Re: [RFC] [PATCH 1/1] blk request timeout handler patches

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On Tue, Oct 09 2007, James Bottomley wrote:
> On Tue, 2007-10-09 at 14:15 +0200, Jens Axboe wrote:
> > On Tue, Oct 09 2007, Matthew Wilcox wrote:
> > > On Mon, Oct 08, 2007 at 10:36:10PM -0700, malahal@xxxxxxxxxx wrote:
> > > > Thank you Randy, Jens for your suggestions. I folded the second patch as
> > > > it is just a clean up. Here is the fixed one patch version.
> > > 
> > > I was thinking about this (in the context of shrinking scsi_cmnd --
> > > obviously, things are not improved if we simply move the timer to request
> > > instead of scsi_cmnd).  Why do we need a timer _per request_?  We don't
> > > need one per network packet.  I appreciate we had one per scsi_cmnd and
> > > this patch is just moving it upwards in the hierarchy, but perhaps we
> > > can do better.
> > > 
> > > What if we have one timer per request queue instead?  It needs to expire
> > > as soon as the earliest request timer would expire, then needs to be
> > > reset to the next earliest one.  We might walk the request queue more
> > > frequently, but we'd save 48 bytes in the struct request.
> > 
> > I agree, adding a full timer to each request is not nice. You jump over
> > the actual implementation details of having just one timer in the queue
> > though, it's pretty cheap to just say it can be done :-). You need to
> > track each request anyways. If all drivers used the block layer tagging
> > it would be easy since we are tracking each pending request in that
> > case, but right now they don't. So pending requests may very well be
> > outside of block layer knowledge.
> 
> Can't we handle this a bit like the Linux timer infrastructure?  Instead
> of a timer per cmnd we have one per queue that's reset by commands
> returning?  If we retained a linked list of commands in timer order and
> expiry times, that's still going to save us an unsigned long and two
> pointers over struct timer_list.

Here's an approach that uses a single timer. I purposely do not sort
commands in expiry times, as that would introduce an O(N) operation far
out weighing the IO scheduling cost, pretty silly for a timeout
mechanism that supposedly should never trigger. Or we could waste more
memory and fewer cycles (but still far more cycles than we need) by
sorting in some sort of tree.

So I don't sort the list, instead I push the cost of locating expired
request to the timeout handler. It should really only run, when a
request times out. Timeout is then reset to next command timeout
(rounded), if further commands exist. It also doesn't fiddle with the
timer unless an incoming command has a lower timeout than the current
one.

Totally untested...

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index ed39313..cb3210a 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -42,6 +42,7 @@ static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io);
 static void init_request_from_bio(struct request *req, struct bio *bio);
 static int __make_request(struct request_queue *q, struct bio *bio);
 static struct io_context *current_io_context(gfp_t gfp_flags, int node);
+static void blk_rq_timed_out_timer(unsigned long);
 
 /*
  * For the allocated request tables
@@ -177,6 +178,18 @@ void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
 
 EXPORT_SYMBOL(blk_queue_softirq_done);
 
+void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
+{
+	q->rq_timeout = timeout;
+}
+EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
+
+void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn)
+{
+	q->rq_timed_out_fn = fn;
+}
+EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);
+
 /**
  * blk_queue_make_request - define an alternate make_request function for a device
  * @q:  the request queue for the device to be affected
@@ -239,7 +252,9 @@ static void rq_init(struct request_queue *q, struct request *rq)
 {
 	INIT_LIST_HEAD(&rq->queuelist);
 	INIT_LIST_HEAD(&rq->donelist);
+	INIT_LIST_HEAD(&rq->timeout_list);
 
+	rq->timeout = 0;
 	rq->errors = 0;
 	rq->bio = rq->biotail = NULL;
 	INIT_HLIST_NODE(&rq->hash);
@@ -1851,6 +1866,8 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 		return NULL;
 
 	init_timer(&q->unplug_timer);
+	setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
+	INIT_LIST_HEAD(&q->timeout_list);
 
 	snprintf(q->kobj.name, KOBJ_NAME_LEN, "%s", "queue");
 	q->kobj.ktype = &queue_ktype;
@@ -2271,6 +2288,7 @@ EXPORT_SYMBOL(blk_start_queueing);
  */
 void blk_requeue_request(struct request_queue *q, struct request *rq)
 {
+	blk_delete_timer(rq);
 	blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
 
 	if (blk_rq_tagged(rq))
@@ -3600,24 +3618,132 @@ static struct notifier_block __devinitdata blk_cpu_notifier = {
 };
 
 /**
- * blk_complete_request - end I/O on a request
- * @req:      the request being processed
+ * blk_delete_timer - Delete/cancel timer for a given function.
+ * @req:	request that we are canceling timer for
  *
- * Description:
- *     Ends all I/O on a request. It does not handle partial completions,
- *     unless the driver actually implements this in its completion callback
- *     through requeueing. Theh actual completion happens out-of-order,
- *     through a softirq handler. The user must have registered a completion
- *     callback through blk_queue_softirq_done().
- **/
+ * Return value:
+ *     1 if we were able to detach the timer.  0 if we blew it, and the
+ *     timer function has already started to run.
+ */
+int blk_delete_timer(struct request *req)
+{
+	if (!req->q->rq_timed_out_fn)
+		return 1;
 
-void blk_complete_request(struct request *req)
+	if (!list_empty(&req->timeout_list)) {
+		list_del_init(&req->timeout_list);
+		return 1;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(blk_delete_timer);
+
+static void blk_rq_timed_out(struct request *req)
+{
+	struct request_queue *q = req->q;
+	enum blk_eh_timer_return ret;
+
+	ret = q->rq_timed_out_fn(req);
+	switch (ret) {
+	case BLK_EH_HANDLED:
+		__blk_complete_request(req);
+		break;
+	case BLK_EH_RESET_TIMER:
+		blk_add_timer(req);
+		break;
+	case BLK_EH_NOT_HANDLED:
+		/*
+		 * LLD handles this for now but in the future
+		 * we can send a request msg to abort the command
+		 * and we can move more of the generic scsi eh code to
+		 * the blk layer.
+		 */
+		break;
+	default:
+		printk(KERN_ERR "block: bad eh return: %d\n", ret);
+		break;
+	}
+}
+
+static void blk_rq_timed_out_timer(unsigned long data)
+{
+	struct request_queue *q = (struct request_queue *) data;
+	unsigned long flags, next = 0;
+	struct request *rq, *tmp;
+
+	spin_lock_irqsave(q->queue_lock, flags);
+
+	list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) {
+		if (!next || time_before(next, rq->timeout))
+			next = rq->timeout;
+		if (time_after_eq(jiffies, rq->timeout))
+			blk_rq_timed_out(rq);
+	}
+
+	if (next)
+		mod_timer(&q->timeout, round_jiffies(next));
+
+	spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+/**
+ * blk_abort_req -- Request request recovery for the specified command
+ * @req:	pointer to the request of interest
+ *
+ * This function requests that the block layer start recovery for the
+ * request by deleting the timer and calling the q's timeout function.
+ * LLDDs who implement their own error recovery MAY ignore the timeout
+ * event if they generated blk_abort_req.
+ */
+void blk_abort_req(struct request *req)
+{
+        if (!blk_delete_timer(req))
+                return;
+        blk_rq_timed_out(req);
+}
+EXPORT_SYMBOL_GPL(blk_abort_req);
+
+/**
+ * blk_add_timer - Start timeout timer for a single request
+ * @req:	request that is about to start running.
+ *
+ * Notes:
+ *    Each request has its own timer, and as it is added to the queue, we
+ *    set up the timer.  When the request completes, we cancel the timer.
+ */
+void blk_add_timer(struct request *req)
+{
+	struct request_queue *q = req->q;
+	unsigned long expiry;
+
+	BUG_ON(!list_empty(&req->timeout_list));
+
+	if (req->timeout)
+		expiry = jiffies + req->timeout;
+	else
+		expiry = jiffies + q->rq_timeout;
+
+	req->timeout = expiry;
+	list_add_tail(&req->timeout_list, &q->timeout_list);
+
+	/*
+	 * This is for timeout purposes, round to next second
+	 */
+	expiry = round_jiffies(expiry);
+
+	if (!timer_pending(&q->timeout) || time_before(expiry, q->timeout.expires))
+		mod_timer(&q->timeout, expiry);
+}
+EXPORT_SYMBOL_GPL(blk_add_timer);
+
+void __blk_complete_request(struct request *req)
 {
 	struct list_head *cpu_list;
 	unsigned long flags;
 
 	BUG_ON(!req->q->softirq_done_fn);
-		
+
 	local_irq_save(flags);
 
 	cpu_list = &__get_cpu_var(blk_cpu_done);
@@ -3627,8 +3753,34 @@ void blk_complete_request(struct request *req)
 	local_irq_restore(flags);
 }
 
+/**
+ * blk_complete_request - end I/O on a request
+ * @req:	the request being processed
+ *
+ * Description:
+ *     Ends all I/O on a request. It does not handle partial completions,
+ *     unless the driver actually implements this in its completion callback
+ *     through requeueing. Theh actual completion happens out-of-order,
+ *     through a softirq handler. The user must have registered a completion
+ *     callback through blk_queue_softirq_done().
+ */
+void blk_complete_request(struct request *req)
+{
+	/*
+	 * We don't have to worry about this one timing out any more.
+	 * If we are unable to remove the timer, then the command
+	 * has already timed out.  In which case, we have no choice but to
+	 * let the timeout function run, as we have no idea where in fact
+	 * that function could really be.  It might be on another processor,
+	 * etc, etc.
+	 */
+	if (!blk_delete_timer(req))
+		return;
+
+	__blk_complete_request(req);
+}
 EXPORT_SYMBOL(blk_complete_request);
-	
+
 /*
  * queue lock must be held
  */
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index ac6ceed..017a236 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -33,6 +33,7 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/blkdev.h>
 #include <scsi/scsi.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_eh.h>
@@ -244,29 +245,29 @@ static void ata_eh_clear_action(struct ata_device *dev,
  *	RETURNS:
  *	EH_HANDLED or EH_NOT_HANDLED
  */
-enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
+enum blk_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
 {
 	struct Scsi_Host *host = cmd->device->host;
 	struct ata_port *ap = ata_shost_to_port(host);
 	unsigned long flags;
 	struct ata_queued_cmd *qc;
-	enum scsi_eh_timer_return ret;
+	enum blk_eh_timer_return ret;
 
 	DPRINTK("ENTER\n");
 
 	if (ap->ops->error_handler) {
-		ret = EH_NOT_HANDLED;
+		ret = BLK_EH_NOT_HANDLED;
 		goto out;
 	}
 
-	ret = EH_HANDLED;
+	ret = BLK_EH_HANDLED;
 	spin_lock_irqsave(ap->lock, flags);
 	qc = ata_qc_from_tag(ap, ap->active_tag);
 	if (qc) {
 		WARN_ON(qc->scsicmd != cmd);
 		qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
 		qc->err_mask |= AC_ERR_TIMEOUT;
-		ret = EH_NOT_HANDLED;
+		ret = BLK_EH_NOT_HANDLED;
 	}
 	spin_unlock_irqrestore(ap->lock, flags);
 
@@ -692,7 +693,7 @@ void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
 	 * Note that ATA_QCFLAG_FAILED is unconditionally set after
 	 * this function completes.
 	 */
-	scsi_req_abort_cmd(qc->scsicmd);
+	blk_abort_req(qc->scsicmd->request);
 }
 
 /**
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 564cd23..6021b9c 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -148,7 +148,7 @@ extern void ata_scsi_dev_rescan(struct work_struct *work);
 extern int ata_bus_probe(struct ata_port *ap);
 
 /* libata-eh.c */
-extern enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd);
+extern enum blk_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd);
 extern void ata_scsi_error(struct Scsi_Host *host);
 extern void ata_port_wait_eh(struct ata_port *ap);
 extern void ata_eh_fastdrain_timerfn(unsigned long arg);
diff --git a/drivers/scsi/aacraid/aachba.c b/drivers/scsi/aacraid/aachba.c
index 6800e57..6fa65c8 100644
--- a/drivers/scsi/aacraid/aachba.c
+++ b/drivers/scsi/aacraid/aachba.c
@@ -1125,7 +1125,7 @@ static struct aac_srb * aac_scsi_common(struct fib * fib, struct scsi_cmnd * cmd
 	srbcmd->id       = cpu_to_le32(scmd_id(cmd));
 	srbcmd->lun      = cpu_to_le32(cmd->device->lun);
 	srbcmd->flags    = cpu_to_le32(flag);
-	timeout = cmd->timeout_per_command/HZ;
+	timeout = cmd->request->timeout/HZ;
 	if (timeout == 0)
 		timeout = 1;
 	srbcmd->timeout  = cpu_to_le32(timeout);  // timeout in seconds
diff --git a/drivers/scsi/advansys.c b/drivers/scsi/advansys.c
index 79c0b6e..d139075 100644
--- a/drivers/scsi/advansys.c
+++ b/drivers/scsi/advansys.c
@@ -7901,7 +7901,7 @@ static void asc_prt_scsi_cmnd(struct scsi_cmnd *s)
 	printk(" serial_number 0x%x, retries %d, allowed %d\n",
 	       (unsigned)s->serial_number, s->retries, s->allowed);
 
-	printk(" timeout_per_command %d\n", s->timeout_per_command);
+	printk(" request timeout %d\n", s->request->timeout);
 
 	printk
 	    (" scsi_done 0x%lx, done 0x%lx, host_scribble 0x%lx, result 0x%x\n",
diff --git a/drivers/scsi/gdth.c b/drivers/scsi/gdth.c
index 55e4d2d..c5fc436 100644
--- a/drivers/scsi/gdth.c
+++ b/drivers/scsi/gdth.c
@@ -733,7 +733,6 @@ int __gdth_execute(struct scsi_device *sdev, gdth_cmd_str *gdtcmd, char *cmnd,
     scp->device = sdev;
     /* use request field to save the ptr. to completion struct. */
     scp->request = (struct request *)&wait;
-    scp->timeout_per_command = timeout*HZ;
     scp->request_buffer = gdtcmd;
     scp->cmd_len = 12;
     memcpy(scp->cmnd, cmnd, 12);
@@ -4948,7 +4947,7 @@ static int gdth_queuecommand(Scsi_Cmnd *scp,void (*done)(Scsi_Cmnd *))
     if (scp->done == gdth_scsi_done)
         priority = scp->SCp.this_residual;
     else
-        gdth_update_timeout(hanum, scp, scp->timeout_per_command * 6);
+        gdth_update_timeout(hanum, scp, scp->request->timeout* 6);
 
     gdth_putq( hanum, scp, priority );
     gdth_next( hanum );
diff --git a/drivers/scsi/gdth_proc.c b/drivers/scsi/gdth_proc.c
index 32982eb..22a9013 100644
--- a/drivers/scsi/gdth_proc.c
+++ b/drivers/scsi/gdth_proc.c
@@ -846,19 +846,19 @@ static int gdth_update_timeout(int hanum, Scsi_Cmnd *scp, int timeout)
 {
     int oldto;
 
-    oldto = scp->timeout_per_command;
-    scp->timeout_per_command = timeout;
+    oldto = scp->request->timeout;
+    scp->request->timeout = timeout;
 
     if (timeout == 0) {
-        del_timer(&scp->eh_timeout);
-        scp->eh_timeout.data = (unsigned long) NULL;
-        scp->eh_timeout.expires = 0;
+        del_timer(&scp->request->timer);
+        scp->request->timer.data = (unsigned long) NULL;
+        scp->request->timer.expires = 0;
     } else {
-        if (scp->eh_timeout.data != (unsigned long) NULL) 
-            del_timer(&scp->eh_timeout);
-        scp->eh_timeout.data = (unsigned long) scp;
-        scp->eh_timeout.expires = jiffies + timeout;
-        add_timer(&scp->eh_timeout);
+        if (scp->request->timer.data != (unsigned long) NULL) 
+            del_timer(&scp->request->timer);
+        scp->request->timer.data = (unsigned long) scp;
+        scp->request->timer.expires = jiffies + timeout;
+        add_timer(&scp->request->timer);
     }
 
     return oldto;
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 5ecc63d..04dbe3b 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -726,7 +726,7 @@ static int ibmvscsi_queuecommand(struct scsi_cmnd *cmnd,
 	init_event_struct(evt_struct,
 			  handle_cmd_rsp,
 			  VIOSRP_SRP_FORMAT,
-			  cmnd->timeout_per_command/HZ);
+			  cmnd->request->timeout/HZ);
 
 	evt_struct->cmnd = cmnd;
 	evt_struct->cmnd_done = done;
diff --git a/drivers/scsi/ide-scsi.c b/drivers/scsi/ide-scsi.c
index 1cc01ac..2035923 100644
--- a/drivers/scsi/ide-scsi.c
+++ b/drivers/scsi/ide-scsi.c
@@ -916,7 +916,7 @@ static int idescsi_queue (struct scsi_cmnd *cmd,
 	pc->request_transfer = pc->buffer_size = cmd->request_bufflen;
 	pc->scsi_cmd = cmd;
 	pc->done = done;
-	pc->timeout = jiffies + cmd->timeout_per_command;
+	pc->timeout = jiffies + cmd->request->timeout;
 
 	if (should_transform(drive, cmd))
 		set_bit(PC_TRANSFORM, &pc->flags);
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index f142eaf..b351f14 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -3654,7 +3654,8 @@ static int ipr_slave_configure(struct scsi_device *sdev)
 			sdev->no_uld_attach = 1;
 		}
 		if (ipr_is_vset_device(res)) {
-			sdev->timeout = IPR_VSET_RW_TIMEOUT;
+			blk_queue_rq_timeout(sdev->request_queue,
+					     IPR_VSET_RW_TIMEOUT);
 			blk_queue_max_sectors(sdev->request_queue, IPR_VSET_MAX_SECTORS);
 		}
 		if (ipr_is_vset_device(res) || ipr_is_scsi_disk(res))
diff --git a/drivers/scsi/ips.c b/drivers/scsi/ips.c
index 492a51b..c81dd8f 100644
--- a/drivers/scsi/ips.c
+++ b/drivers/scsi/ips.c
@@ -3860,7 +3860,7 @@ ips_send_cmd(ips_ha_t * ha, ips_scb_t * scb)
 		scb->cmd.dcdb.segment_4G = 0;
 		scb->cmd.dcdb.enhanced_sg = 0;
 
-		TimeOut = scb->scsi_cmd->timeout_per_command;
+		TimeOut = scb->scsi_cmd->request->timeout;
 
 		if (ha->subsys->param[4] & 0x00100000) {	/* If NEW Tape DCDB is Supported */
 			if (!scb->sg_len) {
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 5e573ef..f3ae2df 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -408,7 +408,7 @@ void sas_ata_task_abort(struct sas_task *task)
 
 	/* Bounce SCSI-initiated commands to the SCSI EH */
 	if (qc->scsicmd) {
-		scsi_req_abort_cmd(qc->scsicmd);
+		blk_abort_req(qc->scsicmd->request);
 		scsi_schedule_eh(qc->scsicmd->device->host);
 		return;
 	}
diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
index 2b8213b..13ac4a3 100644
--- a/drivers/scsi/libsas/sas_internal.h
+++ b/drivers/scsi/libsas/sas_internal.h
@@ -55,7 +55,7 @@ void sas_unregister_phys(struct sas_ha_struct *sas_ha);
 int  sas_register_ports(struct sas_ha_struct *sas_ha);
 void sas_unregister_ports(struct sas_ha_struct *sas_ha);
 
-enum scsi_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *);
+enum blk_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *);
 
 int  sas_init_queue(struct sas_ha_struct *sas_ha);
 int  sas_init_events(struct sas_ha_struct *sas_ha);
diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 7663841..6d6867c 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -654,43 +654,43 @@ out:
 	return;
 }
 
-enum scsi_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *cmd)
+enum blk_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *cmd)
 {
 	struct sas_task *task = TO_SAS_TASK(cmd);
 	unsigned long flags;
 
 	if (!task) {
-		cmd->timeout_per_command /= 2;
+		cmd->request->timeout /= 2;
 		SAS_DPRINTK("command 0x%p, task 0x%p, gone: %s\n",
-			    cmd, task, (cmd->timeout_per_command ?
-			    "EH_RESET_TIMER" : "EH_NOT_HANDLED"));
-		if (!cmd->timeout_per_command)
-			return EH_NOT_HANDLED;
-		return EH_RESET_TIMER;
+			    cmd, task, (cmd->request->timeout ?
+			    "BLK_EH_RESET_TIMER" : "BLK_EH_NOT_HANDLED"));
+		if (!cmd->request->timeout)
+			return BLK_EH_NOT_HANDLED;
+		return BLK_EH_RESET_TIMER;
 	}
 
 	spin_lock_irqsave(&task->task_state_lock, flags);
 	BUG_ON(task->task_state_flags & SAS_TASK_STATE_ABORTED);
 	if (task->task_state_flags & SAS_TASK_STATE_DONE) {
 		spin_unlock_irqrestore(&task->task_state_lock, flags);
-		SAS_DPRINTK("command 0x%p, task 0x%p, timed out: EH_HANDLED\n",
-			    cmd, task);
-		return EH_HANDLED;
+		SAS_DPRINTK("command 0x%p, task 0x%p, timed out: "
+			    "BLK_EH_HANDLED\n", cmd, task);
+		return BLK_EH_HANDLED;
 	}
 	if (!(task->task_state_flags & SAS_TASK_AT_INITIATOR)) {
 		spin_unlock_irqrestore(&task->task_state_lock, flags);
 		SAS_DPRINTK("command 0x%p, task 0x%p, not at initiator: "
-			    "EH_RESET_TIMER\n",
+			    "BLK_EH_RESET_TIMER\n",
 			    cmd, task);
-		return EH_RESET_TIMER;
+		return BLK_EH_RESET_TIMER;
 	}
 	task->task_state_flags |= SAS_TASK_STATE_ABORTED;
 	spin_unlock_irqrestore(&task->task_state_lock, flags);
 
-	SAS_DPRINTK("command 0x%p, task 0x%p, timed out: EH_NOT_HANDLED\n",
+	SAS_DPRINTK("command 0x%p, task 0x%p, timed out: BLK_EH_NOT_HANDLED\n",
 		    cmd, task);
 
-	return EH_NOT_HANDLED;
+	return BLK_EH_NOT_HANDLED;
 }
 
 int sas_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
@@ -1020,7 +1020,7 @@ void sas_task_abort(struct sas_task *task)
 		return;
 	}
 
-	scsi_req_abort_cmd(sc);
+	blk_abort_req(sc->request);
 	scsi_schedule_eh(sc->device->host);
 }
 
diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index ebb948c..84c0eb4 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -969,7 +969,7 @@ static int megasas_generic_reset(struct scsi_cmnd *scmd)
  * cmd has not been completed within the timeout period.
  */
 static enum
-scsi_eh_timer_return megasas_reset_timer(struct scsi_cmnd *scmd)
+blk_eh_timer_return megasas_reset_timer(struct scsi_cmnd *scmd)
 {
 	struct megasas_cmd *cmd = (struct megasas_cmd *)scmd->SCp.ptr;
 	struct megasas_instance *instance;
@@ -977,7 +977,7 @@ scsi_eh_timer_return megasas_reset_timer(struct scsi_cmnd *scmd)
 
 	if (time_after(jiffies, scmd->jiffies_at_alloc +
 				(MEGASAS_DEFAULT_CMD_TIMEOUT * 2) * HZ)) {
-		return EH_NOT_HANDLED;
+		return BLK_EH_NOT_HANDLED;
 	}
 
 	instance = cmd->instance;
@@ -991,7 +991,7 @@ scsi_eh_timer_return megasas_reset_timer(struct scsi_cmnd *scmd)
 
 		spin_unlock_irqrestore(instance->host->host_lock, flags);
 	}
-	return EH_RESET_TIMER;
+	return BLK_EH_RESET_TIMER;
 }
 
 /**
diff --git a/drivers/scsi/ncr53c8xx.c b/drivers/scsi/ncr53c8xx.c
index 030ba49..39c2d4b 100644
--- a/drivers/scsi/ncr53c8xx.c
+++ b/drivers/scsi/ncr53c8xx.c
@@ -4170,8 +4170,8 @@ static int ncr_queue_command (struct ncb *np, struct scsi_cmnd *cmd)
 	**
 	**----------------------------------------------------
 	*/
-	if (np->settle_time && cmd->timeout_per_command >= HZ) {
-		u_long tlimit = jiffies + cmd->timeout_per_command - HZ;
+	if (np->settle_time && cmd->request->timeout >= HZ) {
+		u_long tlimit = jiffies + cmd->request->timeout - HZ;
 		if (time_after(np->settle_time, tlimit))
 			np->settle_time = tlimit;
 	}
diff --git a/drivers/scsi/qla1280.c b/drivers/scsi/qla1280.c
index 54d8bdf..f5d5b2a 100644
--- a/drivers/scsi/qla1280.c
+++ b/drivers/scsi/qla1280.c
@@ -2862,7 +2862,7 @@ qla1280_64bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 	memset(((char *)pkt + 8), 0, (REQUEST_ENTRY_SIZE - 8));
 
 	/* Set ISP command timeout. */
-	pkt->timeout = cpu_to_le16(cmd->timeout_per_command/HZ);
+	pkt->timeout = cpu_to_le16(cmd->request->timeout/HZ);
 
 	/* Set device target ID and LUN */
 	pkt->lun = SCSI_LUN_32(cmd);
@@ -3161,7 +3161,7 @@ qla1280_32bit_start_scsi(struct scsi_qla_host *ha, struct srb * sp)
 	memset(((char *)pkt + 8), 0, (REQUEST_ENTRY_SIZE - 8));
 
 	/* Set ISP command timeout. */
-	pkt->timeout = cpu_to_le16(cmd->timeout_per_command/HZ);
+	pkt->timeout = cpu_to_le16(cmd->request->timeout/HZ);
 
 	/* Set device target ID and LUN */
 	pkt->lun = SCSI_LUN_32(cmd);
diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c
index b1d565c..005eb66 100644
--- a/drivers/scsi/qla4xxx/ql4_os.c
+++ b/drivers/scsi/qla4xxx/ql4_os.c
@@ -1564,7 +1564,7 @@ static int qla4xxx_eh_device_reset(struct scsi_cmnd *cmd)
 	DEBUG2(printk(KERN_INFO
 		      "scsi%ld: DEVICE_RESET cmd=%p jiffies = 0x%lx, to=%x,"
 		      "dpc_flags=%lx, status=%x allowed=%d\n", ha->host_no,
-		      cmd, jiffies, cmd->timeout_per_command / HZ,
+		      cmd, jiffies, cmd->request->timeout / HZ,
 		      ha->dpc_flags, cmd->result, cmd->allowed));
 
 	/* FIXME: wait for hba to go online */
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index a5de1a8..e67eb6e 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -203,7 +203,6 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
 
 		memset(cmd, 0, sizeof(*cmd));
 		cmd->device = dev;
-		init_timer(&cmd->eh_timeout);
 		INIT_LIST_HEAD(&cmd->list);
 		spin_lock_irqsave(&dev->list_lock, flags);
 		list_add_tail(&cmd->list, &dev->cmd_list);
@@ -472,14 +471,19 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 	unsigned long timeout;
 	int rtn = 0;
 
+	/*
+	 * We will use a queued command if possible, otherwise we will
+	 * emulate the queuing and calling of completion function ourselves.
+	 */
+	atomic_inc(&cmd->device->iorequest_cnt);
+
 	/* check if the device is still usable */
 	if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
 		/* in SDEV_DEL we error all commands. DID_NO_CONNECT
 		 * returns an immediate error upwards, and signals
 		 * that the device is no longer present */
 		cmd->result = DID_NO_CONNECT << 16;
-		atomic_inc(&cmd->device->iorequest_cnt);
-		__scsi_done(cmd);
+		scsi_done(cmd);
 		/* return 0 (because the command has been processed) */
 		goto out;
 	}
@@ -492,7 +496,8 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 		 * future requests should not occur until the device 
 		 * transitions out of the suspend state.
 		 */
-		scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
+
+		scsi_queue_retry(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
 
 		SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
 
@@ -534,21 +539,9 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 		host->resetting = 0;
 	}
 
-	/* 
-	 * AK: unlikely race here: for some reason the timer could
-	 * expire before the serial number is set up below.
-	 */
-	scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
-
 	scsi_log_send(cmd);
 
 	/*
-	 * We will use a queued command if possible, otherwise we will
-	 * emulate the queuing and calling of completion function ourselves.
-	 */
-	atomic_inc(&cmd->device->iorequest_cnt);
-
-	/*
 	 * Before we queue this command, check if the command
 	 * length exceeds what the host adapter can handle.
 	 */
@@ -562,6 +555,12 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 	}
 
 	spin_lock_irqsave(host->host_lock, flags);
+	/* 
+	 * AK: unlikely race here: for some reason the timer could
+	 * expire before the serial number is set up below.
+	 *
+	 * TODO: kill serial or move to blk layer
+	 */
 	scsi_cmd_get_serial(host, cmd); 
 
 	if (unlikely(host->shost_state == SHOST_DEL)) {
@@ -572,12 +571,8 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 	}
 	spin_unlock_irqrestore(host->host_lock, flags);
 	if (rtn) {
-		if (scsi_delete_timer(cmd)) {
-			atomic_inc(&cmd->device->iodone_cnt);
-			scsi_queue_insert(cmd,
-					  (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
-					  rtn : SCSI_MLQUEUE_HOST_BUSY);
-		}
+		scsi_queue_retry(cmd, (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
+						rtn : SCSI_MLQUEUE_HOST_BUSY);
 		SCSI_LOG_MLQUEUE(3,
 		    printk("queuecommand : request rejected\n"));
 	}
@@ -588,24 +583,6 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
 }
 
 /**
- * scsi_req_abort_cmd -- Request command recovery for the specified command
- * cmd: pointer to the SCSI command of interest
- *
- * This function requests that SCSI Core start recovery for the
- * command by deleting the timer and adding the command to the eh
- * queue.  It can be called by either LLDDs or SCSI Core.  LLDDs who
- * implement their own error recovery MAY ignore the timeout event if
- * they generated scsi_req_abort_cmd.
- */
-void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
-{
-	if (!scsi_delete_timer(cmd))
-		return;
-	scsi_times_out(cmd);
-}
-EXPORT_SYMBOL(scsi_req_abort_cmd);
-
-/**
  * scsi_done - Enqueue the finished SCSI command into the done queue.
  * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
  * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
@@ -620,42 +597,7 @@ EXPORT_SYMBOL(scsi_req_abort_cmd);
  */
 static void scsi_done(struct scsi_cmnd *cmd)
 {
-	/*
-	 * We don't have to worry about this one timing out any more.
-	 * If we are unable to remove the timer, then the command
-	 * has already timed out.  In which case, we have no choice but to
-	 * let the timeout function run, as we have no idea where in fact
-	 * that function could really be.  It might be on another processor,
-	 * etc, etc.
-	 */
-	if (!scsi_delete_timer(cmd))
-		return;
-	__scsi_done(cmd);
-}
-
-/* Private entry to scsi_done() to complete a command when the timer
- * isn't running --- used by scsi_times_out */
-void __scsi_done(struct scsi_cmnd *cmd)
-{
-	struct request *rq = cmd->request;
-
-	/*
-	 * Set the serial numbers back to zero
-	 */
-	cmd->serial_number = 0;
-
-	atomic_inc(&cmd->device->iodone_cnt);
-	if (cmd->result)
-		atomic_inc(&cmd->device->ioerr_cnt);
-
-	BUG_ON(!rq);
-
-	/*
-	 * The uptodate/nbytes values don't matter, as we allow partial
-	 * completes and thus will check this in the softirq callback
-	 */
-	rq->completion_data = cmd;
-	blk_complete_request(rq);
+	blk_complete_request(cmd->request);
 }
 
 /*
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 8a525ab..4475648 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -112,69 +112,8 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
 }
 
 /**
- * scsi_add_timer - Start timeout timer for a single scsi command.
- * @scmd:	scsi command that is about to start running.
- * @timeout:	amount of time to allow this command to run.
- * @complete:	timeout function to call if timer isn't canceled.
- *
- * Notes:
- *    This should be turned into an inline function.  Each scsi command
- *    has its own timer, and as it is added to the queue, we set up the
- *    timer.  When the command completes, we cancel the timer.
- **/
-void scsi_add_timer(struct scsi_cmnd *scmd, int timeout,
-		    void (*complete)(struct scsi_cmnd *))
-{
-
-	/*
-	 * If the clock was already running for this command, then
-	 * first delete the timer.  The timer handling code gets rather
-	 * confused if we don't do this.
-	 */
-	if (scmd->eh_timeout.function)
-		del_timer(&scmd->eh_timeout);
-
-	scmd->eh_timeout.data = (unsigned long)scmd;
-	scmd->eh_timeout.expires = jiffies + timeout;
-	scmd->eh_timeout.function = (void (*)(unsigned long)) complete;
-
-	SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p, time:"
-					  " %d, (%p)\n", __FUNCTION__,
-					  scmd, timeout, complete));
-
-	add_timer(&scmd->eh_timeout);
-}
-
-/**
- * scsi_delete_timer - Delete/cancel timer for a given function.
- * @scmd:	Cmd that we are canceling timer for
- *
- * Notes:
- *     This should be turned into an inline function.
- *
- * Return value:
- *     1 if we were able to detach the timer.  0 if we blew it, and the
- *     timer function has already started to run.
- **/
-int scsi_delete_timer(struct scsi_cmnd *scmd)
-{
-	int rtn;
-
-	rtn = del_timer(&scmd->eh_timeout);
-
-	SCSI_LOG_ERROR_RECOVERY(5, printk("%s: scmd: %p,"
-					 " rtn: %d\n", __FUNCTION__,
-					 scmd, rtn));
-
-	scmd->eh_timeout.data = (unsigned long)NULL;
-	scmd->eh_timeout.function = NULL;
-
-	return rtn;
-}
-
-/**
  * scsi_times_out - Timeout function for normal scsi commands.
- * @scmd:	Cmd that is timing out.
+ * @req:	request that is timing out.
  *
  * Notes:
  *     We do not need to lock this.  There is the potential for a race
@@ -182,9 +121,11 @@ int scsi_delete_timer(struct scsi_cmnd *scmd)
  *     normal completion function determines that the timer has already
  *     fired, then it mustn't do anything.
  **/
-void scsi_times_out(struct scsi_cmnd *scmd)
+enum blk_eh_timer_return scsi_times_out(struct request *req)
 {
-	enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
+	struct scsi_cmnd *scmd = req->special;
+	enum blk_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
+	enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
 
 	scsi_log_completion(scmd, TIMEOUT_ERROR);
 
@@ -196,22 +137,20 @@ void scsi_times_out(struct scsi_cmnd *scmd)
 		eh_timed_out = NULL;
 
 	if (eh_timed_out)
-		switch (eh_timed_out(scmd)) {
-		case EH_HANDLED:
-			__scsi_done(scmd);
-			return;
-		case EH_RESET_TIMER:
-			scsi_add_timer(scmd, scmd->timeout_per_command,
-				       scsi_times_out);
-			return;
-		case EH_NOT_HANDLED:
+		rtn = eh_timed_out(scmd);
+		switch (rtn) {
+		case BLK_EH_NOT_HANDLED:
 			break;
+		default:
+			return rtn;
 		}
 
 	if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
 		scmd->result |= DID_TIME_OUT << 16;
-		__scsi_done(scmd);
+		return BLK_EH_HANDLED;
 	}
+
+	return BLK_EH_NOT_HANDLED;
 }
 
 /**
@@ -1666,7 +1605,6 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
 	int rtn;
 
 	scmd->request = &req;
-	memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
 
 	memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
     
@@ -1679,8 +1617,6 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
 
 	scmd->sc_data_direction		= DMA_BIDIRECTIONAL;
 
-	init_timer(&scmd->eh_timeout);
-
 	/*
 	 * Sometimes the command can get back into the timer chain,
 	 * so use the pid as an identifier.
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a417a6f..d9c7581 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -162,6 +162,29 @@ int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 }
 
 /**
+ * scsi_queue_retry - Try inserting a command in the midlevel queue.
+ *
+ * @cmd:	command that we are adding to queue.
+ * @reason:	why we are inserting command to queue.
+ *
+ * Notes:       This is very similar to scsi_queue_insert except that we
+ *              call this function when we don't know if the blk layer timer
+ *              is active or not. We could implement this either by calling
+ *              blk_delete_timer and inserting in the midlevel queue if we
+ *              successfully delete the timer OR setting appropriate result
+ *              field in the cmd and letting it go through the normal done
+ *              routines which will retry the command. For now, We call
+ *              blk_delete_timer!
+ */
+void scsi_queue_retry(struct scsi_cmnd *cmd, int reason)
+{
+	if (blk_delete_timer(cmd->request)) {
+		atomic_inc(&cmd->device->iodone_cnt);
+		scsi_queue_insert(cmd, reason);
+	}
+}
+
+/**
  * scsi_execute - insert request and wait for the result
  * @sdev:	scsi device
  * @cmd:	scsi command
@@ -1115,7 +1138,6 @@ static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 	
 	cmd->transfersize = req->data_len;
 	cmd->allowed = req->retries;
-	cmd->timeout_per_command = req->timeout;
 	cmd->done = scsi_blk_pc_done;
 	return BLKPREP_OK;
 }
@@ -1354,17 +1376,26 @@ static void scsi_kill_request(struct request *req, struct request_queue *q)
 	spin_unlock(shost->host_lock);
 	spin_lock(sdev->request_queue->queue_lock);
 
-	__scsi_done(cmd);
+	__blk_complete_request(req);
 }
 
 static void scsi_softirq_done(struct request *rq)
 {
-	struct scsi_cmnd *cmd = rq->completion_data;
-	unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
+	struct scsi_cmnd *cmd = rq->special;
+	unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
 	int disposition;
 
 	INIT_LIST_HEAD(&cmd->eh_entry);
 
+	/*
+	 * Set the serial numbers back to zero
+	 */
+	cmd->serial_number = 0;
+	
+	atomic_inc(&cmd->device->iodone_cnt);
+	if (cmd->result)
+		atomic_inc(&cmd->device->ioerr_cnt);
+
 	disposition = scsi_decide_disposition(cmd);
 	if (disposition != SUCCESS &&
 	    time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
@@ -1581,6 +1612,7 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
 
 	blk_queue_prep_rq(q, scsi_prep_fn);
 	blk_queue_softirq_done(q, scsi_softirq_done);
+	blk_queue_rq_timed_out(q, scsi_times_out);
 	return q;
 }
 
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index ee8efe8..4c29a95 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -4,6 +4,7 @@
 #include <linux/device.h>
 
 struct request_queue;
+struct request;
 struct scsi_cmnd;
 struct scsi_device;
 struct scsi_host_template;
@@ -27,7 +28,6 @@ extern void scsi_exit_hosts(void);
 extern int scsi_dispatch_cmd(struct scsi_cmnd *cmd);
 extern int scsi_setup_command_freelist(struct Scsi_Host *shost);
 extern void scsi_destroy_command_freelist(struct Scsi_Host *shost);
-extern void __scsi_done(struct scsi_cmnd *cmd);
 #ifdef CONFIG_SCSI_LOGGING
 void scsi_log_send(struct scsi_cmnd *cmd);
 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition);
@@ -49,10 +49,7 @@ extern int __init scsi_init_devinfo(void);
 extern void scsi_exit_devinfo(void);
 
 /* scsi_error.c */
-extern void scsi_add_timer(struct scsi_cmnd *, int,
-		void (*)(struct scsi_cmnd *));
-extern int scsi_delete_timer(struct scsi_cmnd *);
-extern void scsi_times_out(struct scsi_cmnd *cmd);
+extern enum blk_eh_timer_return scsi_times_out(struct request *req);
 extern int scsi_error_handler(void *host);
 extern int scsi_decide_disposition(struct scsi_cmnd *cmd);
 extern void scsi_eh_wakeup(struct Scsi_Host *shost);
@@ -67,6 +64,7 @@ int scsi_eh_get_sense(struct list_head *work_q,
 extern int scsi_maybe_unblock_host(struct scsi_device *sdev);
 extern void scsi_device_unbusy(struct scsi_device *sdev);
 extern int scsi_queue_insert(struct scsi_cmnd *cmd, int reason);
+extern void scsi_queue_retry(struct scsi_cmnd *cmd, int reason);
 extern void scsi_next_command(struct scsi_cmnd *cmd);
 extern void scsi_run_host_queues(struct Scsi_Host *shost);
 extern struct request_queue *scsi_alloc_queue(struct scsi_device *sdev);
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 34cdce6..59d1570 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -443,12 +443,15 @@ sdev_rd_attr (vendor, "%.8s\n");
 sdev_rd_attr (model, "%.16s\n");
 sdev_rd_attr (rev, "%.4s\n");
 
+/*
+ * TODO: can we make these symlinks to the block layer ones?
+ */
 static ssize_t
 sdev_show_timeout (struct device *dev, struct device_attribute *attr, char *buf)
 {
 	struct scsi_device *sdev;
 	sdev = to_scsi_device(dev);
-	return snprintf (buf, 20, "%d\n", sdev->timeout / HZ);
+	return snprintf (buf, 20, "%d\n", sdev->request_queue->rq_timeout / HZ);
 }
 
 static ssize_t
@@ -458,7 +461,7 @@ sdev_store_timeout (struct device *dev, struct device_attribute *attr, const cha
 	int timeout;
 	sdev = to_scsi_device(dev);
 	sscanf (buf, "%d\n", &timeout);
-	sdev->timeout = timeout * HZ;
+	blk_queue_rq_timeout(sdev->request_queue, timeout * HZ);
 	return count;
 }
 static DEVICE_ATTR(timeout, S_IRUGO | S_IWUSR, sdev_show_timeout, sdev_store_timeout);
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 4705725..0aef522 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -1920,15 +1920,15 @@ static int fc_vport_match(struct attribute_container *cont,
  * Notes:
  *	This routine assumes no locks are held on entry.
  **/
-static enum scsi_eh_timer_return
+static enum blk_eh_timer_return
 fc_timed_out(struct scsi_cmnd *scmd)
 {
 	struct fc_rport *rport = starget_to_rport(scsi_target(scmd->device));
 
 	if (rport->port_state == FC_PORTSTATE_BLOCKED)
-		return EH_RESET_TIMER;
+		return BLK_EH_RESET_TIMER;
 
-	return EH_NOT_HANDLED;
+	return BLK_EH_NOT_HANDLED;
 }
 
 /*
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 2c6116f..7720698 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -338,7 +338,6 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 	struct gendisk *disk = rq->rq_disk;
 	sector_t block = rq->sector;
 	unsigned int this_count = SCpnt->request_bufflen >> 9;
-	unsigned int timeout = sdp->timeout;
 
 	SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
 					"sd_init_command: block=%llu, "
@@ -489,7 +488,6 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 	SCpnt->transfersize = sdp->sector_size;
 	SCpnt->underflow = this_count << 9;
 	SCpnt->allowed = SD_MAX_RETRIES;
-	SCpnt->timeout_per_command = timeout;
 
 	/*
 	 * This is the completion routine we use.  This is matched in terms
@@ -1629,11 +1627,12 @@ static int sd_probe(struct device *dev)
 	sdkp->index = index;
 	sdkp->openers = 0;
 
-	if (!sdp->timeout) {
+	if (!sdp->request_queue->rq_timeout) {
 		if (sdp->type != TYPE_MOD)
-			sdp->timeout = SD_TIMEOUT;
+			blk_queue_rq_timeout(sdp->request_queue, SD_TIMEOUT);
 		else
-			sdp->timeout = SD_MOD_TIMEOUT;
+			blk_queue_rq_timeout(sdp->request_queue,
+					     SD_MOD_TIMEOUT);
 	}
 
 	class_device_initialize(&sdkp->cdev);
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 902eb11..cb73d58 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -298,7 +298,7 @@ static void rw_intr(struct scsi_cmnd * SCpnt)
 
 static int sr_init_command(struct scsi_cmnd * SCpnt)
 {
-	int block=0, this_count, s_size, timeout = SR_TIMEOUT;
+	int block=0, this_count, s_size;
 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
 
 	SCSI_LOG_HLQUEUE(1, printk("Doing sr request, dev = %s, block = %d\n",
@@ -407,7 +407,6 @@ static int sr_init_command(struct scsi_cmnd * SCpnt)
 	SCpnt->transfersize = cd->device->sector_size;
 	SCpnt->underflow = this_count << 9;
 	SCpnt->allowed = MAX_RETRIES;
-	SCpnt->timeout_per_command = timeout;
 
 	/*
 	 * This is the completion routine we use.  This is matched in terms
@@ -570,6 +569,8 @@ static int sr_probe(struct device *dev)
 	disk->fops = &sr_bdops;
 	disk->flags = GENHD_FL_CD;
 
+	blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
+
 	cd->device = sdev;
 	cd->disk = disk;
 	cd->driver = &sr_template;
diff --git a/drivers/scsi/sym53c8xx_2/sym_glue.c b/drivers/scsi/sym53c8xx_2/sym_glue.c
index 3db2232..702f730 100644
--- a/drivers/scsi/sym53c8xx_2/sym_glue.c
+++ b/drivers/scsi/sym53c8xx_2/sym_glue.c
@@ -571,8 +571,8 @@ static int sym53c8xx_queue_command(struct scsi_cmnd *cmd,
 	 *  Shorten our settle_time if needed for 
 	 *  this command not to time out.
 	 */
-	if (np->s.settle_time_valid && cmd->timeout_per_command) {
-		unsigned long tlimit = jiffies + cmd->timeout_per_command;
+	if (np->s.settle_time_valid && cmd->request->timeout) {
+		unsigned long tlimit = jiffies + cmd->request->timeout;
 		tlimit -= SYM_CONF_TIMER_INTERVAL*2;
 		if (time_after(np->s.settle_time, tlimit)) {
 			np->s.settle_time = tlimit;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b126c6f..bb59cdb 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -309,7 +309,8 @@ struct request {
 	void *data;
 	void *sense;
 
-	unsigned int timeout;
+	unsigned long timeout;
+	struct list_head timeout_list;
 	int retries;
 
 	/*
@@ -348,6 +349,14 @@ typedef int (issue_flush_fn) (struct request_queue *, struct gendisk *, sector_t
 typedef void (prepare_flush_fn) (struct request_queue *, struct request *);
 typedef void (softirq_done_fn)(struct request *);
 
+enum blk_eh_timer_return {
+	BLK_EH_NOT_HANDLED,
+	BLK_EH_HANDLED,
+	BLK_EH_RESET_TIMER,
+};
+
+typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *);
+
 enum blk_queue_state {
 	Queue_down,
 	Queue_up,
@@ -385,6 +394,7 @@ struct request_queue
 	issue_flush_fn		*issue_flush_fn;
 	prepare_flush_fn	*prepare_flush_fn;
 	softirq_done_fn		*softirq_done_fn;
+	rq_timed_out_fn		*rq_timed_out_fn;
 
 	/*
 	 * Dispatch queue sorting
@@ -455,6 +465,10 @@ struct request_queue
 	unsigned int		nr_sorted;
 	unsigned int		in_flight;
 
+	unsigned int		rq_timeout;
+	struct			timer_list timeout;
+	struct list_head	timeout_list;
+
 	/*
 	 * sg stuff
 	 */
@@ -733,6 +747,10 @@ extern int end_that_request_chunk(struct request *, int, int);
 extern void end_that_request_last(struct request *, int);
 extern void end_request(struct request *req, int uptodate);
 extern void blk_complete_request(struct request *);
+extern void __blk_complete_request(struct request *);
+extern void blk_abort_req(struct request *);
+extern int blk_delete_timer(struct request *);
+extern void blk_add_timer(struct request *);
 
 /*
  * end_that_request_first/chunk() takes an uptodate argument. we account
@@ -744,6 +762,8 @@ extern void blk_complete_request(struct request *);
 
 static inline void blkdev_dequeue_request(struct request *req)
 {
+	if (req->q->rq_timed_out_fn)
+		blk_add_timer(req);
 	elv_dequeue_request(req->q, req);
 }
 
@@ -767,6 +787,8 @@ extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *);
 extern void blk_queue_dma_alignment(struct request_queue *, int);
 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
+extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
+extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *);
 extern void blk_queue_issue_flush_fn(struct request_queue *, issue_flush_fn *);
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 53e1705..5841369 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -56,7 +56,6 @@ struct scsi_cmnd {
 
 	int retries;
 	int allowed;
-	int timeout_per_command;
 
 	unsigned char cmd_len;
 	enum dma_data_direction sc_data_direction;
@@ -66,7 +65,6 @@ struct scsi_cmnd {
 	unsigned char cmnd[MAX_COMMAND_SIZE];
 	unsigned request_bufflen;	/* Actual request size */
 
-	struct timer_list eh_timeout;	/* Used to time out the command. */
 	void *request_buffer;		/* Actual requested buffer */
 
 	/* These elements define the operation we ultimately want to perform */
@@ -126,7 +124,6 @@ extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
 			       struct device *);
 extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
 extern void scsi_finish_command(struct scsi_cmnd *cmd);
-extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
 
 extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
 				 size_t *offset, size_t *len);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 3b8a6a8..165ccaf 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -36,13 +36,6 @@ struct blk_queue_tags;
 #define DISABLE_CLUSTERING 0
 #define ENABLE_CLUSTERING 1
 
-enum scsi_eh_timer_return {
-	EH_NOT_HANDLED,
-	EH_HANDLED,
-	EH_RESET_TIMER,
-};
-
-
 struct scsi_host_template {
 	struct module *module;
 	const char *name;
@@ -336,7 +329,7 @@ struct scsi_host_template {
 	 *
 	 * Status: OPTIONAL
 	 */
-	enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
+	enum blk_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
 
 	/*
 	 * Name of proc directory
diff --git a/include/scsi/scsi_transport.h b/include/scsi/scsi_transport.h
index 3c18baa..23e8d97 100644
--- a/include/scsi/scsi_transport.h
+++ b/include/scsi/scsi_transport.h
@@ -21,6 +21,7 @@
 #define SCSI_TRANSPORT_H
 
 #include <linux/transport_class.h>
+#include <linux/blkdev.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_device.h>
 
@@ -64,7 +65,7 @@ struct scsi_transport_template {
 	 *			begin counting again
 	 * EH_NOT_HANDLED	Begin normal error recovery
 	 */
-	enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
+	enum blk_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
 };
 
 #define transport_class_to_shost(tc) \

-- 
Jens Axboe

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