This is a resend of a (slightly updated) patch that was originally
submitted on
24 April 2008
27 April 2008
This patch reduces the number of sequential pointer derefs in drivers/scsi/scsi_error.c
The bennefits 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
before:
text data bss dec hex filename
18829 128 4728 23685 5c85 drivers/scsi/scsi_error.o
after:
text data bss dec hex filename
18775 128 4728 23631 5c4f drivers/scsi/scsi_error.o
Please consider applying.
Signed-off-by: Jesper Juhl <jj@xxxxxxxxxxxxx>
---
scsi_error.c | 61 +++++++++++++++++++++++++++++++++--------------------------
1 file changed, 35 insertions(+), 26 deletions(-)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index f3cf924..75a68a0 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -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;
@@ -605,11 +610,12 @@ 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;
@@ -617,10 +623,13 @@ static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
{
- if (!scmd->device->host->hostt->eh_abort_handler)
+ int (*eh_abort_handler)(struct scsi_cmnd *) =
+ scmd->device->host->hostt->eh_abort_handler;
+
+ if (!eh_abort_handler)
return FAILED;
- return scmd->device->host->hostt->eh_abort_handler(scmd);
+ return eh_abort_handler(scmd);
}
/**
--
Jesper Juhl <jj@xxxxxxxxxxxxx> http://www.chaosbits.net/
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please.
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