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Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r--drivers/scsi/scsi_lib.c230
1 files changed, 105 insertions, 125 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index df4905df5cd4..0ba7a65e7c8d 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -202,24 +202,17 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
blk_mq_requeue_request(cmd->request, true);
}
-/*
- * Function: scsi_queue_insert()
- *
- * Purpose: Insert a command in the midlevel queue.
- *
- * Arguments: cmd - command that we are adding to queue.
- * reason - why we are inserting command to queue.
- *
- * Lock status: Assumed that lock is not held upon entry.
+/**
+ * scsi_queue_insert - Reinsert a command in the queue.
+ * @cmd: command that we are adding to queue.
+ * @reason: why we are inserting command to queue.
*
- * Returns: Nothing.
+ * We do this for one of two cases. Either the host is busy and it cannot accept
+ * any more commands for the time being, or the device returned QUEUE_FULL and
+ * can accept no more commands.
*
- * Notes: We do this for one of two cases. Either the host is busy
- * and it cannot accept any more commands for the time being,
- * or the device returned QUEUE_FULL and can accept no more
- * commands.
- * Notes: This could be called either from an interrupt context or a
- * normal process context.
+ * Context: This could be called either from an interrupt context or a normal
+ * process context.
*/
void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
{
@@ -301,16 +294,12 @@ int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
}
EXPORT_SYMBOL(__scsi_execute);
-/*
- * Function: scsi_init_cmd_errh()
- *
- * Purpose: Initialize cmd fields related to error handling.
- *
- * Arguments: cmd - command that is ready to be queued.
+/**
+ * scsi_init_cmd_errh - Initialize cmd fields related to error handling.
+ * @cmd: command that is ready to be queued.
*
- * Notes: This function has the job of initializing a number of
- * fields related to error handling. Typically this will
- * be called once for each command, as required.
+ * This function has the job of initializing a number of fields related to error
+ * handling. Typically this will be called once for each command, as required.
*/
static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
{
@@ -496,17 +485,11 @@ static void scsi_starved_list_run(struct Scsi_Host *shost)
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
+/**
+ * scsi_run_queue - Select a proper request queue to serve next.
+ * @q: last request's queue
*
- * Notes: The previous command was completely finished, start
- * a new one if possible.
+ * The previous command was completely finished, start a new one if possible.
*/
static void scsi_run_queue(struct request_queue *q)
{
@@ -548,7 +531,7 @@ static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
}
}
-static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
+static void scsi_free_sgtables(struct scsi_cmnd *cmd)
{
if (cmd->sdb.table.nents)
sg_free_table_chained(&cmd->sdb.table,
@@ -560,7 +543,7 @@ static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
{
- scsi_mq_free_sgtables(cmd);
+ scsi_free_sgtables(cmd);
scsi_uninit_cmd(cmd);
}
@@ -896,34 +879,27 @@ static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
return result;
}
-/*
- * Function: scsi_io_completion()
- *
- * Purpose: Completion processing for block device I/O requests.
- *
- * Arguments: cmd - command that is finished.
- *
- * Lock status: Assumed that no lock is held upon entry.
- *
- * Returns: Nothing
- *
- * Notes: We will finish off the specified number of sectors. If we
- * are done, the command block will be released and the queue
- * function will be goosed. If we are not done then we have to
- * figure out what to do next:
- *
- * a) We can call scsi_requeue_command(). The request
- * will be unprepared and put back on the queue. Then
- * a new command will be created for it. This should
- * be used if we made forward progress, or if we want
- * to switch from READ(10) to READ(6) for example.
- *
- * b) We can call __scsi_queue_insert(). The request will
- * be put back on the queue and retried using the same
- * command as before, possibly after a delay.
- *
- * c) We can call scsi_end_request() with blk_stat other than
- * BLK_STS_OK, to fail the remainder of the request.
+/**
+ * scsi_io_completion - Completion processing for SCSI commands.
+ * @cmd: command that is finished.
+ * @good_bytes: number of processed bytes.
+ *
+ * We will finish off the specified number of sectors. If we are done, the
+ * command block will be released and the queue function will be goosed. If we
+ * are not done then we have to figure out what to do next:
+ *
+ * a) We can call scsi_io_completion_reprep(). The request will be
+ * unprepared and put back on the queue. Then a new command will
+ * be created for it. This should be used if we made forward
+ * progress, or if we want to switch from READ(10) to READ(6) for
+ * example.
+ *
+ * b) We can call scsi_io_completion_action(). The request will be
+ * put back on the queue and retried using the same command as
+ * before, possibly after a delay.
+ *
+ * c) We can call scsi_end_request() with blk_stat other than
+ * BLK_STS_OK, to fail the remainder of the request.
*/
void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
{
@@ -951,8 +927,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
blk_rq_sectors(req), good_bytes));
/*
- * Next deal with any sectors which we were able to correctly
- * handle. Failed, zero length commands always need to drop down
+ * Failed, zero length commands always need to drop down
* to retry code. Fast path should return in this block.
*/
if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
@@ -986,16 +961,14 @@ static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
sdev->host->hostt->dma_need_drain(rq);
}
-/*
- * Function: scsi_init_io()
- *
- * Purpose: SCSI I/O initialize function.
- *
- * Arguments: cmd - Command descriptor we wish to initialize
+/**
+ * scsi_init_io - SCSI I/O initialization function.
+ * @cmd: command descriptor we wish to initialize
*
- * Returns: BLK_STS_OK on success
- * BLK_STS_RESOURCE if the failure is retryable
- * BLK_STS_IOERR if the failure is fatal
+ * Returns:
+ * * BLK_STS_OK - on success
+ * * BLK_STS_RESOURCE - if the failure is retryable
+ * * BLK_STS_IOERR - if the failure is fatal
*/
blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
{
@@ -1086,7 +1059,7 @@ blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
return BLK_STS_OK;
out_free_sgtables:
- scsi_mq_free_sgtables(cmd);
+ scsi_free_sgtables(cmd);
return ret;
}
EXPORT_SYMBOL(scsi_init_io);
@@ -1217,6 +1190,7 @@ static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
struct request *req)
{
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
+ blk_status_t ret;
if (!blk_rq_bytes(req))
cmd->sc_data_direction = DMA_NONE;
@@ -1226,9 +1200,14 @@ static blk_status_t scsi_setup_cmnd(struct scsi_device *sdev,
cmd->sc_data_direction = DMA_FROM_DEVICE;
if (blk_rq_is_scsi(req))
- return scsi_setup_scsi_cmnd(sdev, req);
+ ret = scsi_setup_scsi_cmnd(sdev, req);
else
- return scsi_setup_fs_cmnd(sdev, req);
+ ret = scsi_setup_fs_cmnd(sdev, req);
+
+ if (ret != BLK_STS_OK)
+ scsi_free_sgtables(cmd);
+
+ return ret;
}
static blk_status_t
@@ -1893,6 +1872,7 @@ struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
int scsi_mq_setup_tags(struct Scsi_Host *shost)
{
unsigned int cmd_size, sgl_size;
+ struct blk_mq_tag_set *tag_set = &shost->tag_set;
sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
scsi_mq_inline_sgl_size(shost));
@@ -1901,21 +1881,21 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
cmd_size += sizeof(struct scsi_data_buffer) +
sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
- memset(&shost->tag_set, 0, sizeof(shost->tag_set));
+ memset(tag_set, 0, sizeof(*tag_set));
if (shost->hostt->commit_rqs)
- shost->tag_set.ops = &scsi_mq_ops;
+ tag_set->ops = &scsi_mq_ops;
else
- shost->tag_set.ops = &scsi_mq_ops_no_commit;
- shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
- shost->tag_set.queue_depth = shost->can_queue;
- shost->tag_set.cmd_size = cmd_size;
- shost->tag_set.numa_node = NUMA_NO_NODE;
- shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
- shost->tag_set.flags |=
+ tag_set->ops = &scsi_mq_ops_no_commit;
+ tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
+ tag_set->queue_depth = shost->can_queue;
+ tag_set->cmd_size = cmd_size;
+ tag_set->numa_node = NUMA_NO_NODE;
+ tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
+ tag_set->flags |=
BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
- shost->tag_set.driver_data = shost;
+ tag_set->driver_data = shost;
- return blk_mq_alloc_tag_set(&shost->tag_set);
+ return blk_mq_alloc_tag_set(tag_set);
}
void scsi_mq_destroy_tags(struct Scsi_Host *shost)
@@ -1944,21 +1924,13 @@ struct scsi_device *scsi_device_from_queue(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(scsi_device_from_queue);
-/*
- * Function: scsi_block_requests()
- *
- * Purpose: Utility function used by low-level drivers to prevent further
- * commands from being queued to the device.
- *
- * Arguments: shost - Host in question
- *
- * Returns: Nothing
- *
- * Lock status: No locks are assumed held.
+/**
+ * scsi_block_requests - Utility function used by low-level drivers to prevent
+ * further commands from being queued to the device.
+ * @shost: host in question
*
- * Notes: There is no timer nor any other means by which the requests
- * get unblocked other than the low-level driver calling
- * scsi_unblock_requests().
+ * There is no timer nor any other means by which the requests get unblocked
+ * other than the low-level driver calling scsi_unblock_requests().
*/
void scsi_block_requests(struct Scsi_Host *shost)
{
@@ -1966,25 +1938,15 @@ void scsi_block_requests(struct Scsi_Host *shost)
}
EXPORT_SYMBOL(scsi_block_requests);
-/*
- * Function: scsi_unblock_requests()
- *
- * Purpose: Utility function used by low-level drivers to allow further
- * commands from being queued to the device.
- *
- * Arguments: shost - Host in question
- *
- * Returns: Nothing
- *
- * Lock status: No locks are assumed held.
- *
- * Notes: There is no timer nor any other means by which the requests
- * get unblocked other than the low-level driver calling
- * scsi_unblock_requests().
- *
- * This is done as an API function so that changes to the
- * internals of the scsi mid-layer won't require wholesale
- * changes to drivers that use this feature.
+/**
+ * scsi_unblock_requests - Utility function used by low-level drivers to allow
+ * further commands to be queued to the device.
+ * @shost: host in question
+ *
+ * There is no timer nor any other means by which the requests get unblocked
+ * other than the low-level driver calling scsi_unblock_requests(). This is done
+ * as an API function so that changes to the internals of the scsi mid-layer
+ * won't require wholesale changes to drivers that use this feature.
*/
void scsi_unblock_requests(struct Scsi_Host *shost)
{
@@ -2865,11 +2827,27 @@ scsi_host_block(struct Scsi_Host *shost)
struct scsi_device *sdev;
int ret = 0;
+ /*
+ * Call scsi_internal_device_block_nowait so we can avoid
+ * calling synchronize_rcu() for each LUN.
+ */
shost_for_each_device(sdev, shost) {
- ret = scsi_internal_device_block(sdev);
+ mutex_lock(&sdev->state_mutex);
+ ret = scsi_internal_device_block_nowait(sdev);
+ mutex_unlock(&sdev->state_mutex);
if (ret)
break;
}
+
+ /*
+ * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
+ * calling synchronize_rcu() once is enough.
+ */
+ WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
+
+ if (!ret)
+ synchronize_rcu();
+
return ret;
}
EXPORT_SYMBOL_GPL(scsi_host_block);
@@ -2882,8 +2860,10 @@ scsi_host_unblock(struct Scsi_Host *shost, int new_state)
shost_for_each_device(sdev, shost) {
ret = scsi_internal_device_unblock(sdev, new_state);
- if (ret)
+ if (ret) {
+ scsi_device_put(sdev);
break;
+ }
}
return ret;
}