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authorGeorge Spelvin <lkml@sdf.org>2019-05-14 15:42:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 19:52:49 -0700
commit043b3f7b6388fca6be86ca82979f66c5723a0d10 (patch)
tree94745d080f6a24cea043ea6e6f964a7828cd604d /include/linux/list_sort.h
parent8fb583c4258d08f0aff105aa2ae5157b7d414ea2 (diff)
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 <lkml@sdf.org> Acked-by: Andrey Abramov <st5pub@yandex.ru> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Daniel Wagner <daniel.wagner@siemens.com> Cc: Dave Chinner <dchinner@redhat.com> Cc: Don Mullis <don.mullis@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/list_sort.h')
-rw-r--r--include/linux/list_sort.h1
1 files changed, 1 insertions, 0 deletions
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));