From 5fb3bc4ddcdda8d2a6b2185075d140b9009f99b5 Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Fri, 20 Mar 2015 16:15:24 +0100 Subject: [PATCH] drbd: use bitmap_weight() helper, don't open code Suggested by Akinobu Mita Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe --- drivers/block/drbd/drbd_bitmap.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c index 8bdc34dbaedf..0dabc9b93725 100644 --- a/drivers/block/drbd/drbd_bitmap.c +++ b/drivers/block/drbd/drbd_bitmap.c @@ -24,7 +24,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -#include +#include #include #include #include @@ -565,21 +565,19 @@ static unsigned long bm_count_bits(struct drbd_bitmap *b) unsigned long *p_addr; unsigned long bits = 0; unsigned long mask = (1UL << (b->bm_bits & BITS_PER_LONG_MASK)) -1; - int idx, i, last_word; + int idx, last_word; /* all but last page */ for (idx = 0; idx < b->bm_number_of_pages - 1; idx++) { p_addr = __bm_map_pidx(b, idx); - for (i = 0; i < LWPP; i++) - bits += hweight_long(p_addr[i]); + bits += bitmap_weight(p_addr, BITS_PER_PAGE); __bm_unmap(p_addr); cond_resched(); } /* last (or only) page */ last_word = ((b->bm_bits - 1) & BITS_PER_PAGE_MASK) >> LN2_BPL; p_addr = __bm_map_pidx(b, idx); - for (i = 0; i < last_word; i++) - bits += hweight_long(p_addr[i]); + bits += bitmap_weight(p_addr, last_word * BITS_PER_LONG); p_addr[last_word] &= cpu_to_lel(mask); bits += hweight_long(p_addr[last_word]); /* 32bit arch, may have an unused padding long */ @@ -1425,6 +1423,9 @@ static inline void bm_set_full_words_within_one_page(struct drbd_bitmap *b, int bits; int changed = 0; unsigned long *paddr = kmap_atomic(b->bm_pages[page_nr]); + + /* I think it is more cache line friendly to hweight_long then set to ~0UL, + * than to first bitmap_weight() all words, then bitmap_fill() all words */ for (i = first_word; i < last_word; i++) { bits = hweight_long(paddr[i]); paddr[i] = ~0UL; @@ -1634,8 +1635,7 @@ int drbd_bm_e_weight(struct drbd_device *device, unsigned long enr) int n = e-s; p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, s)); bm = p_addr + MLPP(s); - while (n--) - count += hweight_long(*bm++); + count += bitmap_weight(bm, n * BITS_PER_LONG); bm_unmap(p_addr); } else { drbd_err(device, "start offset (%d) too large in drbd_bm_e_weight\n", s); -- 2.20.1