From: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Date: Fri, 25 Aug 2017 22:18:03 +0000 (-0500)
Subject: scsi: cxlflash: Avoid double mutex unlock
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1a9e394154e34728f58c1f697b993aaaf89a4db2;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

scsi: cxlflash: Avoid double mutex unlock

The AFU recovery routine uses an interruptible mutex to control the flow
of in-flight recoveries. Upon receiving an interruptible signal the code
branches to a common exit path which wrongly assumes the mutex is
held. Add a local variable to track when the mutex should be unlocked.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---

diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c
index 08da593cb2f6..ed46e8df2e42 100644
--- a/drivers/scsi/cxlflash/superpipe.c
+++ b/drivers/scsi/cxlflash/superpipe.c
@@ -1651,6 +1651,7 @@ static int cxlflash_afu_recover(struct scsi_device *sdev,
 	u64 ctxid = DECODE_CTXID(recover->context_id),
 	    rctxid = recover->context_id;
 	long reg;
+	bool locked = true;
 	int lretry = 20; /* up to 2 seconds */
 	int new_adap_fd = -1;
 	int rc = 0;
@@ -1659,8 +1660,11 @@ static int cxlflash_afu_recover(struct scsi_device *sdev,
 	up_read(&cfg->ioctl_rwsem);
 	rc = mutex_lock_interruptible(mutex);
 	down_read(&cfg->ioctl_rwsem);
-	if (rc)
+	if (rc) {
+		locked = false;
 		goto out;
+	}
+
 	rc = check_state(cfg);
 	if (rc) {
 		dev_err(dev, "%s: Failed state rc=%d\n", __func__, rc);
@@ -1694,8 +1698,10 @@ retry_recover:
 				mutex_unlock(mutex);
 				msleep(100);
 				rc = mutex_lock_interruptible(mutex);
-				if (rc)
+				if (rc) {
+					locked = false;
 					goto out;
+				}
 				goto retry_recover;
 			}
 
@@ -1739,7 +1745,8 @@ retry_recover:
 out:
 	if (likely(ctxi))
 		put_context(ctxi);
-	mutex_unlock(mutex);
+	if (locked)
+		mutex_unlock(mutex);
 	atomic_dec_if_positive(&cfg->recovery_threads);
 	return rc;
 }