mm: remove worrying dead code from find_get_pages()

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 <[email protected]>
Cc: Nick Piggin <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: Wu Fengguang <[email protected]>
Cc: Salman Qazi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions