[PATCH] raid5 and raid6 fixes to current bk tree

This fixes the raid5 and raid6 prolems that crept in with the recent
introduction of "bi_max_vecs".

Since raid5/raid6 allocate their own bio's, they need to make sure
that bi_max_vecs is updated along with bi_vcnt.

drivers/md/raid5.c

@@ -458,6 +458,7 @@ static void raid5_build_block (struct stripe_head *sh, int i)
 	bio_init(&dev->req);
 	dev->req.bi_io_vec = &dev->vec;
 	dev->req.bi_vcnt++;
+	dev->req.bi_max_vecs++;
 	dev->vec.bv_page = dev->page;
 	dev->vec.bv_len = STRIPE_SIZE;
 	dev->vec.bv_offset = 0;
@@ -1288,6 +1289,7 @@ static void handle_stripe(struct stripe_head *sh)
 			bi->bi_sector = sh->sector + rdev->data_offset;
 			bi->bi_flags = 1 << BIO_UPTODATE;
 			bi->bi_vcnt = 1;	
+			bi->bi_max_vecs = 1;
 			bi->bi_idx = 0;
 			bi->bi_io_vec = &sh->dev[i].vec;
 			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;

drivers/md/raid6main.c

@@ -478,6 +478,7 @@ static void raid6_build_block (struct stripe_head *sh, int i)
 	bio_init(&dev->req);
 	dev->req.bi_io_vec = &dev->vec;
 	dev->req.bi_vcnt++;
+	dev->req.bi_max_vecs++;
 	dev->vec.bv_page = dev->page;
 	dev->vec.bv_len = STRIPE_SIZE;
 	dev->vec.bv_offset = 0;
@@ -1447,6 +1448,7 @@ static void handle_stripe(struct stripe_head *sh)
 			bi->bi_sector = sh->sector + rdev->data_offset;
 			bi->bi_flags = 1 << BIO_UPTODATE;
 			bi->bi_vcnt = 1;
+			bi->bi_max_vecs = 1;
 			bi->bi_idx = 0;
 			bi->bi_io_vec = &sh->dev[i].vec;
 			bi->bi_io_vec[0].bv_len = STRIPE_SIZE;