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Commit 329a402c authored by Li Zhong's avatar Li Zhong Committed by James Bottomley
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[SCSI] Shorten the path length of scsi_cmd_to_driver() 



This patch tries to shorten the path length of scsi_cmd_to_driver(). As only
REQ_TYPE_BLOCK_PC commands can be submitted without a driver, so we could
avoid the related NULL checking, as long as we make sure we don't use it for
REQ_TYPE_BLOCK_PC type commands. Plus, this fixes a bug where you get
different behaviors from REQ_TYPE_BLOCK_PC commands when a driver is and isn't
attached.

Signed-off-by: default avatarLi Zhong <zhong@linux.vnet.ibm.com>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 865b58c0

drivers/scsi/scsi_error.c

+5 −3
Original line number Diff line number Diff line
@@ -789,7 +789,6 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, 
			     int cmnd_size, int timeout, unsigned sense_bytes)

{

	struct scsi_device *sdev = scmd->device;

	struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);

	struct Scsi_Host *shost = sdev->host;

	DECLARE_COMPLETION_ONSTACK(done);

	unsigned long timeleft;
@@ -845,8 +844,11 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, 


	scsi_eh_restore_cmnd(scmd, &ses);



	if (sdrv && sdrv->eh_action)

	if (scmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {

		struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);

		if (sdrv->eh_action)

			rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn);

	}



	return rtn;

}

include/scsi/scsi_cmnd.h

+2 −10
Original line number Diff line number Diff line
@@ -132,18 +132,10 @@ struct scsi_cmnd { 
	unsigned char tag;	/* SCSI-II queued command tag */

};



/* make sure not to use it with REQ_TYPE_BLOCK_PC commands */

static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)

{

	struct scsi_driver **sdp;



	if (!cmd->request->rq_disk)

		return NULL;



	sdp = (struct scsi_driver **)cmd->request->rq_disk->private_data;

	if (!sdp)

		return NULL;



	return *sdp;

	return *(struct scsi_driver **)cmd->request->rq_disk->private_data;

}



extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);