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Reduce sequential pointer derefs in scsi_error.c and reduce size as well 

This patch reduces the number of sequential pointer derefs in
drivers/scsi/scsi_error.c

This has been submitted a number of times over a couple of years.  I
believe this version adresses all comments it has gathered over time.
Please apply or reject with a reason.

The benefits are:

 - makes the code easier to read.  Lots of sequential derefs of the same
   pointers is not easy on the eye.

 - theoretically at least, just dereferencing the pointers once can
   allow the compiler to generally slightly faster code, so in theory
   this could also be a micro speed optimization.

 - reduces size of object file (tiny effect: on x86-64, in at least one
   configuration, the text size decreased from 9439 bytes to 9400)

 - removes some pointless (mostly trailing) whitespace.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jesper Juhl 2011-03-21 20:47:31 +01:00 committed by Linus Torvalds
parent 38f7aa23c4
commit 0bf8c86970
1 changed files with 49 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
drivers/scsi/scsi_error.c
View File

@ -129,14 +129,15 @@ enum blk_eh_timer_return scsi_times_out(struct request *req)
{
struct scsi_cmnd *scmd = req->special;
enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
struct Scsi_Host *host = scmd->device->host;
trace_scsi_dispatch_cmd_timeout(scmd);
scsi_log_completion(scmd, TIMEOUT_ERROR);
if (scmd->device->host->transportt->eh_timed_out)
rtn = scmd->device->host->transportt->eh_timed_out(scmd);
else if (scmd->device->host->hostt->eh_timed_out)
rtn = scmd->device->host->hostt->eh_timed_out(scmd);
if (host->transportt->eh_timed_out)
rtn = host->transportt->eh_timed_out(scmd);
else if (host->hostt->eh_timed_out)
rtn = host->hostt->eh_timed_out(scmd);
if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
@ -507,22 +508,23 @@ static int scsi_try_host_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
struct Scsi_Host *host = scmd->device->host;
struct scsi_host_template *hostt = host->hostt;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
__func__));
if (!scmd->device->host->hostt->eh_host_reset_handler)
if (!hostt->eh_host_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
rtn = hostt->eh_host_reset_handler(scmd);
if (rtn == SUCCESS) {
if (!scmd->device->host->hostt->skip_settle_delay)
if (!hostt->skip_settle_delay)
ssleep(HOST_RESET_SETTLE_TIME);
spin_lock_irqsave(scmd->device->host->host_lock, flags);
scsi_report_bus_reset(scmd->device->host,
scmd_channel(scmd));
spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
spin_lock_irqsave(host->host_lock, flags);
scsi_report_bus_reset(host, scmd_channel(scmd));
spin_unlock_irqrestore(host->host_lock, flags);
}
return rtn;
@ -536,22 +538,23 @@ static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
struct Scsi_Host *host = scmd->device->host;
struct scsi_host_template *hostt = host->hostt;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
__func__));
if (!scmd->device->host->hostt->eh_bus_reset_handler)
if (!hostt->eh_bus_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
rtn = hostt->eh_bus_reset_handler(scmd);
if (rtn == SUCCESS) {
if (!scmd->device->host->hostt->skip_settle_delay)
if (!hostt->skip_settle_delay)
ssleep(BUS_RESET_SETTLE_TIME);
spin_lock_irqsave(scmd->device->host->host_lock, flags);
scsi_report_bus_reset(scmd->device->host,
scmd_channel(scmd));
spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
spin_lock_irqsave(host->host_lock, flags);
scsi_report_bus_reset(host, scmd_channel(scmd));
spin_unlock_irqrestore(host->host_lock, flags);
}
return rtn;
@ -577,16 +580,18 @@ static int scsi_try_target_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
struct Scsi_Host *host = scmd->device->host;
struct scsi_host_template *hostt = host->hostt;
if (!scmd->device->host->hostt->eh_target_reset_handler)
if (!hostt->eh_target_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
rtn = hostt->eh_target_reset_handler(scmd);
if (rtn == SUCCESS) {
spin_lock_irqsave(scmd->device->host->host_lock, flags);
spin_lock_irqsave(host->host_lock, flags);
__starget_for_each_device(scsi_target(scmd->device), NULL,
__scsi_report_device_reset);
spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
spin_unlock_irqrestore(host->host_lock, flags);
}
return rtn;
@ -605,27 +610,28 @@ static int scsi_try_target_reset(struct scsi_cmnd *scmd)
static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
{
int rtn;
struct scsi_host_template *hostt = scmd->device->host->hostt;
if (!scmd->device->host->hostt->eh_device_reset_handler)
if (!hostt->eh_device_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
rtn = hostt->eh_device_reset_handler(scmd);
if (rtn == SUCCESS)
__scsi_report_device_reset(scmd->device, NULL);
return rtn;
}
static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
{
if (!scmd->device->host->hostt->eh_abort_handler)
if (!hostt->eh_abort_handler)
return FAILED;
return scmd->device->host->hostt->eh_abort_handler(scmd);
return hostt->eh_abort_handler(scmd);
}
static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
{
if (scsi_try_to_abort_cmd(scmd) != SUCCESS)
if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
if (scsi_try_bus_device_reset(scmd) != SUCCESS)
if (scsi_try_target_reset(scmd) != SUCCESS)
if (scsi_try_bus_reset(scmd) != SUCCESS)
@ -958,7 +964,7 @@ static int scsi_eh_abort_cmds(struct list_head *work_q,
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
"0x%p\n", current->comm,
scmd));
rtn = scsi_try_to_abort_cmd(scmd);
rtn = scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd);
if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
if (!scsi_device_online(scmd->device) ||
@ -966,7 +972,6 @@ static int scsi_eh_abort_cmds(struct list_head *work_q,
!scsi_eh_tur(scmd)) {
scsi_eh_finish_cmd(scmd, done_q);
}
} else
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
" cmd failed:"
@ -1414,7 +1419,6 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
*/
break;
/* fallthrough */
case DID_BUS_BUSY:
case DID_PARITY:
goto maybe_retry;