From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick Mansfield Subject: [PATCH] 6/7 add and use a per-scsi_device queue_lock Date: Mon, 24 Mar 2003 18:03:41 -0800 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20030324180341.E15047@beaverton.ibm.com> References: <20030324175337.A14957@beaverton.ibm.com> <20030324175422.A14996@beaverton.ibm.com> <20030324180227.A15047@beaverton.ibm.com> <20030324180247.B15047@beaverton.ibm.com> <20030324180304.C15047@beaverton.ibm.com> <20030324180325.D15047@beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e32.co.us.ibm.com (8.12.8/8.12.2) with ESMTP id h2P26DTr072820 for ; Mon, 24 Mar 2003 21:06:13 -0500 Received: from localhost.localdomain (d03av02.boulder.ibm.com [9.17.193.82]) by westrelay02.boulder.ibm.com (8.12.8/NCO/VER6.5) with ESMTP id h2P27EBS100216 for ; Mon, 24 Mar 2003 19:07:15 -0700 Received: (from patman@localhost) by localhost.localdomain (8.11.2/8.11.6) id h2P23fM15158 for linux-scsi@vger.kernel.org; Mon, 24 Mar 2003 18:03:41 -0800 Content-Disposition: inline In-Reply-To: <20030324180325.D15047@beaverton.ibm.com>; from patmans@us.ibm.com on Mon, Mar 24, 2003 at 06:03:25PM -0800 List-Id: linux-scsi@vger.kernel.org To: linux-scsi@vger.kernel.org Add and use a per scsi_device queue_lock. diff -purN -X /home/patman/dontdiff salloc_queue-25/drivers/scsi/hosts.c lksplit-25/drivers/scsi/hosts.c --- salloc_queue-25/drivers/scsi/hosts.c Mon Mar 24 12:14:28 2003 +++ lksplit-25/drivers/scsi/hosts.c Mon Mar 24 12:15:10 2003 @@ -620,7 +620,6 @@ void scsi_host_busy_dec_and_test(struct spin_lock_irqsave(shost->host_lock, flags); shost->host_busy--; - sdev->device_busy--; if (shost->in_recovery && shost->host_failed && (shost->host_busy == shost->host_failed)) { diff -purN -X /home/patman/dontdiff salloc_queue-25/drivers/scsi/scsi.c lksplit-25/drivers/scsi/scsi.c --- salloc_queue-25/drivers/scsi/scsi.c Mon Mar 24 11:57:13 2003 +++ lksplit-25/drivers/scsi/scsi.c Mon Mar 24 12:15:10 2003 @@ -447,8 +447,6 @@ int scsi_dispatch_cmd(Scsi_Cmnd * SCpnt) host = SCpnt->device->host; - ASSERT_LOCK(host->host_lock, 0); - /* Assign a unique nonzero serial_number. */ if (++serial_number == 0) serial_number = 1; @@ -574,8 +572,6 @@ void scsi_init_cmd_from_req(Scsi_Cmnd * { struct Scsi_Host *host = SCpnt->device->host; - ASSERT_LOCK(host->host_lock, 0); - SCpnt->owner = SCSI_OWNER_MIDLEVEL; SRpnt->sr_command = SCpnt; @@ -819,12 +815,11 @@ void scsi_finish_command(Scsi_Cmnd * SCp struct Scsi_Host *host; Scsi_Device *device; Scsi_Request * SRpnt; + unsigned int flags; host = SCpnt->device->host; device = SCpnt->device; - ASSERT_LOCK(host->host_lock, 0); - /* * We need to protect the decrement, as otherwise a race condition * would exist. Fiddling with SCpnt isn't a problem as the @@ -833,6 +828,9 @@ void scsi_finish_command(Scsi_Cmnd * SCp * shared. */ scsi_host_busy_dec_and_test(host, device); + spin_lock_irqsave(SCpnt->device->request_queue->queue_lock, flags); + SCpnt->device->device_busy--; + spin_unlock_irqrestore(SCpnt->device->request_queue->queue_lock, flags); /* * Clear the flags which say that the device/host is no longer diff -purN -X /home/patman/dontdiff salloc_queue-25/drivers/scsi/scsi.h lksplit-25/drivers/scsi/scsi.h --- salloc_queue-25/drivers/scsi/scsi.h Mon Mar 24 12:14:51 2003 +++ lksplit-25/drivers/scsi/scsi.h Mon Mar 24 12:15:10 2003 @@ -418,7 +418,7 @@ extern void scsi_io_completion(Scsi_Cmnd int block_sectors); extern int scsi_queue_insert(struct scsi_cmnd *cmd, int reason); extern void scsi_queue_next_request(request_queue_t *q, struct scsi_cmnd *cmd); -extern request_queue_t *scsi_alloc_queue(struct Scsi_Host *shost); +extern request_queue_t *scsi_alloc_queue(struct scsi_device *sdev); extern void scsi_free_queue(request_queue_t *q); extern int scsi_init_queue(void); extern void scsi_exit_queue(void); @@ -554,6 +554,7 @@ struct scsi_device { struct Scsi_Host *host; request_queue_t *request_queue; volatile unsigned short device_busy; /* commands actually active on low-level */ + spinlock_t sdev_lock; /* also the request queue_lock */ spinlock_t list_lock; struct list_head cmd_list; /* queue of in use SCSI Command structures */ struct list_head starved_entry; diff -purN -X /home/patman/dontdiff salloc_queue-25/drivers/scsi/scsi_error.c lksplit-25/drivers/scsi/scsi_error.c --- salloc_queue-25/drivers/scsi/scsi_error.c Mon Mar 24 12:14:51 2003 +++ lksplit-25/drivers/scsi/scsi_error.c Mon Mar 24 12:15:10 2003 @@ -431,8 +431,6 @@ static int scsi_send_eh_cmnd(struct scsi unsigned long flags; int rtn = SUCCESS; - ASSERT_LOCK(host->host_lock, 0); - /* * we will use a queued command if possible, otherwise we will * emulate the queuing and calling of completion function ourselves. @@ -1405,8 +1403,6 @@ static void scsi_restart_operations(stru struct scsi_device *sdev; unsigned long flags; - ASSERT_LOCK(shost->host_lock, 0); - /* * If the door was locked, we need to insert a door lock request * onto the head of the SCSI request queue for the device. There @@ -1434,18 +1430,11 @@ static void scsi_restart_operations(stru * now that error recovery is done, we will need to ensure that these * requests are started. */ - spin_lock_irqsave(shost->host_lock, flags); list_for_each_entry(sdev, &shost->my_devices, siblings) { - if ((shost->can_queue > 0 && - (shost->host_busy >= shost->can_queue)) - || (shost->host_blocked) - || (shost->host_self_blocked)) { - break; - } - + spin_lock_irqsave(sdev->request_queue->queue_lock, flags); __blk_run_queue(sdev->request_queue); + spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); } - spin_unlock_irqrestore(shost->host_lock, flags); } /** diff -purN -X /home/patman/dontdiff salloc_queue-25/drivers/scsi/scsi_lib.c lksplit-25/drivers/scsi/scsi_lib.c --- salloc_queue-25/drivers/scsi/scsi_lib.c Mon Mar 24 12:15:01 2003 +++ lksplit-25/drivers/scsi/scsi_lib.c Mon Mar 24 12:15:10 2003 @@ -92,6 +92,7 @@ int scsi_queue_insert(struct scsi_cmnd * { struct Scsi_Host *host = cmd->device->host; struct scsi_device *device = cmd->device; + unsigned long flags; SCSI_LOG_MLQUEUE(1, printk("Inserting command %p into mlqueue\n", cmd)); @@ -130,6 +131,9 @@ int scsi_queue_insert(struct scsi_cmnd * * Decrement the counters, since these commands are no longer * active on the host/device. */ + spin_lock_irqsave(device->request_queue->queue_lock, flags); + device->device_busy--; + spin_unlock_irqrestore(device->request_queue->queue_lock, flags); scsi_host_busy_dec_and_test(host, device); /* @@ -343,7 +347,7 @@ static int scsi_single_lun_check(struct * outstanding for current_sdev, call __blk_run_queue for the next * scsi_device on the same target that has requests. * - * Called with queue_lock held. + * Called with *no* scsi locks held. */ static void scsi_single_lun_run(struct scsi_device *current_sdev, struct request_queue *q) @@ -407,9 +411,6 @@ void scsi_queue_next_request(request_que struct Scsi_Host *shost; unsigned long flags; - ASSERT_LOCK(q->queue_lock, 0); - - spin_lock_irqsave(q->queue_lock, flags); if (cmd != NULL) { /* @@ -418,6 +419,7 @@ void scsi_queue_next_request(request_que * in which case we need to request the blocks that come after * the bad sector. */ + spin_lock_irqsave(q->queue_lock, flags); cmd->request->special = cmd; if (blk_rq_tagged(cmd->request)) blk_queue_end_tag(q, cmd->request); @@ -430,6 +432,7 @@ void scsi_queue_next_request(request_que cmd->request->flags |= REQ_SPECIAL; cmd->request->flags &= ~REQ_DONTPREP; __elv_add_request(q, cmd->request, 0, 0); + spin_unlock_irqrestore(q->queue_lock, flags); } sdev = q->queuedata; @@ -438,6 +441,7 @@ void scsi_queue_next_request(request_que scsi_single_lun_run(sdev, q); shost = sdev->host; + spin_lock_irqsave(shost->host_lock, flags); while (!list_empty(&shost->starved_list) && !shost->host_blocked && !shost->host_self_blocked && !((shost->can_queue > 0) && @@ -447,15 +451,26 @@ void scsi_queue_next_request(request_que * starved queues, call __blk_run_queue. scsi_request_fn * drops the queue_lock and can add us back to the * starved_list. + * + * host_lock protects the starved_list and starved_entry. + * scsi_request_fn must get the host_lock before checking + * or modifying starved_list or starved_entry. */ sdev2 = list_entry(shost->starved_list.next, struct scsi_device, starved_entry); list_del_init(&sdev2->starved_entry); + spin_unlock_irqrestore(shost->host_lock, flags); + + spin_lock_irqsave(sdev2->request_queue->queue_lock, flags); __blk_run_queue(sdev2->request_queue); + spin_unlock_irqrestore(sdev2->request_queue->queue_lock, flags); + + spin_lock_irqsave(shost->host_lock, flags); } + spin_unlock_irqrestore(shost->host_lock, flags); + spin_lock_irqsave(q->queue_lock, flags); __blk_run_queue(q); - spin_unlock_irqrestore(q->queue_lock, flags); } @@ -489,8 +504,6 @@ static struct scsi_cmnd *scsi_end_reques struct request *req = cmd->request; unsigned long flags; - ASSERT_LOCK(q->queue_lock, 0); - /* * If there are blocks left over at the end, set up the command * to queue the remainder of them. @@ -588,8 +601,6 @@ static void scsi_release_buffers(struct { struct request *req = cmd->request; - ASSERT_LOCK(cmd->device->host->host_lock, 0); - /* * Free up any indirection buffers we allocated for DMA purposes. */ @@ -670,8 +681,6 @@ void scsi_io_completion(struct scsi_cmnd * would be used if we just wanted to retry, for example. * */ - ASSERT_LOCK(q->queue_lock, 0); - /* * Free up any indirection buffers we allocated for DMA purposes. * For the case of a READ, we need to copy the data out of the @@ -1075,7 +1084,7 @@ static inline int scsi_check_sdev(struct /* * scsi_check_shost: if we can send requests to shost, return 0 else return 1. * - * Called with the queue_lock held. + * Called with queue_lock and host_lock held. */ static inline int scsi_check_shost(struct request_queue *q, struct Scsi_Host *shost, @@ -1132,8 +1141,7 @@ static void scsi_request_fn(request_queu struct Scsi_Host *shost = sdev->host; struct scsi_cmnd *cmd; struct request *req; - - ASSERT_LOCK(q->queue_lock, 1); + unsigned int flags; /* * To start with, we keep looping until the queue is empty, or until @@ -1141,7 +1149,7 @@ static void scsi_request_fn(request_queu */ for (;;) { if (blk_queue_plugged(q)) - break; + goto completed; /* * get next queueable request. We do this early to make sure @@ -1152,28 +1160,29 @@ static void scsi_request_fn(request_queu req = elv_next_request(q); if (scsi_check_sdev(q, sdev)) - break; + goto completed; + spin_lock_irqsave(shost->host_lock, flags); if (scsi_check_shost(q, shost, sdev)) - break; + goto after_host_lock; if (sdev->single_lun && scsi_single_lun_check(sdev)) - break; + goto after_host_lock; /* * If we couldn't find a request that could be queued, then we * can also quit. */ if (blk_queue_empty(q)) - break; + goto after_host_lock; if (!req) { /* If the device is busy, a returning I/O * will restart the queue. Otherwise, we have * to plug the queue */ - if (sdev->device_busy == 0) + if (sdev->device_busy == 1) blk_plug_device(q); - break; + goto after_host_lock; } cmd = req->special; @@ -1195,11 +1204,9 @@ static void scsi_request_fn(request_queu if (!(blk_queue_tagged(q) && (blk_queue_start_tag(q, req) == 0))) blkdev_dequeue_request(req); - /* - * Now bump the usage count for both the host and the - * device. - */ shost->host_busy++; + spin_unlock_irqrestore(shost->host_lock, flags); + sdev->device_busy++; spin_unlock_irq(q->queue_lock); @@ -1220,6 +1227,11 @@ static void scsi_request_fn(request_queu */ spin_lock_irq(q->queue_lock); } +completed: + return; + +after_host_lock: + spin_unlock_irqrestore(shost->host_lock, flags); } u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) @@ -1241,15 +1253,20 @@ u64 scsi_calculate_bounce_limit(struct S return BLK_BOUNCE_HIGH; } -request_queue_t *scsi_alloc_queue(struct Scsi_Host *shost) +request_queue_t *scsi_alloc_queue(struct scsi_device *sdev) { request_queue_t *q; + struct Scsi_Host *shost; q = kmalloc(sizeof(*q), GFP_ATOMIC); if (!q) return NULL; memset(q, 0, sizeof(*q)); + /* + * XXX move host code to scsi_register + */ + shost = sdev->host; if (!shost->max_sectors) { /* * Driver imposes no hard sector transfer limit. @@ -1258,7 +1275,7 @@ request_queue_t *scsi_alloc_queue(struct shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS; } - blk_init_queue(q, scsi_request_fn, shost->host_lock); + blk_init_queue(q, scsi_request_fn, &sdev->sdev_lock); blk_queue_prep_rq(q, scsi_prep_fn); blk_queue_max_hw_segments(q, shost->sg_tablesize); diff -purN -X /home/patman/dontdiff salloc_queue-25/drivers/scsi/scsi_scan.c lksplit-25/drivers/scsi/scsi_scan.c --- salloc_queue-25/drivers/scsi/scsi_scan.c Mon Mar 24 12:15:05 2003 +++ lksplit-25/drivers/scsi/scsi_scan.c Mon Mar 24 12:15:10 2003 @@ -415,7 +415,8 @@ static struct scsi_device *scsi_alloc_sd */ sdev->borken = 1; - sdev->request_queue = scsi_alloc_queue(shost); + spin_lock_init(&sdev->sdev_lock); + sdev->request_queue = scsi_alloc_queue(sdev); if (!sdev->request_queue) goto out_free_dev;