linux-kernel - [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do

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Date:   Mon,  3 Jun 2019 15:19:42 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Tyrel Datwyler <tyreld@...ux.ibm.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>
Cc:     linux-scsi@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com,
        Nathan Chancellor <natechancellor@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH v2] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

clang warns:

drivers/scsi/ibmvscsi/ibmvscsi.c:2126:7: warning: variable 'rc' is used
uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
        case IBMVSCSI_HOST_ACTION_NONE:
             ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/ibmvscsi/ibmvscsi.c:2151:6: note: uninitialized use occurs
here
        if (rc) {
            ^~

Initialize rc to zero in the case statements that clang mentions so that
the atomic_set and dev_err statement don't trigger for them.

Fixes: 035a3c4046b5 ("scsi: ibmvscsi: redo driver work thread to use enum action states")
Link: https://github.com/ClangBuiltLinux/linux/issues/502
Suggested-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---

v1 -> v2:

* Initialize rc in the case statements, rather than at the top of the
  function, as suggested by Michael.

 drivers/scsi/ibmvscsi/ibmvscsi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index 65053daef5f7..3b5647d622d9 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -2109,9 +2109,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 
 	spin_lock_irqsave(hostdata->host->host_lock, flags);
 	switch (hostdata->action) {
-	case IBMVSCSI_HOST_ACTION_NONE:
-	case IBMVSCSI_HOST_ACTION_UNBLOCK:
-		break;
 	case IBMVSCSI_HOST_ACTION_RESET:
 		spin_unlock_irqrestore(hostdata->host->host_lock, flags);
 		rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
@@ -2128,7 +2125,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
 		if (!rc)
 			rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
 		break;
+	case IBMVSCSI_HOST_ACTION_NONE:
+	case IBMVSCSI_HOST_ACTION_UNBLOCK:
 	default:
+		rc = 0;
 		break;
 	}
 
-- 
2.22.0.rc3