Messages in this thread | | | Date | Thu, 9 Apr 2009 17:06:10 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] devcgroup: skip superfluous checks when found the DEV_ALL elem |
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On Tue, 07 Apr 2009 13:47:16 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote:
> While walking through the whitelist, if the DEV_ALL item is found, > no more check is needed. >
It's unobvious whether this is a behavioural change, a bugfix or just a speedup?
> > 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; > }
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