);
|
|
|
|
/*
|
|
* If there's no "feature-barrier" defined, then it means
|
|
* we're dealing with a very old backend which writes
|
|
* synchronously; nothing to do.
|
|
*
|
|
* If there are barriers, then we use flush.
|
|
*/
|
|
if (!err && barrier)
|
|
info->feature_flush = REQ_FLUSH | REQ_FUA;
|
|
/*
|
|
* And if there is "feature-flush-cache" use that above
|
|
* barriers.
|
|
*/
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"feature-flush-cache", "%d", &flush,
|
|
NULL);
|
|
|
|
if (!err && flush)
|
|
info->feature_flush = REQ_FLUSH;
|
|
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"feature-discard", "%d", &discard,
|
|
NULL);
|
|
|
|
if (!err && discard)
|
|
blkfront_setup_discard(info);
|
|
|
|
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
|
|
"feature-persistent", "%u", &persistent,
|
|
NULL);
|
|
if (err)
|
|
info->feature_persistent = 0;
|
|
else
|
|
info->feature_persistent = persistent;
|
|
|
|
err = blkfront_setup_indirect(info);
|
|
if (err) {
|
|
xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s",
|
|
info->xbdev->otherend);
|
|
return;
|
|
}
|
|
|
|
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size,
|
|
physical_sector_size);
|
|
if (err) {
|
|
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
|
|
info->xbdev->otherend);
|
|
return;
|
|
}
|
|
|
|
xenbus_switch_state(info->xbdev, XenbusStateConnected);
|
|
|
|
/* Kick pending requests. */
|
|
spin_lock_irq(&info->io_lock);
|
|
info->connected = BLKIF_STATE_CONNECTED;
|
|
kick_pending_request_queues(info);
|
|
spin_unlock_irq(&info->io_lock);
|
|
|
|
add_disk(info->gd);
|
|
|
|
info->is_ready = 1;
|
|
}
|
|
|
|
/**
|
|
* Callback received when the backend's state changes.
|
|
*/
|
|
static void blkback_changed(struct xenbus_device *dev,
|
|
enum xenbus_state backend_state)
|
|
{
|
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
|
|
|
|
dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
|
|
|
|
switch (backend_state) {
|
|
case XenbusStateInitialising:
|
|
case XenbusStateInitWait:
|
|
case XenbusStateInitialised:
|
|
case XenbusStateReconfiguring:
|
|
case XenbusStateReconfigured:
|
|
case XenbusStateUnknown:
|
|
break;
|
|
|
|
case XenbusStateConnected:
|
|
blkfront_connect(info);
|
|
break;
|
|
|
|
case XenbusStateClosed:
|
|
if (dev->state == XenbusStateClosed)
|
|
break;
|
|
/* Missed the backend's Closing state -- fallthrough */
|
|
case XenbusStateClosing:
|
|
blkfront_closing(info);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static int blkfront_remove(struct xenbus_device *xbdev)
|
|
{
|
|
struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
|
|
struct block_device *bdev = NULL;
|
|
struct gendisk *disk;
|
|
|
|
dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
|
|
|
|
blkif_free(info, 0);
|
|
|
|
mutex_lock(&info->mutex);
|
|
|
|
disk = info->gd;
|
|
if (disk)
|
|
bdev = bdget_disk(disk, 0);
|
|
|
|
info->xbdev = NULL;
|
|
mutex_unlock(&info->mutex);
|
|
|
|
if (!bdev) {
|
|
kfree(info);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* The xbdev was removed before we reached the Closed
|
|
* state. See if it's safe to remove the disk. If the bdev
|
|
* isn't closed yet, we let release take care of it.
|
|
*/
|
|
|
|
mutex_lock(&bdev->bd_mutex);
|
|
info = disk->private_data;
|
|
|
|
dev_warn(disk_to_dev(disk),
|
|
"%s was hot-unplugged, %d stale handles\n",
|
|
xbdev->nodename, bdev->bd_openers);
|
|
|
|
if (info && !bdev->bd_openers) {
|
|
xlvbd_release_gendisk(info);
|
|
disk->private_data = NULL;
|
|
kfree(info);
|
|
}
|
|
|
|
mutex_unlock(&bdev->bd_mutex);
|
|
bdput(bdev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int blkfront_is_ready(struct xenbus_device *dev)
|
|
{
|
|
struct blkfront_info *info = dev_get_drvdata(&dev->dev);
|
|
|
|
return info->is_ready && info->xbdev;
|
|
}
|
|
|
|
static int blkif_open(struct block_device *bdev, fmode_t mode)
|
|
{
|
|
struct gendisk *disk = bdev->bd_disk;
|
|
struct blkfront_info *info;
|
|
int err = 0;
|
|
|
|
mutex_lock(&blkfront_mutex);
|
|
|
|
info = disk->private_data;
|
|
if (!info) {
|
|
/* xbdev gone */
|
|
err = -ERESTARTSYS;
|
|
goto out;
|
|
}
|
|
|
|
mutex_lock(&info->mutex);
|
|
|
|
if (!info->gd)
|
|
/* xbdev is closed */
|
|
err = -ERESTARTSYS;
|
|
|
|
mutex_unlock(&info->mutex);
|
|
|
|
out:
|
|
mutex_unlock(&blkfront_mutex);
|
|
return err;
|
|
}
|
|
|
|
static void blkif_release(struct gendisk *disk, fmode_t mode)
|
|
{
|
|
struct blkfront_info *info = disk->private_data;
|
|
struct block_device *bdev;
|
|
struct xenbus_device *xbdev;
|
|
|
|
mutex_lock(&blkfront_mutex);
|
|
|
|
bdev = bdget_disk(disk, 0);
|
|
|
|
if (!bdev) {
|
|
WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
|
|
goto out_mutex;
|
|
}
|
|
if (bdev->bd_openers)
|
|
goto out;
|
|
|
|
/*
|
|
* Check if we have been instructed to close. We will have
|
|
* deferred this request, because the bdev was still open.
|
|
*/
|
|
|
|
mutex_lock(&info->mutex);
|
|
xbdev = info->xbdev;
|
|
|
|
if (xbdev && xbdev->state == XenbusStateClosing) {
|
|
/* pending switch to state closed */
|
|
dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
|
|
xlvbd_release_gendisk(info);
|
|
xenbus_frontend_closed(info->xbdev);
|
|
}
|
|
|
|
mutex_unlock(&info->mutex);
|
|
|
|
if (!xbdev) {
|
|
/* sudden device removal */
|
|
dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
|
|
xlvbd_release_gendisk(info);
|
|
disk->private_data = NULL;
|
|
kfree(info);
|
|
}
|
|
|
|
out:
|
|
bdput(bdev);
|
|
out_mutex:
|
|
mutex_unlock(&blkfront_mutex);
|
|
}
|
|
|
|
static const struct block_device_operations xlvbd_block_fops =
|
|
{
|
|
.owner = THIS_MODULE,
|
|
.open = blkif_open,
|
|
.release = blkif_release,
|
|
.getgeo = blkif_getgeo,
|
|
.ioctl = blkif_ioctl,
|
|
};
|
|
|
|
|
|
static const struct xenbus_device_id blkfront_ids[] = {
|
|
{ "vbd" },
|
|
{ "" }
|
|
};
|
|
|
|
static struct xenbus_driver blkfront_driver = {
|
|
.ids = blkfront_ids,
|
|
.probe = blkfront_probe,
|
|
.remove = blkfront_remove,
|
|
.resume = blkfront_resume,
|
|
.otherend_changed = blkback_changed,
|
|
.is_ready = blkfront_is_ready,
|
|
};
|
|
|
|
static int __init xlblk_init(void)
|
|
{
|
|
int ret;
|
|
|
|
if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
if (!xen_has_pv_disk_devices())
|
|
return -ENODEV;
|
|
|
|
if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
|
|
printk(KERN_WARNING "xen_blk: can't get major %d with name %s\n",
|
|
XENVBD_MAJOR, DEV_NAME);
|
|
return -ENODEV;
|
|
}
|
|
|
|
ret = xenbus_register_frontend(&blkfront_driver);
|
|
if (ret) {
|
|
unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
module_init(xlblk_init);
|
|
|
|
|
|
static void __exit xlblk_exit(void)
|
|
{
|
|
xenbus_unregister_driver(&blkfront_driver);
|
|
unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
|
|
kfree(minors);
|
|
}
|
|
module_exit(xlblk_exit);
|
|
|
|
MODULE_DESCRIPTION("Xen virtual block device frontend");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_BLOCKDEV_MAJOR(XENVBD_MAJOR);
|
|
MODULE_ALIAS("xen:vbd");
|
|
MODULE_ALIAS("xenblk");
|