simplify some logic in ext4_mb_normalize_request

While reading through some of the mballoc code it seems that a couple
spots in the size normalization function could be streamlined.

The test for non-overlapping PAs can be or'd for the start & end
conditions, and the tests for adjacent PAs can be else-if'd -
it's essentially independently testing:

	if (A + B <= C)
		...
	if (A > C)
		...

These cannot both be true so it seems like the else-if might
be slightly more efficient and/or informative.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 833d87236881f05000a8f1f083a14917a16d2836..1a9cd7de04dd9ae95c1ad6ece82f36c4bfd483b5 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3184,23 +3184,18 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
                BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
                        ac->ac_o_ex.fe_logical < pa->pa_lstart));
 
-               /* skip PA normalized request doesn't overlap with */
-               if (pa->pa_lstart >= end) {
-                       spin_unlock(&pa->pa_lock);
-                       continue;
-               }
-               if (pa_end <= start) {
+               /* skip PAs this normalized request doesn't overlap with */
+               if (pa->pa_lstart >= end || pa_end <= start) {
                        spin_unlock(&pa->pa_lock);
                        continue;
                }
                BUG_ON(pa->pa_lstart <= start && pa_end >= end);
 
+               /* adjust start or end to be adjacent to this pa */
                if (pa_end <= ac->ac_o_ex.fe_logical) {
                        BUG_ON(pa_end < start);
                        start = pa_end;
-               }
-
-               if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
+               } else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
                        BUG_ON(pa->pa_lstart > end);
                        end = pa->pa_lstart;
                }