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Date: Sun, 27 Apr 2008 22:15:06 +0200 (CEST)
From: Jesper Juhl <jesper.juhl@...il.com>
To: James Bottomley <James.Bottomley@...senpartnership.com>
cc: linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
Eric Youngdale <eric@...ante.org>,
David Miller <davem@...emloft.net>,
Mike Anderson <andmike@...ibm.com>,
Russell King <rmk@....linux.org.uk>,
Jesper Juhl <jesper.juhl@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH][Resend] fewer pointer derefs in scsi_error
From: Jesper Juhl <jesper.juhl@...il.com>
[This patch previously submitted on 24 April 2008 00:18]
This patch reduces the number of sequential pointer derefs in scsi_error
( drivers/scsi/scsi_error.c ).
The bennefits are:
- makes the code easier to read. Lots of sequential derefs of the
same pointers are not easy on the eye.
- makes the size of the source file 55 bytes smaller.
- makes the size of the object file 48 bytes smaller.
- 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.
Please consider applying.
Signed-off-by: Jesper Juhl <jesper.juhl@...il.com>
---
scsi_error.c | 58 ++++++++++++++++++++++++++++++++--------------------------
1 file changed, 32 insertions(+), 26 deletions(-)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 221f31e..94395a7 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -185,13 +185,14 @@ int scsi_delete_timer(struct scsi_cmnd *scmd)
void scsi_times_out(struct scsi_cmnd *scmd)
{
enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
+ struct Scsi_Host *host = scmd->device->host;
scsi_log_completion(scmd, TIMEOUT_ERROR);
- if (scmd->device->host->transportt->eh_timed_out)
- eh_timed_out = scmd->device->host->transportt->eh_timed_out;
- else if (scmd->device->host->hostt->eh_timed_out)
- eh_timed_out = scmd->device->host->hostt->eh_timed_out;
+ if (host->transportt->eh_timed_out)
+ eh_timed_out = host->transportt->eh_timed_out;
+ else if (host->hostt->eh_timed_out)
+ eh_timed_out = host->hostt->eh_timed_out;
else
eh_timed_out = NULL;
@@ -474,22 +475,22 @@ static int scsi_try_host_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
+ struct Scsi_Host *host = scmd->device->host;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
__FUNCTION__));
- if (!scmd->device->host->hostt->eh_host_reset_handler)
+ if (!host->hostt->eh_host_reset_handler)
return FAILED;
- rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
+ rtn = host->hostt->eh_host_reset_handler(scmd);
if (rtn == SUCCESS) {
- if (!scmd->device->host->hostt->skip_settle_delay)
+ if (!host->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;
@@ -503,22 +504,22 @@ static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
+ struct Scsi_Host *host = scmd->device->host;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
__FUNCTION__));
- if (!scmd->device->host->hostt->eh_bus_reset_handler)
+ if (!host->hostt->eh_bus_reset_handler)
return FAILED;
- rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
+ rtn = host->hostt->eh_bus_reset_handler(scmd);
if (rtn == SUCCESS) {
- if (!scmd->device->host->hostt->skip_settle_delay)
+ if (!host->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;
@@ -544,16 +545,17 @@ static int scsi_try_target_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
+ struct Scsi_Host *host = scmd->device->host;
- if (!scmd->device->host->hostt->eh_target_reset_handler)
+ if (!host->hostt->eh_target_reset_handler)
return FAILED;
- rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
+ rtn = host->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;
@@ -572,11 +574,12 @@ 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 *host = scmd->device->host;
- if (!scmd->device->host->hostt->eh_device_reset_handler)
+ if (!host->hostt->eh_device_reset_handler)
return FAILED;
- rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
+ rtn = host->hostt->eh_device_reset_handler(scmd);
if (rtn == SUCCESS)
__scsi_report_device_reset(scmd->device, NULL);
return rtn;
@@ -584,10 +587,13 @@ 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);
}
/**
--
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