Commit ce9d2b4f authored Apr 19, 2021 by Tom Rix Committed by Jens Axboe Apr 20, 2021

block/rnbd-clt: Improve find_or_create_sess() return check



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 <trix@redhat.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-12-gi-oh.kim@ionos.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent c77bfa8f

drivers/block/rnbd/rnbd-clt.c

+4 −6

Original line number	Diff line number	Diff line
		@@ -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) {