From: Li Zhong <zhong@linux.vnet.ibm.com>
To: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-scsi@vger.kernel.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH v2 scsi] Short the path length of scsi_cmd_to_driver()
Date: Sat, 29 Sep 2012 12:23:37 +0800 [thread overview]
Message-ID: <1348892617.6455.4.camel@ThinkPad-T420> (raw)
In-Reply-To: <1348818498.2411.8.camel@dabdike.int.hansenpartnership.com>
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@linux.vnet.ibm.com>
---
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
next prev parent reply other threads:[~2012-09-29 4:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-24 5:30 [PATCH scsi] Add NULL checking of return value from scsi_cmd_to_driver() Li Zhong
2012-09-24 5:44 ` James Bottomley
2012-09-24 7:03 ` Li Zhong
2012-09-24 7:35 ` James Bottomley
2012-09-24 9:25 ` Li Zhong
2012-09-24 9:33 ` James Bottomley
2012-09-27 2:02 ` Martin K. Petersen
2012-09-27 4:44 ` James Bottomley
2012-09-27 9:51 ` [PATCH scsi] Short the path length of scsi_cmd_to_driver() Li Zhong
2012-09-27 17:43 ` Martin K. Petersen
2012-09-28 7:13 ` Li Zhong
2012-09-28 7:45 ` James Bottomley
2012-09-27 17:41 ` [PATCH scsi] Add NULL checking of return value from scsi_cmd_to_driver() Martin K. Petersen
2012-09-28 7:48 ` James Bottomley
2012-09-29 4:23 ` Li Zhong [this message]
2012-10-02 22:22 ` [PATCH v2 scsi] Short the path length of scsi_cmd_to_driver() Martin K. Petersen
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