linux-kernel - [PATCH] devcgroup: skip superfluous checks when found the DEV

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Message-ID: <49DAE8E4.2030106@cn.fujitsu.com>
Date:	Tue, 07 Apr 2009 13:47:16 +0800
From:	Li Zefan <lizf@...fujitsu.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	"Serge E. Hallyn" <serue@...ibm.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux Containers <containers@...ts.linux-foundation.org>
Subject: [PATCH] devcgroup: skip superfluous checks when found the DEV_ALL
 elem

While walking through the whitelist, if the DEV_ALL item is found,
no more check is needed.

Signed-off-by: Li Zefan <lizf@...fujitsu.com>
---
 security/device_cgroup.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 5fda7df..b8186ba 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -490,7 +490,7 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
 
 	list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
 		if (wh->type & DEV_ALL)
-			goto acc_check;
+			goto found;
 		if ((wh->type & DEV_BLOCK) && !S_ISBLK(inode->i_mode))
 			continue;
 		if ((wh->type & DEV_CHAR) && !S_ISCHR(inode->i_mode))
@@ -499,11 +499,12 @@ int devcgroup_inode_permission(struct inode *inode, int mask)
 			continue;
 		if (wh->minor != ~0 && wh->minor != iminor(inode))
 			continue;
-acc_check:
+
 		if ((mask & MAY_WRITE) && !(wh->access & ACC_WRITE))
 			continue;
 		if ((mask & MAY_READ) && !(wh->access & ACC_READ))
 			continue;
+found:
 		rcu_read_unlock();
 		return 0;
 	}
@@ -527,7 +528,7 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
 
 	list_for_each_entry_rcu(wh, &dev_cgroup->whitelist, list) {
 		if (wh->type & DEV_ALL)
-			goto acc_check;
+			goto found;
 		if ((wh->type & DEV_BLOCK) && !S_ISBLK(mode))
 			continue;
 		if ((wh->type & DEV_CHAR) && !S_ISCHR(mode))
@@ -536,9 +537,10 @@ int devcgroup_inode_mknod(int mode, dev_t dev)
 			continue;
 		if (wh->minor != ~0 && wh->minor != MINOR(dev))
 			continue;
-acc_check:
+
 		if (!(wh->access & ACC_MKNOD))
 			continue;
+found:
 		rcu_read_unlock();
 		return 0;
 	}
-- 
1.5.4.rc3

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