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Date: Fri, 02 Mar 2012 13:23:03 +0800
From: Li Zefan <lizf@cn.fujitsu.com>
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To: Hillf Danton <dhillf@gmail.com>
CC: Tejun Heo <tj@kernel.org>, Andrew Morton <akpm@linux-foundation.org>,
        Lennart Poettering <mzxreary@0pointer.de>,
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        LKML <linux-kernel@vger.kernel.org>, Cgroups <cgroups@vger.kernel.org>,
        Eric Paris <eparis@redhat.com>
Subject: Re: [PATCH v2 1/3] xattr: extract kmem_xattr code from tmpfs
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Hillf Danton wrote:
> On Thu, Mar 1, 2012 at 2:17 PM, Li Zefan <lizf@cn.fujitsu.com> wrote:
>> +/*
>> + * free all the xattrs
>> + */
>> +void kmem_xattrs_free(struct kmem_xattrs *xattrs)
>> +{
>> +       struct kmem_xattr *xattr, *node;
>> +
>> +       spin_lock(&xattrs->lock);
>> +       list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
>> +               kfree(xattr->name);
>> +               kfree(xattr);
>> +       }
>> +       spin_unlock(&xattrs->lock);
> 
> In your work it is a library function, operations on &xattrs->head
> are no longer allowed, say list_empty(), after it called, though I
> dunno if such operations exist.
> 

I'd prefer to make it safer to use, so I'll re-init the list head
after freeing all the list items.

> And kmem_xattrs is too close to kmem_xattr, kmem_xattr_list
> is not pron of typo.
> 

Then you won't pass compile. ;)

kmem_xattr_list exposed the data structure we used internally.
We might change to use an rbtree.