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[95.90.238.229]) by smtp.googlemail.com with ESMTPSA id g22sm8701833ejz.46.2021.04.19.00.37.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Apr 2021 00:37:57 -0700 (PDT) From: Gioh Kim To: linux-block@vger.kernel.org, linux-doc@vger.kernel.org Cc: axboe@kernel.dk, akinobu.mita@gmail.com, corbet@lwn.net, hch@infradead.org, sagi@grimberg.me, bvanassche@acm.org, haris.iqbal@ionos.com, jinpu.wang@ionos.com, Tom Rix , Gioh Kim Subject: [PATCHv5 for-next 11/19] block/rnbd-clt: Improve find_or_create_sess() return check Date: Mon, 19 Apr 2021 09:37:14 +0200 Message-Id: <20210419073722.15351-12-gi-oh.kim@ionos.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210419073722.15351-1-gi-oh.kim@ionos.com> References: <20210419073722.15351-1-gi-oh.kim@ionos.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Tom Rix clang static analysis reports this problem rnbd-clt.c:1212:11: warning: Branch condition evaluates to a garbage value else if (!first) ^~~~~~ This is triggered in the find_and_get_or_create_sess() call because the variable first is not initialized and the earlier check is specifically for if (sess == ERR_PTR(-ENOMEM)) This is false positive. But the if-check can be reduced by initializing first to false and then returning if the call to find_or_creat_sess() does not set it to true. When it remains false, either sess will be valid or not. The not case is caught by find_and_get_or_create_sess()'s caller rnbd_clt_map_device() sess = find_and_get_or_create_sess(...); if (IS_ERR(sess)) return ERR_CAST(sess); Since find_and_get_or_create_sess() initializes first to false setting it in find_or_create_sess() is not needed. Signed-off-by: Tom Rix Signed-off-by: Jack Wang Signed-off-by: Gioh Kim --- drivers/block/rnbd/rnbd-clt.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/block/rnbd/rnbd-clt.c b/drivers/block/rnbd/rnbd-clt.c index 652b41cc4492..9b44aac680d5 100644 --- a/drivers/block/rnbd/rnbd-clt.c +++ b/drivers/block/rnbd/rnbd-clt.c @@ -910,6 +910,7 @@ static struct rnbd_clt_session *__find_and_get_sess(const char *sessname) return NULL; } +/* caller is responsible for initializing 'first' to false */ static struct rnbd_clt_session *find_or_create_sess(const char *sessname, bool *first) { @@ -925,8 +926,7 @@ rnbd_clt_session *find_or_create_sess(const char *sessname, bool *first) } list_add(&sess->list, &sess_list); *first = true; - } else - *first = false; + } mutex_unlock(&sess_lock); return sess; @@ -1194,13 +1194,11 @@ find_and_get_or_create_sess(const char *sessname, struct rnbd_clt_session *sess; struct rtrs_attrs attrs; int err; - bool first; + bool first = false; struct rtrs_clt_ops rtrs_ops; sess = find_or_create_sess(sessname, &first); - if (sess == ERR_PTR(-ENOMEM)) - return ERR_PTR(-ENOMEM); - else if (!first) + if (!first) return sess; if (!path_cnt) { -- 2.25.1