From 043b3f7b6388fca6be86ca82979f66c5723a0d10 Mon Sep 17 00:00:00 2001 From: George Spelvin Date: Tue, 14 May 2019 15:42:58 -0700 Subject: lib/list_sort: simplify and remove MAX_LIST_LENGTH_BITS Rather than a fixed-size array of pending sorted runs, use the ->prev links to keep track of things. This reduces stack usage, eliminates some ugly overflow handling, and reduces the code size. Also: * merge() no longer needs to handle NULL inputs, so simplify. * The same applies to merge_and_restore_back_links(), which is renamed to the less ponderous merge_final(). (It's a static helper function, so we don't need a super-descriptive name; comments will do.) * Document the actual return value requirements on the (*cmp)() function; some callers are already using this feature. x86-64 code size 1086 -> 739 bytes (-347) (Yes, I see checkpatch complaining about no space after comma in "__attribute__((nonnull(2,3,4,5)))". Checkpatch is wrong.) Feedback from Rasmus Villemoes, Andy Shevchenko and Geert Uytterhoeven. [akpm@linux-foundation.org: remove __pure usage due to mysterious warning] Link: http://lkml.kernel.org/r/f63c410e0ff76009c9b58e01027e751ff7fdb749.1552704200.git.lkml@sdf.org Signed-off-by: George Spelvin Acked-by: Andrey Abramov Acked-by: Rasmus Villemoes Reviewed-by: Andy Shevchenko Cc: Geert Uytterhoeven Cc: Daniel Wagner Cc: Dave Chinner Cc: Don Mullis Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/list_sort.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/list_sort.h b/include/linux/list_sort.h index ba79956e848d..20f178c24e9d 100644 --- a/include/linux/list_sort.h +++ b/include/linux/list_sort.h @@ -6,6 +6,7 @@ struct list_head; +__attribute__((nonnull(2,3))) void list_sort(void *priv, struct list_head *head, int (*cmp)(void *priv, struct list_head *a, struct list_head *b)); -- cgit