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From:   Nathan Chancellor <natechancellor@gmail.com>
To:     Dennis Dalessandro <dennis.dalessandro@intel.com>,
        Mike Marciniszyn <mike.marciniszyn@intel.com>,
        Doug Ledford <dledford@redhat.com>,
        Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Kamenee Arumugam <kamenee.arumugam@intel.com>,
        linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
        clang-built-linux@googlegroups.com,
        Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH] IB/rdmavt: Remove err declaration in if statement in rvt_create_cq
Date:   Tue,  9 Jul 2019 15:13:12 -0700
Message-Id: <20190709221312.7089-1-natechancellor@gmail.com>
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Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

clang warns:

drivers/infiniband/sw/rdmavt/cq.c:260:7: warning: variable 'err' is used
uninitialized whenever 'if' condition is true
[-Wsometimes-uninitialized]
                if (err)
                    ^~~
drivers/infiniband/sw/rdmavt/cq.c:310:9: note: uninitialized use occurs
here
        return err;
               ^~~
drivers/infiniband/sw/rdmavt/cq.c:260:3: note: remove the 'if' if its
condition is always false
                if (err)
                ^~~~~~~~
drivers/infiniband/sw/rdmavt/cq.c:253:7: warning: variable 'err' is used
uninitialized whenever 'if' condition is true
[-Wsometimes-uninitialized]
                if (!cq->ip) {
                    ^~~~~~~
drivers/infiniband/sw/rdmavt/cq.c:310:9: note: uninitialized use occurs
here
        return err;
               ^~~
drivers/infiniband/sw/rdmavt/cq.c:253:3: note: remove the 'if' if its
condition is always false
                if (!cq->ip) {
                ^~~~~~~~~~~~~~
drivers/infiniband/sw/rdmavt/cq.c:211:9: note: initialize the variable
'err' to silence this warning
        int err;
               ^
                = 0
2 warnings generated.

There are two err declarations in this function: at the top and within
an if statement; clang warns because the assignments to err in the if
statement are local to the if statement so err will be used
uninitialized if this error handling is used. Remove the if statement's
err declaration so that everything works properly.

Fixes: 239b0e52d8aa ("IB/hfi1: Move rvt_cq_wc struct into uapi directory")
Link: https://github.com/ClangBuiltLinux/linux/issues/594
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 drivers/infiniband/sw/rdmavt/cq.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/infiniband/sw/rdmavt/cq.c b/drivers/infiniband/sw/rdmavt/cq.c
index fac87b13329d..a85571a4cf57 100644
--- a/drivers/infiniband/sw/rdmavt/cq.c
+++ b/drivers/infiniband/sw/rdmavt/cq.c
@@ -247,8 +247,6 @@ int rvt_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
 	 * See rvt_mmap() for details.
 	 */
 	if (udata && udata->outlen >= sizeof(__u64)) {
-		int err;
-
 		cq->ip = rvt_create_mmap_info(rdi, sz, udata, u_wc);
 		if (!cq->ip) {
 			err = -ENOMEM;
-- 
2.22.0