raid1: Refactor narrow_write_error() to not use bi_idx

More bi_idx removal. This code was just open coding bio_clone(). This
could probably be further improved by using bio_advance() instead of
skipping over null pages, but that'd be a larger rework.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index bb5ec77..b362318 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2063,8 +2063,6 @@ static int narrow_write_error(struct r1bio *r1_bio, int i)
        struct mddev *mddev = r1_bio->mddev;
        struct r1conf *conf = mddev->private;
        struct md_rdev *rdev = conf->mirrors[i].rdev;
-       int vcnt, idx;
-       struct bio_vec *vec;
 
        /* bio has the data to be written to device 'i' where
         * we just recently had a write error.
@@ -2092,30 +2090,32 @@ static int narrow_write_error(struct r1bio *r1_bio, int i)
                   & ~(sector_t)(block_sectors - 1))
                - sector;
 
-       if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
-               vcnt = r1_bio->behind_page_count;
-               vec = r1_bio->behind_bvecs;
-               idx = 0;
-               while (vec[idx].bv_page == NULL)
-                       idx++;
-       } else {
-               vcnt = r1_bio->master_bio->bi_vcnt;
-               vec = r1_bio->master_bio->bi_io_vec;
-               idx = r1_bio->master_bio->bi_idx;
-       }
        while (sect_to_write) {
                struct bio *wbio;
                if (sectors > sect_to_write)
                        sectors = sect_to_write;
                /* Write at 'sector' for 'sectors'*/
 
-               wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
-               memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
-               wbio->bi_sector = r1_bio->sector;
+               if (test_bit(R1BIO_BehindIO, &r1_bio->state)) {
+                       unsigned vcnt = r1_bio->behind_page_count;
+                       struct bio_vec *vec = r1_bio->behind_bvecs;
+
+                       while (!vec->bv_page) {
+                               vec++;
+                               vcnt--;
+                       }
+
+                       wbio = bio_alloc_mddev(GFP_NOIO, vcnt, mddev);
+                       memcpy(wbio->bi_io_vec, vec, vcnt * sizeof(struct bio_vec));
+
+                       wbio->bi_vcnt = vcnt;
+               } else {
+                       wbio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
+               }
+
                wbio->bi_rw = WRITE;
-               wbio->bi_vcnt = vcnt;
+               wbio->bi_sector = r1_bio->sector;
                wbio->bi_size = r1_bio->sectors << 9;
-               wbio->bi_idx = idx;
 
                md_trim_bio(wbio, sector - r1_bio->sector, sectors);
                wbio->bi_sector += rdev->data_offset;