From 0479633686d370303e3430256ace4bd5f7f138dc Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 20 Feb 2014 14:20:55 -0800 Subject: [SCSI] do not manipulate device reference counts in scsi_get/put_command Many callers won't need this and we can optimize them away. In addition the handling in the __-prefixed variants was inconsistant to start with. Based on an earlier patch from Bart Van Assche. [jejb: fix kerneldoc probelm picked up by Fengguang Wu] Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: James Bottomley --- drivers/scsi/scsi.c | 37 ++++++++++++------------------------- drivers/scsi/scsi_error.c | 6 ++++++ drivers/scsi/scsi_lib.c | 12 +++++++++++- drivers/scsi/scsi_tgt_lib.c | 3 ++- include/scsi/scsi_cmnd.h | 3 +-- 5 files changed, 32 insertions(+), 29 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index fb86479ffd4a..2b12983d2b2d 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -284,27 +284,19 @@ EXPORT_SYMBOL_GPL(__scsi_get_command); */ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask) { - struct scsi_cmnd *cmd; + struct scsi_cmnd *cmd = __scsi_get_command(dev->host, gfp_mask); + unsigned long flags; - /* Bail if we can't get a reference to the device */ - if (!get_device(&dev->sdev_gendev)) + if (unlikely(cmd == NULL)) return NULL; - cmd = __scsi_get_command(dev->host, gfp_mask); - - if (likely(cmd != NULL)) { - unsigned long flags; - - cmd->device = dev; - INIT_LIST_HEAD(&cmd->list); - INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); - spin_lock_irqsave(&dev->list_lock, flags); - list_add_tail(&cmd->list, &dev->cmd_list); - spin_unlock_irqrestore(&dev->list_lock, flags); - cmd->jiffies_at_alloc = jiffies; - } else - put_device(&dev->sdev_gendev); - + cmd->device = dev; + INIT_LIST_HEAD(&cmd->list); + INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); + spin_lock_irqsave(&dev->list_lock, flags); + list_add_tail(&cmd->list, &dev->cmd_list); + spin_unlock_irqrestore(&dev->list_lock, flags); + cmd->jiffies_at_alloc = jiffies; return cmd; } EXPORT_SYMBOL(scsi_get_command); @@ -313,10 +305,8 @@ EXPORT_SYMBOL(scsi_get_command); * __scsi_put_command - Free a struct scsi_cmnd * @shost: dev->host * @cmd: Command to free - * @dev: parent scsi device */ -void __scsi_put_command(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; @@ -331,8 +321,6 @@ void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd, if (likely(cmd != NULL)) scsi_pool_free_command(shost->cmd_pool, cmd); - - put_device(dev); } EXPORT_SYMBOL(__scsi_put_command); @@ -346,7 +334,6 @@ EXPORT_SYMBOL(__scsi_put_command); */ void scsi_put_command(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 */ @@ -357,7 +344,7 @@ void scsi_put_command(struct scsi_cmnd *cmd) cancel_delayed_work(&cmd->abort_work); - __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev); + __scsi_put_command(cmd->device->host, cmd); } EXPORT_SYMBOL(scsi_put_command); diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 78b004da2885..771c16bfdbac 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -2288,6 +2288,11 @@ scsi_reset_provider(struct scsi_device *dev, int flag) if (scsi_autopm_get_host(shost) < 0) return FAILED; + if (!get_device(&dev->sdev_gendev)) { + rtn = FAILED; + goto out_put_autopm_host; + } + scmd = scsi_get_command(dev, GFP_KERNEL); blk_rq_init(NULL, &req); scmd->request = &req; @@ -2345,6 +2350,7 @@ scsi_reset_provider(struct scsi_device *dev, int flag) scsi_run_host_queues(shost); scsi_next_command(scmd); +out_put_autopm_host: scsi_autopm_put_host(shost); return rtn; } diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 492071ca45d1..007e979fa437 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -95,6 +95,7 @@ static void scsi_unprep_request(struct request *req) req->special = NULL; scsi_put_command(cmd); + put_device(&cmd->device->sdev_gendev); } /** @@ -529,6 +530,7 @@ void scsi_next_command(struct scsi_cmnd *cmd) get_device(&sdev->sdev_gendev); scsi_put_command(cmd); + put_device(&sdev->sdev_gendev); scsi_run_queue(q); /* ok to remove device now */ @@ -1123,6 +1125,7 @@ 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); @@ -1133,9 +1136,15 @@ 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; @@ -1298,6 +1307,7 @@ 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; diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c index 84a1fdf67864..e51add05fb8d 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(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 91558a1f97f4..414edf9b1272 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -142,8 +142,7 @@ static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd) extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t); extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t); extern void scsi_put_command(struct scsi_cmnd *); -extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *, - struct device *); +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, -- cgit v1.2.3