drbd: use bitmap_weight() helper, don't open code

Suggested by Akinobu Mita <akinobu.mita@gmail.com>

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index 8bdc34dbaedfc94eb4b9c469bef8d4c9c09a9254..0dabc9b93725b3f1c5de274128ea7aeaa832c79d 100644 (file)
--- 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 <linux/bitops.h>
+#include <linux/bitmap.h>
 #include <linux/vmalloc.h>
 #include <linux/string.h>
 #include <linux/drbd.h>
@@ -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);