Patch "sbitmap: rewrite sbitmap_find_bit_in_index to reduce repeat code" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    sbitmap: rewrite sbitmap_find_bit_in_index to reduce repeat code

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sbitmap-rewrite-sbitmap_find_bit_in_index-to-reduce-.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit c1a5baba184e0b87dbdf4ca2c9cbd091b9cb42db
Author: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
Date:   Tue Jan 17 04:50:57 2023 +0800

    sbitmap: rewrite sbitmap_find_bit_in_index to reduce repeat code
    
    [ Upstream commit 08470a98a7d7e32c787b23b87353f13b03c23195 ]
    
    Rewrite sbitmap_find_bit_in_index as following:
    1. Rename sbitmap_find_bit_in_index to sbitmap_find_bit_in_word
    2. Accept "struct sbitmap_word *" directly instead of accepting
    "struct sbitmap *" and "int index" to get "struct sbitmap_word *".
    3. Accept depth/shallow_depth and wrap for __sbitmap_get_word from caller
    to support need of both __sbitmap_get_shallow and __sbitmap_get.
    
    With helper function sbitmap_find_bit_in_word, we can remove repeat
    code in __sbitmap_get_shallow to find bit considring deferred clear.
    
    Reviewed-by: Jan Kara <jack@xxxxxxx>
    Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230116205059.3821738-4-shikemeng@xxxxxxxxxxxxxxx
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Stable-dep-of: 72d04bdcf3f7 ("sbitmap: fix io hung due to race on sbitmap_word::cleared")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index b9dd0a0a28f89..b942f2ba9a415 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -167,15 +167,16 @@ static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
 	return nr;
 }
 
-static int sbitmap_find_bit_in_index(struct sbitmap *sb, int index,
-				     unsigned int alloc_hint)
+static int sbitmap_find_bit_in_word(struct sbitmap_word *map,
+				    unsigned int depth,
+				    unsigned int alloc_hint,
+				    bool wrap)
 {
-	struct sbitmap_word *map = &sb->map[index];
 	int nr;
 
 	do {
-		nr = __sbitmap_get_word(&map->word, __map_depth(sb, index),
-					alloc_hint, !sb->round_robin);
+		nr = __sbitmap_get_word(&map->word, depth,
+					alloc_hint, wrap);
 		if (nr != -1)
 			break;
 		if (!sbitmap_deferred_clear(map))
@@ -203,7 +204,9 @@ static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint)
 		alloc_hint = 0;
 
 	for (i = 0; i < sb->map_nr; i++) {
-		nr = sbitmap_find_bit_in_index(sb, index, alloc_hint);
+		nr = sbitmap_find_bit_in_word(&sb->map[index],
+					      __map_depth(sb, index),
+					      alloc_hint, !sb->round_robin);
 		if (nr != -1) {
 			nr += index << sb->shift;
 			break;
@@ -246,20 +249,17 @@ static int __sbitmap_get_shallow(struct sbitmap *sb,
 	alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
 
 	for (i = 0; i < sb->map_nr; i++) {
-again:
-		nr = __sbitmap_get_word(&sb->map[index].word,
-					min_t(unsigned int,
-					      __map_depth(sb, index),
-					      shallow_depth),
-					alloc_hint, true);
+		nr = sbitmap_find_bit_in_word(&sb->map[index],
+					      min_t(unsigned int,
+						    __map_depth(sb, index),
+						    shallow_depth),
+					      alloc_hint, true);
+
 		if (nr != -1) {
 			nr += index << sb->shift;
 			break;
 		}
 
-		if (sbitmap_deferred_clear(&sb->map[index]))
-			goto again;
-
 		/* Jump to next index. */
 		alloc_hint = 0;
 		if (++index >= sb->map_nr)