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Commit 38877f4e authored by Eric Sandeen's avatar Eric Sandeen Committed by Theodore Ts'o
Browse files

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: default avatarEric Sandeen <sandeen@redhat.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 0373130d

fs/ext4/mballoc.c

+4 −9
Original line number Diff line number Diff line
@@ -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;

		}