diff options
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r-- | drivers/scsi/scsi_lib.c | 116 |
1 files changed, 48 insertions, 68 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 62ec84b42e31..65a123d9c676 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -75,28 +75,6 @@ struct kmem_cache *scsi_sdb_cache; */ #define SCSI_QUEUE_DELAY 3 -/* - * Function: scsi_unprep_request() - * - * Purpose: Remove all preparation done for a request, including its - * associated scsi_cmnd, so that it can be requeued. - * - * Arguments: req - request to unprepare - * - * Lock status: Assumed that no locks are held upon entry. - * - * Returns: Nothing. - */ -static void scsi_unprep_request(struct request *req) -{ - struct scsi_cmnd *cmd = req->special; - - blk_unprep_request(req); - req->special = NULL; - - scsi_put_command(cmd); -} - /** * __scsi_queue_insert - private queue insertion * @cmd: The SCSI command being requeued @@ -206,7 +184,7 @@ void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) */ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, int data_direction, void *buffer, unsigned bufflen, - unsigned char *sense, int timeout, int retries, int flags, + unsigned char *sense, int timeout, int retries, u64 flags, int *resid) { struct request *req; @@ -257,7 +235,7 @@ EXPORT_SYMBOL(scsi_execute); int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd, int data_direction, void *buffer, unsigned bufflen, struct scsi_sense_hdr *sshdr, int timeout, int retries, - int *resid, int flags) + int *resid, u64 flags) { char *sense = NULL; int result; @@ -385,29 +363,12 @@ static inline int scsi_host_is_busy(struct Scsi_Host *shost) return 0; } -/* - * Function: scsi_run_queue() - * - * Purpose: Select a proper request queue to serve next - * - * Arguments: q - last request's queue - * - * Returns: Nothing - * - * Notes: The previous command was completely finished, start - * a new one if possible. - */ -static void scsi_run_queue(struct request_queue *q) +static void scsi_starved_list_run(struct Scsi_Host *shost) { - struct scsi_device *sdev = q->queuedata; - struct Scsi_Host *shost; LIST_HEAD(starved_list); + struct scsi_device *sdev; unsigned long flags; - shost = sdev->host; - if (scsi_target(sdev)->single_lun) - scsi_single_lun_run(sdev); - spin_lock_irqsave(shost->host_lock, flags); list_splice_init(&shost->starved_list, &starved_list); @@ -459,6 +420,28 @@ static void scsi_run_queue(struct request_queue *q) /* put any unprocessed entries back */ list_splice(&starved_list, &shost->starved_list); spin_unlock_irqrestore(shost->host_lock, flags); +} + +/* + * Function: scsi_run_queue() + * + * Purpose: Select a proper request queue to serve next + * + * Arguments: q - last request's queue + * + * Returns: Nothing + * + * Notes: The previous command was completely finished, start + * a new one if possible. + */ +static void scsi_run_queue(struct request_queue *q) +{ + struct scsi_device *sdev = q->queuedata; + + if (scsi_target(sdev)->single_lun) + scsi_single_lun_run(sdev); + if (!list_empty(&sdev->host->starved_list)) + scsi_starved_list_run(sdev->host); blk_run_queue(q); } @@ -497,16 +480,10 @@ static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) struct request *req = cmd->request; unsigned long flags; - /* - * We need to hold a reference on the device to avoid the queue being - * killed after the unlock and before scsi_run_queue is invoked which - * may happen because scsi_unprep_request() puts the command which - * releases its reference on the device. - */ - get_device(&sdev->sdev_gendev); - spin_lock_irqsave(q->queue_lock, flags); - scsi_unprep_request(req); + blk_unprep_request(req); + req->special = NULL; + scsi_put_command(cmd); blk_requeue_request(q, req); spin_unlock_irqrestore(q->queue_lock, flags); @@ -520,13 +497,9 @@ void scsi_next_command(struct scsi_cmnd *cmd) struct scsi_device *sdev = cmd->device; struct request_queue *q = sdev->request_queue; - /* need to hold a reference on the device before we let go of the cmd */ - get_device(&sdev->sdev_gendev); - scsi_put_command(cmd); scsi_run_queue(q); - /* ok to remove device now */ put_device(&sdev->sdev_gendev); } @@ -788,6 +761,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, ACTION_DELAYED_RETRY} action; char *description = NULL; + unsigned long wait_for = (cmd->allowed + 1) * req->timeout; if (result) { sense_valid = scsi_command_normalize_sense(cmd, &sshdr); @@ -989,6 +963,12 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) action = ACTION_FAIL; } + if (action != ACTION_FAIL && + time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { + action = ACTION_FAIL; + description = "Command timed out"; + } + switch (action) { case ACTION_FAIL: /* Give up and fail the remainder of the request */ @@ -1111,6 +1091,7 @@ err_exit: scsi_release_buffers(cmd); cmd->request->special = NULL; scsi_put_command(cmd); + put_device(&cmd->device->sdev_gendev); return error; } EXPORT_SYMBOL(scsi_init_io); @@ -1121,9 +1102,15 @@ static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, struct scsi_cmnd *cmd; if (!req->special) { + /* Bail if we can't get a reference to the device */ + if (!get_device(&sdev->sdev_gendev)) + return NULL; + cmd = scsi_get_command(sdev, GFP_ATOMIC); - if (unlikely(!cmd)) + if (unlikely(!cmd)) { + put_device(&sdev->sdev_gendev); return NULL; + } req->special = cmd; } else { cmd = req->special; @@ -1286,6 +1273,7 @@ int scsi_prep_return(struct request_queue *q, struct request *req, int ret) struct scsi_cmnd *cmd = req->special; scsi_release_buffers(cmd); scsi_put_command(cmd); + put_device(&cmd->device->sdev_gendev); req->special = NULL; } break; @@ -1543,16 +1531,14 @@ static void scsi_softirq_done(struct request *rq) * Lock status: IO request lock assumed to be held when called. */ static void scsi_request_fn(struct request_queue *q) + __releases(q->queue_lock) + __acquires(q->queue_lock) { struct scsi_device *sdev = q->queuedata; struct Scsi_Host *shost; struct scsi_cmnd *cmd; struct request *req; - if(!get_device(&sdev->sdev_gendev)) - /* We must be tearing the block queue down already */ - return; - /* * To start with, we keep looping until the queue is empty, or until * the host is no longer able to accept any more requests. @@ -1641,7 +1627,7 @@ static void scsi_request_fn(struct request_queue *q) goto out_delay; } - goto out; + return; not_ready: spin_unlock_irq(shost->host_lock); @@ -1660,12 +1646,6 @@ static void scsi_request_fn(struct request_queue *q) 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); - put_device(&sdev->sdev_gendev); - spin_lock_irq(q->queue_lock); } u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) |