xen: support suspend/resume in pvscsi frontend
Up to now the pvscsi frontend hasn't supported domain suspend and resume. When a domain with an assigned pvscsi device was suspended and resumed again, it was not able to use the device any more: trying to do so resulted in hanging processes. Support suspend and resume of pvscsi devices. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
This commit is contained in:
Juergen Gross
David Vrabel
parent
169e6cf066
commit
85617dc7ee
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@ -63,6 +63,7 @@
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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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@ -113,8 +114,13 @@ struct vscsifrnt_info {
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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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@ -274,31 +280,31 @@ static void scsifront_sync_cmd_done(struct vscsifrnt_info *info,
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wake_up(&shadow->wq_reset);
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}
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static int scsifront_cmd_done(struct vscsifrnt_info *info)
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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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if (WARN(ring_rsp->rqid >= VSCSIIF_MAX_REQS ||
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test_bit(ring_rsp->rqid, info->shadow_free_bitmap),
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"illegal rqid %u returned by backend!\n", ring_rsp->rqid))
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return;
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if (info->shadow[ring_rsp->rqid]->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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{
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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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unsigned long flags;
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spin_lock_irqsave(info->host->host_lock, flags);
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rp = info->ring.sring->rsp_prod;
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rmb(); /* ordering required respective to dom0 */
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for (i = info->ring.rsp_cons; i != rp; i++) {
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ring_rsp = RING_GET_RESPONSE(&info->ring, i);
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if (WARN(ring_rsp->rqid >= VSCSIIF_MAX_REQS ||
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test_bit(ring_rsp->rqid, info->shadow_free_bitmap),
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"illegal rqid %u returned by backend!\n",
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ring_rsp->rqid))
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continue;
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if (info->shadow[ring_rsp->rqid]->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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scsifront_do_response(info, ring_rsp);
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}
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info->ring.rsp_cons = i;
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@ -308,6 +314,18 @@ static int scsifront_cmd_done(struct vscsifrnt_info *info)
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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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{
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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);
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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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@ -328,6 +346,24 @@ static irqreturn_t scsifront_irq_fn(int irq, void *dev_id)
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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 i;
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struct vscsiif_response resp;
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scsifront_ring_drain(info);
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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;
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resp.rslt = DID_RESET << 16;
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resp.residual_len = 0;
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scsifront_do_response(info, &resp);
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}
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}
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static int map_data_for_request(struct vscsifrnt_info *info,
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struct scsi_cmnd *sc,
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struct vscsiif_request *ring_req,
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@ -475,6 +511,27 @@ static struct vscsiif_request *scsifront_command2ring(
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return ring_req;
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}
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static int scsifront_enter(struct vscsifrnt_info *info)
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{
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if (info->pause)
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return 1;
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info->callers++;
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return 0;
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}
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static void scsifront_return(struct vscsifrnt_info *info)
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{
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info->callers--;
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if (info->callers)
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return;
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if (!info->waiting_pause)
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return;
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info->waiting_pause = 0;
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wake_up(&info->wq_pause);
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}
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static int scsifront_queuecommand(struct Scsi_Host *shost,
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struct scsi_cmnd *sc)
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{
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@ -486,6 +543,10 @@ static int scsifront_queuecommand(struct Scsi_Host *shost,
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uint16_t rqid;
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spin_lock_irqsave(shost->host_lock, flags);
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if (scsifront_enter(info)) {
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spin_unlock_irqrestore(shost->host_lock, flags);
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return SCSI_MLQUEUE_HOST_BUSY;
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}
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if (RING_FULL(&info->ring))
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goto busy;
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@ -505,6 +566,7 @@ static int scsifront_queuecommand(struct Scsi_Host *shost,
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if (err < 0) {
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pr_debug("%s: err %d\n", __func__, err);
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scsifront_put_rqid(info, rqid);
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scsifront_return(info);
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spin_unlock_irqrestore(shost->host_lock, flags);
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if (err == -ENOMEM)
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return SCSI_MLQUEUE_HOST_BUSY;
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@ -514,11 +576,13 @@ static int scsifront_queuecommand(struct Scsi_Host *shost,
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}
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scsifront_do_request(info);
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scsifront_return(info);
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spin_unlock_irqrestore(shost->host_lock, flags);
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return 0;
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busy:
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scsifront_return(info);
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spin_unlock_irqrestore(shost->host_lock, flags);
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pr_debug("%s: busy\n", __func__);
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return SCSI_MLQUEUE_HOST_BUSY;
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@ -549,7 +613,7 @@ static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
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if (ring_req)
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break;
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}
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if (err) {
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if (err || info->pause) {
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spin_unlock_irq(host->host_lock);
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kfree(shadow);
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return FAILED;
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@ -561,6 +625,11 @@ static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
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spin_lock_irq(host->host_lock);
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}
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if (scsifront_enter(info)) {
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spin_unlock_irq(host->host_lock);
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return FAILED;
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}
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ring_req->act = act;
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ring_req->ref_rqid = s->rqid;
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@ -587,6 +656,7 @@ static int scsifront_action_handler(struct scsi_cmnd *sc, uint8_t act)
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err = FAILED;
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}
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scsifront_return(info);
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spin_unlock_irq(host->host_lock);
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return err;
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}
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@ -698,6 +768,13 @@ free_gnttab:
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return err;
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}
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static void scsifront_free_ring(struct vscsifrnt_info *info)
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{
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unbind_from_irqhandler(info->irq, info);
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gnttab_end_foreign_access(info->ring_ref, 0,
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(unsigned long)info->ring.sring);
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}
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static int scsifront_init_ring(struct vscsifrnt_info *info)
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{
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struct xenbus_device *dev = info->dev;
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@ -744,9 +821,7 @@ again:
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fail:
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xenbus_transaction_end(xbt, 1);
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free_sring:
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unbind_from_irqhandler(info->irq, info);
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gnttab_end_foreign_access(info->ring_ref, 0,
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(unsigned long)info->ring.sring);
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scsifront_free_ring(info);
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return err;
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}
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@ -779,6 +854,7 @@ static int scsifront_probe(struct xenbus_device *dev,
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}
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init_waitqueue_head(&info->wq_sync);
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init_waitqueue_head(&info->wq_pause);
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spin_lock_init(&info->shadow_lock);
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snprintf(name, TASK_COMM_LEN, "vscsiif.%d", host->host_no);
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@ -802,13 +878,60 @@ static int scsifront_probe(struct xenbus_device *dev,
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return 0;
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free_sring:
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unbind_from_irqhandler(info->irq, info);
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gnttab_end_foreign_access(info->ring_ref, 0,
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(unsigned long)info->ring.sring);
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scsifront_free_ring(info);
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scsi_host_put(host);
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return err;
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}
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static int scsifront_resume(struct xenbus_device *dev)
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{
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struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
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struct Scsi_Host *host = info->host;
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int err;
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spin_lock_irq(host->host_lock);
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/* Finish all still pending commands. */
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scsifront_finish_all(info);
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spin_unlock_irq(host->host_lock);
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/* Reconnect to dom0. */
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scsifront_free_ring(info);
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err = scsifront_init_ring(info);
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if (err) {
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dev_err(&dev->dev, "fail to resume %d\n", err);
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scsi_host_put(host);
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return err;
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}
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xenbus_switch_state(dev, XenbusStateInitialised);
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return 0;
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}
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static int scsifront_suspend(struct xenbus_device *dev)
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{
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struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
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struct Scsi_Host *host = info->host;
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int err = 0;
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/* No new commands for the backend. */
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spin_lock_irq(host->host_lock);
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info->pause = 1;
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while (info->callers && !err) {
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info->waiting_pause = 1;
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info->wait_ring_available = 0;
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spin_unlock_irq(host->host_lock);
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wake_up(&info->wq_sync);
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err = wait_event_interruptible(info->wq_pause,
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!info->waiting_pause);
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spin_lock_irq(host->host_lock);
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}
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spin_unlock_irq(host->host_lock);
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return err;
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}
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static int scsifront_remove(struct xenbus_device *dev)
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{
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struct vscsifrnt_info *info = dev_get_drvdata(&dev->dev);
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@ -823,10 +946,7 @@ static int scsifront_remove(struct xenbus_device *dev)
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}
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mutex_unlock(&scsifront_mutex);
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gnttab_end_foreign_access(info->ring_ref, 0,
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(unsigned long)info->ring.sring);
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unbind_from_irqhandler(info->irq, info);
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scsifront_free_ring(info);
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scsi_host_put(info->host);
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return 0;
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@ -919,6 +1039,12 @@ static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op)
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scsi_device_put(sdev);
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}
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break;
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case VSCSIFRONT_OP_READD_LUN:
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if (device_state == XenbusStateConnected)
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xenbus_printf(XBT_NIL, dev->nodename,
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info->dev_state_path,
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"%d", XenbusStateConnected);
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break;
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default:
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break;
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}
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@ -932,21 +1058,29 @@ static void scsifront_do_lun_hotplug(struct vscsifrnt_info *info, int op)
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static void scsifront_read_backend_params(struct xenbus_device *dev,
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struct vscsifrnt_info *info)
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{
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unsigned int sg_grant;
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unsigned int sg_grant, nr_segs;
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int ret;
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struct Scsi_Host *host = info->host;
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ret = xenbus_scanf(XBT_NIL, dev->otherend, "feature-sg-grant", "%u",
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&sg_grant);
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if (ret == 1 && sg_grant) {
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sg_grant = min_t(unsigned int, sg_grant, SG_ALL);
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sg_grant = max_t(unsigned int, sg_grant, VSCSIIF_SG_TABLESIZE);
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host->sg_tablesize = min_t(unsigned int, sg_grant,
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if (ret != 1)
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sg_grant = 0;
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nr_segs = min_t(unsigned int, sg_grant, SG_ALL);
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nr_segs = max_t(unsigned int, nr_segs, VSCSIIF_SG_TABLESIZE);
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nr_segs = min_t(unsigned int, nr_segs,
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VSCSIIF_SG_TABLESIZE * PAGE_SIZE /
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sizeof(struct scsiif_request_segment));
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host->max_sectors = (host->sg_tablesize - 1) * PAGE_SIZE / 512;
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}
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dev_info(&dev->dev, "using up to %d SG entries\n", host->sg_tablesize);
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if (!info->pause && sg_grant)
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dev_info(&dev->dev, "using up to %d SG entries\n", nr_segs);
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else if (info->pause && nr_segs < host->sg_tablesize)
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dev_warn(&dev->dev,
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"SG entries decreased from %d to %u - device may not work properly anymore\n",
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host->sg_tablesize, nr_segs);
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host->sg_tablesize = nr_segs;
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host->max_sectors = (nr_segs - 1) * PAGE_SIZE / 512;
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}
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static void scsifront_backend_changed(struct xenbus_device *dev,
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@ -965,6 +1099,14 @@ static void scsifront_backend_changed(struct xenbus_device *dev,
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case XenbusStateConnected:
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scsifront_read_backend_params(dev, info);
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if (info->pause) {
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scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_READD_LUN);
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xenbus_switch_state(dev, XenbusStateConnected);
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info->pause = 0;
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return;
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}
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if (xenbus_read_driver_state(dev->nodename) ==
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XenbusStateInitialised)
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scsifront_do_lun_hotplug(info, VSCSIFRONT_OP_ADD_LUN);
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@ -1002,6 +1144,8 @@ static struct xenbus_driver scsifront_driver = {
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.ids = scsifront_ids,
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.probe = scsifront_probe,
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.remove = scsifront_remove,
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.resume = scsifront_resume,
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.suspend = scsifront_suspend,
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.otherend_changed = scsifront_backend_changed,
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};
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