bcache: Fix flash_dev_cache_miss() for real this time

The code was using sectors to count the number of sectors it was zeroing... but
then it passed it to bio_advance()... after it had been set to 0. Amusing...

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 5d5d031cf3813247adb89653f2fe5fcd227ce764..fc14ba3f6d050971c3f6f7e459b20b3e553915bf 100644 (file)
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -1203,22 +1203,13 @@ void bch_cached_dev_request_init(struct cached_dev *dc)
 static int flash_dev_cache_miss(struct btree *b, struct search *s,
                                struct bio *bio, unsigned sectors)
 {
-       struct bio_vec bv;
-       struct bvec_iter iter;
-
-       /* Zero fill bio */
-
-       bio_for_each_segment(bv, bio, iter) {
-               unsigned j = min(bv.bv_len >> 9, sectors);
-
-               void *p = kmap(bv.bv_page);
-               memset(p + bv.bv_offset, 0, j << 9);
-               kunmap(bv.bv_page);
+       unsigned bytes = min(sectors, bio_sectors(bio)) << 9;
 
-               sectors -= j;
-       }
+       swap(bio->bi_iter.bi_size, bytes);
+       zero_fill_bio(bio);
+       swap(bio->bi_iter.bi_size, bytes);
 
-       bio_advance(bio, min(sectors << 9, bio->bi_iter.bi_size));
+       bio_advance(bio, bytes);
 
        if (!bio->bi_iter.bi_size)
                return MAP_DONE;