Messages in this thread | | | Date | Mon, 20 Jun 2011 14:18:18 +0100 | From | Al Viro <> | Subject | Re: [RFC] get_write_access()/deny_write_access() without inode->i_lock |
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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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