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Date: Fri, 9 Dec 2022 06:01:44 +0800 From: Kemeng Shi <shikemeng@...weicloud.com> To: axboe@...nel.dk Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org, linfeilong@...wei.com, liuzhiqiang26@...wei.com Subject: [PATCH 1/4] sbitmap: remove unnecessary calculation of alloc_hint in __sbitmap_get_shallow We calculate allow_hint in next word as following: /* low sb->shift bit of alloc_hint will be 0 after this shift */ alloc_hint = index << sb->shift; /* get low sb->shift bit of alloc_hit */ SB_NR_TO_BIT(sb, alloc_hint) So alloc_hit in next word will always be zero. Simpfy alloc_hit calculation in __sbitmap_get_shallow according to the alloc_hit calculation in __sbitmap_get. Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com> --- lib/sbitmap.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/lib/sbitmap.c b/lib/sbitmap.c index 586deb333237..cb5e03a2d65b 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -243,6 +243,7 @@ static int __sbitmap_get_shallow(struct sbitmap *sb, int nr = -1; index = SB_NR_TO_INDEX(sb, alloc_hint); + alloc_hint = SB_NR_TO_BIT(sb, alloc_hint); for (i = 0; i < sb->map_nr; i++) { again: @@ -250,7 +251,7 @@ static int __sbitmap_get_shallow(struct sbitmap *sb, min_t(unsigned int, __map_depth(sb, index), shallow_depth), - SB_NR_TO_BIT(sb, alloc_hint), true); + alloc_hint, true); if (nr != -1) { nr += index << sb->shift; break; @@ -260,13 +261,9 @@ static int __sbitmap_get_shallow(struct sbitmap *sb, goto again; /* Jump to next index. */ - index++; - alloc_hint = index << sb->shift; - - if (index >= sb->map_nr) { + alloc_hint = 0; + if (++index >= sb->map_nr) index = 0; - alloc_hint = 0; - } } return nr; -- 2.30.0
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