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>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index ee6be59..dbeb86c 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -291,7 +291,6 @@
unsigned long flags;
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);
@@ -652,14 +651,19 @@
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;
}
@@ -672,6 +676,7 @@
* future requests should not occur until the device
* transitions out of the suspend state.
*/
+
scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
@@ -714,21 +719,9 @@
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.
*/
@@ -744,6 +737,12 @@
}
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)) {
@@ -754,12 +753,8 @@
}
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_insert(cmd, (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
+ rtn : SCSI_MLQUEUE_HOST_BUSY);
SCSI_LOG_MLQUEUE(3,
printk("queuecommand : request rejected\n"));
}
@@ -770,24 +765,6 @@
}
/**
- * 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.
@@ -802,42 +779,7 @@
*/
static void scsi_done(struct scsi_cmnd *cmd)
{
- /*
- * We don't have to worry about this one timing out anymore.
- * 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);
}
/* Move this to a header if it becomes more generally useful */