linux-kernel - [RESEND PATCH] PM / devfreq: Fix static checker warning in try_then_request

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Date:   Wed, 13 Mar 2019 13:22:53 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     linux-kernel@...r.kernel.org
Cc:     kernel@...labora.com, Dan Carpenter <dan.carpenter@...cle.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        linux-pm@...r.kernel.org
Subject: [RESEND PATCH] PM / devfreq: Fix static checker warning in try_then_request_governor

The patch 23c7b54ca1cd: "PM / devfreq: Fix devfreq_add_device() when
drivers are built as modules." leads to the following static checker
warning:

    drivers/devfreq/devfreq.c:1043 governor_store()
    warn: 'governor' can also be NULL

The reason is that the try_then_request_governor() function returns both
error pointers and NULL. It should just return error pointers, so fix
this by returning a ERR_PTR to the error intead of returning NULL.

Fixes: 23c7b54ca1cd ("PM / devfreq: Fix devfreq_add_device() when drivers are built as modules.")
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>
---
Hi,

This is a resend of [1] as seems that got lost at some point and I just
noticed that was never merged.

Thanks,
 Enric

[1] https://lkml.org/lkml/2018/10/16/744


 drivers/devfreq/devfreq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 0ae3de76833b..839621b044f4 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -228,7 +228,7 @@ static struct devfreq_governor *find_devfreq_governor(const char *name)
  * if is not found. This can happen when both drivers (the governor driver
  * and the driver that call devfreq_add_device) are built as modules.
  * devfreq_list_lock should be held by the caller. Returns the matched
- * governor's pointer.
+ * governor's pointer or an error pointer.
  */
 static struct devfreq_governor *try_then_request_governor(const char *name)
 {
@@ -254,7 +254,7 @@ static struct devfreq_governor *try_then_request_governor(const char *name)
 		/* Restore previous state before return */
 		mutex_lock(&devfreq_list_lock);
 		if (err)
-			return NULL;
+			return ERR_PTR(err);
 
 		governor = find_devfreq_governor(name);
 	}
-- 
2.20.1