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![Juergen Gross](/assets/img/avatar_default.png)
Simplify scsifront's ring creation and removal via xenbus_setup_ring() and xenbus_teardown_ring(). Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
1247 lines
31 KiB
C
1247 lines
31 KiB
C
/*
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* Xen SCSI frontend driver
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*
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* Copyright (c) 2008, FUJITSU Limited
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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/module.h>
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#include <linux/kernel.h>
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#include <linux/device.h>
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#include <linux/wait.h>
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#include <linux/interrupt.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/sched.h>
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#include <linux/blkdev.h>
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#include <linux/pfn.h>
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#include <linux/slab.h>
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#include <linux/bitops.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_host.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/interface/grant_table.h>
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#include <xen/interface/io/vscsiif.h>
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#include <xen/interface/io/protocols.h>
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#include <asm/xen/hypervisor.h>
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#define VSCSIFRONT_OP_ADD_LUN 1
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#define VSCSIFRONT_OP_DEL_LUN 2
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#define VSCSIFRONT_OP_READD_LUN 3
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/* Tuning point. */
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#define VSCSIIF_DEFAULT_CMD_PER_LUN 10
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#define VSCSIIF_MAX_TARGET 64
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#define VSCSIIF_MAX_LUN 255
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#define VSCSIIF_RING_SIZE __CONST_RING_SIZE(vscsiif, PAGE_SIZE)
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#define VSCSIIF_MAX_REQS VSCSIIF_RING_SIZE
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#define vscsiif_grants_sg(_sg) (PFN_UP((_sg) * \
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sizeof(struct scsiif_request_segment)))
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struct vscsifrnt_shadow {
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/* command between backend and frontend */
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unsigned char act;
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uint8_t nr_segments;
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uint16_t rqid;
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uint16_t ref_rqid;
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bool inflight;
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unsigned int nr_grants; /* number of grants in gref[] */
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struct scsiif_request_segment *sg; /* scatter/gather elements */
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struct scsiif_request_segment seg[VSCSIIF_SG_TABLESIZE];
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/* Do reset or abort function. */
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wait_queue_head_t wq_reset; /* reset work queue */
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int wait_reset; /* reset work queue condition */
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int32_t rslt_reset; /* reset response status: */
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/* SUCCESS or FAILED or: */
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#define RSLT_RESET_WAITING 0
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#define RSLT_RESET_ERR -1
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/* Requested struct scsi_cmnd is stored from kernel. */
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struct scsi_cmnd *sc;
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int gref[vscsiif_grants_sg(SG_ALL) + SG_ALL];
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};
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struct vscsifrnt_info {
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struct xenbus_device *dev;
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struct Scsi_Host *host;
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enum {
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STATE_INACTIVE,
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STATE_ACTIVE,
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STATE_ERROR
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} host_active;
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unsigned int evtchn;
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unsigned int irq;
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grant_ref_t ring_ref;
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struct vscsiif_front_ring ring;
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struct vscsiif_response ring_rsp;
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spinlock_t shadow_lock;
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DECLARE_BITMAP(shadow_free_bitmap, VSCSIIF_MAX_REQS);
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struct vscsifrnt_shadow *shadow[VSCSIIF_MAX_REQS];
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/* Following items are protected by the host lock. */
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wait_queue_head_t wq_sync;
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wait_queue_head_t wq_pause;
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unsigned int wait_ring_available:1;
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unsigned int waiting_pause:1;
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unsigned int pause:1;
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unsigned callers;
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char dev_state_path[64];
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struct task_struct *curr;
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};
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static DEFINE_MUTEX(scsifront_mutex);
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static void scsifront_wake_up(struct vscsifrnt_info *info)
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{
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info->wait_ring_available = 0;
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wake_up(&info->wq_sync);
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}
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static int scsifront_get_rqid(struct vscsifrnt_info *info)
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{
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unsigned long flags;
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int free;
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spin_lock_irqsave(&info->shadow_lock, flags);
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free = find_first_bit(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
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__clear_bit(free, info->shadow_free_bitmap);
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spin_unlock_irqrestore(&info->shadow_lock, flags);
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return free;
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}
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static int _scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id)
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{
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int empty = bitmap_empty(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
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__set_bit(id, info->shadow_free_bitmap);
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info->shadow[id] = NULL;
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return empty || info->wait_ring_available;
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}
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static void scsifront_put_rqid(struct vscsifrnt_info *info, uint32_t id)
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{
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unsigned long flags;
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int kick;
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spin_lock_irqsave(&info->shadow_lock, flags);
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kick = _scsifront_put_rqid(info, id);
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spin_unlock_irqrestore(&info->shadow_lock, flags);
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if (kick)
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scsifront_wake_up(info);
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}
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static int scsifront_do_request(struct vscsifrnt_info *info,
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struct vscsifrnt_shadow *shadow)
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{
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struct vscsiif_front_ring *ring = &(info->ring);
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struct vscsiif_request *ring_req;
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struct scsi_cmnd *sc = shadow->sc;
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uint32_t id;
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int i, notify;
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if (RING_FULL(&info->ring))
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return -EBUSY;
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id = scsifront_get_rqid(info); /* use id in response */
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if (id >= VSCSIIF_MAX_REQS)
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return -EBUSY;
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info->shadow[id] = shadow;
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shadow->rqid = id;
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ring_req = RING_GET_REQUEST(&(info->ring), ring->req_prod_pvt);
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ring->req_prod_pvt++;
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ring_req->rqid = id;
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ring_req->act = shadow->act;
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ring_req->ref_rqid = shadow->ref_rqid;
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ring_req->nr_segments = shadow->nr_segments;
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ring_req->id = sc->device->id;
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ring_req->lun = sc->device->lun;
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ring_req->channel = sc->device->channel;
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ring_req->cmd_len = sc->cmd_len;
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BUG_ON(sc->cmd_len > VSCSIIF_MAX_COMMAND_SIZE);
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memcpy(ring_req->cmnd, sc->cmnd, sc->cmd_len);
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ring_req->sc_data_direction = (uint8_t)sc->sc_data_direction;
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ring_req->timeout_per_command = scsi_cmd_to_rq(sc)->timeout / HZ;
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for (i = 0; i < (shadow->nr_segments & ~VSCSIIF_SG_GRANT); i++)
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ring_req->seg[i] = shadow->seg[i];
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shadow->inflight = true;
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RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(ring, notify);
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if (notify)
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notify_remote_via_irq(info->irq);
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return 0;
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}
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static void scsifront_set_error(struct vscsifrnt_info *info, const char *msg)
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{
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shost_printk(KERN_ERR, info->host, KBUILD_MODNAME "%s\n"
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"Disabling device for further use\n", msg);
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info->host_active = STATE_ERROR;
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}
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static void scsifront_gnttab_done(struct vscsifrnt_info *info,
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struct vscsifrnt_shadow *shadow)
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{
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int i;
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if (shadow->sc->sc_data_direction == DMA_NONE)
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return;
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for (i = 0; i < shadow->nr_grants; i++) {
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if (unlikely(!gnttab_try_end_foreign_access(shadow->gref[i]))) {
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scsifront_set_error(info, "grant still in use by backend");
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return;
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}
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}
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kfree(shadow->sg);
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}
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static unsigned int scsifront_host_byte(int32_t rslt)
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{
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switch (XEN_VSCSIIF_RSLT_HOST(rslt)) {
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case XEN_VSCSIIF_RSLT_HOST_OK:
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return DID_OK;
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case XEN_VSCSIIF_RSLT_HOST_NO_CONNECT:
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return DID_NO_CONNECT;
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case XEN_VSCSIIF_RSLT_HOST_BUS_BUSY:
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return DID_BUS_BUSY;
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case XEN_VSCSIIF_RSLT_HOST_TIME_OUT:
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return DID_TIME_OUT;
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case XEN_VSCSIIF_RSLT_HOST_BAD_TARGET:
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return DID_BAD_TARGET;
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case XEN_VSCSIIF_RSLT_HOST_ABORT:
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return DID_ABORT;
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case XEN_VSCSIIF_RSLT_HOST_PARITY:
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return DID_PARITY;
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case XEN_VSCSIIF_RSLT_HOST_ERROR:
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return DID_ERROR;
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case XEN_VSCSIIF_RSLT_HOST_RESET:
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return DID_RESET;
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case XEN_VSCSIIF_RSLT_HOST_BAD_INTR:
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return DID_BAD_INTR;
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case XEN_VSCSIIF_RSLT_HOST_PASSTHROUGH:
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return DID_PASSTHROUGH;
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case XEN_VSCSIIF_RSLT_HOST_SOFT_ERROR:
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return DID_SOFT_ERROR;
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case XEN_VSCSIIF_RSLT_HOST_IMM_RETRY:
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return DID_IMM_RETRY;
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case XEN_VSCSIIF_RSLT_HOST_REQUEUE:
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return DID_REQUEUE;
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case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_DISRUPTED:
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return DID_TRANSPORT_DISRUPTED;
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case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_FAILFAST:
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return DID_TRANSPORT_FAILFAST;
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case XEN_VSCSIIF_RSLT_HOST_TARGET_FAILURE:
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return DID_TARGET_FAILURE;
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case XEN_VSCSIIF_RSLT_HOST_NEXUS_FAILURE:
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return DID_NEXUS_FAILURE;
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case XEN_VSCSIIF_RSLT_HOST_ALLOC_FAILURE:
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return DID_ALLOC_FAILURE;
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case XEN_VSCSIIF_RSLT_HOST_MEDIUM_ERROR:
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return DID_MEDIUM_ERROR;
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case XEN_VSCSIIF_RSLT_HOST_TRANSPORT_MARGINAL:
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return DID_TRANSPORT_MARGINAL;
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default:
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return DID_ERROR;
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}
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}
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static void scsifront_cdb_cmd_done(struct vscsifrnt_info *info,
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struct vscsiif_response *ring_rsp)
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{
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struct vscsifrnt_shadow *shadow;
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struct scsi_cmnd *sc;
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uint32_t id;
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uint8_t sense_len;
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id = ring_rsp->rqid;
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shadow = info->shadow[id];
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sc = shadow->sc;
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BUG_ON(sc == NULL);
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scsifront_gnttab_done(info, shadow);
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if (info->host_active == STATE_ERROR)
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return;
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scsifront_put_rqid(info, id);
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set_host_byte(sc, scsifront_host_byte(ring_rsp->rslt));
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set_status_byte(sc, XEN_VSCSIIF_RSLT_STATUS(ring_rsp->rslt));
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scsi_set_resid(sc, ring_rsp->residual_len);
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sense_len = min_t(uint8_t, VSCSIIF_SENSE_BUFFERSIZE,
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ring_rsp->sense_len);
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if (sense_len)
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memcpy(sc->sense_buffer, ring_rsp->sense_buffer, sense_len);
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scsi_done(sc);
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}
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static void scsifront_sync_cmd_done(struct vscsifrnt_info *info,
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struct vscsiif_response *ring_rsp)
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{
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uint16_t id = ring_rsp->rqid;
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unsigned long flags;
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struct vscsifrnt_shadow *shadow = info->shadow[id];
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int kick;
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spin_lock_irqsave(&info->shadow_lock, flags);
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shadow->wait_reset = 1;
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switch (shadow->rslt_reset) {
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case RSLT_RESET_WAITING:
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if (ring_rsp->rslt == XEN_VSCSIIF_RSLT_RESET_SUCCESS)
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shadow->rslt_reset = SUCCESS;
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else
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shadow->rslt_reset = FAILED;
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break;
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case RSLT_RESET_ERR:
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kick = _scsifront_put_rqid(info, id);
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spin_unlock_irqrestore(&info->shadow_lock, flags);
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kfree(shadow);
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if (kick)
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scsifront_wake_up(info);
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return;
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default:
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scsifront_set_error(info, "bad reset state");
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break;
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}
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spin_unlock_irqrestore(&info->shadow_lock, flags);
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wake_up(&shadow->wq_reset);
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}
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static void scsifront_do_response(struct vscsifrnt_info *info,
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struct vscsiif_response *ring_rsp)
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{
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struct vscsifrnt_shadow *shadow;
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if (ring_rsp->rqid >= VSCSIIF_MAX_REQS ||
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!info->shadow[ring_rsp->rqid]->inflight) {
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scsifront_set_error(info, "illegal rqid returned by backend!");
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return;
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}
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shadow = info->shadow[ring_rsp->rqid];
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shadow->inflight = false;
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if (shadow->act == VSCSIIF_ACT_SCSI_CDB)
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scsifront_cdb_cmd_done(info, ring_rsp);
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else
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scsifront_sync_cmd_done(info, ring_rsp);
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}
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static int scsifront_ring_drain(struct vscsifrnt_info *info,
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unsigned int *eoiflag)
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{
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struct vscsiif_response ring_rsp;
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RING_IDX i, rp;
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int more_to_do = 0;
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rp = READ_ONCE(info->ring.sring->rsp_prod);
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virt_rmb(); /* ordering required respective to backend */
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if (RING_RESPONSE_PROD_OVERFLOW(&info->ring, rp)) {
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scsifront_set_error(info, "illegal number of responses");
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return 0;
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}
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for (i = info->ring.rsp_cons; i != rp; i++) {
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RING_COPY_RESPONSE(&info->ring, i, &ring_rsp);
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scsifront_do_response(info, &ring_rsp);
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if (info->host_active == STATE_ERROR)
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return 0;
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*eoiflag &= ~XEN_EOI_FLAG_SPURIOUS;
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}
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info->ring.rsp_cons = i;
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if (i != info->ring.req_prod_pvt)
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RING_FINAL_CHECK_FOR_RESPONSES(&info->ring, more_to_do);
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else
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info->ring.sring->rsp_event = i + 1;
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return more_to_do;
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}
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static int scsifront_cmd_done(struct vscsifrnt_info *info,
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unsigned int *eoiflag)
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{
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int more_to_do;
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unsigned long flags;
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spin_lock_irqsave(info->host->host_lock, flags);
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more_to_do = scsifront_ring_drain(info, eoiflag);
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info->wait_ring_available = 0;
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spin_unlock_irqrestore(info->host->host_lock, flags);
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wake_up(&info->wq_sync);
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return more_to_do;
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}
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static irqreturn_t scsifront_irq_fn(int irq, void *dev_id)
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{
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struct vscsifrnt_info *info = dev_id;
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unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
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if (info->host_active == STATE_ERROR) {
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xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
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return IRQ_HANDLED;
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}
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while (scsifront_cmd_done(info, &eoiflag))
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/* Yield point for this unbounded loop. */
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cond_resched();
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xen_irq_lateeoi(irq, eoiflag);
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return IRQ_HANDLED;
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}
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static void scsifront_finish_all(struct vscsifrnt_info *info)
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{
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unsigned int i, dummy;
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struct vscsiif_response resp;
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scsifront_ring_drain(info, &dummy);
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for (i = 0; i < VSCSIIF_MAX_REQS; i++) {
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if (test_bit(i, info->shadow_free_bitmap))
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continue;
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resp.rqid = i;
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resp.sense_len = 0;
|
|
resp.rslt = DID_RESET << 16;
|
|
resp.residual_len = 0;
|
|
scsifront_do_response(info, &resp);
|
|
}
|
|
}
|
|
|
|
static int map_data_for_request(struct vscsifrnt_info *info,
|
|
struct scsi_cmnd *sc,
|
|
struct vscsifrnt_shadow *shadow)
|
|
{
|
|
grant_ref_t gref_head;
|
|
struct page *page;
|
|
int err, ref, ref_cnt = 0;
|
|
int grant_ro = (sc->sc_data_direction == DMA_TO_DEVICE);
|
|
unsigned int i, off, len, bytes;
|
|
unsigned int data_len = scsi_bufflen(sc);
|
|
unsigned int data_grants = 0, seg_grants = 0;
|
|
struct scatterlist *sg;
|
|
struct scsiif_request_segment *seg;
|
|
|
|
if (sc->sc_data_direction == DMA_NONE || !data_len)
|
|
return 0;
|
|
|
|
scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i)
|
|
data_grants += PFN_UP(sg->offset + sg->length);
|
|
|
|
if (data_grants > VSCSIIF_SG_TABLESIZE) {
|
|
if (data_grants > info->host->sg_tablesize) {
|
|
shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
|
|
"Unable to map request_buffer for command!\n");
|
|
return -E2BIG;
|
|
}
|
|
seg_grants = vscsiif_grants_sg(data_grants);
|
|
shadow->sg = kcalloc(data_grants,
|
|
sizeof(struct scsiif_request_segment), GFP_ATOMIC);
|
|
if (!shadow->sg)
|
|
return -ENOMEM;
|
|
}
|
|
seg = shadow->sg ? : shadow->seg;
|
|
|
|
err = gnttab_alloc_grant_references(seg_grants + data_grants,
|
|
&gref_head);
|
|
if (err) {
|
|
kfree(shadow->sg);
|
|
shost_printk(KERN_ERR, info->host, KBUILD_MODNAME
|
|
"gnttab_alloc_grant_references() error\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
if (seg_grants) {
|
|
page = virt_to_page(seg);
|
|
off = offset_in_page(seg);
|
|
len = sizeof(struct scsiif_request_segment) * data_grants;
|
|
while (len > 0) {
|
|
bytes = min_t(unsigned int, len, PAGE_SIZE - off);
|
|
|
|
ref = gnttab_claim_grant_reference(&gref_head);
|
|
BUG_ON(ref == -ENOSPC);
|
|
|
|
gnttab_grant_foreign_access_ref(ref,
|
|
info->dev->otherend_id,
|
|
xen_page_to_gfn(page), 1);
|
|
shadow->gref[ref_cnt] = ref;
|
|
shadow->seg[ref_cnt].gref = ref;
|
|
shadow->seg[ref_cnt].offset = (uint16_t)off;
|
|
shadow->seg[ref_cnt].length = (uint16_t)bytes;
|
|
|
|
page++;
|
|
len -= bytes;
|
|
off = 0;
|
|
ref_cnt++;
|
|
}
|
|
BUG_ON(seg_grants < ref_cnt);
|
|
seg_grants = ref_cnt;
|
|
}
|
|
|
|
scsi_for_each_sg(sc, sg, scsi_sg_count(sc), i) {
|
|
page = sg_page(sg);
|
|
off = sg->offset;
|
|
len = sg->length;
|
|
|
|
while (len > 0 && data_len > 0) {
|
|
/*
|
|
* sg sends a scatterlist that is larger than
|
|
* the data_len it wants transferred for certain
|
|
* IO sizes.
|
|
*/
|
|
bytes = min_t(unsigned int, len, PAGE_SIZE - off);
|
|
bytes = min(bytes, data_len);
|
|
|
|
ref = gnttab_claim_grant_reference(&gref_head);
|
|
BUG_ON(ref == -ENOSPC);
|
|
|
|
gnttab_grant_foreign_access_ref(ref,
|
|
info->dev->otherend_id,
|
|
xen_page_to_gfn(page),
|
|
grant_ro);
|
|
|
|
shadow->gref[ref_cnt] = ref;
|
|
seg->gref = ref;
|
|
seg->offset = (uint16_t)off;
|
|
seg->length = (uint16_t)bytes;
|
|
|
|
page++;
|
|
seg++;
|
|
len -= bytes;
|
|
data_len -= bytes;
|
|
off = 0;
|
|
ref_cnt++;
|
|
}
|
|
}
|
|
|
|
if (seg_grants)
|
|
shadow->nr_segments = VSCSIIF_SG_GRANT | seg_grants;
|
|
else
|
|
shadow->nr_segments = (uint8_t)ref_cnt;
|
|
shadow->nr_grants = ref_cnt;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int scsifront_enter(struct vscsifrnt_info *info)
|
|
{
|
|
if (info->pause)
|
|
return 1;
|
|
info->callers++;
|
|
return 0;
|
|
}
|
|
|
|
static void scsifront_return(struct vscsifrnt_info *info)
|
|
{
|
|
info->callers--;
|
|
if (info->callers)
|
|
return;
|
|
|
|
if (!info->waiting_pause)
|
|
return;
|
|
|
|
info->waiting_pause = 0;
|
|
wake_up(&info->wq_pause);
|
|
}
|
|
|
|
static int scsifront_queuecommand(struct Scsi_Host *shost,
|
|
struct scsi_cmnd *sc)
|
|
{
|
|
struct vscsifrnt_info *info = shost_priv(shost);
|
|
struct vscsifrnt_shadow *shadow = scsi_cmd_priv(sc);
|
|
unsigned long flags;
|
|
int err;
|
|
|
|
if (info->host_active == STATE_ERROR)
|
|
return SCSI_MLQUEUE_HOST_BUSY;
|
|
|
|
sc->result = 0;
|
|
|
|
shadow->sc = sc;
|
|
shadow->act = VSCSIIF_ACT_SCSI_CDB;
|
|
|
|
spin_lock_irqsave(shost->host_lock, flags);
|
|
if (scsifront_enter(info)) {
|
|
spin_unlock_irqrestore(shost->host_lock, flags);
|
|
return SCSI_MLQUEUE_HOST_BUSY;
|
|
}
|
|
|
|
err = map_data_for_request(info, sc, shadow);
|
|
if (err < 0) {
|
|
pr_debug("%s: err %d\n", __func__, err);
|
|
scsifront_return(info);
|
|
spin_unlock_irqrestore(shost->host_lock, flags);
|
|
if (err == -ENOMEM)
|
|
return SCSI_MLQUEUE_HOST_BUSY;
|
|
sc->result = DID_ERROR << 16;
|
|
scsi_done(sc);
|
|
return 0;
|
|
}
|
|
|
|
if (scsifront_do_request(info, shadow)) {
|
|
scsifront_gnttab_done(info, shadow);
|
|
goto busy;
|
|
}
|
|
|
|
scsifront_return(info);
|
|
spin_unlock_irqrestore(shost->host_lock, flags);
|
|
|
|
return 0;
|
|
|
|
busy:
|
|
scsifront_return(info);
|
|
spin_unlock_irqrestore(shost->host_lock, flags);
|
|
pr_debug("%s: busy\n", __func__);
|
|
return SCSI_MLQUEUE_HOST_BUSY;
|
|
}
|
|
|
|
/*
|
|
* Any exception handling (reset or abort) must be forwarded to the backend.
|
|
* We have to wait until an answer is returned. This answer contains the
|
|
* result to be returned to the requestor.
|
|
*/
|
|
static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
|
|
{
|
|
struct Scsi_Host *host = sc->device->host;
|
|
struct vscsifrnt_info *info = shost_priv(host);
|
|
struct vscsifrnt_shadow *shadow, *s = scsi_cmd_priv(sc);
|
|
int err = 0;
|
|
|
|
if (info->host_active == STATE_ERROR)
|
|
return FAILED;
|
|
|
|
shadow = kzalloc(sizeof(*shadow), GFP_NOIO);
|
|
if (!shadow)
|
|
return FAILED;
|
|
|
|
shadow->act = act;
|
|
shadow->rslt_reset = RSLT_RESET_WAITING;
|
|
shadow->sc = sc;
|
|
shadow->ref_rqid = s->rqid;
|
|
init_waitqueue_head(&shadow->wq_reset);
|
|
|
|
spin_lock_irq(host->host_lock);
|
|
|
|
for (;;) {
|
|
if (scsifront_enter(info))
|
|
goto fail;
|
|
|
|
if (!scsifront_do_request(info, shadow))
|
|
break;
|
|
|
|
scsifront_return(info);
|
|
if (err)
|
|
goto fail;
|
|
info->wait_ring_available = 1;
|
|
spin_unlock_irq(host->host_lock);
|
|
err = wait_event_interruptible(info->wq_sync,
|
|
!info->wait_ring_available);
|
|
spin_lock_irq(host->host_lock);
|
|
}
|
|
|
|
spin_unlock_irq(host->host_lock);
|
|
err = wait_event_interruptible(shadow->wq_reset, shadow->wait_reset);
|
|
spin_lock_irq(host->host_lock);
|
|
|
|
if (!err) {
|
|
err = shadow->rslt_reset;
|
|
scsifront_put_rqid(info, shadow->rqid);
|
|
kfree(shadow);
|
|
} else {
|
|
spin_lock(&info->shadow_lock);
|
|
shadow->rslt_reset = RSLT_RESET_ERR;
|
|
spin_unlock(&info->shadow_lock);
|
|
err = FAILED;
|
|
}
|
|
|
|
scsifront_return(info);
|
|
spin_unlock_irq(host->host_lock);
|
|
return err;
|
|
|
|
fail:
|
|
spin_unlock_irq(host->host_lock);
|
|
kfree(shadow);
|
|
return FAILED;
|
|
}
|
|
|
|
static int scsifront_eh_abort_handler(struct scsi_cmnd *sc)
|
|
{
|
|
pr_debug("%s\n", __func__);
|
|
return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_ABORT);
|
|
}
|
|
|
|
static int scsifront_dev_reset_handler(struct scsi_cmnd *sc)
|
|
{
|
|
pr_debug("%s\n", __func__);
|
|
return scsifront_action_handler(sc, VSCSIIF_ACT_SCSI_RESET);
|
|
}
|
|
|
|
static int scsifront_sdev_configure(struct scsi_device *sdev)
|
|
{
|
|
struct vscsifrnt_info *info = shost_priv(sdev->host);
|
|
int err;
|
|
|
|
if (info->host_active == STATE_ERROR)
|
|
return -EIO;
|
|
|
|
if (info && current == info->curr) {
|
|
err = xenbus_printf(XBT_NIL, info->dev->nodename,
|
|
info->dev_state_path, "%d", XenbusStateConnected);
|
|
if (err) {
|
|
xenbus_dev_error(info->dev, err,
|
|
"%s: writing dev_state_path", __func__);
|
|
return err;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void scsifront_sdev_destroy(struct scsi_device *sdev)
|
|
{
|
|
struct vscsifrnt_info *info = shost_priv(sdev->host);
|
|
int err;
|
|
|
|
if (info && current == info->curr) {
|
|
err = xenbus_printf(XBT_NIL, info->dev->nodename,
|
|
info->dev_state_path, "%d", XenbusStateClosed);
|
|
if (err)
|
|
xenbus_dev_error(info->dev, err,
|
|
"%s: writing dev_state_path", __func__);
|
|
}
|
|
}
|
|
|
|
static struct scsi_host_template scsifront_sht = {
|
|
.module = THIS_MODULE,
|
|
.name = "Xen SCSI frontend driver",
|
|
.queuecommand = scsifront_queuecommand,
|
|
.eh_abort_handler = scsifront_eh_abort_handler,
|
|
.eh_device_reset_handler = scsifront_dev_reset_handler,
|
|
.slave_configure = scsifront_sdev_configure,
|
|
.slave_destroy = scsifront_sdev_destroy,
|
|
.cmd_per_lun = VSCSIIF_DEFAULT_CMD_PER_LUN,
|
|
.can_queue = VSCSIIF_MAX_REQS,
|
|
.this_id = -1,
|
|
.cmd_size = sizeof(struct vscsifrnt_shadow),
|
|
.sg_tablesize = VSCSIIF_SG_TABLESIZE,
|
|
.proc_name = "scsifront",
|
|
};
|
|
|
|
static int scsifront_alloc_ring(struct vscsifrnt_info *info)
|
|
{
|
|
struct xenbus_device *dev = info->dev;
|
|
struct vscsiif_sring *sring;
|
|
int err;
|
|
|
|
/***** Frontend to Backend ring start *****/
|
|
err = xenbus_setup_ring(dev, GFP_KERNEL, (void **)&sring, 1,
|
|
&info->ring_ref);
|
|
if (err)
|
|
return err;
|
|
|
|
XEN_FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
|
|
|
|
err = xenbus_alloc_evtchn(dev, &info->evtchn);
|
|
if (err) {
|
|
xenbus_dev_fatal(dev, err, "xenbus_alloc_evtchn");
|
|
goto free_gnttab;
|
|
}
|
|
|
|
err = bind_evtchn_to_irq_lateeoi(info->evtchn);
|
|
if (err <= 0) {
|
|
xenbus_dev_fatal(dev, err, "bind_evtchn_to_irq");
|
|
goto free_gnttab;
|
|
}
|
|
|
|
info->irq = err;
|
|
|
|
err = request_threaded_irq(info->irq, NULL, scsifront_irq_fn,
|
|
IRQF_ONESHOT, "scsifront", info);
|
|
if (err) {
|
|
xenbus_dev_fatal(dev, err, "request_threaded_irq");
|
|
goto free_irq;
|
|
}
|
|
|
|
return 0;
|
|
|
|
/* free resource */
|
|
free_irq:
|
|
unbind_from_irqhandler(info->irq, info);
|
|
free_gnttab:
|
|
xenbus_teardown_ring((void **)&sring, 1, &info->ring_ref);
|
|
|
|
return err;
|
|
}
|
|
|
|
static void scsifront_free_ring(struct vscsifrnt_info *info)
|
|
{
|
|
unbind_from_irqhandler(info->irq, info);
|
|
xenbus_teardown_ring((void **)&info->ring.sring, 1, &info->ring_ref);
|
|
}
|
|
|
|
static int scsifront_init_ring(struct vscsifrnt_info *info)
|
|
{
|
|
struct xenbus_device *dev = info->dev;
|
|
struct xenbus_transaction xbt;
|
|
int err;
|
|
|
|
pr_debug("%s\n", __func__);
|
|
|
|
err = scsifront_alloc_ring(info);
|
|
if (err)
|
|
return err;
|
|
pr_debug("%s: %u %u\n", __func__, info->ring_ref, info->evtchn);
|
|
|
|
again:
|
|
err = xenbus_transaction_start(&xbt);
|
|
if (err)
|
|
xenbus_dev_fatal(dev, err, "starting transaction");
|
|
|
|
err = xenbus_printf(xbt, dev->nodename, "ring-ref", "%u",
|
|
info->ring_ref);
|
|
if (err) {
|
|
xenbus_dev_fatal(dev, err, "%s", "writing ring-ref");
|
|
goto fail;
|
|
}
|
|
|
|
err = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
|
|
info->evtchn);
|
|
|
|
if (err) {
|
|
xenbus_dev_fatal(dev, err, "%s", "writing event-channel");
|
|
goto fail;
|
|
}
|
|
|
|
err = xenbus_transaction_end(xbt, 0);
|
|
if (err) {
|
|
if (err == -EAGAIN)
|
|
goto again;
|
|
xenbus_dev_fatal(dev, err, "completing transaction");
|
|
goto free_sring;
|
|
}
|
|
|
|
return 0;
|
|
|
|
fail:
|
|
xenbus_transaction_end(xbt, 1);
|
|
free_sring:
|
|
scsifront_free_ring(info);
|
|
|
|
return err;
|
|
}
|
|
|
|
|
|
static int scsifront_probe(struct xenbus_device *dev,
|
|
const struct xenbus_device_id *id)
|
|
{
|
|
struct vscsifrnt_info *info;
|
|
struct Scsi_Host *host;
|
|
int err = -ENOMEM;
|
|
char name[TASK_COMM_LEN];
|
|
|
|
host = scsi_host_alloc(&scsifront_sht, sizeof(*info));
|
|
if (!host) {
|
|
xenbus_dev_fatal(dev, err, "fail to allocate scsi host");
|
|
return err;
|
|
}
|
|
info = (struct vscsifrnt_info *)host->hostdata;
|
|
|
|
dev_set_drvdata(&dev->dev, info);
|
|
info->dev = dev;
|
|
|
|
bitmap_fill(info->shadow_free_bitmap, VSCSIIF_MAX_REQS);
|
|
|
|
err = scsifront_init_ring(info);
|
|
if (err) {
|
|
scsi_host_put(host);
|
|
return err;
|
|
}
|
|
|
|
init_waitqueue_head(&info->wq_sync);
|
|
init_waitqueue_head(&info->wq_pause);
|
|
spin_lock_init(&info->shadow_lock);
|
|
|
|
snprintf(name, TASK_COMM_LEN, "vscsiif.%d", host->host_no);
|
|
|
|
host->max_id = VSCSIIF_MAX_TARGET;
|
|
host->max_channel = 0;
|
|
host->max_lun = VSCSIIF_MAX_LUN;
|
|
host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512;
|
|
host->max_cmd_len = VSCSIIF_MAX_COMMAND_SIZE;
|
|
|
|
err = scsi_add_host(host, &dev->dev);
|
|
if (err) {
|
|
dev_err(&dev->dev, "fail to add scsi host %d\n", err);
|
|
goto free_sring;
|
|
}
|
|
info->host = host;
|
|
info->host_active = STATE_ACTIVE;
|
|
|
|
xenbus_switch_state(dev, XenbusStateInitialised);
|
|
|
|
return 0;
|
|
|
|
free_sring:
|
|
scsifront_free_ring(info);
|
|
scsi_host_put(host);
|
|
return err;
|
|
}
|
|
|
|
static int scsifront_resume(struct xenbus_device *dev)
|
|
{
|
|
struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
|
|
struct Scsi_Host *host = info->host;
|
|
int err;
|
|
|
|
spin_lock_irq(host->host_lock);
|
|
|
|
/* Finish all still pending commands. */
|
|
scsifront_finish_all(info);
|
|
|
|
spin_unlock_irq(host->host_lock);
|
|
|
|
/* Reconnect to dom0. */
|
|
scsifront_free_ring(info);
|
|
err = scsifront_init_ring(info);
|
|
if (err) {
|
|
dev_err(&dev->dev, "fail to resume %d\n", err);
|
|
scsi_host_put(host);
|
|
return err;
|
|
}
|
|
|
|
xenbus_switch_state(dev, XenbusStateInitialised);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int scsifront_suspend(struct xenbus_device *dev)
|
|
{
|
|
struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
|
|
struct Scsi_Host *host = info->host;
|
|
int err = 0;
|
|
|
|
/* No new commands for the backend. */
|
|
spin_lock_irq(host->host_lock);
|
|
info->pause = 1;
|
|
while (info->callers && !err) {
|
|
info->waiting_pause = 1;
|
|
info->wait_ring_available = 0;
|
|
spin_unlock_irq(host->host_lock);
|
|
wake_up(&info->wq_sync);
|
|
err = wait_event_interruptible(info->wq_pause,
|
|
!info->waiting_pause);
|
|
spin_lock_irq(host->host_lock);
|
|
}
|
|
spin_unlock_irq(host->host_lock);
|
|
return err;
|
|
}
|
|
|
|
static int scsifront_remove(struct xenbus_device *dev)
|
|
{
|
|
struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
|
|
|
|
pr_debug("%s: %s removed\n", __func__, dev->nodename);
|
|
|
|
mutex_lock(&scsifront_mutex);
|
|
if (info->host_active != STATE_INACTIVE) {
|
|
/* Scsi_host not yet removed */
|
|
scsi_remove_host(info->host);
|
|
info->host_active = STATE_INACTIVE;
|
|
}
|
|
mutex_unlock(&scsifront_mutex);
|
|
|
|
scsifront_free_ring(info);
|
|
scsi_host_put(info->host);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void scsifront_disconnect(struct vscsifrnt_info *info)
|
|
{
|
|
struct xenbus_device *dev = info->dev;
|
|
struct Scsi_Host *host = info->host;
|
|
|
|
pr_debug("%s: %s disconnect\n", __func__, dev->nodename);
|
|
|
|
/*
|
|
* When this function is executed, all devices of
|
|
* Frontend have been deleted.
|
|
* Therefore, it need not block I/O before remove_host.
|
|
*/
|
|
|
|
mutex_lock(&scsifront_mutex);
|
|
if (info->host_active != STATE_INACTIVE) {
|
|
scsi_remove_host(host);
|
|
info->host_active = STATE_INACTIVE;
|
|
}
|
|
mutex_unlock(&scsifront_mutex);
|
|
|
|
xenbus_frontend_closed(dev);
|
|
}
|
|
|
|
static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op)
|
|
{
|
|
struct xenbus_device *dev = info->dev;
|
|
int i, err = 0;
|
|
char str[64];
|
|
char **dir;
|
|
unsigned int dir_n = 0;
|
|
unsigned int device_state;
|
|
unsigned int hst, chn, tgt, lun;
|
|
struct scsi_device *sdev;
|
|
|
|
if (info->host_active == STATE_ERROR)
|
|
return;
|
|
|
|
dir = xenbus_directory(XBT_NIL, dev->otherend, "vscsi-devs", &dir_n);
|
|
if (IS_ERR(dir))
|
|
return;
|
|
|
|
/* mark current task as the one allowed to modify device states */
|
|
BUG_ON(info->curr);
|
|
info->curr = current;
|
|
|
|
for (i = 0; i < dir_n; i++) {
|
|
/* read status */
|
|
snprintf(str, sizeof(str), "vscsi-devs/%s/state", dir[i]);
|
|
err = xenbus_scanf(XBT_NIL, dev->otherend, str, "%u",
|
|
&device_state);
|
|
if (XENBUS_EXIST_ERR(err))
|
|
continue;
|
|
|
|
/* virtual SCSI device */
|
|
snprintf(str, sizeof(str), "vscsi-devs/%s/v-dev", dir[i]);
|
|
err = xenbus_scanf(XBT_NIL, dev->otherend, str,
|
|
"%u:%u:%u:%u", &hst, &chn, &tgt, &lun);
|
|
if (XENBUS_EXIST_ERR(err))
|
|
continue;
|
|
|
|
/*
|
|
* Front device state path, used in slave_configure called
|
|
* on successfull scsi_add_device, and in slave_destroy called
|
|
* on remove of a device.
|
|
*/
|
|
snprintf(info->dev_state_path, sizeof(info->dev_state_path),
|
|
"vscsi-devs/%s/state", dir[i]);
|
|
|
|
switch (op) {
|
|
case VSCSIFRONT_OP_ADD_LUN:
|
|
if (device_state != XenbusStateInitialised)
|
|
break;
|
|
|
|
if (scsi_add_device(info->host, chn, tgt, lun)) {
|
|
dev_err(&dev->dev, "scsi_add_device\n");
|
|
err = xenbus_printf(XBT_NIL, dev->nodename,
|
|
info->dev_state_path,
|
|
"%d", XenbusStateClosed);
|
|
if (err)
|
|
xenbus_dev_error(dev, err,
|
|
"%s: writing dev_state_path", __func__);
|
|
}
|
|
break;
|
|
case VSCSIFRONT_OP_DEL_LUN:
|
|
if (device_state != XenbusStateClosing)
|
|
break;
|
|
|
|
sdev = scsi_device_lookup(info->host, chn, tgt, lun);
|
|
if (sdev) {
|
|
scsi_remove_device(sdev);
|
|
scsi_device_put(sdev);
|
|
}
|
|
break;
|
|
case VSCSIFRONT_OP_READD_LUN:
|
|
if (device_state == XenbusStateConnected) {
|
|
err = xenbus_printf(XBT_NIL, dev->nodename,
|
|
info->dev_state_path,
|
|
"%d", XenbusStateConnected);
|
|
if (err)
|
|
xenbus_dev_error(dev, err,
|
|
"%s: writing dev_state_path", __func__);
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
info->curr = NULL;
|
|
|
|
kfree(dir);
|
|
}
|
|
|
|
static void scsifront_read_backend_params(struct xenbus_device *dev,
|
|
struct vscsifrnt_info *info)
|
|
{
|
|
unsigned int sg_grant, nr_segs;
|
|
struct Scsi_Host *host = info->host;
|
|
|
|
sg_grant = xenbus_read_unsigned(dev->otherend, "feature-sg-grant", 0);
|
|
nr_segs = min_t(unsigned int, sg_grant, SG_ALL);
|
|
nr_segs = max_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE);
|
|
nr_segs = min_t(unsigned int, nr_segs,
|
|
VSCSIIF_SG_TABLESIZE * PAGE_SIZE /
|
|
sizeof(struct scsiif_request_segment));
|
|
|
|
if (!info->pause && sg_grant)
|
|
dev_info(&dev->dev, "using up to %d SG entries\n", nr_segs);
|
|
else if (info->pause && nr_segs < host->sg_tablesize)
|
|
dev_warn(&dev->dev,
|
|
"SG entries decreased from %d to %u - device may not work properly anymore\n",
|
|
host->sg_tablesize, nr_segs);
|
|
|
|
host->sg_tablesize = nr_segs;
|
|
host->max_sectors = (nr_segs - 1) * PAGE_SIZE / 512;
|
|
}
|
|
|
|
static void scsifront_backend_changed(struct xenbus_device *dev,
|
|
enum xenbus_state backend_state)
|
|
{
|
|
struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
|
|
|
|
pr_debug("%s: %p %u %u\n", __func__, dev, dev->state, backend_state);
|
|
|
|
switch (backend_state) {
|
|
case XenbusStateUnknown:
|
|
case XenbusStateInitialising:
|
|
case XenbusStateInitWait:
|
|
case XenbusStateInitialised:
|
|
break;
|
|
|
|
case XenbusStateConnected:
|
|
scsifront_read_backend_params(dev, info);
|
|
|
|
if (info->pause) {
|
|
scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_READD_LUN);
|
|
xenbus_switch_state(dev, XenbusStateConnected);
|
|
info->pause = 0;
|
|
return;
|
|
}
|
|
|
|
if (xenbus_read_driver_state(dev->nodename) ==
|
|
XenbusStateInitialised)
|
|
scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
|
|
|
|
if (dev->state != XenbusStateConnected)
|
|
xenbus_switch_state(dev, XenbusStateConnected);
|
|
break;
|
|
|
|
case XenbusStateClosed:
|
|
if (dev->state == XenbusStateClosed)
|
|
break;
|
|
fallthrough; /* Missed the backend's Closing state */
|
|
case XenbusStateClosing:
|
|
scsifront_disconnect(info);
|
|
break;
|
|
|
|
case XenbusStateReconfiguring:
|
|
scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_DEL_LUN);
|
|
xenbus_switch_state(dev, XenbusStateReconfiguring);
|
|
break;
|
|
|
|
case XenbusStateReconfigured:
|
|
scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
|
|
xenbus_switch_state(dev, XenbusStateConnected);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static const struct xenbus_device_id scsifront_ids[] = {
|
|
{ "vscsi" },
|
|
{ "" }
|
|
};
|
|
|
|
static struct xenbus_driver scsifront_driver = {
|
|
.ids = scsifront_ids,
|
|
.probe = scsifront_probe,
|
|
.remove = scsifront_remove,
|
|
.resume = scsifront_resume,
|
|
.suspend = scsifront_suspend,
|
|
.otherend_changed = scsifront_backend_changed,
|
|
};
|
|
|
|
static int __init scsifront_init(void)
|
|
{
|
|
if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
return xenbus_register_frontend(&scsifront_driver);
|
|
}
|
|
module_init(scsifront_init);
|
|
|
|
static void __exit scsifront_exit(void)
|
|
{
|
|
xenbus_unregister_driver(&scsifront_driver);
|
|
}
|
|
module_exit(scsifront_exit);
|
|
|
|
MODULE_DESCRIPTION("Xen SCSI frontend driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("xen:vscsi");
|
|
MODULE_AUTHOR("Juergen Gross <jgross@suse.com>");
|