Eliminate a get_device() / put_device() pair from scsi_next_command(). Both are atomic operations hence removing these slightly improves performance.
Signed-off-by: Bart Van Assche <[email protected]> Cc: Mike Christie <[email protected]> Cc: Hannes Reinecke <[email protected]> --- drivers/scsi/scsi.c | 34 ++++++++++++++++++++-------------- drivers/scsi/scsi_lib.c | 7 +------ drivers/scsi/scsi_tgt_lib.c | 3 ++- include/scsi/scsi_cmnd.h | 4 ++-- 4 files changed, 25 insertions(+), 23 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 3d3eb74..721f3cc 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -315,13 +315,11 @@ struct scsi_cmnd *scsi_get_command_and_dev(struct scsi_device *dev, EXPORT_SYMBOL(scsi_get_command_and_dev); /** - * __scsi_put_command_and_dev() - Free a struct scsi_cmnd + * __scsi_put_command() - Free a struct scsi_cmnd but keep the sdev reference * @shost: dev->host * @cmd: Command to free - * @dev: parent scsi device */ -void __scsi_put_command_and_dev(struct Scsi_Host *shost, struct scsi_cmnd *cmd, - struct device *dev) +void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd) { unsigned long flags; @@ -335,10 +333,24 @@ void __scsi_put_command_and_dev(struct Scsi_Host *shost, struct scsi_cmnd *cmd, if (likely(cmd != NULL)) scsi_pool_free_command(shost->cmd_pool, cmd); +} +EXPORT_SYMBOL(__scsi_put_command); - put_device(dev); +/** + * scsi_put_command() - put the command but keep the sdev reference + */ +void scsi_put_command(struct scsi_cmnd *cmd) +{ + unsigned long flags; + + /* serious error if the command hasn't come from a device list */ + spin_lock_irqsave(&cmd->device->list_lock, flags); + BUG_ON(list_empty(&cmd->list)); + list_del_init(&cmd->list); + spin_unlock_irqrestore(&cmd->device->list_lock, flags); + + __scsi_put_command(cmd->device->host, cmd); } -EXPORT_SYMBOL(__scsi_put_command_and_dev); /** * scsi_put_command_and_dev() - Free a scsi command block @@ -351,15 +363,9 @@ EXPORT_SYMBOL(__scsi_put_command_and_dev); void scsi_put_command_and_dev(struct scsi_cmnd *cmd) { struct scsi_device *sdev = cmd->device; - unsigned long flags; - - /* serious error if the command hasn't come from a device list */ - spin_lock_irqsave(&cmd->device->list_lock, flags); - BUG_ON(list_empty(&cmd->list)); - list_del_init(&cmd->list); - spin_unlock_irqrestore(&cmd->device->list_lock, flags); - __scsi_put_command_and_dev(cmd->device->host, cmd, &sdev->sdev_gendev); + scsi_put_command(cmd); + put_device(&sdev->sdev_gendev); } EXPORT_SYMBOL(scsi_put_command_and_dev); diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index fc18403..f382f7d 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -542,13 +542,8 @@ 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_and_dev(cmd); + scsi_put_command(cmd); scsi_run_queue(q); - - /* ok to remove device now */ put_device(&sdev->sdev_gendev); } diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c index 79d18c5..e51add0 100644 --- a/drivers/scsi/scsi_tgt_lib.c +++ b/drivers/scsi/scsi_tgt_lib.c @@ -155,7 +155,8 @@ void scsi_host_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd) __blk_put_request(q, rq); spin_unlock_irqrestore(q->queue_lock, flags); - __scsi_put_command_and_dev(shost, cmd, &shost->shost_gendev); + __scsi_put_command(shost, cmd); + put_device(&shost->shost_gendev); } EXPORT_SYMBOL_GPL(scsi_host_put_command); diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index 3649eef..f2eb304 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -141,8 +141,8 @@ static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd) extern struct scsi_cmnd *scsi_get_command_and_dev(struct scsi_device *, gfp_t); extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t); extern void scsi_put_command_and_dev(struct scsi_cmnd *); -extern void __scsi_put_command_and_dev(struct Scsi_Host *, struct scsi_cmnd *, - struct device *); +extern void scsi_put_command(struct scsi_cmnd *); +extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *); extern void scsi_finish_command(struct scsi_cmnd *cmd); extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count, -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
