As suggested by James: this patch tries to short 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.
v2: mirror code != REQ_TYPE_BLOCK_PC in scsi.c, rather than == REQ_TYPE_FS
Signed-off-by: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
---
drivers/scsi/scsi_error.c | 8 +++++---
include/scsi/scsi_cmnd.h | 12 ++----------
2 files changed, 7 insertions(+), 13 deletions(-)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index de2337f..c1b05a8 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -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;
}
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index ac06cc5..de5f5d8 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -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);
--
1.7.7.6
--
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