Skip to content

Commit

Permalink
[SCSI] ibmvfc: Fix soft lockup on resume
Browse files Browse the repository at this point in the history 
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: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
  • Loading branch information
Brian King authored and James Bottomley committed Jul 27, 2010
1 parent 15f7fc0 commit 73ee5d8
Show file tree
Hide file tree
Showing 2 changed files with 56 additions and 27 deletions.
81 changes: 54 additions & 27 deletions drivers/scsi/ibmvscsi/ibmvfc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -641,14 +652,16 @@ 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;

ibmvfc_dbg(vhost, "Releasing CRQ\n");
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));

Expand All @@ -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));

Expand All @@ -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);
Expand All @@ -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;
}
Expand Down Expand Up @@ -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_link_down(vhost, IBMVFC_LINK_DOWN);
ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_RESET);
}

/**
Expand Down Expand Up @@ -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_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_link_down(vhost, IBMVFC_LINK_DOWN);
ibmvfc_set_host_action(vhost, IBMVFC_HOST_ACTION_RESET);
}
return;
case IBMVFC_CRQ_CMD_RSP:
Expand Down Expand Up @@ -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;
};
Expand Down Expand Up @@ -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);
Expand All @@ -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;
Expand Down
2 changes: 2 additions & 0 deletions drivers/scsi/ibmvscsi/ibmvfc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand Down

0 comments on commit 73ee5d8

Please sign in to comment.