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

From: Sam Bradshaw
Date: Tue May 14 2013 - 18:30:41 EST



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@xxxxxxxxxx>
---
diff --git a/drivers/block/mtip32xx/mtip32xx.c
b/drivers/block/mtip32xx/mtip32xx.c
index 847107e..7c77ae1 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3863,7 +3863,7 @@ 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)) {
@@ -3921,11 +3921,12 @@ 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. */
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/