linux-kernel - [PATCH v4 5/5] ibmvfc: reinitialize sub-CRQs and perform channel enquiry after LPM

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Message-Id: <20210225215057.23020-6-tyreld@linux.ibm.com>
Date:   Thu, 25 Feb 2021 15:50:57 -0600
From:   Tyrel Datwyler <tyreld@...ux.ibm.com>
To:     james.bottomley@...senpartnership.com
Cc:     martin.petersen@...cle.com, linux-scsi@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        brking@...ux.ibm.com, Tyrel Datwyler <tyreld@...ux.ibm.com>
Subject: [PATCH v4 5/5] ibmvfc: reinitialize sub-CRQs and perform channel enquiry after LPM

A live partition migration (LPM) results in a CRQ disconnect similar to
a hard reset. In this LPM case the hypervisor moslty perserves the CRQ
transport such that it simply needs to be reenabled. However, the
capabilities may have changed such as fewer channels, or no channels at
all. Further, its possible that there may be sub-CRQ support, but no
channel support. The CRQ reenable path currently doesn't take any of
this into consideration.

For simpilicty release and reinitialize sub-CRQs during reenable, and
set do_enquiry and using_channels with the appropriate values to trigger
channel renegotiation.

fixes: faacf8c5f1d5 ("ibmvfc: add alloc/dealloc routines for SCSI Sub-CRQ Channels")
Signed-off-by: Tyrel Datwyler <tyreld@...ux.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvfc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index ef03fa559433..1e2ea21713ad 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -903,6 +903,9 @@ static int ibmvfc_reenable_crq_queue(struct ibmvfc_host *vhost)
 {
 	int rc = 0;
 	struct vio_dev *vdev = to_vio_dev(vhost->dev);
+	unsigned long flags;
+
+	ibmvfc_release_sub_crqs(vhost);
 
 	/* Re-enable the CRQ */
 	do {
@@ -914,6 +917,15 @@ static int ibmvfc_reenable_crq_queue(struct ibmvfc_host *vhost)
 	if (rc)
 		dev_err(vhost->dev, "Error enabling adapter (rc=%d)\n", rc);
 
+	spin_lock_irqsave(vhost->host->host_lock, flags);
+	spin_lock(vhost->crq.q_lock);
+	vhost->do_enquiry = 1;
+	vhost->using_channels = 0;
+	spin_unlock(vhost->crq.q_lock);
+	spin_unlock_irqrestore(vhost->host->host_lock, flags);
+
+	ibmvfc_init_sub_crqs(vhost);
+
 	return rc;
 }
 
-- 
2.27.0