diff options
Diffstat (limited to 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/scsi_lib.c | 44 | ||||
| -rw-r--r-- | drivers/scsi/scsi_transport_fc.c | 2 | ||||
| -rw-r--r-- | drivers/scsi/scsi_transport_sas.c | 6 |
3 files changed, 21 insertions, 31 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 2d63c8a..6d5c7ff 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -67,6 +67,13 @@ static struct scsi_host_sg_pool scsi_sg_pools[] = { struct kmem_cache *scsi_sdb_cache; +/* + * When to reinvoke queueing after a resource shortage. It's 3 msecs to + * not change behaviour from the previous unplug mechanism, experimentation + * may prove this needs changing. + */ +#define SCSI_QUEUE_DELAY 3 + static void scsi_run_queue(struct request_queue *q); /* @@ -149,14 +156,7 @@ static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) /* * Requeue this command. It will go before all other commands * that are already in the queue. - * - * NOTE: there is magic here about the way the queue is plugged if - * we have no outstanding commands. - * - * Although we *don't* plug the queue, we call the request - * function. The SCSI request function detects the blocked condition - * and plugs the queue appropriately. - */ + */ spin_lock_irqsave(q->queue_lock, flags); blk_requeue_request(q, cmd->request); spin_unlock_irqrestore(q->queue_lock, flags); @@ -1226,11 +1226,11 @@ int scsi_prep_return(struct request_queue *q, struct request *req, int ret) case BLKPREP_DEFER: /* * If we defer, the blk_peek_request() returns NULL, but the - * queue must be restarted, so we plug here if no returning - * command will automatically do that. + * queue must be restarted, so we schedule a callback to happen + * shortly. */ if (sdev->device_busy == 0) - blk_plug_device(q); + blk_delay_queue(q, SCSI_QUEUE_DELAY); break; default: req->cmd_flags |= REQ_DONTPREP; @@ -1269,7 +1269,7 @@ static inline int scsi_dev_queue_ready(struct request_queue *q, sdev_printk(KERN_INFO, sdev, "unblocking device at zero depth\n")); } else { - blk_plug_device(q); + blk_delay_queue(q, SCSI_QUEUE_DELAY); return 0; } } @@ -1499,7 +1499,7 @@ static void scsi_request_fn(struct request_queue *q) * the host is no longer able to accept any more requests. */ shost = sdev->host; - while (!blk_queue_plugged(q)) { + for (;;) { int rtn; /* * get next queueable request. We do this early to make sure @@ -1578,15 +1578,8 @@ static void scsi_request_fn(struct request_queue *q) */ rtn = scsi_dispatch_cmd(cmd); spin_lock_irq(q->queue_lock); - if(rtn) { - /* we're refusing the command; because of - * the way locks get dropped, we need to - * check here if plugging is required */ - if(sdev->device_busy == 0) - blk_plug_device(q); - - break; - } + if (rtn) + goto out_delay; } goto out; @@ -1605,9 +1598,10 @@ static void scsi_request_fn(struct request_queue *q) spin_lock_irq(q->queue_lock); blk_requeue_request(q, req); sdev->device_busy--; - if(sdev->device_busy == 0) - blk_plug_device(q); - out: +out_delay: + if (sdev->device_busy == 0) + blk_delay_queue(q, SCSI_QUEUE_DELAY); +out: /* must be careful here...if we trigger the ->remove() function * we cannot be holding the q lock */ spin_unlock_irq(q->queue_lock); diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c index 5c3ccfc..2941d2d 100644 --- a/drivers/scsi/scsi_transport_fc.c +++ b/drivers/scsi/scsi_transport_fc.c @@ -3913,7 +3913,7 @@ fc_bsg_request_handler(struct request_queue *q, struct Scsi_Host *shost, if (!get_device(dev)) return; - while (!blk_queue_plugged(q)) { + while (1) { if (rport && (rport->port_state == FC_PORTSTATE_BLOCKED) && !(rport->flags & FC_RPORT_FAST_FAIL_TIMEDOUT)) break; diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c index 927e99c..c6fcf76 100644 --- a/drivers/scsi/scsi_transport_sas.c +++ b/drivers/scsi/scsi_transport_sas.c @@ -173,11 +173,7 @@ static void sas_smp_request(struct request_queue *q, struct Scsi_Host *shost, int ret; int (*handler)(struct Scsi_Host *, struct sas_rphy *, struct request *); - while (!blk_queue_plugged(q)) { - req = blk_fetch_request(q); - if (!req) - break; - + while ((req = blk_fetch_request(q)) != NULL) { spin_unlock_irq(q->queue_lock); handler = to_sas_internal(shost->transportt)->f->smp_handler; |
