[PATCH 031 of 35] Use bio_multi_split to fully split bios for pktcdvd.

[NeilBrown <neilb@suse.de>]

pktcdvd now accepts arbitrarily large bios and will split as necessary.

Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./drivers/block/pktcdvd.c |   44 ++++++++++++--------------------------------
 1 file changed, 12 insertions(+), 32 deletions(-)

diff .prev/drivers/block/pktcdvd.c ./drivers/block/pktcdvd.c
--- .prev/drivers/block/pktcdvd.c	2007-07-31 11:21:13.000000000 +1000
+++ ./drivers/block/pktcdvd.c	2007-07-31 11:21:26.000000000 +1000
@@ -2515,21 +2515,23 @@ static int pkt_make_request(struct reque
 
 	/* Check if we have to split the bio */
 	{
-		struct bio_pair *bp;
+		struct bio *remainder = bio;
 		sector_t last_zone;
 		int first_sectors;
 
 		last_zone = ZONE(bio->bi_sector + bio_sectors(bio) - 1, pd);
-		if (last_zone != zone) {
-			BUG_ON(last_zone != zone + pd->settings.size);
-			first_sectors = last_zone - bio->bi_sector;
-			bp = bio_split(bio, bio_split_pool, first_sectors);
-			BUG_ON(!bp);
-			pkt_make_request(q, &bp->bio1);
-			pkt_make_request(q, &bp->bio2);
-			bio_pair_release(bp);
-			return 0;
+		while (last_zone != zone) {
+			struct bio *new;
+			first_sectors = zone + pd->settings.size
+				- remainder->bi_sector;
+
+			new = bio_multi_split(bio, first_sectors, &remainder);
+
+			pkt_make_request(q, new);
+			last_zone = ZONE(remainder->bi_sector +
+					 bio_sectors(remainder) - 1, pd);
 		}
+		bio = remainder;
 	}
 
 	/*
@@ -2610,27 +2612,6 @@ end_io:
 	return 0;
 }
 
-
-
-static int pkt_merge_bvec(struct request_queue *q, struct bio *bio, struct bio_vec *bvec)
-{
-	struct pktcdvd_device *pd = q->queuedata;
-	sector_t zone = ZONE(bio->bi_sector, pd);
-	int used = ((bio->bi_sector - zone) << 9) + bio->bi_size;
-	int remaining = (pd->settings.size << 9) - used;
-	int remaining2;
-
-	/*
-	 * A bio <= PAGE_SIZE must be allowed. If it crosses a packet
-	 * boundary, pkt_make_request() will split the bio.
-	 */
-	remaining2 = PAGE_SIZE - bio->bi_size;
-	remaining = max(remaining, remaining2);
-
-	BUG_ON(remaining < 0);
-	return remaining;
-}
-
 static void pkt_init_queue(struct pktcdvd_device *pd)
 {
 	struct request_queue *q = pd->disk->queue;
@@ -2638,7 +2619,6 @@ static void pkt_init_queue(struct pktcdv
 	blk_queue_make_request(q, pkt_make_request);
 	blk_queue_hardsect_size(q, CD_FRAMESIZE);
 	blk_queue_max_sectors(q, PACKET_MAX_SECTORS);
-	blk_queue_merge_bvec(q, pkt_merge_bvec);
 	q->queuedata = pd;
 }
 
-
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