Messages in this thread | | | Subject | Re: [PATCH] mm: remove worrying dead code from find_get_pages() | From | Peter Zijlstra <> | Date | Thu, 24 Feb 2011 13:38:00 +0100 |
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On Wed, 2011-02-23 at 21:31 -0800, Hugh Dickins wrote: > The radix_tree_deref_retry() case in find_get_pages() has a strange > little excrescence, not seen in the other gang lookups: it looks like > the start of an abandoned attempt to guarantee forward progress in a > case that cannot arise. > > ret should always be 0 here: if it isn't, then going back to restart > will leak references to pages already gotten. There used to be a > comment saying nr_found is necessarily 1 here: that's not quite true, > but the radix_tree_deref_retry() case is peculiar to the entry at index > 0, when we race with it being moved out of the radix_tree root or back. > > Remove the worrisome two lines, add a brief comment here and in > find_get_pages_contig() and find_get_pages_tag(), and a WARN_ON > in find_get_pages() should it ever be seen elsewhere than at 0. > > Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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