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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: Li Zhong <zhong@linux.vnet.ibm.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Li Zhong 2012-09-29 12:23:37 +08:00 committed by James Bottomley
parent 865b58c05b
commit 329a402cb0
2 changed files with 7 additions and 13 deletions
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8
drivers/scsi/scsi_error.c
View File

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

12
include/scsi/scsi_cmnd.h
View File

@ -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);