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SubjectRe: [RFC] get_write_access()/deny_write_access() without inode->i_lock
On Mon, Jun 20, 2011 at 01:47:17PM +0100, David Howells wrote:
> Al Viro <viro@ZenIV.linux.org.uk> wrote:
>
> > + for (v = atomic_read(&inode->i_writecount); v >= 0; v = v1) {
> > + v1 = atomic_cmpxchg(&inode->i_writecount, v, v + 1);
> > + if (likely(v1 == v))
> > + return 0;
> > + }
>
> You don't need to reissue the atomic_read(). atomic_cmpxchg() returns the
> current value of the memory location. Just set v to v1 before going round the
> loop again.

That's precisely what that loop is doing...


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