2022-08-26 03:34:43

by Liu Song

Subject: [RFC PATCH] sbitmap: remove unnecessary code in __sbitmap_queue_get_batch

From: Liu Song <[email protected]>

If "nr + nr_tags <= map_depth", then the value of nr_tags will not be
greater than map_depth, so no additional comparison is required.

Signed-off-by: Liu Song <[email protected]>
---
lib/sbitmap.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 29eb048..34c904b 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -533,10 +533,9 @@ unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
nr = find_first_zero_bit(&map->word, map_depth);
if (nr + nr_tags <= map_depth) {
atomic_long_t *ptr = (atomic_long_t *) &map->word;
- int map_tags = min_t(int, nr_tags, map_depth);
unsigned long val, ret;

- get_mask = ((1UL << map_tags) - 1) << nr;
+ get_mask = ((1UL << nr_tags) - 1) << nr;
do {
val = READ_ONCE(map->word);
if ((val & ~get_mask) != val)
@@ -547,7 +546,7 @@ unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
if (get_mask) {
*offset = nr + (index << sb->shift);
update_alloc_hint_after_get(sb, depth, hint,
- *offset + map_tags - 1);
+ *offset + nr_tags - 1);
return get_mask;
}
}
--
1.8.3.1

2022-08-26 13:42:13

by Jens Axboe

Subject: Re: [RFC PATCH] sbitmap: remove unnecessary code in __sbitmap_queue_get_batch

On Fri, 26 Aug 2022 11:14:13 +0800, Liu Song wrote:
> From: Liu Song <[email protected]>
>
> If "nr + nr_tags <= map_depth", then the value of nr_tags will not be
> greater than map_depth, so no additional comparison is required.
>
>

Applied, thanks!

[1/1] sbitmap: remove unnecessary code in __sbitmap_queue_get_batch
commit: ddbfc34fcf5d0bc33b006b90c580c56edeb31068

Best regards,
--
Jens Axboe