[PATCH v17 04/13] scsi: ibmvfc: fix stale rc and IRQ mapping leak in ibmvfc_register_channel()

[Dave Marquardt via B4 Relay <devnull+davemarq.linux.ibm.com@kernel.org>]

From: Dave Marquardt <davemarq@linux.ibm.com>

The default: case of the protocol switch in ibmvfc_register_channel()
jumps to irq_failed without setting rc, leaving a stale value from
h_reg_sub_crq() (0 or H_CLOSED) that the caller sees as success even
though the sub-CRQ was just freed. The mapping created by
irq_create_mapping() is also never disposed, leaving scrq->irq non-zero.

Set rc = -EINVAL in the default: case. Introduce an irq_mapping_failed:
label that calls irq_dispose_mapping() and clears scrq->irq before
falling through to irq_failed, and jump to it from both the default:
case and the request_irq() failure path, eliminating the duplicate
inline dispose/clear in the latter.

Signed-off-by: Dave Marquardt <davemarq@linux.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvfc-core.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc-core.c b/drivers/scsi/ibmvscsi/ibmvfc-core.c
index 65829c3d2eea..77c685f6f959 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc-core.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc-core.c
@@ -6429,16 +6429,15 @@ static int ibmvfc_register_channel(struct ibmvfc_host *vhost,
 	default:
 		dev_err(dev, "Unknown channel protocol (%d)\n",
 			channels->protocol);
-		goto irq_failed;
+		rc = -EINVAL;
+		goto irq_mapping_failed;
 	}
 
 	rc = request_irq(scrq->irq, scrq->handler, 0, scrq->name, scrq);
 
 	if (rc) {
 		dev_err(dev, "Couldn't register sub-crq[%d] irq\n", index);
-		irq_dispose_mapping(scrq->irq);
-		scrq->irq = 0;
-		goto irq_failed;
+		goto irq_mapping_failed;
 	}
 
 	scrq->hwq_id = index;
@@ -6446,6 +6445,9 @@ static int ibmvfc_register_channel(struct ibmvfc_host *vhost,
 	LEAVE;
 	return 0;
 
+irq_mapping_failed:
+	irq_dispose_mapping(scrq->irq);
+	scrq->irq = 0;
 irq_failed:
 	do {
 		hcall_rc = plpar_hcall_norets(H_FREE_SUB_CRQ, vdev->unit_address, scrq->cookie);

-- 
2.56.0