From 45e621d45e24ffc4cb2b2935e8438987b860063a Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@redhat.com>
Date: Fri, 21 Dec 2012 20:23:41 +0000
Subject: dm stripe: add WRITE SAME support

Rename stripe_map_discard to stripe_map_range and reuse it for WRITE
SAME bio processing.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
---
 drivers/md/dm-stripe.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index 6b0e5ea38027..c89cde86d400 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -162,6 +162,7 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
 	ti->num_flush_requests = stripes;
 	ti->num_discard_requests = stripes;
+	ti->num_write_same_requests = stripes;
 
 	sc->chunk_size = chunk_size;
 	if (chunk_size & (chunk_size - 1))
@@ -251,8 +252,8 @@ static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
 		*result += sc->chunk_size;		/* next chunk */
 }
 
-static int stripe_map_discard(struct stripe_c *sc, struct bio *bio,
-			      uint32_t target_stripe)
+static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
+			    uint32_t target_stripe)
 {
 	sector_t begin, end;
 
@@ -283,10 +284,11 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
 		bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev;
 		return DM_MAPIO_REMAPPED;
 	}
-	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
+	if (unlikely(bio->bi_rw & REQ_DISCARD) ||
+	    unlikely(bio->bi_rw & REQ_WRITE_SAME)) {
 		target_request_nr = dm_bio_get_target_request_nr(bio);
 		BUG_ON(target_request_nr >= sc->stripes);
-		return stripe_map_discard(sc, bio, target_request_nr);
+		return stripe_map_range(sc, bio, target_request_nr);
 	}
 
 	stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector);
-- 
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