2021-02-25 21:54:39

by Tyrel Datwyler

Subject: [PATCH v4 2/5] ibmvfc: fix invalid sub-CRQ handles after hard reset

A hard reset results in a complete transport disconnect such that the
CRQ connection with the partner VIOS is broken. This has the side effect
of also invalidating the associated sub-CRQs. The current code assumes
that the sub-CRQs are perserved resulting in a protocol violation after
trying to reconnect them with the VIOS. This introduces an infinite loop
such that the VIOS forces a disconnect after each subsequent attempt to
re-register with invalid handles.

Avoid the aforementioned issue by releasing the sub-CRQs prior to CRQ
disconnect, and driving a reinitialization of the sub-CRQs once a new
CRQ is registered with the hypervisor.

fixes: faacf8c5f1d5 ("ibmvfc: add alloc/dealloc routines for SCSI Sub-CRQ Channels")
Signed-off-by: Tyrel Datwyler <[email protected]>
---
drivers/scsi/ibmvscsi/ibmvfc.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 384960036f8b..d34e1a4f74d9 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -158,6 +158,9 @@ static void ibmvfc_npiv_logout(struct ibmvfc_host *);
static void ibmvfc_tgt_implicit_logout_and_del(struct ibmvfc_target *);
static void ibmvfc_tgt_move_login(struct ibmvfc_target *);

+static void ibmvfc_release_sub_crqs(struct ibmvfc_host *);
+static void ibmvfc_init_sub_crqs(struct ibmvfc_host *);
+
static const char *unknown_error = "unknown error";

static long h_reg_sub_crq(unsigned long unit_address, unsigned long ioba,
@@ -926,8 +929,8 @@ static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)
unsigned long flags;
struct vio_dev *vdev = to_vio_dev(vhost->dev);
struct ibmvfc_queue *crq = &vhost->crq;
- struct ibmvfc_queue *scrq;
- int i;
+
+ ibmvfc_release_sub_crqs(vhost);

/* Close the CRQ */
do {
@@ -947,16 +950,6 @@ static int ibmvfc_reset_crq(struct ibmvfc_host *vhost)
memset(crq->msgs.crq, 0, PAGE_SIZE);
crq->cur = 0;

- if (vhost->scsi_scrqs.scrqs) {
- for (i = 0; i < nr_scsi_hw_queues; i++) {
- scrq = &vhost->scsi_scrqs.scrqs[i];
- spin_lock(scrq->q_lock);
- memset(scrq->msgs.scrq, 0, PAGE_SIZE);
- scrq->cur = 0;
- spin_unlock(scrq->q_lock);
- }
- }
-
/* And re-open it again */
rc = plpar_hcall_norets(H_REG_CRQ, vdev->unit_address,
crq->msg_token, PAGE_SIZE);
@@ -966,9 +959,12 @@ 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(vhost->crq.q_lock);
spin_unlock_irqrestore(vhost->host->host_lock, flags);

+ ibmvfc_init_sub_crqs(vhost);
+
return rc;
}

@@ -5692,6 +5688,7 @@ static void ibmvfc_deregister_scsi_channel(struct ibmvfc_host *vhost, int index)

free_irq(scrq->irq, scrq);
irq_dispose_mapping(scrq->irq);
+ scrq->irq = 0;

do {
rc = plpar_hcall_norets(H_FREE_SUB_CRQ, vdev->unit_address,
--
2.27.0

2021-02-26 16:41:35

by Brian King

Subject: Re: [PATCH v4 2/5] ibmvfc: fix invalid sub-CRQ handles after hard reset

Reviewed-by: Brian King <[email protected]>

--
Brian King
Power Linux I/O
IBM Linux Technology Center