btrfs: index check-integrity state hash by a dev_t

We won't have the struct block_device available in the bio soon, so switch
to the numerical dev_t instead of the block_device pointer for looking up
the check-integrity state.
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/btrfs/check-integrity.c

@@ -296,8 +296,7 @@ static void btrfsic_dev_state_hashtable_add(
 		struct btrfsic_dev_state *ds,
 		struct btrfsic_dev_state_hashtable *h);
 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
-static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
-		struct block_device *bdev,
+static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 		struct btrfsic_dev_state_hashtable *h);
 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
@@ -385,8 +384,7 @@ static int btrfsic_process_superblock_dev_mirror(
 		int superblock_mirror_num,
 		struct btrfsic_dev_state **selected_dev_state,
 		struct btrfs_super_block *selected_super);
-static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
-		struct block_device *bdev);
+static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev);
 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 					   u64 bytenr,
 					   struct btrfsic_dev_state *dev_state,
@@ -626,17 +624,15 @@ static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 	list_del(&ds->collision_resolving_node);
 }
 
-static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
-		struct block_device *bdev,
+static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 		struct btrfsic_dev_state_hashtable *h)
 {
 	const unsigned int hashval =
-	    (((unsigned int)((uintptr_t)bdev)) &
-	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
+		dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
 	struct btrfsic_dev_state *ds;
 
 	list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
-		if (ds->bdev == bdev)
+		if (ds->bdev->bd_dev == dev)
 			return ds;
 	}
 
@@ -668,7 +664,7 @@ static int btrfsic_process_superblock(struct btrfsic_state *state,
 		if (!device->bdev || !device->name)
 			continue;
 
-		dev_state = btrfsic_dev_state_lookup(device->bdev);
+		dev_state = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 		BUG_ON(NULL == dev_state);
 		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 			ret = btrfsic_process_superblock_dev_mirror(
@@ -1556,7 +1552,7 @@ static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 	}
 
 	device = multi->stripes[0].dev;
-	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
+	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
 	block_ctx_out->start = bytenr;
 	block_ctx_out->len = len;
@@ -2654,7 +2650,7 @@ static struct btrfsic_block *btrfsic_block_lookup_or_add(
 			pr_info("btrfsic: error, kmalloc failed!\n");
 			return NULL;
 		}
-		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
+		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev->bd_dev);
 		if (NULL == dev_state) {
 			pr_info("btrfsic: error, lookup dev_state failed!\n");
 			btrfsic_block_free(block);
@@ -2734,10 +2730,9 @@ static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 	}
 }
 
-static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
-		struct block_device *bdev)
+static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev)
 {
-	return btrfsic_dev_state_hashtable_lookup(bdev,
+	return btrfsic_dev_state_hashtable_lookup(dev,
 						  &btrfsic_dev_state_hashtable);
 }
 
@@ -2751,7 +2746,7 @@ int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
 	mutex_lock(&btrfsic_mutex);
 	/* since btrfsic_submit_bh() might also be called before
 	 * btrfsic_mount(), this might return NULL */
-	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
+	dev_state = btrfsic_dev_state_lookup(bh->b_bdev->bd_dev);
 
 	/* Only called to write the superblock (incl. FLUSH/FUA) */
 	if (NULL != dev_state &&
@@ -2808,7 +2803,7 @@ static void __btrfsic_submit_bio(struct bio *bio)
 	mutex_lock(&btrfsic_mutex);
 	/* since btrfsic_submit_bio() is also called before
 	 * btrfsic_mount(), this might return NULL */
-	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
+	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev->bd_dev);
 	if (NULL != dev_state &&
 	    (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
 		unsigned int i = 0;
@@ -2998,7 +2993,7 @@ void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
 			continue;
 
 		ds = btrfsic_dev_state_hashtable_lookup(
-				device->bdev,
+				device->bdev->bd_dev,
 				&btrfsic_dev_state_hashtable);
 		if (NULL != ds) {
 			state = ds->state;