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path: root/drivers/scsi/scsi_lib.c
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Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r--drivers/scsi/scsi_lib.c114
1 files changed, 47 insertions, 67 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 7bd7f0d5f050..5681c05ac506 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
@@ -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)
@@ -1684,7 +1664,7 @@ u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
host_dev = scsi_get_device(shost);
if (host_dev && host_dev->dma_mask)
- bounce_limit = dma_max_pfn(host_dev) << PAGE_SHIFT;
+ bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
return bounce_limit;
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-20 21:25:27 +0300