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
Linus Torvalds
parent
38f7aa23c4
commit
0bf8c86970
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@ -3,14 +3,14 @@
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*
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* SCSI error/timeout handling
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* Initial versions: Eric Youngdale. Based upon conversations with
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* Leonard Zubkoff and David Miller at Linux Expo,
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* Leonard Zubkoff and David Miller at Linux Expo,
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* ideas originating from all over the place.
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*
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* Restructured scsi_unjam_host and associated functions.
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* September 04, 2002 Mike Anderson (andmike@us.ibm.com)
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*
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* Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
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* minor cleanups.
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* minor cleanups.
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* September 30, 2002 Mike Anderson (andmike@us.ibm.com)
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*/
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@ -129,14 +129,15 @@ enum blk_eh_timer_return scsi_times_out(struct request *req)
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{
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struct scsi_cmnd *scmd = req->special;
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enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
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struct Scsi_Host *host = scmd->device->host;
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trace_scsi_dispatch_cmd_timeout(scmd);
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scsi_log_completion(scmd, TIMEOUT_ERROR);
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if (scmd->device->host->transportt->eh_timed_out)
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rtn = scmd->device->host->transportt->eh_timed_out(scmd);
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else if (scmd->device->host->hostt->eh_timed_out)
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rtn = scmd->device->host->hostt->eh_timed_out(scmd);
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if (host->transportt->eh_timed_out)
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rtn = host->transportt->eh_timed_out(scmd);
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else if (host->hostt->eh_timed_out)
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rtn = host->hostt->eh_timed_out(scmd);
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if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
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!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
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@ -195,7 +196,7 @@ static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
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++total_failures;
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if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
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++cmd_cancel;
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else
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else
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++cmd_failed;
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}
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}
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@ -214,7 +215,7 @@ static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
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SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
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" devices require eh work\n",
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total_failures, devices_failed));
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total_failures, devices_failed));
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}
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#endif
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@ -294,7 +295,7 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
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return NEEDS_RETRY;
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}
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/*
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* if the device is in the process of becoming ready, we
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* if the device is in the process of becoming ready, we
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* should retry.
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*/
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if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
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@ -488,7 +489,7 @@ static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
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*/
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static void scsi_eh_done(struct scsi_cmnd *scmd)
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{
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struct completion *eh_action;
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struct completion *eh_action;
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SCSI_LOG_ERROR_RECOVERY(3,
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printk("%s scmd: %p result: %x\n",
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@ -507,22 +508,23 @@ static int scsi_try_host_reset(struct scsi_cmnd *scmd)
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{
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unsigned long flags;
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int rtn;
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struct Scsi_Host *host = scmd->device->host;
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struct scsi_host_template *hostt = host->hostt;
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SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
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__func__));
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if (!scmd->device->host->hostt->eh_host_reset_handler)
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if (!hostt->eh_host_reset_handler)
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return FAILED;
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rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
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rtn = hostt->eh_host_reset_handler(scmd);
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if (rtn == SUCCESS) {
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if (!scmd->device->host->hostt->skip_settle_delay)
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if (!hostt->skip_settle_delay)
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ssleep(HOST_RESET_SETTLE_TIME);
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spin_lock_irqsave(scmd->device->host->host_lock, flags);
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scsi_report_bus_reset(scmd->device->host,
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scmd_channel(scmd));
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spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
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spin_lock_irqsave(host->host_lock, flags);
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scsi_report_bus_reset(host, scmd_channel(scmd));
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spin_unlock_irqrestore(host->host_lock, flags);
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}
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return rtn;
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@ -536,22 +538,23 @@ static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
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{
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unsigned long flags;
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int rtn;
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struct Scsi_Host *host = scmd->device->host;
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struct scsi_host_template *hostt = host->hostt;
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SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
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__func__));
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if (!scmd->device->host->hostt->eh_bus_reset_handler)
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if (!hostt->eh_bus_reset_handler)
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return FAILED;
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rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
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rtn = hostt->eh_bus_reset_handler(scmd);
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if (rtn == SUCCESS) {
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if (!scmd->device->host->hostt->skip_settle_delay)
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if (!hostt->skip_settle_delay)
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ssleep(BUS_RESET_SETTLE_TIME);
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spin_lock_irqsave(scmd->device->host->host_lock, flags);
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scsi_report_bus_reset(scmd->device->host,
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scmd_channel(scmd));
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spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
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spin_lock_irqsave(host->host_lock, flags);
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scsi_report_bus_reset(host, scmd_channel(scmd));
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spin_unlock_irqrestore(host->host_lock, flags);
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}
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return rtn;
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@ -577,16 +580,18 @@ static int scsi_try_target_reset(struct scsi_cmnd *scmd)
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{
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unsigned long flags;
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int rtn;
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struct Scsi_Host *host = scmd->device->host;
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struct scsi_host_template *hostt = host->hostt;
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if (!scmd->device->host->hostt->eh_target_reset_handler)
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if (!hostt->eh_target_reset_handler)
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return FAILED;
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rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
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rtn = hostt->eh_target_reset_handler(scmd);
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if (rtn == SUCCESS) {
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spin_lock_irqsave(scmd->device->host->host_lock, flags);
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spin_lock_irqsave(host->host_lock, flags);
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__starget_for_each_device(scsi_target(scmd->device), NULL,
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__scsi_report_device_reset);
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spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
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spin_unlock_irqrestore(host->host_lock, flags);
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}
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return rtn;
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@ -605,27 +610,28 @@ static int scsi_try_target_reset(struct scsi_cmnd *scmd)
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static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
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{
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int rtn;
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struct scsi_host_template *hostt = scmd->device->host->hostt;
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if (!scmd->device->host->hostt->eh_device_reset_handler)
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if (!hostt->eh_device_reset_handler)
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return FAILED;
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rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
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rtn = hostt->eh_device_reset_handler(scmd);
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if (rtn == SUCCESS)
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__scsi_report_device_reset(scmd->device, NULL);
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return rtn;
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}
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static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
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static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
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{
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if (!scmd->device->host->hostt->eh_abort_handler)
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if (!hostt->eh_abort_handler)
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return FAILED;
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return scmd->device->host->hostt->eh_abort_handler(scmd);
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return hostt->eh_abort_handler(scmd);
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}
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static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
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{
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if (scsi_try_to_abort_cmd(scmd) != SUCCESS)
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if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
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if (scsi_try_bus_device_reset(scmd) != SUCCESS)
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if (scsi_try_target_reset(scmd) != SUCCESS)
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if (scsi_try_bus_reset(scmd) != SUCCESS)
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@ -846,7 +852,7 @@ EXPORT_SYMBOL(scsi_eh_finish_cmd);
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*
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* Description:
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* See if we need to request sense information. if so, then get it
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* now, so we have a better idea of what to do.
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* now, so we have a better idea of what to do.
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*
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* Notes:
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* This has the unfortunate side effect that if a shost adapter does
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@ -958,7 +964,7 @@ static int scsi_eh_abort_cmds(struct list_head *work_q,
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SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
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"0x%p\n", current->comm,
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scmd));
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rtn = scsi_try_to_abort_cmd(scmd);
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rtn = scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd);
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if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
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scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
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if (!scsi_device_online(scmd->device) ||
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@ -966,7 +972,6 @@ static int scsi_eh_abort_cmds(struct list_head *work_q,
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!scsi_eh_tur(scmd)) {
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scsi_eh_finish_cmd(scmd, done_q);
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}
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} else
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SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
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" cmd failed:"
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@ -1010,7 +1015,7 @@ static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
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*
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* Notes:
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* If commands are failing due to not ready, initializing command required,
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* try revalidating the device, which will end up sending a start unit.
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* try revalidating the device, which will end up sending a start unit.
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*/
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static int scsi_eh_stu(struct Scsi_Host *shost,
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struct list_head *work_q,
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@ -1064,7 +1069,7 @@ static int scsi_eh_stu(struct Scsi_Host *shost,
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* Try a bus device reset. Still, look to see whether we have multiple
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* devices that are jammed or not - if we have multiple devices, it
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* makes no sense to try bus_device_reset - we really would need to try
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* a bus_reset instead.
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* a bus_reset instead.
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*/
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static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
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struct list_head *work_q,
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@ -1164,7 +1169,7 @@ static int scsi_eh_target_reset(struct Scsi_Host *shost,
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}
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/**
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* scsi_eh_bus_reset - send a bus reset
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* scsi_eh_bus_reset - send a bus reset
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* @shost: &scsi host being recovered.
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* @work_q: &list_head for pending commands.
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* @done_q: &list_head for processed commands.
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@ -1181,7 +1186,7 @@ static int scsi_eh_bus_reset(struct Scsi_Host *shost,
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* we really want to loop over the various channels, and do this on
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* a channel by channel basis. we should also check to see if any
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* of the failed commands are on soft_reset devices, and if so, skip
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* the reset.
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* the reset.
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*/
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for (channel = 0; channel <= shost->max_channel; channel++) {
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@ -1223,7 +1228,7 @@ static int scsi_eh_bus_reset(struct Scsi_Host *shost,
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}
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/**
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* scsi_eh_host_reset - send a host reset
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* scsi_eh_host_reset - send a host reset
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* @work_q: list_head for processed commands.
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* @done_q: list_head for processed commands.
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*/
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@ -1376,7 +1381,7 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
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return SUCCESS;
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/*
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* when the low level driver returns did_soft_error,
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* it is responsible for keeping an internal retry counter
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* it is responsible for keeping an internal retry counter
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* in order to avoid endless loops (db)
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*
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* actually this is a bug in this function here. we should
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@ -1414,7 +1419,6 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
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*/
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break;
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/* fallthrough */
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case DID_BUS_BUSY:
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case DID_PARITY:
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goto maybe_retry;
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@ -1982,7 +1986,7 @@ int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
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if (sb_len > 7)
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sshdr->additional_length = sense_buffer[7];
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} else {
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/*
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/*
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* fixed format
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*/
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if (sb_len > 2)
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