From 242f9dcb8ba6f68fcd217a119a7648a4f69290e9 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 14 Sep 2008 05:55:09 -0700 Subject: 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 Signed-off-by: Jens Axboe --- drivers/scsi/scsi.c | 92 ++++++++++------------------------------------------- 1 file changed, 17 insertions(+), 75 deletions(-) (limited to 'drivers/scsi/scsi.c') diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index ee6be596503..dbeb86cafc0 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -291,7 +291,6 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask) 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 @@ 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; } @@ -672,6 +676,7 @@ 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_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n")); @@ -714,20 +719,8 @@ 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. @@ -744,6 +737,12 @@ 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)) { @@ -754,12 +753,8 @@ 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_insert(cmd, (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ? + rtn : SCSI_MLQUEUE_HOST_BUSY); SCSI_LOG_MLQUEUE(3, printk("queuecommand : request rejected\n")); } @@ -769,24 +764,6 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd) return rtn; } -/** - * 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 @@ -802,42 +779,7 @@ 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 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 */ -- cgit v1.2.3