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[SCSI] libsas: pre-clean commands that won the eh vs completion race

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When scrolling forward through the eh list (in a clear_q scenario) it is
possible to encounter commands that won the completion vs eh race.  Rather
than sprinkle more "if (!task)" throughout the handler just make a pass
through the list and delete the race winners before handling the rest.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Dan Williams 2012-01-09 10:12:52 -08:00 • committed by James Bottomley
parent 5a99832829
commit 45c73b6519
1 changed files with 16 additions and 9 deletions
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25
drivers/scsi/libsas/sas_scsi_host.c
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@ -249,8 +249,8 @@ out_done:
static void sas_eh_finish_cmd(struct scsi_cmnd *cmd) static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
{ {
struct sas_task *task = TO_SAS_TASK(cmd);
struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(cmd->device->host); struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(cmd->device->host);
struct sas_task *task = TO_SAS_TASK(cmd);
/* At this point, we only get called following an actual abort /* At this point, we only get called following an actual abort
* of the task, so we should be guaranteed not to be racing with * of the task, so we should be guaranteed not to be racing with
@ -267,9 +267,9 @@ static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
static void sas_eh_defer_cmd(struct scsi_cmnd *cmd) static void sas_eh_defer_cmd(struct scsi_cmnd *cmd)
{ {
struct sas_task *task = TO_SAS_TASK(cmd); struct domain_device *dev = cmd_to_domain_dev(cmd);
struct domain_device *dev = task->dev;
struct sas_ha_struct *ha = dev->port->ha; struct sas_ha_struct *ha = dev->port->ha;
struct sas_task *task = TO_SAS_TASK(cmd);
if (!dev_is_sata(dev)) { if (!dev_is_sata(dev)) {
sas_eh_finish_cmd(cmd); sas_eh_finish_cmd(cmd);
@ -530,8 +530,9 @@ static int sas_eh_handle_sas_errors(struct Scsi_Host *shost,
struct sas_internal *i = to_sas_internal(shost->transportt); struct sas_internal *i = to_sas_internal(shost->transportt);
unsigned long flags; unsigned long flags;
struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost); struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
LIST_HEAD(done);
Again: /* clean out any commands that won the completion vs eh race */
list_for_each_entry_safe(cmd, n, work_q, eh_entry) { list_for_each_entry_safe(cmd, n, work_q, eh_entry) {
struct domain_device *dev = cmd_to_domain_dev(cmd); struct domain_device *dev = cmd_to_domain_dev(cmd);
struct sas_task *task; struct sas_task *task;
@ -545,7 +546,12 @@ Again:
spin_unlock_irqrestore(&dev->done_lock, flags); spin_unlock_irqrestore(&dev->done_lock, flags);
if (!task) if (!task)
continue; list_move_tail(&cmd->eh_entry, &done);
}
Again:
list_for_each_entry_safe(cmd, n, work_q, eh_entry) {
struct sas_task *task = TO_SAS_TASK(cmd);
list_del_init(&cmd->eh_entry); list_del_init(&cmd->eh_entry);
@ -649,15 +655,16 @@ Again:
goto clear_q; goto clear_q;
} }
} }
out:
list_splice_tail(&done, work_q);
list_splice_tail_init(&ha->eh_ata_q, work_q); list_splice_tail_init(&ha->eh_ata_q, work_q);
return list_empty(work_q); return list_empty(work_q);
clear_q:
clear_q:
SAS_DPRINTK("--- Exit %s -- clear_q\n", __func__); SAS_DPRINTK("--- Exit %s -- clear_q\n", __func__);
list_for_each_entry_safe(cmd, n, work_q, eh_entry) list_for_each_entry_safe(cmd, n, work_q, eh_entry)
sas_eh_finish_cmd(cmd); sas_eh_finish_cmd(cmd);
goto out;
list_splice_tail_init(&ha->eh_ata_q, work_q);
return list_empty(work_q);
} }
void sas_scsi_recover_host(struct Scsi_Host *shost) void sas_scsi_recover_host(struct Scsi_Host *shost)