From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Omar Sandoval <osandov@osandov.com>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH v2 4/4] sbitmap: simplify wrap check
Date: Sun, 22 Nov 2020 15:35:48 +0000 [thread overview]
Message-ID: <120b9b0870719675c91764822016597bdfa3ee15.1606058975.git.asml.silence@gmail.com> (raw)
In-Reply-To: <cover.1606058975.git.asml.silence@gmail.com>
__sbitmap_get_word() doesn't warp if it's starting from the beginning
(i.e. initial hint is 0). Instead of stashing the original hint just set
@wrap accordingly.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
lib/sbitmap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index c18b518a16ba..d693d9213ceb 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -97,9 +97,11 @@ EXPORT_SYMBOL_GPL(sbitmap_resize);
static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
unsigned int hint, bool wrap)
{
- unsigned int orig_hint = hint;
int nr;
+ /* don't wrap if starting from 0 */
+ wrap = wrap && hint;
+
while (1) {
nr = find_next_zero_bit(word, depth, hint);
if (unlikely(nr >= depth)) {
@@ -108,8 +110,8 @@ static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
* offset to 0 in a failure case, so start from 0 to
* exhaust the map.
*/
- if (orig_hint && hint && wrap) {
- hint = orig_hint = 0;
+ if (hint && wrap) {
+ hint = 0;
continue;
}
return -1;
--
2.24.0
next prev parent reply other threads:[~2020-11-22 15:39 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-22 15:35 [PATCH v2 for-next 0/4] optimise sbitmap deferred clear Pavel Begunkov
2020-11-22 15:35 ` [PATCH v2 1/4] sbitmap: optimise sbitmap_deferred_clear() Pavel Begunkov
2020-11-24 14:11 ` John Garry
2020-11-24 15:01 ` Pavel Begunkov
2020-11-22 15:35 ` [PATCH v2 2/4] sbitmap: remove swap_lock Pavel Begunkov
2020-11-24 14:22 ` John Garry
2020-11-24 14:43 ` Pavel Begunkov
2020-11-26 2:46 ` Ming Lei
2020-11-26 13:44 ` Pavel Begunkov
2020-11-27 2:06 ` Ming Lei
2020-11-22 15:35 ` [PATCH v2 3/4] sbitmap: replace CAS with atomic and Pavel Begunkov
2020-11-22 15:35 ` Pavel Begunkov [this message]
2020-12-08 0:13 ` [PATCH v2 for-next 0/4] optimise sbitmap deferred clear Jens Axboe
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