linux-kernel - [PATCH] media: em28xx: fix function pointer check

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Date:   Thu,  3 Sep 2020 07:50:38 -0700
From:   trix@...hat.com
To:     mchehab@...nel.org, natechancellor@...il.com,
        ndesaulniers@...gle.com, brad@...tdimension.cc, mkrufky@...uxtv.org
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com, Tom Rix <trix@...hat.com>
Subject: [PATCH] media: em28xx: fix function pointer check

From: Tom Rix <trix@...hat.com>

clang static analyzer reports this problem

em28xx-core.c:1162:4: warning: Called function pointer
  is null (null dereference)
        ops->suspend(dev->dev_next);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~

This is the problem block

	if (ops->suspend)
		ops->suspend(dev);
	if (dev->dev_next)
		ops->suspend(dev->dev_next);

The check for ops->suspend only covers one statement.
So fix the check consistent with other similar in
the file.

Change a similar check in em28xx_resume_extension()
to use consistent logic as its siblings.

Fixes: be7fd3c3a8c5 ("media: em28xx: Hauppauge DualHD second tuner functionality")
Signed-off-by: Tom Rix <trix@...hat.com>
---
 drivers/media/usb/em28xx/em28xx-core.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index e6088b5d1b80..d60f4c2a661d 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -1156,10 +1156,11 @@ int em28xx_suspend_extension(struct em28xx *dev)
 	dev_info(&dev->intf->dev, "Suspending extensions\n");
 	mutex_lock(&em28xx_devlist_mutex);
 	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
-		if (ops->suspend)
+		if (ops->suspend) {
 			ops->suspend(dev);
-		if (dev->dev_next)
-			ops->suspend(dev->dev_next);
+			if (dev->dev_next)
+				ops->suspend(dev->dev_next);
+		}
 	}
 	mutex_unlock(&em28xx_devlist_mutex);
 	return 0;
@@ -1172,11 +1173,11 @@ int em28xx_resume_extension(struct em28xx *dev)
 	dev_info(&dev->intf->dev, "Resuming extensions\n");
 	mutex_lock(&em28xx_devlist_mutex);
 	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
-		if (!ops->resume)
-			continue;
-		ops->resume(dev);
-		if (dev->dev_next)
-			ops->resume(dev->dev_next);
+		if (ops->resume) {
+			ops->resume(dev);
+			if (dev->dev_next)
+				ops->resume(dev->dev_next);
+		}
 	}
 	mutex_unlock(&em28xx_devlist_mutex);
 	return 0;
-- 
2.18.1