Commit cb7fc545 authored by Jason Yan's avatar Jason Yan Committed by Xie XiuQi
Browse files

ahci: prevent freezing port when EH is running 



euler inclusion
category: bugfix
bugzilla: NA
CVE: NA

---------------------------

Trinity report a warning for this patch:
WARNING: CPU: 1 PID: 118 at ../drivers/ata/libata-eh.c:4016
ata_eh_finish+0x15a/0x170

Fixing the race condition between EH and interrupt by making the EH
thread re-enter again is a little overkill and IO will get through
after the scsi_run_host_queues() and before SHOST_RECOVERY is set agian
in scsi_restart_operations().

If EH thread is already running, no need to freeze port and schedule
EH again.

Fixes: a7d2fef75b83 ("scsi: ata: Fix a race condition between scsi error handler and ahci interrupt")
Signed-off-by: default avatarJason Yan <yanaijie@huawei.com>
Reviewed-by: default avatarzhengbin <zhengbin13@huawei.com>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
parent 73f1359d

drivers/ata/libahci.c

+10 −2
Original line number Diff line number Diff line
@@ -1805,9 +1805,17 @@ static void ahci_error_intr(struct ata_port *ap, u32 irq_stat) 


	/* okay, let's hand over to EH */



	if (irq_stat & PORT_IRQ_FREEZE)

	if (irq_stat & PORT_IRQ_FREEZE) {

		/*

		 * EH already running, this may happen if the port is

		 * thawed in the EH. But we cannot freeze it again

		 * otherwise the port will never be thawed.

		 */

		if (ap->pflags & (ATA_PFLAG_EH_PENDING |

			ATA_PFLAG_EH_IN_PROGRESS))

			return;

		ata_port_freeze(ap);

	else if (fbs_need_dec) {

	} else if (fbs_need_dec) {

		ata_link_abort(link);

		ahci_fbs_dec_intr(ap);

	} else

drivers/ata/libata-eh.c

+1 −1
Original line number Diff line number Diff line
@@ -974,7 +974,7 @@ void ata_std_end_eh(struct ata_port *ap) 
{

	struct Scsi_Host *host = ap->scsi_host;



	atomic_dec(&host->host_eh_scheduled);

	host->host_eh_scheduled = 0;

}

EXPORT_SYMBOL(ata_std_end_eh);

drivers/scsi/libsas/sas_scsi_host.c

+2 −2
Original line number Diff line number Diff line
@@ -492,7 +492,7 @@ int sas_eh_abort_handler(struct scsi_cmnd *cmd) 


	spin_lock_irqsave(host->host_lock, flags);

	/* We cannot do async aborts for SATA devices */

	if (dev_is_sata(dev) && !atomic_read(&host->host_eh_scheduled)) {

	if (dev_is_sata(dev) && !host->host_eh_scheduled) {

		spin_unlock_irqrestore(host->host_lock, flags);

		return FAILED;

	}
@@ -792,7 +792,7 @@ void sas_scsi_recover_host(struct Scsi_Host *shost) 
	/* check if any new eh work was scheduled during the last run */

	spin_lock_irq(&ha->lock);

	if (ha->eh_active == 0) {

		atomic_set(&shost->host_eh_scheduled, 0);

		shost->host_eh_scheduled = 0;

		retry = false;

	}

	spin_unlock_irq(&ha->lock);

drivers/scsi/scsi_error.c

+4 −6
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ void scsi_schedule_eh(struct Scsi_Host *shost) 


	if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||

	    scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {

		atomic_inc(&shost->host_eh_scheduled);

		shost->host_eh_scheduled++;

		scsi_eh_wakeup(shost);

	}
@@ -2029,7 +2029,7 @@ static void scsi_restart_operations(struct Scsi_Host *shost) 
	 * pending commands complete.

	 */

	spin_lock_irqsave(shost->host_lock, flags);

	if (atomic_read(&shost->host_eh_scheduled))

	if (shost->host_eh_scheduled)

		if (scsi_host_set_state(shost, SHOST_RECOVERY))

			WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));

	spin_unlock_irqrestore(shost->host_lock, flags);
@@ -2165,8 +2165,7 @@ int scsi_error_handler(void *data) 
		if (kthread_should_stop())

			break;



		if ((shost->host_failed == 0 &&

		     atomic_read(&shost->host_eh_scheduled) == 0) ||

		if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||

		    shost->host_failed != scsi_host_busy(shost)) {

			SCSI_LOG_ERROR_RECOVERY(1,

				shost_printk(KERN_INFO, shost,
@@ -2180,8 +2179,7 @@ int scsi_error_handler(void *data) 
		SCSI_LOG_ERROR_RECOVERY(1,

			shost_printk(KERN_INFO, shost,

				     "scsi_eh_%d: waking up %d/%d/%d\n",

				     shost->host_no,

				     atomic_read(&shost->host_eh_scheduled),

				     shost->host_no, shost->host_eh_scheduled,

				     shost->host_failed,

				     scsi_host_busy(shost)));

drivers/scsi/scsi_lib.c

+1 −2
Original line number Diff line number Diff line
@@ -348,8 +348,7 @@ static void scsi_dec_host_busy(struct Scsi_Host *shost) 
	atomic_dec(&shost->host_busy);

	if (unlikely(scsi_host_in_recovery(shost))) {

		spin_lock_irqsave(shost->host_lock, flags);

		if (shost->host_failed ||

		    atomic_read(&shost->host_eh_scheduled))

		if (shost->host_failed || shost->host_eh_scheduled)

			scsi_eh_wakeup(shost);

		spin_unlock_irqrestore(shost->host_lock, flags);

	}