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Commit 73ee5d86 authored by Brian King's avatar Brian King Committed by James Bottomley
Browse files

[SCSI] ibmvfc: Fix soft lockup on resume 



This fixes a softlockup seen on resume. During resume, the CRQ
must be reenabled. However, the H_ENABLE_CRQ hcall used to do
this may return H_BUSY or H_LONG_BUSY. When this happens, the
caller is expected to retry later. Normally the H_ENABLE_CRQ
succeeds relatively soon. However, we have seen cases where
this can take long enough to see softlockup warnings.
This patch changes a simple loop, which was causing the
softlockup, to a loop at task level which sleeps between
retries rather than simply spinning.

Signed-off-by: default avatarBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent 15f7fc06

drivers/scsi/ibmvscsi/ibmvfc.c

+54 −27
Original line number Diff line number Diff line
@@ -504,12 +504,23 @@ static void ibmvfc_set_host_action(struct ibmvfc_host *vhost, 
		if (vhost->action == IBMVFC_HOST_ACTION_ALLOC_TGTS)

			vhost->action = action;

		break;

	case IBMVFC_HOST_ACTION_LOGO:

	case IBMVFC_HOST_ACTION_INIT:

	case IBMVFC_HOST_ACTION_TGT_DEL:

		switch (vhost->action) {

		case IBMVFC_HOST_ACTION_RESET:

		case IBMVFC_HOST_ACTION_REENABLE:

			break;

		default:

			vhost->action = action;

			break;

		};

		break;

	case IBMVFC_HOST_ACTION_LOGO:

	case IBMVFC_HOST_ACTION_QUERY_TGTS:

	case IBMVFC_HOST_ACTION_TGT_DEL_FAILED:

	case IBMVFC_HOST_ACTION_NONE:

	case IBMVFC_HOST_ACTION_RESET:

	case IBMVFC_HOST_ACTION_REENABLE:

	default:

		vhost->action = action;

		break;
@@ -641,7 +652,7 @@ static int ibmvfc_send_crq_init_complete(struct ibmvfc_host *vhost) 
 **/

static void ibmvfc_release_crq_queue(struct ibmvfc_host *vhost)

{

	long rc;

	long rc = 0;

	struct vio_dev *vdev = to_vio_dev(vhost->dev);

	struct ibmvfc_crq_queue *crq = &vhost->crq;
@@ -649,6 +660,8 @@ static void ibmvfc_release_crq_queue(struct ibmvfc_host *vhost) 
	free_irq(vdev->irq, vhost);

	tasklet_kill(&vhost->tasklet);

	do {

		if (rc)

			msleep(100);

		rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);

	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));
@@ -667,11 +680,13 @@ static void ibmvfc_release_crq_queue(struct ibmvfc_host *vhost) 
 **/

static int ibmvfc_reenable_crq_queue(struct ibmvfc_host *vhost)

{

	int rc;

	int rc = 0;

	struct vio_dev *vdev = to_vio_dev(vhost->dev);



	/* Re-enable the CRQ */

	do {

		if (rc)

			msleep(100);

		rc = plpar_hcall_norets(H_ENABLE_CRQ, vdev->unit_address);

	} while (rc == H_IN_PROGRESS || rc == H_BUSY || H_IS_LONG_BUSY(rc));
@@ -690,15 +705,19 @@ static int ibmvfc_reenable_crq_queue(struct ibmvfc_host *vhost) 
 **/

static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)

{

	int rc;

	int rc = 0;

	unsigned long flags;

	struct vio_dev *vdev = to_vio_dev(vhost->dev);

	struct ibmvfc_crq_queue *crq = &vhost->crq;



	/* Close the CRQ */

	do {

		if (rc)

			msleep(100);

		rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);

	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));



	spin_lock_irqsave(vhost->host->host_lock, flags);

	vhost->state = IBMVFC_NO_CRQ;

	vhost->logged_in = 0;

	ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_NONE);
@@ -716,6 +735,7 @@ static int ibmvfc_reset_crq(struct ibmvfc_host *vhost) 
		dev_warn(vhost->dev, "Partner adapter not ready\n");

	else if (rc != 0)

		dev_warn(vhost->dev, "Couldn't register crq (rc=%d)\n", rc);

	spin_unlock_irqrestore(vhost->host->host_lock, flags);



	return rc;

}
@@ -821,17 +841,9 @@ static void ibmvfc_purge_requests(struct ibmvfc_host *vhost, int error_code) 
 **/

static void ibmvfc_hard_reset_host(struct ibmvfc_host *vhost)

{

	int rc;



	scsi_block_requests(vhost->host);

	ibmvfc_purge_requests(vhost, DID_ERROR);

	if ((rc = ibmvfc_reset_crq(vhost)) ||

	    (rc = ibmvfc_send_crq_init(vhost)) ||

	    (rc = vio_enable_interrupts(to_vio_dev(vhost->dev)))) {

		dev_err(vhost->dev, "Error after reset rc=%d\n", rc);

		ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);

	} else

	ibmvfc_link_down(vhost, IBMVFC_LINK_DOWN);

	ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_RESET);

}



/**
@@ -2606,22 +2618,13 @@ static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost) 
			dev_info(vhost->dev, "Re-enabling adapter\n");

			vhost->client_migrated = 1;

			ibmvfc_purge_requests(vhost, DID_REQUEUE);

			if ((rc = ibmvfc_reenable_crq_queue(vhost)) ||

			    (rc = ibmvfc_send_crq_init(vhost))) {

				ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);

				dev_err(vhost->dev, "Error after enable (rc=%ld)\n", rc);

			} else

			ibmvfc_link_down(vhost, IBMVFC_LINK_DOWN);

			ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_REENABLE);

		} else {

			dev_err(vhost->dev, "Virtual adapter failed (rc=%d)\n", crq->format);



			ibmvfc_purge_requests(vhost, DID_ERROR);

			if ((rc = ibmvfc_reset_crq(vhost)) ||

			    (rc = ibmvfc_send_crq_init(vhost))) {

				ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);

				dev_err(vhost->dev, "Error after reset (rc=%ld)\n", rc);

			} else

			ibmvfc_link_down(vhost, IBMVFC_LINK_DOWN);

			ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_RESET);

		}

		return;

	case IBMVFC_CRQ_CMD_RSP:
@@ -4123,6 +4126,8 @@ static int __ibmvfc_work_to_do(struct ibmvfc_host *vhost) 
	case IBMVFC_HOST_ACTION_TGT_DEL:

	case IBMVFC_HOST_ACTION_TGT_DEL_FAILED:

	case IBMVFC_HOST_ACTION_QUERY:

	case IBMVFC_HOST_ACTION_RESET:

	case IBMVFC_HOST_ACTION_REENABLE:

	default:

		break;

	};
@@ -4220,6 +4225,7 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost) 
	struct ibmvfc_target *tgt;

	unsigned long flags;

	struct fc_rport *rport;

	int rc;



	ibmvfc_log_ae(vhost, vhost->events_to_log);

	spin_lock_irqsave(vhost->host->host_lock, flags);
@@ -4229,6 +4235,27 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost) 
	case IBMVFC_HOST_ACTION_LOGO_WAIT:

	case IBMVFC_HOST_ACTION_INIT_WAIT:

		break;

	case IBMVFC_HOST_ACTION_RESET:

		vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;

		spin_unlock_irqrestore(vhost->host->host_lock, flags);

		rc = ibmvfc_reset_crq(vhost);

		spin_lock_irqsave(vhost->host->host_lock, flags);

		if (rc || (rc = ibmvfc_send_crq_init(vhost)) ||

		    (rc = vio_enable_interrupts(to_vio_dev(vhost->dev)))) {

			ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);

			dev_err(vhost->dev, "Error after reset (rc=%d)\n", rc);

		}

		break;

	case IBMVFC_HOST_ACTION_REENABLE:

		vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;

		spin_unlock_irqrestore(vhost->host->host_lock, flags);

		rc = ibmvfc_reenable_crq_queue(vhost);

		spin_lock_irqsave(vhost->host->host_lock, flags);

		if (rc || (rc = ibmvfc_send_crq_init(vhost))) {

			ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);

			dev_err(vhost->dev, "Error after enable (rc=%d)\n", rc);

		}

		break;

	case IBMVFC_HOST_ACTION_LOGO:

		vhost->job_step(vhost);

		break;

drivers/scsi/ibmvscsi/ibmvfc.h

+2 −0
Original line number Diff line number Diff line
@@ -649,6 +649,8 @@ struct ibmvfc_event_pool { 


enum ibmvfc_host_action {

	IBMVFC_HOST_ACTION_NONE = 0,

	IBMVFC_HOST_ACTION_RESET,

	IBMVFC_HOST_ACTION_REENABLE,

	IBMVFC_HOST_ACTION_LOGO,

	IBMVFC_HOST_ACTION_LOGO_WAIT,

	IBMVFC_HOST_ACTION_INIT,