Commit 04796336 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by James Bottomley
Browse files

[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: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 21a05df5

drivers/scsi/scsi.c

+12 −25
Original line number Diff line number Diff line
@@ -284,17 +284,12 @@ 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);
@@ -302,9 +297,6 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask) 
	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);



	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);

drivers/scsi/scsi_error.c

+6 −0
Original line number Diff line number Diff line
@@ -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;

}

drivers/scsi/scsi_lib.c

+11 −1
Original line number Diff line number Diff line
@@ -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;

drivers/scsi/scsi_tgt_lib.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

include/scsi/scsi_cmnd.h

+1 −2
Original line number Diff line number Diff line
@@ -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,

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