1 files changed, 14 insertions, 27 deletions

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 93fbf87bdc8d..8c31357f08ed 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -233,8 +233,7 @@ int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
 	}
 
 	x = cmpxchg(&info->stripe_hash_table, NULL, table);
-	if (x)
-		kvfree(x);
+	kvfree(x);
 	return 0;
 }
 
@@ -250,8 +249,6 @@ int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
 static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
 {
 	int i;
-	char *s;
-	char *d;
 	int ret;
 
 	ret = alloc_rbio_pages(rbio);
@@ -262,13 +259,7 @@ static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
 		if (!rbio->bio_pages[i])
 			continue;
 
-		s = kmap(rbio->bio_pages[i]);
-		d = kmap(rbio->stripe_pages[i]);
-
-		copy_page(d, s);
-
-		kunmap(rbio->bio_pages[i]);
-		kunmap(rbio->stripe_pages[i]);
+		copy_highpage(rbio->stripe_pages[i], rbio->bio_pages[i]);
 		SetPageUptodate(rbio->stripe_pages[i]);
 	}
 	set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
@@ -1105,8 +1096,7 @@ static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
 		 * devices or if they are not contiguous
 		 */
 		if (last_end == disk_start && !last->bi_status &&
-		    last->bi_disk == stripe->dev->bdev->bd_disk &&
-		    last->bi_partno == stripe->dev->bdev->bd_partno) {
+		    last->bi_bdev == stripe->dev->bdev) {
 			ret = bio_add_page(last, page, PAGE_SIZE, 0);
 			if (ret == PAGE_SIZE)
 				return 0;
@@ -1357,9 +1347,7 @@ static int find_bio_stripe(struct btrfs_raid_bio *rbio,
 	for (i = 0; i < rbio->bbio->num_stripes; i++) {
 		stripe = &rbio->bbio->stripes[i];
 		if (in_range(physical, stripe->physical, rbio->stripe_len) &&
-		    stripe->dev->bdev &&
-		    bio->bi_disk == stripe->dev->bdev->bd_disk &&
-		    bio->bi_partno == stripe->dev->bdev->bd_partno) {
+		    stripe->dev->bdev && bio->bi_bdev == stripe->dev->bdev) {
 			return i;
 		}
 	}
@@ -2363,16 +2351,21 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 	SetPageUptodate(p_page);
 
 	if (has_qstripe) {
+		/* RAID6, allocate and map temp space for the Q stripe */
 		q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
 		if (!q_page) {
 			__free_page(p_page);
 			goto cleanup;
 		}
 		SetPageUptodate(q_page);
+		pointers[rbio->real_stripes - 1] = kmap(q_page);
 	}
 
 	atomic_set(&rbio->error, 0);
 
+	/* Map the parity stripe just once */
+	pointers[nr_data] = kmap(p_page);
+
 	for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
 		struct page *p;
 		void *parity;
@@ -2382,16 +2375,8 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 			pointers[stripe] = kmap(p);
 		}
 
-		/* then add the parity stripe */
-		pointers[stripe++] = kmap(p_page);
-
 		if (has_qstripe) {
-			/*
-			 * raid6, add the qstripe and call the
-			 * library function to fill in our p/q
-			 */
-			pointers[stripe++] = kmap(q_page);
-
+			/* RAID6, call the library function to fill in our P/Q */
 			raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
 						pointers);
 		} else {
@@ -2412,12 +2397,14 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
 
 		for (stripe = 0; stripe < nr_data; stripe++)
 			kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
-		kunmap(p_page);
 	}
 
+	kunmap(p_page);
 	__free_page(p_page);
-	if (q_page)
+	if (q_page) {
+		kunmap(q_page);
 		__free_page(q_page);
+	}
 
 writeback:
 	/*