tree 709cd0702c1ae1366994382bcd170c37ea857149
parent 5bc9188aa207dafd47eab57df7c4fe5b3d3f636a
author Michel Lespinasse <walken@google.com> 1349739050 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1349767354 +0900

rbtree: adjust node color in __rb_erase_color() only when necessary

In __rb_erase_color(), we were always setting a node to black after
exiting the main loop.  And in one case, after fixing up the tree to
satisfy all rbtree invariants, we were setting the current node to root
just to guarantee a loop exit, at which point the root would be set to
black.  However this is not necessary, as the root of an rbtree is already
known to be black.  The only case where the color flip is required is when
we exit the loop due to the current node being red, and it's easiest to
just do the flip at that point instead of doing it after the loop.

[adrian.hunter@intel.com: perf tools: fix build for another rbtree.c change]
Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>