mtip32xx: Correctly handle bio->bi_idx != 0 conditions

Stacking drivers may append bvecs to existing bio's, resulting
in non-zero bi_idx conditions.  This patch counts the loops of
bio_for_each_segment() rather than inheriting the bi_idx value
to pass as a segment count to the hardware submission routine.

Signed-off-by: Sam Bradshaw <sbradshaw@micron.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index e366c745ec18..20dd52a2f92f 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3864,7 +3864,7 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio)
         struct driver_data *dd = queue->queuedata;
         struct scatterlist *sg;
         struct bio_vec *bvec;
-        int nents = 0;
+        int i, nents = 0;
         int tag = 0, unaligned = 0;
 
         if (unlikely(dd->dd_flag & MTIP_DDF_STOP_IO)) {
@@ -3922,11 +3922,12 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio)
                 }
 
                 /* Create the scatter list for this bio. */
-                bio_for_each_segment(bvec, bio, nents) {
+                bio_for_each_segment(bvec, bio, i) {
                         sg_set_page(&sg[nents],
                                         bvec->bv_page,
                                         bvec->bv_len,
                                         bvec->bv_offset);
+                        nents++;
                 }
 
                 /* Issue the read/write. */