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From: Keith Packard <>
Cc: Keith Packard <>
Subject: [PATCH] [drivers/video/fb] Eliminate recursive mutex in compat fb ioctl path
Date: Sun,  2 Nov 2008 23:06:50 -0800	[thread overview]
Message-ID: <> (raw)

fb_compat_ioctl grabbed the fb mutex and then called fb_ioctl, which also
grabs the same mutex. I traced through all existing fb_compat_ioctl
functions in the various fb drivers and found that they also transform their
arguments and call the native fb_ioctl function. So, it is correct to just
remove the mutex_lock/mutex_unlock pair in the top-level compat path.

Signed-off-by: Keith Packard <>
 drivers/video/fbmem.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index cd5f20d..548cf26 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1253,7 +1253,6 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	struct fb_ops *fb = info->fbops;
 	long ret = -ENOIOCTLCMD;
-	mutex_lock(&info->lock);
 	switch(cmd) {
@@ -1279,7 +1278,6 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			ret = fb->fb_compat_ioctl(info, cmd, arg);
-	mutex_unlock(&info->lock);
 	return ret;

             reply	other threads:[~2008-11-03  7:07 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-03  7:06 Keith Packard [this message]
2008-11-03 10:12 ` [PATCH] [drivers/video/fb] Eliminate recursive mutex in compat fb ioctl path Geert Uytterhoeven

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