block: unify request timeout handling

Right now SCSI and others do their own command timeout handling.
Move those bits to the block layer.

Instead of having a timer per command, we try to be a bit more clever
and simply have one per-queue. This avoids the overhead of having to
tear down and setup a timer for each command, so it will result in a lot
less timer fiddling.

Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 13 insertions, 77 deletions

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 39ce3ab..fecefa0 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", __func__,
-					  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", __func__,
-					 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;
 }
 
 /**
@@ -1793,7 +1732,6 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
 
 	blk_rq_init(NULL, &req);
 	scmd->request = &req;
-	memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout));
 
 	scmd->cmnd = req.cmd;
 
@@ -1804,8 +1742,6 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
 
 	scmd->sc_data_direction		= DMA_BIDIRECTIONAL;
 
-	init_timer(&scmd->eh_timeout);
-
 	spin_lock_irqsave(shost->host_lock, flags);
 	shost->tmf_in_progress = 1;
 	spin_unlock_irqrestore(shost->host_lock, flags);