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Commit 45c73b65 authored by Dan Williams's avatar Dan Williams Committed by James Bottomley
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[SCSI] libsas: pre-clean commands that won the eh vs completion race 



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: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 5a998328

drivers/scsi/libsas/sas_scsi_host.c

+16 −9
Original line number Diff line number Diff line
@@ -249,8 +249,8 @@ int sas_queuecommand(struct Scsi_Host *host, 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_task *task = TO_SAS_TASK(cmd);



	/* At this point, we only get called following an actual abort

	 * 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)

{

	struct sas_task *task = TO_SAS_TASK(cmd);

	struct domain_device *dev = task->dev;

	struct domain_device *dev = cmd_to_domain_dev(cmd);

	struct sas_ha_struct *ha = dev->port->ha;

	struct sas_task *task = TO_SAS_TASK(cmd);



	if (!dev_is_sata(dev)) {

		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);

	unsigned long flags;

	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) {

		struct domain_device *dev = cmd_to_domain_dev(cmd);

		struct sas_task *task;
@@ -545,7 +546,12 @@ static int sas_eh_handle_sas_errors(struct Scsi_Host *shost, 
		spin_unlock_irqrestore(&dev->done_lock, flags);



		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);
@@ -649,15 +655,16 @@ static int sas_eh_handle_sas_errors(struct Scsi_Host *shost, 
			goto clear_q;

		}

	}

 out:

	list_splice_tail(&done, work_q);

	list_splice_tail_init(&ha->eh_ata_q, work_q);

	return list_empty(work_q);



 clear_q:

	SAS_DPRINTK("--- Exit %s -- clear_q\n", __func__);

	list_for_each_entry_safe(cmd, n, work_q, eh_entry)

		sas_eh_finish_cmd(cmd);



	list_splice_tail_init(&ha->eh_ata_q, work_q);

	return list_empty(work_q);

	goto out;

}



void sas_scsi_recover_host(struct Scsi_Host *shost)