linux-kernel - [PATCH 6/7] drivers/video: Release mutex in error handling code

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Date:	Mon, 21 Jul 2008 09:58:55 +0200 (CEST)
From:	Julia Lawall <julia@...u.dk>
To:	adaplas@...il.com, linux-fbdev-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH 6/7] drivers/video: Release mutex in error handling code

From: Julia Lawall <julia@...u.dk>

The mutex is released on a successful return, so it would seem that it
should be released on an error return as well.

The semantic patch finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression l;
@@

mutex_lock(l);
... when != mutex_unlock(l)
    when any
    when strict
(
if (...) { ... when != mutex_unlock(l)
+   mutex_unlock(l);
    return ...;
}
|
mutex_unlock(l);
)
// </smpl>

Signed-off-by: Julia Lawall <julia@...u.dk>

---
 drivers/video/arkfb.c    |    9 +++------
 drivers/video/vt8623fb.c |    9 +++------
 2 files changed, 6 insertions(+), 12 deletions(-)

diff -u -p a/drivers/video/arkfb.c b/drivers/video/arkfb.c
--- a/drivers/video/arkfb.c
+++ b/drivers/video/arkfb.c
@@ -1126,11 +1126,8 @@ static int ark_pci_resume (struct pci_de
 	acquire_console_sem();
 	mutex_lock(&(par->open_lock));
 
-	if (par->ref_count == 0) {
-		mutex_unlock(&(par->open_lock));
-		release_console_sem();
-		return 0;
-	}
+	if (par->ref_count == 0)
+		goto fail;
 
 	pci_set_power_state(dev, PCI_D0);
 	pci_restore_state(dev);
@@ -1143,8 +1140,8 @@ static int ark_pci_resume (struct pci_de
 	arkfb_set_par(info);
 	fb_set_suspend(info, 0);
 
-	mutex_unlock(&(par->open_lock));
 fail:
+	mutex_unlock(&(par->open_lock));
 	release_console_sem();
 	return 0;
 }
diff -u -p a/drivers/video/vt8623fb.c b/drivers/video/vt8623fb.c
--- a/drivers/video/vt8623fb.c
+++ b/drivers/video/vt8623fb.c
@@ -853,11 +853,8 @@ static int vt8623_pci_resume(struct pci_
 	acquire_console_sem();
 	mutex_lock(&(par->open_lock));
 
-	if (par->ref_count == 0) {
-		mutex_unlock(&(par->open_lock));
-		release_console_sem();
-		return 0;
-	}
+	if (par->ref_count == 0)
+		goto fail;
 
 	pci_set_power_state(dev, PCI_D0);
 	pci_restore_state(dev);
@@ -870,8 +867,8 @@ static int vt8623_pci_resume(struct pci_
 	vt8623fb_set_par(info);
 	fb_set_suspend(info, 0);
 
-	mutex_unlock(&(par->open_lock));
 fail:
+	mutex_unlock(&(par->open_lock));
 	release_console_sem();
 
 	return 0;
--
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