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 833d8723..1a9cd7d 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3184,23 +3184,18 @@
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;
}