mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![Christoph Hellwig](/assets/img/avatar_default.png)
Now that all drivers that call blk_mq_complete_requests have a ->complete callback we can remove the direct call to blk_mq_end_request, as well as the error argument to blk_mq_complete_request. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2722 lines
73 KiB
C
2722 lines
73 KiB
C
/*
|
|
* blkfront.c
|
|
*
|
|
* XenLinux virtual block device driver.
|
|
*
|
|
* Copyright (c) 2003-2004, Keir Fraser & Steve Hand
|
|
* Modifications by Mark A. Williamson are (c) Intel Research Cambridge
|
|
* Copyright (c) 2004, Christian Limpach
|
|
* Copyright (c) 2004, Andrew Warfield
|
|
* Copyright (c) 2005, Christopher Clark
|
|
* Copyright (c) 2005, XenSource Ltd
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License version 2
|
|
* as published by the Free Software Foundation; or, when distributed
|
|
* separately from the Linux kernel or incorporated into other
|
|
* software packages, subject to the following license:
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this source file (the "Software"), to deal in the Software without
|
|
* restriction, including without limitation the rights to use, copy, modify,
|
|
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
|
|
* and to permit persons to whom the Software is furnished to do so, subject to
|
|
* the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
|
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
|
|
* IN THE SOFTWARE.
|
|
*/
|
|
|
|
#include <linux/interrupt.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/blk-mq.h>
|
|
#include <linux/hdreg.h>
|
|
#include <linux/cdrom.h>
|
|
#include <linux/module.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/scatterlist.h>
|
|
#include <linux/bitmap.h>
|
|
#include <linux/list.h>
|
|
|
|
#include <xen/xen.h>
|
|
#include <xen/xenbus.h>
|
|
#include <xen/grant_table.h>
|
|
#include <xen/events.h>
|
|
#include <xen/page.h>
|
|
#include <xen/platform_pci.h>
|
|
|
|
#include <xen/interface/grant_table.h>
|
|
#include <xen/interface/io/blkif.h>
|
|
#include <xen/interface/io/protocols.h>
|
|
|
|
#include <asm/xen/hypervisor.h>
|
|
|
|
/*
|
|
* The minimal size of segment supported by the block framework is PAGE_SIZE.
|
|
* When Linux is using a different page size than Xen, it may not be possible
|
|
* to put all the data in a single segment.
|
|
* This can happen when the backend doesn't support indirect descriptor and
|
|
* therefore the maximum amount of data that a request can carry is
|
|
* BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE = 44KB
|
|
*
|
|
* Note that we only support one extra request. So the Linux page size
|
|
* should be <= ( 2 * BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) =
|
|
* 88KB.
|
|
*/
|
|
#define HAS_EXTRA_REQ (BLKIF_MAX_SEGMENTS_PER_REQUEST < XEN_PFN_PER_PAGE)
|
|
|
|
enum blkif_state {
|
|
BLKIF_STATE_DISCONNECTED,
|
|
BLKIF_STATE_CONNECTED,
|
|
BLKIF_STATE_SUSPENDED,
|
|
};
|
|
|
|
struct grant {
|
|
grant_ref_t gref;
|
|
struct page *page;
|
|
struct list_head node;
|
|
};
|
|
|
|
enum blk_req_status {
|
|
REQ_WAITING,
|
|
REQ_DONE,
|
|
REQ_ERROR,
|
|
REQ_EOPNOTSUPP,
|
|
};
|
|
|
|
struct blk_shadow {
|
|
struct blkif_request req;
|
|
struct request *request;
|
|
struct grant **grants_used;
|
|
struct grant **indirect_grants;
|
|
struct scatterlist *sg;
|
|
unsigned int num_sg;
|
|
enum blk_req_status status;
|
|
|
|
#define NO_ASSOCIATED_ID ~0UL
|
|
/*
|
|
* Id of the sibling if we ever need 2 requests when handling a
|
|
* block I/O request
|
|
*/
|
|
unsigned long associated_id;
|
|
};
|
|
|
|
struct split_bio {
|
|
struct bio *bio;
|
|
atomic_t pending;
|
|
};
|
|
|
|
struct blkif_req {
|
|
int error;
|
|
};
|
|
|
|
static inline struct blkif_req *blkif_req(struct request *rq)
|
|
{
|
|
return blk_mq_rq_to_pdu(rq);
|
|
}
|
|
|
|
static DEFINE_MUTEX(blkfront_mutex);
|
|
static const struct block_device_operations xlvbd_block_fops;
|
|
|
|
/*
|
|
* Maximum number of segments in indirect requests, the actual value used by
|
|
* the frontend driver is the minimum of this value and the value provided
|
|
* by the backend driver.
|
|
*/
|
|
|
|
static unsigned int xen_blkif_max_segments = 32;
|
|
module_param_named(max_indirect_segments, xen_blkif_max_segments, uint,
|
|
S_IRUGO);
|
|
MODULE_PARM_DESC(max_indirect_segments,
|
|
"Maximum amount of segments in indirect requests (default is 32)");
|
|
|
|
static unsigned int xen_blkif_max_queues = 4;
|
|
module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
|
|
MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used per virtual disk");
|
|
|
|
/*
|
|
* Maximum order of pages to be used for the shared ring between front and
|
|
* backend, 4KB page granularity is used.
|
|
*/
|
|
static unsigned int xen_blkif_max_ring_order;
|
|
module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, S_IRUGO);
|
|
MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring");
|
|
|
|
#define BLK_RING_SIZE(info) \
|
|
__CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages)
|
|
|
|
#define BLK_MAX_RING_SIZE \
|
|
__CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * XENBUS_MAX_RING_GRANTS)
|
|
|
|
/*
|
|
* ring-ref%u i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19
|
|
* characters are enough. Define to 20 to keep consistent with backend.
|
|
*/
|
|
#define RINGREF_NAME_LEN (20)
|
|
/*
|
|
* queue-%u would take 7 + 10(UINT_MAX) = 17 characters.
|
|
*/
|
|
#define QUEUE_NAME_LEN (17)
|
|
|
|
/*
|
|
* Per-ring info.
|
|
* Every blkfront device can associate with one or more blkfront_ring_info,
|
|
* depending on how many hardware queues/rings to be used.
|
|
*/
|
|
struct blkfront_ring_info {
|
|
/* Lock to protect data in every ring buffer. */
|
|
spinlock_t ring_lock;
|
|
struct blkif_front_ring ring;
|
|
unsigned int ring_ref[XENBUS_MAX_RING_GRANTS];
|
|
unsigned int evtchn, irq;
|
|
struct work_struct work;
|
|
struct gnttab_free_callback callback;
|
|
struct blk_shadow shadow[BLK_MAX_RING_SIZE];
|
|
struct list_head indirect_pages;
|
|
struct list_head grants;
|
|
unsigned int persistent_gnts_c;
|
|
unsigned long shadow_free;
|
|
struct blkfront_info *dev_info;
|
|
};
|
|
|
|
/*
|
|
* We have one of these per vbd, whether ide, scsi or 'other'. They
|
|
* hang in private_data off the gendisk structure. We may end up
|
|
* putting all kinds of interesting stuff here :-)
|
|
*/
|
|
struct blkfront_info
|
|
{
|
|
struct mutex mutex;
|
|
struct xenbus_device *xbdev;
|
|
struct gendisk *gd;
|
|
u16 sector_size;
|
|
unsigned int physical_sector_size;
|
|
int vdevice;
|
|
blkif_vdev_t handle;
|
|
enum blkif_state connected;
|
|
/* Number of pages per ring buffer. */
|
|
unsigned int nr_ring_pages;
|
|
struct request_queue *rq;
|
|
unsigned int feature_flush:1;
|
|
unsigned int feature_fua:1;
|
|
unsigned int feature_discard:1;
|
|
unsigned int feature_secdiscard:1;
|
|
unsigned int feature_persistent:1;
|
|
unsigned int discard_granularity;
|
|
unsigned int discard_alignment;
|
|
/* Number of 4KB segments handled */
|
|
unsigned int max_indirect_segments;
|
|
int is_ready;
|
|
struct blk_mq_tag_set tag_set;
|
|
struct blkfront_ring_info *rinfo;
|
|
unsigned int nr_rings;
|
|
/* Save uncomplete reqs and bios for migration. */
|
|
struct list_head requests;
|
|
struct bio_list bio_list;
|
|
};
|
|
|
|
static unsigned int nr_minors;
|
|
static unsigned long *minors;
|
|
static DEFINE_SPINLOCK(minor_lock);
|
|
|
|
#define GRANT_INVALID_REF 0
|
|
|
|
#define PARTS_PER_DISK 16
|
|
#define PARTS_PER_EXT_DISK 256
|
|
|
|
#define BLKIF_MAJOR(dev) ((dev)>>8)
|
|
#define BLKIF_MINOR(dev) ((dev) & 0xff)
|
|
|
|
#define EXT_SHIFT 28
|
|
#define EXTENDED (1<<EXT_SHIFT)
|
|
#define VDEV_IS_EXTENDED(dev) ((dev)&(EXTENDED))
|
|
#define BLKIF_MINOR_EXT(dev) ((dev)&(~EXTENDED))
|
|
#define EMULATED_HD_DISK_MINOR_OFFSET (0)
|
|
#define EMULATED_HD_DISK_NAME_OFFSET (EMULATED_HD_DISK_MINOR_OFFSET / 256)
|
|
#define EMULATED_SD_DISK_MINOR_OFFSET (0)
|
|
#define EMULATED_SD_DISK_NAME_OFFSET (EMULATED_SD_DISK_MINOR_OFFSET / 256)
|
|
|
|
#define DEV_NAME "xvd" /* name in /dev */
|
|
|
|
/*
|
|
* Grants are always the same size as a Xen page (i.e 4KB).
|
|
* A physical segment is always the same size as a Linux page.
|
|
* Number of grants per physical segment
|
|
*/
|
|
#define GRANTS_PER_PSEG (PAGE_SIZE / XEN_PAGE_SIZE)
|
|
|
|
#define GRANTS_PER_INDIRECT_FRAME \
|
|
(XEN_PAGE_SIZE / sizeof(struct blkif_request_segment))
|
|
|
|
#define PSEGS_PER_INDIRECT_FRAME \
|
|
(GRANTS_INDIRECT_FRAME / GRANTS_PSEGS)
|
|
|
|
#define INDIRECT_GREFS(_grants) \
|
|
DIV_ROUND_UP(_grants, GRANTS_PER_INDIRECT_FRAME)
|
|
|
|
#define GREFS(_psegs) ((_psegs) * GRANTS_PER_PSEG)
|
|
|
|
static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo);
|
|
static void blkfront_gather_backend_features(struct blkfront_info *info);
|
|
|
|
static int get_id_from_freelist(struct blkfront_ring_info *rinfo)
|
|
{
|
|
unsigned long free = rinfo->shadow_free;
|
|
|
|
BUG_ON(free >= BLK_RING_SIZE(rinfo->dev_info));
|
|
rinfo->shadow_free = rinfo->shadow[free].req.u.rw.id;
|
|
rinfo->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
|
|
return free;
|
|
}
|
|
|
|
static int add_id_to_freelist(struct blkfront_ring_info *rinfo,
|
|
unsigned long id)
|
|
{
|
|
if (rinfo->shadow[id].req.u.rw.id != id)
|
|
return -EINVAL;
|
|
if (rinfo->shadow[id].request == NULL)
|
|
return -EINVAL;
|
|
rinfo->shadow[id].req.u.rw.id = rinfo->shadow_free;
|
|
rinfo->shadow[id].request = NULL;
|
|
rinfo->shadow_free = id;
|
|
return 0;
|
|
}
|
|
|
|
static int fill_grant_buffer(struct blkfront_ring_info *rinfo, int num)
|
|
{
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
struct page *granted_page;
|
|
struct grant *gnt_list_entry, *n;
|
|
int i = 0;
|
|
|
|
while (i < num) {
|
|
gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO);
|
|
if (!gnt_list_entry)
|
|
goto out_of_memory;
|
|
|
|
if (info->feature_persistent) {
|
|
granted_page = alloc_page(GFP_NOIO);
|
|
if (!granted_page) {
|
|
kfree(gnt_list_entry);
|
|
goto out_of_memory;
|
|
}
|
|
gnt_list_entry->page = granted_page;
|
|
}
|
|
|
|
gnt_list_entry->gref = GRANT_INVALID_REF;
|
|
list_add(&gnt_list_entry->node, &rinfo->grants);
|
|
i++;
|
|
}
|
|
|
|
return 0;
|
|
|
|
out_of_memory:
|
|
list_for_each_entry_safe(gnt_list_entry, n,
|
|
&rinfo->grants, node) {
|
|
list_del(&gnt_list_entry->node);
|
|
if (info->feature_persistent)
|
|
__free_page(gnt_list_entry->page);
|
|
kfree(gnt_list_entry);
|
|
i--;
|
|
}
|
|
BUG_ON(i != 0);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static struct grant *get_free_grant(struct blkfront_ring_info *rinfo)
|
|
{
|
|
struct grant *gnt_list_entry;
|
|
|
|
BUG_ON(list_empty(&rinfo->grants));
|
|
gnt_list_entry = list_first_entry(&rinfo->grants, struct grant,
|
|
node);
|
|
list_del(&gnt_list_entry->node);
|
|
|
|
if (gnt_list_entry->gref != GRANT_INVALID_REF)
|
|
rinfo->persistent_gnts_c--;
|
|
|
|
return gnt_list_entry;
|
|
}
|
|
|
|
static inline void grant_foreign_access(const struct grant *gnt_list_entry,
|
|
const struct blkfront_info *info)
|
|
{
|
|
gnttab_page_grant_foreign_access_ref_one(gnt_list_entry->gref,
|
|
info->xbdev->otherend_id,
|
|
gnt_list_entry->page,
|
|
0);
|
|
}
|
|
|
|
static struct grant *get_grant(grant_ref_t *gref_head,
|
|
unsigned long gfn,
|
|
struct blkfront_ring_info *rinfo)
|
|
{
|
|
struct grant *gnt_list_entry = get_free_grant(rinfo);
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
|
|
if (gnt_list_entry->gref != GRANT_INVALID_REF)
|
|
return gnt_list_entry;
|
|
|
|
/* Assign a gref to this page */
|
|
gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
|
|
BUG_ON(gnt_list_entry->gref == -ENOSPC);
|
|
if (info->feature_persistent)
|
|
grant_foreign_access(gnt_list_entry, info);
|
|
else {
|
|
/* Grant access to the GFN passed by the caller */
|
|
gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
|
|
info->xbdev->otherend_id,
|
|
gfn, 0);
|
|
}
|
|
|
|
return gnt_list_entry;
|
|
}
|
|
|
|
static struct grant *get_indirect_grant(grant_ref_t *gref_head,
|
|
struct blkfront_ring_info *rinfo)
|
|
{
|
|
struct grant *gnt_list_entry = get_free_grant(rinfo);
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
|
|
if (gnt_list_entry->gref != GRANT_INVALID_REF)
|
|
return gnt_list_entry;
|
|
|
|
/* Assign a gref to this page */
|
|
gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
|
|
BUG_ON(gnt_list_entry->gref == -ENOSPC);
|
|
if (!info->feature_persistent) {
|
|
struct page *indirect_page;
|
|
|
|
/* Fetch a pre-allocated page to use for indirect grefs */
|
|
BUG_ON(list_empty(&rinfo->indirect_pages));
|
|
indirect_page = list_first_entry(&rinfo->indirect_pages,
|
|
struct page, lru);
|
|
list_del(&indirect_page->lru);
|
|
gnt_list_entry->page = indirect_page;
|
|
}
|
|
grant_foreign_access(gnt_list_entry, info);
|
|
|
|
return gnt_list_entry;
|
|
}
|
|
|
|
static const char *op_name(int op)
|
|
{
|
|
static const char *const names[] = {
|
|
[BLKIF_OP_READ] = "read",
|
|
[BLKIF_OP_WRITE] = "write",
|
|
[BLKIF_OP_WRITE_BARRIER] = "barrier",
|
|
[BLKIF_OP_FLUSH_DISKCACHE] = "flush",
|
|
[BLKIF_OP_DISCARD] = "discard" };
|
|
|
|
if (op < 0 || op >= ARRAY_SIZE(names))
|
|
return "unknown";
|
|
|
|
if (!names[op])
|
|
return "reserved";
|
|
|
|
return names[op];
|
|
}
|
|
static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
|
|
{
|
|
unsigned int end = minor + nr;
|
|
int rc;
|
|
|
|
if (end > nr_minors) {
|
|
unsigned long *bitmap, *old;
|
|
|
|
bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
|
|
GFP_KERNEL);
|
|
if (bitmap == NULL)
|
|
return -ENOMEM;
|
|
|
|
spin_lock(&minor_lock);
|
|
if (end > nr_minors) {
|
|
old = minors;
|
|
memcpy(bitmap, minors,
|
|
BITS_TO_LONGS(nr_minors) * sizeof(*bitmap));
|
|
minors = bitmap;
|
|
nr_minors = BITS_TO_LONGS(end) * BITS_PER_LONG;
|
|
} else
|
|
old = bitmap;
|
|
spin_unlock(&minor_lock);
|
|
kfree(old);
|
|
}
|
|
|
|
spin_lock(&minor_lock);
|
|
if (find_next_bit(minors, end, minor) >= end) {
|
|
bitmap_set(minors, minor, nr);
|
|
rc = 0;
|
|
} else
|
|
rc = -EBUSY;
|
|
spin_unlock(&minor_lock);
|
|
|
|
return rc;
|
|
}
|
|
|
|
static void xlbd_release_minors(unsigned int minor, unsigned int nr)
|
|
{
|
|
unsigned int end = minor + nr;
|
|
|
|
BUG_ON(end > nr_minors);
|
|
spin_lock(&minor_lock);
|
|
bitmap_clear(minors, minor, nr);
|
|
spin_unlock(&minor_lock);
|
|
}
|
|
|
|
static void blkif_restart_queue_callback(void *arg)
|
|
{
|
|
struct blkfront_ring_info *rinfo = (struct blkfront_ring_info *)arg;
|
|
schedule_work(&rinfo->work);
|
|
}
|
|
|
|
static int blkif_getgeo(struct block_device *bd, struct hd_geometry *hg)
|
|
{
|
|
/* We don't have real geometry info, but let's at least return
|
|
values consistent with the size of the device */
|
|
sector_t nsect = get_capacity(bd->bd_disk);
|
|
sector_t cylinders = nsect;
|
|
|
|
hg->heads = 0xff;
|
|
hg->sectors = 0x3f;
|
|
sector_div(cylinders, hg->heads * hg->sectors);
|
|
hg->cylinders = cylinders;
|
|
if ((sector_t)(hg->cylinders + 1) * hg->heads * hg->sectors < nsect)
|
|
hg->cylinders = 0xffff;
|
|
return 0;
|
|
}
|
|
|
|
static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
|
|
unsigned command, unsigned long argument)
|
|
{
|
|
struct blkfront_info *info = bdev->bd_disk->private_data;
|
|
int i;
|
|
|
|
dev_dbg(&info->xbdev->dev, "command: 0x%x, argument: 0x%lx\n",
|
|
command, (long)argument);
|
|
|
|
switch (command) {
|
|
case CDROMMULTISESSION:
|
|
dev_dbg(&info->xbdev->dev, "FIXME: support multisession CDs later\n");
|
|
for (i = 0; i < sizeof(struct cdrom_multisession); i++)
|
|
if (put_user(0, (char __user *)(argument + i)))
|
|
return -EFAULT;
|
|
return 0;
|
|
|
|
case CDROM_GET_CAPABILITY: {
|
|
struct gendisk *gd = info->gd;
|
|
if (gd->flags & GENHD_FL_CD)
|
|
return 0;
|
|
return -EINVAL;
|
|
}
|
|
|
|
default:
|
|
/*printk(KERN_ALERT "ioctl %08x not supported by Xen blkdev\n",
|
|
command);*/
|
|
return -EINVAL; /* same return as native Linux */
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long blkif_ring_get_request(struct blkfront_ring_info *rinfo,
|
|
struct request *req,
|
|
struct blkif_request **ring_req)
|
|
{
|
|
unsigned long id;
|
|
|
|
*ring_req = RING_GET_REQUEST(&rinfo->ring, rinfo->ring.req_prod_pvt);
|
|
rinfo->ring.req_prod_pvt++;
|
|
|
|
id = get_id_from_freelist(rinfo);
|
|
rinfo->shadow[id].request = req;
|
|
rinfo->shadow[id].status = REQ_WAITING;
|
|
rinfo->shadow[id].associated_id = NO_ASSOCIATED_ID;
|
|
|
|
(*ring_req)->u.rw.id = id;
|
|
|
|
return id;
|
|
}
|
|
|
|
static int blkif_queue_discard_req(struct request *req, struct blkfront_ring_info *rinfo)
|
|
{
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
struct blkif_request *ring_req;
|
|
unsigned long id;
|
|
|
|
/* Fill out a communications ring structure. */
|
|
id = blkif_ring_get_request(rinfo, req, &ring_req);
|
|
|
|
ring_req->operation = BLKIF_OP_DISCARD;
|
|
ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
|
|
ring_req->u.discard.id = id;
|
|
ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(req);
|
|
if (req_op(req) == REQ_OP_SECURE_ERASE && info->feature_secdiscard)
|
|
ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
|
|
else
|
|
ring_req->u.discard.flag = 0;
|
|
|
|
/* Keep a private copy so we can reissue requests when recovering. */
|
|
rinfo->shadow[id].req = *ring_req;
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct setup_rw_req {
|
|
unsigned int grant_idx;
|
|
struct blkif_request_segment *segments;
|
|
struct blkfront_ring_info *rinfo;
|
|
struct blkif_request *ring_req;
|
|
grant_ref_t gref_head;
|
|
unsigned int id;
|
|
/* Only used when persistent grant is used and it's a read request */
|
|
bool need_copy;
|
|
unsigned int bvec_off;
|
|
char *bvec_data;
|
|
|
|
bool require_extra_req;
|
|
struct blkif_request *extra_ring_req;
|
|
};
|
|
|
|
static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset,
|
|
unsigned int len, void *data)
|
|
{
|
|
struct setup_rw_req *setup = data;
|
|
int n, ref;
|
|
struct grant *gnt_list_entry;
|
|
unsigned int fsect, lsect;
|
|
/* Convenient aliases */
|
|
unsigned int grant_idx = setup->grant_idx;
|
|
struct blkif_request *ring_req = setup->ring_req;
|
|
struct blkfront_ring_info *rinfo = setup->rinfo;
|
|
/*
|
|
* We always use the shadow of the first request to store the list
|
|
* of grant associated to the block I/O request. This made the
|
|
* completion more easy to handle even if the block I/O request is
|
|
* split.
|
|
*/
|
|
struct blk_shadow *shadow = &rinfo->shadow[setup->id];
|
|
|
|
if (unlikely(setup->require_extra_req &&
|
|
grant_idx >= BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
|
|
/*
|
|
* We are using the second request, setup grant_idx
|
|
* to be the index of the segment array.
|
|
*/
|
|
grant_idx -= BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
ring_req = setup->extra_ring_req;
|
|
}
|
|
|
|
if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
|
|
(grant_idx % GRANTS_PER_INDIRECT_FRAME == 0)) {
|
|
if (setup->segments)
|
|
kunmap_atomic(setup->segments);
|
|
|
|
n = grant_idx / GRANTS_PER_INDIRECT_FRAME;
|
|
gnt_list_entry = get_indirect_grant(&setup->gref_head, rinfo);
|
|
shadow->indirect_grants[n] = gnt_list_entry;
|
|
setup->segments = kmap_atomic(gnt_list_entry->page);
|
|
ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
|
|
}
|
|
|
|
gnt_list_entry = get_grant(&setup->gref_head, gfn, rinfo);
|
|
ref = gnt_list_entry->gref;
|
|
/*
|
|
* All the grants are stored in the shadow of the first
|
|
* request. Therefore we have to use the global index.
|
|
*/
|
|
shadow->grants_used[setup->grant_idx] = gnt_list_entry;
|
|
|
|
if (setup->need_copy) {
|
|
void *shared_data;
|
|
|
|
shared_data = kmap_atomic(gnt_list_entry->page);
|
|
/*
|
|
* 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 + offset,
|
|
setup->bvec_data + setup->bvec_off,
|
|
len);
|
|
|
|
kunmap_atomic(shared_data);
|
|
setup->bvec_off += len;
|
|
}
|
|
|
|
fsect = offset >> 9;
|
|
lsect = fsect + (len >> 9) - 1;
|
|
if (ring_req->operation != BLKIF_OP_INDIRECT) {
|
|
ring_req->u.rw.seg[grant_idx] =
|
|
(struct blkif_request_segment) {
|
|
.gref = ref,
|
|
.first_sect = fsect,
|
|
.last_sect = lsect };
|
|
} else {
|
|
setup->segments[grant_idx % GRANTS_PER_INDIRECT_FRAME] =
|
|
(struct blkif_request_segment) {
|
|
.gref = ref,
|
|
.first_sect = fsect,
|
|
.last_sect = lsect };
|
|
}
|
|
|
|
(setup->grant_idx)++;
|
|
}
|
|
|
|
static void blkif_setup_extra_req(struct blkif_request *first,
|
|
struct blkif_request *second)
|
|
{
|
|
uint16_t nr_segments = first->u.rw.nr_segments;
|
|
|
|
/*
|
|
* The second request is only present when the first request uses
|
|
* all its segments. It's always the continuity of the first one.
|
|
*/
|
|
first->u.rw.nr_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
|
|
second->u.rw.nr_segments = nr_segments - BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
second->u.rw.sector_number = first->u.rw.sector_number +
|
|
(BLKIF_MAX_SEGMENTS_PER_REQUEST * XEN_PAGE_SIZE) / 512;
|
|
|
|
second->u.rw.handle = first->u.rw.handle;
|
|
second->operation = first->operation;
|
|
}
|
|
|
|
static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *rinfo)
|
|
{
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
struct blkif_request *ring_req, *extra_ring_req = NULL;
|
|
unsigned long id, extra_id = NO_ASSOCIATED_ID;
|
|
bool require_extra_req = false;
|
|
int i;
|
|
struct setup_rw_req setup = {
|
|
.grant_idx = 0,
|
|
.segments = NULL,
|
|
.rinfo = rinfo,
|
|
.need_copy = rq_data_dir(req) && info->feature_persistent,
|
|
};
|
|
|
|
/*
|
|
* Used to store if we are able to queue the request by just using
|
|
* existing persistent grants, or if we have to get new grants,
|
|
* as there are not sufficiently many free.
|
|
*/
|
|
struct scatterlist *sg;
|
|
int num_sg, max_grefs, num_grant;
|
|
|
|
max_grefs = req->nr_phys_segments * GRANTS_PER_PSEG;
|
|
if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST)
|
|
/*
|
|
* If we are using indirect segments we need to account
|
|
* for the indirect grefs used in the request.
|
|
*/
|
|
max_grefs += INDIRECT_GREFS(max_grefs);
|
|
|
|
/*
|
|
* We have to reserve 'max_grefs' grants because persistent
|
|
* grants are shared by all rings.
|
|
*/
|
|
if (max_grefs > 0)
|
|
if (gnttab_alloc_grant_references(max_grefs, &setup.gref_head) < 0) {
|
|
gnttab_request_free_callback(
|
|
&rinfo->callback,
|
|
blkif_restart_queue_callback,
|
|
rinfo,
|
|
max_grefs);
|
|
return 1;
|
|
}
|
|
|
|
/* Fill out a communications ring structure. */
|
|
id = blkif_ring_get_request(rinfo, req, &ring_req);
|
|
|
|
num_sg = blk_rq_map_sg(req->q, req, rinfo->shadow[id].sg);
|
|
num_grant = 0;
|
|
/* Calculate the number of grant used */
|
|
for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i)
|
|
num_grant += gnttab_count_grant(sg->offset, sg->length);
|
|
|
|
require_extra_req = info->max_indirect_segments == 0 &&
|
|
num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
BUG_ON(!HAS_EXTRA_REQ && require_extra_req);
|
|
|
|
rinfo->shadow[id].num_sg = num_sg;
|
|
if (num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST &&
|
|
likely(!require_extra_req)) {
|
|
/*
|
|
* The indirect operation can only be a BLKIF_OP_READ or
|
|
* BLKIF_OP_WRITE
|
|
*/
|
|
BUG_ON(req_op(req) == REQ_OP_FLUSH || req->cmd_flags & REQ_FUA);
|
|
ring_req->operation = BLKIF_OP_INDIRECT;
|
|
ring_req->u.indirect.indirect_op = rq_data_dir(req) ?
|
|
BLKIF_OP_WRITE : BLKIF_OP_READ;
|
|
ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req);
|
|
ring_req->u.indirect.handle = info->handle;
|
|
ring_req->u.indirect.nr_segments = num_grant;
|
|
} else {
|
|
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_op(req) == REQ_OP_FLUSH || req->cmd_flags & 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.)
|
|
*/
|
|
if (info->feature_flush && info->feature_fua)
|
|
ring_req->operation =
|
|
BLKIF_OP_WRITE_BARRIER;
|
|
else if (info->feature_flush)
|
|
ring_req->operation =
|
|
BLKIF_OP_FLUSH_DISKCACHE;
|
|
else
|
|
ring_req->operation = 0;
|
|
}
|
|
ring_req->u.rw.nr_segments = num_grant;
|
|
if (unlikely(require_extra_req)) {
|
|
extra_id = blkif_ring_get_request(rinfo, req,
|
|
&extra_ring_req);
|
|
/*
|
|
* Only the first request contains the scatter-gather
|
|
* list.
|
|
*/
|
|
rinfo->shadow[extra_id].num_sg = 0;
|
|
|
|
blkif_setup_extra_req(ring_req, extra_ring_req);
|
|
|
|
/* Link the 2 requests together */
|
|
rinfo->shadow[extra_id].associated_id = id;
|
|
rinfo->shadow[id].associated_id = extra_id;
|
|
}
|
|
}
|
|
|
|
setup.ring_req = ring_req;
|
|
setup.id = id;
|
|
|
|
setup.require_extra_req = require_extra_req;
|
|
if (unlikely(require_extra_req))
|
|
setup.extra_ring_req = extra_ring_req;
|
|
|
|
for_each_sg(rinfo->shadow[id].sg, sg, num_sg, i) {
|
|
BUG_ON(sg->offset + sg->length > PAGE_SIZE);
|
|
|
|
if (setup.need_copy) {
|
|
setup.bvec_off = sg->offset;
|
|
setup.bvec_data = kmap_atomic(sg_page(sg));
|
|
}
|
|
|
|
gnttab_foreach_grant_in_range(sg_page(sg),
|
|
sg->offset,
|
|
sg->length,
|
|
blkif_setup_rw_req_grant,
|
|
&setup);
|
|
|
|
if (setup.need_copy)
|
|
kunmap_atomic(setup.bvec_data);
|
|
}
|
|
if (setup.segments)
|
|
kunmap_atomic(setup.segments);
|
|
|
|
/* Keep a private copy so we can reissue requests when recovering. */
|
|
rinfo->shadow[id].req = *ring_req;
|
|
if (unlikely(require_extra_req))
|
|
rinfo->shadow[extra_id].req = *extra_ring_req;
|
|
|
|
if (max_grefs > 0)
|
|
gnttab_free_grant_references(setup.gref_head);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Generate a Xen blkfront IO request from a blk layer request. Reads
|
|
* and writes are handled as expected.
|
|
*
|
|
* @req: a request struct
|
|
*/
|
|
static int blkif_queue_request(struct request *req, struct blkfront_ring_info *rinfo)
|
|
{
|
|
if (unlikely(rinfo->dev_info->connected != BLKIF_STATE_CONNECTED))
|
|
return 1;
|
|
|
|
if (unlikely(req_op(req) == REQ_OP_DISCARD ||
|
|
req_op(req) == REQ_OP_SECURE_ERASE))
|
|
return blkif_queue_discard_req(req, rinfo);
|
|
else
|
|
return blkif_queue_rw_req(req, rinfo);
|
|
}
|
|
|
|
static inline void flush_requests(struct blkfront_ring_info *rinfo)
|
|
{
|
|
int notify;
|
|
|
|
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&rinfo->ring, notify);
|
|
|
|
if (notify)
|
|
notify_remote_via_irq(rinfo->irq);
|
|
}
|
|
|
|
static inline bool blkif_request_flush_invalid(struct request *req,
|
|
struct blkfront_info *info)
|
|
{
|
|
return (blk_rq_is_passthrough(req) ||
|
|
((req_op(req) == REQ_OP_FLUSH) &&
|
|
!info->feature_flush) ||
|
|
((req->cmd_flags & REQ_FUA) &&
|
|
!info->feature_fua));
|
|
}
|
|
|
|
static int blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
|
|
const struct blk_mq_queue_data *qd)
|
|
{
|
|
unsigned long flags;
|
|
int qid = hctx->queue_num;
|
|
struct blkfront_info *info = hctx->queue->queuedata;
|
|
struct blkfront_ring_info *rinfo = NULL;
|
|
|
|
BUG_ON(info->nr_rings <= qid);
|
|
rinfo = &info->rinfo[qid];
|
|
blk_mq_start_request(qd->rq);
|
|
spin_lock_irqsave(&rinfo->ring_lock, flags);
|
|
if (RING_FULL(&rinfo->ring))
|
|
goto out_busy;
|
|
|
|
if (blkif_request_flush_invalid(qd->rq, rinfo->dev_info))
|
|
goto out_err;
|
|
|
|
if (blkif_queue_request(qd->rq, rinfo))
|
|
goto out_busy;
|
|
|
|
flush_requests(rinfo);
|
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags);
|
|
return BLK_MQ_RQ_QUEUE_OK;
|
|
|
|
out_err:
|
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags);
|
|
return BLK_MQ_RQ_QUEUE_ERROR;
|
|
|
|
out_busy:
|
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags);
|
|
blk_mq_stop_hw_queue(hctx);
|
|
return BLK_MQ_RQ_QUEUE_BUSY;
|
|
}
|
|
|
|
static void blkif_complete_rq(struct request *rq)
|
|
{
|
|
blk_mq_end_request(rq, blkif_req(rq)->error);
|
|
}
|
|
|
|
static const struct blk_mq_ops blkfront_mq_ops = {
|
|
.queue_rq = blkif_queue_rq,
|
|
.complete = blkif_complete_rq,
|
|
};
|
|
|
|
static void blkif_set_queue_limits(struct blkfront_info *info)
|
|
{
|
|
struct request_queue *rq = info->rq;
|
|
struct gendisk *gd = info->gd;
|
|
unsigned int segments = info->max_indirect_segments ? :
|
|
BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
|
|
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_SECERASE, rq);
|
|
}
|
|
|
|
/* Hard sector size and max sectors impersonate the equiv. hardware. */
|
|
blk_queue_logical_block_size(rq, info->sector_size);
|
|
blk_queue_physical_block_size(rq, info->physical_sector_size);
|
|
blk_queue_max_hw_sectors(rq, (segments * XEN_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 / GRANTS_PER_PSEG);
|
|
|
|
/* 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);
|
|
}
|
|
|
|
static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
|
|
unsigned int physical_sector_size)
|
|
{
|
|
struct request_queue *rq;
|
|
struct blkfront_info *info = gd->private_data;
|
|
|
|
memset(&info->tag_set, 0, sizeof(info->tag_set));
|
|
info->tag_set.ops = &blkfront_mq_ops;
|
|
info->tag_set.nr_hw_queues = info->nr_rings;
|
|
if (HAS_EXTRA_REQ && info->max_indirect_segments == 0) {
|
|
/*
|
|
* When indirect descriptior is not supported, the I/O request
|
|
* will be split between multiple request in the ring.
|
|
* To avoid problems when sending the request, divide by
|
|
* 2 the depth of the queue.
|
|
*/
|
|
info->tag_set.queue_depth = BLK_RING_SIZE(info) / 2;
|
|
} else
|
|
info->tag_set.queue_depth = BLK_RING_SIZE(info);
|
|
info->tag_set.numa_node = NUMA_NO_NODE;
|
|
info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
|
|
info->tag_set.cmd_size = sizeof(struct blkif_req);
|
|
info->tag_set.driver_data = info;
|
|
|
|
if (blk_mq_alloc_tag_set(&info->tag_set))
|
|
return -EINVAL;
|
|
rq = blk_mq_init_queue(&info->tag_set);
|
|
if (IS_ERR(rq)) {
|
|
blk_mq_free_tag_set(&info->tag_set);
|
|
return PTR_ERR(rq);
|
|
}
|
|
|
|
rq->queuedata = info;
|
|
info->rq = gd->queue = rq;
|
|
info->gd = gd;
|
|
info->sector_size = sector_size;
|
|
info->physical_sector_size = physical_sector_size;
|
|
blkif_set_queue_limits(info);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const char *flush_info(struct blkfront_info *info)
|
|
{
|
|
if (info->feature_flush && info->feature_fua)
|
|
return "barrier: enabled;";
|
|
else if (info->feature_flush)
|
|
return "flush diskcache: enabled;";
|
|
else
|
|
return "barrier or flush: disabled;";
|
|
}
|
|
|
|
static void xlvbd_flush(struct blkfront_info *info)
|
|
{
|
|
blk_queue_write_cache(info->rq, info->feature_flush ? true : false,
|
|
info->feature_fua ? true : false);
|
|
pr_info("blkfront: %s: %s %s %s %s %s\n",
|
|
info->gd->disk_name, flush_info(info),
|
|
"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;
|
|
set_capacity(gd, capacity);
|
|
|
|
if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size)) {
|
|
del_gendisk(gd);
|
|
goto release;
|
|
}
|
|
|
|
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, i;
|
|
|
|
if (info->rq == NULL)
|
|
return;
|
|
|
|
/* No more blkif_request(). */
|
|
blk_mq_stop_hw_queues(info->rq);
|
|
|
|
for (i = 0; i < info->nr_rings; i++) {
|
|
struct blkfront_ring_info *rinfo = &info->rinfo[i];
|
|
|
|
/* No more gnttab callback work. */
|
|
gnttab_cancel_free_callback(&rinfo->callback);
|
|
|
|
/* Flush gnttab callback work. Must be done with no locks held. */
|
|
flush_work(&rinfo->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);
|
|
blk_mq_free_tag_set(&info->tag_set);
|
|
info->rq = NULL;
|
|
|
|
put_disk(info->gd);
|
|
info->gd = NULL;
|
|
}
|
|
|
|
/* Already hold rinfo->ring_lock. */
|
|
static inline void kick_pending_request_queues_locked(struct blkfront_ring_info *rinfo)
|
|
{
|
|
if (!RING_FULL(&rinfo->ring))
|
|
blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true);
|
|
}
|
|
|
|
static void kick_pending_request_queues(struct blkfront_ring_info *rinfo)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&rinfo->ring_lock, flags);
|
|
kick_pending_request_queues_locked(rinfo);
|
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags);
|
|
}
|
|
|
|
static void blkif_restart_queue(struct work_struct *work)
|
|
{
|
|
struct blkfront_ring_info *rinfo = container_of(work, struct blkfront_ring_info, work);
|
|
|
|
if (rinfo->dev_info->connected == BLKIF_STATE_CONNECTED)
|
|
kick_pending_request_queues(rinfo);
|
|
}
|
|
|
|
static void blkif_free_ring(struct blkfront_ring_info *rinfo)
|
|
{
|
|
struct grant *persistent_gnt, *n;
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
int i, j, segs;
|
|
|
|
/*
|
|
* Remove indirect pages, this only happens when using indirect
|
|
* descriptors but not persistent grants
|
|
*/
|
|
if (!list_empty(&rinfo->indirect_pages)) {
|
|
struct page *indirect_page, *n;
|
|
|
|
BUG_ON(info->feature_persistent);
|
|
list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
|
|
list_del(&indirect_page->lru);
|
|
__free_page(indirect_page);
|
|
}
|
|
}
|
|
|
|
/* Remove all persistent grants. */
|
|
if (!list_empty(&rinfo->grants)) {
|
|
list_for_each_entry_safe(persistent_gnt, n,
|
|
&rinfo->grants, node) {
|
|
list_del(&persistent_gnt->node);
|
|
if (persistent_gnt->gref != GRANT_INVALID_REF) {
|
|
gnttab_end_foreign_access(persistent_gnt->gref,
|
|
0, 0UL);
|
|
rinfo->persistent_gnts_c--;
|
|
}
|
|
if (info->feature_persistent)
|
|
__free_page(persistent_gnt->page);
|
|
kfree(persistent_gnt);
|
|
}
|
|
}
|
|
BUG_ON(rinfo->persistent_gnts_c != 0);
|
|
|
|
for (i = 0; i < BLK_RING_SIZE(info); i++) {
|
|
/*
|
|
* Clear persistent grants present in requests already
|
|
* on the shared ring
|
|
*/
|
|
if (!rinfo->shadow[i].request)
|
|
goto free_shadow;
|
|
|
|
segs = rinfo->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
|
|
rinfo->shadow[i].req.u.indirect.nr_segments :
|
|
rinfo->shadow[i].req.u.rw.nr_segments;
|
|
for (j = 0; j < segs; j++) {
|
|
persistent_gnt = rinfo->shadow[i].grants_used[j];
|
|
gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
|
|
if (info->feature_persistent)
|
|
__free_page(persistent_gnt->page);
|
|
kfree(persistent_gnt);
|
|
}
|
|
|
|
if (rinfo->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 = rinfo->shadow[i].indirect_grants[j];
|
|
gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
|
|
__free_page(persistent_gnt->page);
|
|
kfree(persistent_gnt);
|
|
}
|
|
|
|
free_shadow:
|
|
kfree(rinfo->shadow[i].grants_used);
|
|
rinfo->shadow[i].grants_used = NULL;
|
|
kfree(rinfo->shadow[i].indirect_grants);
|
|
rinfo->shadow[i].indirect_grants = NULL;
|
|
kfree(rinfo->shadow[i].sg);
|
|
rinfo->shadow[i].sg = NULL;
|
|
}
|
|
|
|
/* No more gnttab callback work. */
|
|
gnttab_cancel_free_callback(&rinfo->callback);
|
|
|
|
/* Flush gnttab callback work. Must be done with no locks held. */
|
|
flush_work(&rinfo->work);
|
|
|
|
/* Free resources associated with old device channel. */
|
|
for (i = 0; i < info->nr_ring_pages; i++) {
|
|
if (rinfo->ring_ref[i] != GRANT_INVALID_REF) {
|
|
gnttab_end_foreign_access(rinfo->ring_ref[i], 0, 0);
|
|
rinfo->ring_ref[i] = GRANT_INVALID_REF;
|
|
}
|
|
}
|
|
free_pages((unsigned long)rinfo->ring.sring, get_order(info->nr_ring_pages * XEN_PAGE_SIZE));
|
|
rinfo->ring.sring = NULL;
|
|
|
|
if (rinfo->irq)
|
|
unbind_from_irqhandler(rinfo->irq, rinfo);
|
|
rinfo->evtchn = rinfo->irq = 0;
|
|
}
|
|
|
|
static void blkif_free(struct blkfront_info *info, int suspend)
|
|
{
|
|
unsigned int i;
|
|
|
|
/* Prevent new requests being issued until we fix things up. */
|
|
info->connected = suspend ?
|
|
BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
|
|
/* No more blkif_request(). */
|
|
if (info->rq)
|
|
blk_mq_stop_hw_queues(info->rq);
|
|
|
|
for (i = 0; i < info->nr_rings; i++)
|
|
blkif_free_ring(&info->rinfo[i]);
|
|
|
|
kfree(info->rinfo);
|
|
info->rinfo = NULL;
|
|
info->nr_rings = 0;
|
|
}
|
|
|
|
struct copy_from_grant {
|
|
const struct blk_shadow *s;
|
|
unsigned int grant_idx;
|
|
unsigned int bvec_offset;
|
|
char *bvec_data;
|
|
};
|
|
|
|
static void blkif_copy_from_grant(unsigned long gfn, unsigned int offset,
|
|
unsigned int len, void *data)
|
|
{
|
|
struct copy_from_grant *info = data;
|
|
char *shared_data;
|
|
/* Convenient aliases */
|
|
const struct blk_shadow *s = info->s;
|
|
|
|
shared_data = kmap_atomic(s->grants_used[info->grant_idx]->page);
|
|
|
|
memcpy(info->bvec_data + info->bvec_offset,
|
|
shared_data + offset, len);
|
|
|
|
info->bvec_offset += len;
|
|
info->grant_idx++;
|
|
|
|
kunmap_atomic(shared_data);
|
|
}
|
|
|
|
static enum blk_req_status blkif_rsp_to_req_status(int rsp)
|
|
{
|
|
switch (rsp)
|
|
{
|
|
case BLKIF_RSP_OKAY:
|
|
return REQ_DONE;
|
|
case BLKIF_RSP_EOPNOTSUPP:
|
|
return REQ_EOPNOTSUPP;
|
|
case BLKIF_RSP_ERROR:
|
|
/* Fallthrough. */
|
|
default:
|
|
return REQ_ERROR;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get the final status of the block request based on two ring response
|
|
*/
|
|
static int blkif_get_final_status(enum blk_req_status s1,
|
|
enum blk_req_status s2)
|
|
{
|
|
BUG_ON(s1 == REQ_WAITING);
|
|
BUG_ON(s2 == REQ_WAITING);
|
|
|
|
if (s1 == REQ_ERROR || s2 == REQ_ERROR)
|
|
return BLKIF_RSP_ERROR;
|
|
else if (s1 == REQ_EOPNOTSUPP || s2 == REQ_EOPNOTSUPP)
|
|
return BLKIF_RSP_EOPNOTSUPP;
|
|
return BLKIF_RSP_OKAY;
|
|
}
|
|
|
|
static bool blkif_completion(unsigned long *id,
|
|
struct blkfront_ring_info *rinfo,
|
|
struct blkif_response *bret)
|
|
{
|
|
int i = 0;
|
|
struct scatterlist *sg;
|
|
int num_sg, num_grant;
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
struct blk_shadow *s = &rinfo->shadow[*id];
|
|
struct copy_from_grant data = {
|
|
.grant_idx = 0,
|
|
};
|
|
|
|
num_grant = s->req.operation == BLKIF_OP_INDIRECT ?
|
|
s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
|
|
|
|
/* The I/O request may be split in two. */
|
|
if (unlikely(s->associated_id != NO_ASSOCIATED_ID)) {
|
|
struct blk_shadow *s2 = &rinfo->shadow[s->associated_id];
|
|
|
|
/* Keep the status of the current response in shadow. */
|
|
s->status = blkif_rsp_to_req_status(bret->status);
|
|
|
|
/* Wait the second response if not yet here. */
|
|
if (s2->status == REQ_WAITING)
|
|
return 0;
|
|
|
|
bret->status = blkif_get_final_status(s->status,
|
|
s2->status);
|
|
|
|
/*
|
|
* All the grants is stored in the first shadow in order
|
|
* to make the completion code simpler.
|
|
*/
|
|
num_grant += s2->req.u.rw.nr_segments;
|
|
|
|
/*
|
|
* The two responses may not come in order. Only the
|
|
* first request will store the scatter-gather list.
|
|
*/
|
|
if (s2->num_sg != 0) {
|
|
/* Update "id" with the ID of the first response. */
|
|
*id = s->associated_id;
|
|
s = s2;
|
|
}
|
|
|
|
/*
|
|
* We don't need anymore the second request, so recycling
|
|
* it now.
|
|
*/
|
|
if (add_id_to_freelist(rinfo, s->associated_id))
|
|
WARN(1, "%s: can't recycle the second part (id = %ld) of the request\n",
|
|
info->gd->disk_name, s->associated_id);
|
|
}
|
|
|
|
data.s = s;
|
|
num_sg = s->num_sg;
|
|
|
|
if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
|
|
for_each_sg(s->sg, sg, num_sg, i) {
|
|
BUG_ON(sg->offset + sg->length > PAGE_SIZE);
|
|
|
|
data.bvec_offset = sg->offset;
|
|
data.bvec_data = kmap_atomic(sg_page(sg));
|
|
|
|
gnttab_foreach_grant_in_range(sg_page(sg),
|
|
sg->offset,
|
|
sg->length,
|
|
blkif_copy_from_grant,
|
|
&data);
|
|
|
|
kunmap_atomic(data.bvec_data);
|
|
}
|
|
}
|
|
/* Add the persistent grant into the list of free grants */
|
|
for (i = 0; i < num_grant; 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, &rinfo->grants);
|
|
rinfo->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, &rinfo->grants);
|
|
}
|
|
}
|
|
if (s->req.operation == BLKIF_OP_INDIRECT) {
|
|
for (i = 0; i < INDIRECT_GREFS(num_grant); 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, &rinfo->grants);
|
|
rinfo->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.
|
|
*/
|
|
if (!info->feature_persistent) {
|
|
indirect_page = s->indirect_grants[i]->page;
|
|
list_add(&indirect_page->lru, &rinfo->indirect_pages);
|
|
}
|
|
s->indirect_grants[i]->gref = GRANT_INVALID_REF;
|
|
list_add_tail(&s->indirect_grants[i]->node, &rinfo->grants);
|
|
}
|
|
}
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
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_ring_info *rinfo = (struct blkfront_ring_info *)dev_id;
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
|
|
if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
|
|
return IRQ_HANDLED;
|
|
|
|
spin_lock_irqsave(&rinfo->ring_lock, flags);
|
|
again:
|
|
rp = rinfo->ring.sring->rsp_prod;
|
|
rmb(); /* Ensure we see queued responses up to 'rp'. */
|
|
|
|
for (i = rinfo->ring.rsp_cons; i != rp; i++) {
|
|
unsigned long id;
|
|
|
|
bret = RING_GET_RESPONSE(&rinfo->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(info)) {
|
|
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 = rinfo->shadow[id].request;
|
|
|
|
if (bret->operation != BLKIF_OP_DISCARD) {
|
|
/*
|
|
* We may need to wait for an extra response if the
|
|
* I/O request is split in 2
|
|
*/
|
|
if (!blkif_completion(&id, rinfo, bret))
|
|
continue;
|
|
}
|
|
|
|
if (add_id_to_freelist(rinfo, id)) {
|
|
WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
|
|
info->gd->disk_name, op_name(bret->operation), id);
|
|
continue;
|
|
}
|
|
|
|
blkif_req(req)->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));
|
|
blkif_req(req)->error = -EOPNOTSUPP;
|
|
info->feature_discard = 0;
|
|
info->feature_secdiscard = 0;
|
|
queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
|
|
queue_flag_clear(QUEUE_FLAG_SECERASE, rq);
|
|
}
|
|
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));
|
|
blkif_req(req)->error = -EOPNOTSUPP;
|
|
}
|
|
if (unlikely(bret->status == BLKIF_RSP_ERROR &&
|
|
rinfo->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));
|
|
blkif_req(req)->error = -EOPNOTSUPP;
|
|
}
|
|
if (unlikely(blkif_req(req)->error)) {
|
|
if (blkif_req(req)->error == -EOPNOTSUPP)
|
|
blkif_req(req)->error = 0;
|
|
info->feature_fua = 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);
|
|
|
|
break;
|
|
default:
|
|
BUG();
|
|
}
|
|
|
|
blk_mq_complete_request(req);
|
|
}
|
|
|
|
rinfo->ring.rsp_cons = i;
|
|
|
|
if (i != rinfo->ring.req_prod_pvt) {
|
|
int more_to_do;
|
|
RING_FINAL_CHECK_FOR_RESPONSES(&rinfo->ring, more_to_do);
|
|
if (more_to_do)
|
|
goto again;
|
|
} else
|
|
rinfo->ring.sring->rsp_event = i + 1;
|
|
|
|
kick_pending_request_queues_locked(rinfo);
|
|
|
|
spin_unlock_irqrestore(&rinfo->ring_lock, flags);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
|
|
static int setup_blkring(struct xenbus_device *dev,
|
|
struct blkfront_ring_info *rinfo)
|
|
{
|
|
struct blkif_sring *sring;
|
|
int err, i;
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE;
|
|
grant_ref_t gref[XENBUS_MAX_RING_GRANTS];
|
|
|
|
for (i = 0; i < info->nr_ring_pages; i++)
|
|
rinfo->ring_ref[i] = GRANT_INVALID_REF;
|
|
|
|
sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
|
|
get_order(ring_size));
|
|
if (!sring) {
|
|
xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
|
|
return -ENOMEM;
|
|
}
|
|
SHARED_RING_INIT(sring);
|
|
FRONT_RING_INIT(&rinfo->ring, sring, ring_size);
|
|
|
|
err = xenbus_grant_ring(dev, rinfo->ring.sring, info->nr_ring_pages, gref);
|
|
if (err < 0) {
|
|
free_pages((unsigned long)sring, get_order(ring_size));
|
|
rinfo->ring.sring = NULL;
|
|
goto fail;
|
|
}
|
|
for (i = 0; i < info->nr_ring_pages; i++)
|
|
rinfo->ring_ref[i] = gref[i];
|
|
|
|
err = xenbus_alloc_evtchn(dev, &rinfo->evtchn);
|
|
if (err)
|
|
goto fail;
|
|
|
|
err = bind_evtchn_to_irqhandler(rinfo->evtchn, blkif_interrupt, 0,
|
|
"blkif", rinfo);
|
|
if (err <= 0) {
|
|
xenbus_dev_fatal(dev, err,
|
|
"bind_evtchn_to_irqhandler failed");
|
|
goto fail;
|
|
}
|
|
rinfo->irq = err;
|
|
|
|
return 0;
|
|
fail:
|
|
blkif_free(info, 0);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Write out per-ring/queue nodes including ring-ref and event-channel, and each
|
|
* ring buffer may have multi pages depending on ->nr_ring_pages.
|
|
*/
|
|
static int write_per_ring_nodes(struct xenbus_transaction xbt,
|
|
struct blkfront_ring_info *rinfo, const char *dir)
|
|
{
|
|
int err;
|
|
unsigned int i;
|
|
const char *message = NULL;
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
|
|
if (info->nr_ring_pages == 1) {
|
|
err = xenbus_printf(xbt, dir, "ring-ref", "%u", rinfo->ring_ref[0]);
|
|
if (err) {
|
|
message = "writing ring-ref";
|
|
goto abort_transaction;
|
|
}
|
|
} else {
|
|
for (i = 0; i < info->nr_ring_pages; i++) {
|
|
char ring_ref_name[RINGREF_NAME_LEN];
|
|
|
|
snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
|
|
err = xenbus_printf(xbt, dir, ring_ref_name,
|
|
"%u", rinfo->ring_ref[i]);
|
|
if (err) {
|
|
message = "writing ring-ref";
|
|
goto abort_transaction;
|
|
}
|
|
}
|
|
}
|
|
|
|
err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
|
|
if (err) {
|
|
message = "writing event-channel";
|
|
goto abort_transaction;
|
|
}
|
|
|
|
return 0;
|
|
|
|
abort_transaction:
|
|
xenbus_transaction_end(xbt, 1);
|
|
if (message)
|
|
xenbus_dev_fatal(info->xbdev, err, "%s", message);
|
|
|
|
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;
|
|
unsigned int i, max_page_order;
|
|
unsigned int ring_page_order;
|
|
|
|
max_page_order = xenbus_read_unsigned(info->xbdev->otherend,
|
|
"max-ring-page-order", 0);
|
|
ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
|
|
info->nr_ring_pages = 1 << ring_page_order;
|
|
|
|
for (i = 0; i < info->nr_rings; i++) {
|
|
struct blkfront_ring_info *rinfo = &info->rinfo[i];
|
|
|
|
/* Create shared ring, alloc event channel. */
|
|
err = setup_blkring(dev, rinfo);
|
|
if (err)
|
|
goto destroy_blkring;
|
|
}
|
|
|
|
again:
|
|
err = xenbus_transaction_start(&xbt);
|
|
if (err) {
|
|
xenbus_dev_fatal(dev, err, "starting transaction");
|
|
goto destroy_blkring;
|
|
}
|
|
|
|
if (info->nr_ring_pages > 1) {
|
|
err = xenbus_printf(xbt, dev->nodename, "ring-page-order", "%u",
|
|
ring_page_order);
|
|
if (err) {
|
|
message = "writing ring-page-order";
|
|
goto abort_transaction;
|
|
}
|
|
}
|
|
|
|
/* We already got the number of queues/rings in _probe */
|
|
if (info->nr_rings == 1) {
|
|
err = write_per_ring_nodes(xbt, &info->rinfo[0], dev->nodename);
|
|
if (err)
|
|
goto destroy_blkring;
|
|
} else {
|
|
char *path;
|
|
size_t pathsize;
|
|
|
|
err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues", "%u",
|
|
info->nr_rings);
|
|
if (err) {
|
|
message = "writing multi-queue-num-queues";
|
|
goto abort_transaction;
|
|
}
|
|
|
|
pathsize = strlen(dev->nodename) + QUEUE_NAME_LEN;
|
|
path = kmalloc(pathsize, GFP_KERNEL);
|
|
if (!path) {
|
|
err = -ENOMEM;
|
|
message = "ENOMEM while writing ring references";
|
|
goto abort_transaction;
|
|
}
|
|
|
|
for (i = 0; i < info->nr_rings; i++) {
|
|
memset(path, 0, pathsize);
|
|
snprintf(path, pathsize, "%s/queue-%u", dev->nodename, i);
|
|
err = write_per_ring_nodes(xbt, &info->rinfo[i], path);
|
|
if (err) {
|
|
kfree(path);
|
|
goto destroy_blkring;
|
|
}
|
|
}
|
|
kfree(path);
|
|
}
|
|
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;
|
|
}
|
|
|
|
for (i = 0; i < info->nr_rings; i++) {
|
|
unsigned int j;
|
|
struct blkfront_ring_info *rinfo = &info->rinfo[i];
|
|
|
|
for (j = 0; j < BLK_RING_SIZE(info); j++)
|
|
rinfo->shadow[j].req.u.rw.id = j + 1;
|
|
rinfo->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
|
|
}
|
|
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);
|
|
|
|
kfree(info);
|
|
dev_set_drvdata(&dev->dev, NULL);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int negotiate_mq(struct blkfront_info *info)
|
|
{
|
|
unsigned int backend_max_queues;
|
|
unsigned int i;
|
|
|
|
BUG_ON(info->nr_rings);
|
|
|
|
/* Check if backend supports multiple queues. */
|
|
backend_max_queues = xenbus_read_unsigned(info->xbdev->otherend,
|
|
"multi-queue-max-queues", 1);
|
|
info->nr_rings = min(backend_max_queues, xen_blkif_max_queues);
|
|
/* We need at least one ring. */
|
|
if (!info->nr_rings)
|
|
info->nr_rings = 1;
|
|
|
|
info->rinfo = kzalloc(sizeof(struct blkfront_ring_info) * info->nr_rings, GFP_KERNEL);
|
|
if (!info->rinfo) {
|
|
xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
for (i = 0; i < info->nr_rings; i++) {
|
|
struct blkfront_ring_info *rinfo;
|
|
|
|
rinfo = &info->rinfo[i];
|
|
INIT_LIST_HEAD(&rinfo->indirect_pages);
|
|
INIT_LIST_HEAD(&rinfo->grants);
|
|
rinfo->dev_info = info;
|
|
INIT_WORK(&rinfo->work, blkif_restart_queue);
|
|
spin_lock_init(&rinfo->ring_lock);
|
|
}
|
|
return 0;
|
|
}
|
|
/**
|
|
* 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;
|
|
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;
|
|
}
|
|
|
|
info->xbdev = dev;
|
|
err = negotiate_mq(info);
|
|
if (err) {
|
|
kfree(info);
|
|
return err;
|
|
}
|
|
|
|
mutex_init(&info->mutex);
|
|
info->vdevice = vdevice;
|
|
info->connected = BLKIF_STATE_DISCONNECTED;
|
|
|
|
/* 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);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void split_bio_end(struct bio *bio)
|
|
{
|
|
struct split_bio *split_bio = bio->bi_private;
|
|
|
|
if (atomic_dec_and_test(&split_bio->pending)) {
|
|
split_bio->bio->bi_phys_segments = 0;
|
|
split_bio->bio->bi_error = bio->bi_error;
|
|
bio_endio(split_bio->bio);
|
|
kfree(split_bio);
|
|
}
|
|
bio_put(bio);
|
|
}
|
|
|
|
static int blkif_recover(struct blkfront_info *info)
|
|
{
|
|
unsigned int i, r_index;
|
|
struct request *req, *n;
|
|
int rc;
|
|
struct bio *bio, *cloned_bio;
|
|
unsigned int segs, offset;
|
|
int pending, size;
|
|
struct split_bio *split_bio;
|
|
|
|
blkfront_gather_backend_features(info);
|
|
/* Reset limits changed by blk_mq_update_nr_hw_queues(). */
|
|
blkif_set_queue_limits(info);
|
|
segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
blk_queue_max_segments(info->rq, segs / GRANTS_PER_PSEG);
|
|
|
|
for (r_index = 0; r_index < info->nr_rings; r_index++) {
|
|
struct blkfront_ring_info *rinfo = &info->rinfo[r_index];
|
|
|
|
rc = blkfront_setup_indirect(rinfo);
|
|
if (rc)
|
|
return rc;
|
|
}
|
|
xenbus_switch_state(info->xbdev, XenbusStateConnected);
|
|
|
|
/* Now safe for us to use the shared ring */
|
|
info->connected = BLKIF_STATE_CONNECTED;
|
|
|
|
for (r_index = 0; r_index < info->nr_rings; r_index++) {
|
|
struct blkfront_ring_info *rinfo;
|
|
|
|
rinfo = &info->rinfo[r_index];
|
|
/* Kick any other new requests queued since we resumed */
|
|
kick_pending_request_queues(rinfo);
|
|
}
|
|
|
|
list_for_each_entry_safe(req, n, &info->requests, queuelist) {
|
|
/* Requeue pending requests (flush or discard) */
|
|
list_del_init(&req->queuelist);
|
|
BUG_ON(req->nr_phys_segments > segs);
|
|
blk_mq_requeue_request(req, false);
|
|
}
|
|
blk_mq_start_stopped_hw_queues(info->rq, true);
|
|
blk_mq_kick_requeue_list(info->rq);
|
|
|
|
while ((bio = bio_list_pop(&info->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 * XEN_PAGE_SIZE) >> 9;
|
|
size = min((unsigned int)(segs * XEN_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);
|
|
}
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
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 = 0;
|
|
unsigned int i, j;
|
|
|
|
dev_dbg(&dev->dev, "blkfront_resume: %s\n", dev->nodename);
|
|
|
|
bio_list_init(&info->bio_list);
|
|
INIT_LIST_HEAD(&info->requests);
|
|
for (i = 0; i < info->nr_rings; i++) {
|
|
struct blkfront_ring_info *rinfo = &info->rinfo[i];
|
|
struct bio_list merge_bio;
|
|
struct blk_shadow *shadow = rinfo->shadow;
|
|
|
|
for (j = 0; j < BLK_RING_SIZE(info); j++) {
|
|
/* Not in use? */
|
|
if (!shadow[j].request)
|
|
continue;
|
|
|
|
/*
|
|
* Get the bios in the request so we can re-queue them.
|
|
*/
|
|
if (req_op(shadow[i].request) == REQ_OP_FLUSH ||
|
|
req_op(shadow[i].request) == REQ_OP_DISCARD ||
|
|
req_op(shadow[i].request) == REQ_OP_SECURE_ERASE ||
|
|
shadow[j].request->cmd_flags & REQ_FUA) {
|
|
/*
|
|
* Flush operations don't contain bios, so
|
|
* we need to requeue the whole request
|
|
*
|
|
* XXX: but this doesn't make any sense for a
|
|
* write with the FUA flag set..
|
|
*/
|
|
list_add(&shadow[j].request->queuelist, &info->requests);
|
|
continue;
|
|
}
|
|
merge_bio.head = shadow[j].request->bio;
|
|
merge_bio.tail = shadow[j].request->biotail;
|
|
bio_list_merge(&info->bio_list, &merge_bio);
|
|
shadow[j].request->bio = NULL;
|
|
blk_mq_end_request(shadow[j].request, 0);
|
|
}
|
|
}
|
|
|
|
blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
|
|
|
|
err = negotiate_mq(info);
|
|
if (err)
|
|
return err;
|
|
|
|
err = talk_to_blkback(dev, info);
|
|
if (!err)
|
|
blk_mq_update_nr_hw_queues(&info->tag_set, info->nr_rings);
|
|
|
|
/*
|
|
* 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;
|
|
|
|
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;
|
|
}
|
|
info->feature_secdiscard =
|
|
!!xenbus_read_unsigned(info->xbdev->otherend, "discard-secure",
|
|
0);
|
|
}
|
|
|
|
static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
|
|
{
|
|
unsigned int psegs, grants;
|
|
int err, i;
|
|
struct blkfront_info *info = rinfo->dev_info;
|
|
|
|
if (info->max_indirect_segments == 0) {
|
|
if (!HAS_EXTRA_REQ)
|
|
grants = BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
else {
|
|
/*
|
|
* When an extra req is required, the maximum
|
|
* grants supported is related to the size of the
|
|
* Linux block segment.
|
|
*/
|
|
grants = GRANTS_PER_PSEG;
|
|
}
|
|
}
|
|
else
|
|
grants = info->max_indirect_segments;
|
|
psegs = DIV_ROUND_UP(grants, GRANTS_PER_PSEG);
|
|
|
|
err = fill_grant_buffer(rinfo,
|
|
(grants + INDIRECT_GREFS(grants)) * BLK_RING_SIZE(info));
|
|
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(grants) * BLK_RING_SIZE(info);
|
|
|
|
BUG_ON(!list_empty(&rinfo->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, &rinfo->indirect_pages);
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < BLK_RING_SIZE(info); i++) {
|
|
rinfo->shadow[i].grants_used = kzalloc(
|
|
sizeof(rinfo->shadow[i].grants_used[0]) * grants,
|
|
GFP_NOIO);
|
|
rinfo->shadow[i].sg = kzalloc(sizeof(rinfo->shadow[i].sg[0]) * psegs, GFP_NOIO);
|
|
if (info->max_indirect_segments)
|
|
rinfo->shadow[i].indirect_grants = kzalloc(
|
|
sizeof(rinfo->shadow[i].indirect_grants[0]) *
|
|
INDIRECT_GREFS(grants),
|
|
GFP_NOIO);
|
|
if ((rinfo->shadow[i].grants_used == NULL) ||
|
|
(rinfo->shadow[i].sg == NULL) ||
|
|
(info->max_indirect_segments &&
|
|
(rinfo->shadow[i].indirect_grants == NULL)))
|
|
goto out_of_memory;
|
|
sg_init_table(rinfo->shadow[i].sg, psegs);
|
|
}
|
|
|
|
|
|
return 0;
|
|
|
|
out_of_memory:
|
|
for (i = 0; i < BLK_RING_SIZE(info); i++) {
|
|
kfree(rinfo->shadow[i].grants_used);
|
|
rinfo->shadow[i].grants_used = NULL;
|
|
kfree(rinfo->shadow[i].sg);
|
|
rinfo->shadow[i].sg = NULL;
|
|
kfree(rinfo->shadow[i].indirect_grants);
|
|
rinfo->shadow[i].indirect_grants = NULL;
|
|
}
|
|
if (!list_empty(&rinfo->indirect_pages)) {
|
|
struct page *indirect_page, *n;
|
|
list_for_each_entry_safe(indirect_page, n, &rinfo->indirect_pages, lru) {
|
|
list_del(&indirect_page->lru);
|
|
__free_page(indirect_page);
|
|
}
|
|
}
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Gather all backend feature-*
|
|
*/
|
|
static void blkfront_gather_backend_features(struct blkfront_info *info)
|
|
{
|
|
unsigned int indirect_segments;
|
|
|
|
info->feature_flush = 0;
|
|
info->feature_fua = 0;
|
|
|
|
/*
|
|
* 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 (xenbus_read_unsigned(info->xbdev->otherend, "feature-barrier", 0)) {
|
|
info->feature_flush = 1;
|
|
info->feature_fua = 1;
|
|
}
|
|
|
|
/*
|
|
* And if there is "feature-flush-cache" use that above
|
|
* barriers.
|
|
*/
|
|
if (xenbus_read_unsigned(info->xbdev->otherend, "feature-flush-cache",
|
|
0)) {
|
|
info->feature_flush = 1;
|
|
info->feature_fua = 0;
|
|
}
|
|
|
|
if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0))
|
|
blkfront_setup_discard(info);
|
|
|
|
info->feature_persistent =
|
|
!!xenbus_read_unsigned(info->xbdev->otherend,
|
|
"feature-persistent", 0);
|
|
|
|
indirect_segments = xenbus_read_unsigned(info->xbdev->otherend,
|
|
"feature-max-indirect-segments", 0);
|
|
if (indirect_segments > xen_blkif_max_segments)
|
|
indirect_segments = xen_blkif_max_segments;
|
|
if (indirect_segments <= BLKIF_MAX_SEGMENTS_PER_REQUEST)
|
|
indirect_segments = 0;
|
|
info->max_indirect_segments = indirect_segments;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
char *envp[] = { "RESIZE=1", NULL };
|
|
int err, i;
|
|
|
|
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);
|
|
kobject_uevent_env(&disk_to_dev(info->gd)->kobj,
|
|
KOBJ_CHANGE, envp);
|
|
|
|
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.
|
|
*/
|
|
physical_sector_size = xenbus_read_unsigned(info->xbdev->otherend,
|
|
"physical-sector-size",
|
|
sector_size);
|
|
blkfront_gather_backend_features(info);
|
|
for (i = 0; i < info->nr_rings; i++) {
|
|
err = blkfront_setup_indirect(&info->rinfo[i]);
|
|
if (err) {
|
|
xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s",
|
|
info->xbdev->otherend);
|
|
blkif_free(info, 0);
|
|
break;
|
|
}
|
|
}
|
|
|
|
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);
|
|
goto fail;
|
|
}
|
|
|
|
xenbus_switch_state(info->xbdev, XenbusStateConnected);
|
|
|
|
/* Kick pending requests. */
|
|
info->connected = BLKIF_STATE_CONNECTED;
|
|
for (i = 0; i < info->nr_rings; i++)
|
|
kick_pending_request_queues(&info->rinfo[i]);
|
|
|
|
device_add_disk(&info->xbdev->dev, info->gd);
|
|
|
|
info->is_ready = 1;
|
|
return;
|
|
|
|
fail:
|
|
blkif_free(info, 0);
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* 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 XenbusStateInitWait:
|
|
if (dev->state != XenbusStateInitialising)
|
|
break;
|
|
if (talk_to_blkback(dev, info))
|
|
break;
|
|
case XenbusStateInitialising:
|
|
case XenbusStateInitialised:
|
|
case XenbusStateReconfiguring:
|
|
case XenbusStateReconfigured:
|
|
case XenbusStateUnknown:
|
|
break;
|
|
|
|
case XenbusStateConnected:
|
|
/*
|
|
* talk_to_blkback sets state to XenbusStateInitialised
|
|
* and blkfront_connect sets it to XenbusStateConnected
|
|
* (if connection went OK).
|
|
*
|
|
* If the backend (or toolstack) decides to poke at backend
|
|
* state (and re-trigger the watch by setting the state repeatedly
|
|
* to XenbusStateConnected (4)) we need to deal with this.
|
|
* This is allowed as this is used to communicate to the guest
|
|
* that the size of disk has changed!
|
|
*/
|
|
if ((dev->state != XenbusStateInitialised) &&
|
|
(dev->state != XenbusStateConnected)) {
|
|
if (talk_to_blkback(dev, info))
|
|
break;
|
|
}
|
|
|
|
blkfront_connect(info);
|
|
break;
|
|
|
|
case XenbusStateClosed:
|
|
if (dev->state == XenbusStateClosed)
|
|
break;
|
|
/* Missed the backend's Closing state -- fallthrough */
|
|
case XenbusStateClosing:
|
|
if (info)
|
|
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;
|
|
int nr_cpus = num_online_cpus();
|
|
|
|
if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
if (xen_blkif_max_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST)
|
|
xen_blkif_max_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
|
|
if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) {
|
|
pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
|
|
xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
|
|
xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER;
|
|
}
|
|
|
|
if (xen_blkif_max_queues > nr_cpus) {
|
|
pr_info("Invalid max_queues (%d), will use default max: %d.\n",
|
|
xen_blkif_max_queues, nr_cpus);
|
|
xen_blkif_max_queues = nr_cpus;
|
|
}
|
|
|
|
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");
|