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 39ce3aba1dac..fecefa05cb62 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);