btrfs: remove redundant parameters from btrfs_bio_alloc

All callers pass gfp_flags=GFP_NOFS and nr_vecs=BIO_MAX_PAGES.

submit_extent_page adds __GFP_HIGH that does not make a difference in
our case as it allows access to memory reserves but otherwise does not
change the constraints.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/compression.c

@@ -57,7 +57,7 @@ static inline int compressed_bio_size(struct btrfs_fs_info *fs_info,
 static struct bio *compressed_bio_alloc(struct block_device *bdev,
 					u64 first_byte, gfp_t gfp_flags)
 {
-	return btrfs_bio_alloc(bdev, first_byte >> 9, BIO_MAX_PAGES, gfp_flags);
+	return btrfs_bio_alloc(bdev, first_byte >> 9);
 }
 
 static int check_compressed_csum(struct btrfs_inode *inode,

fs/btrfs/extent_io.c

@@ -2658,14 +2658,12 @@ static void end_bio_extent_readpage(struct bio *bio)
  * never fail.  We're returning a bio right now but you can call btrfs_io_bio
  * for the appropriate container_of magic
  */
-struct bio *
-btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
-		gfp_t gfp_flags)
+struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_sector)
 {
 	struct btrfs_io_bio *btrfs_bio;
 	struct bio *bio;
 
-	bio = bio_alloc_bioset(gfp_flags, nr_vecs, btrfs_bioset);
+	bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_PAGES, btrfs_bioset);
 	bio->bi_bdev = bdev;
 	bio->bi_iter.bi_sector = first_sector;
 	btrfs_bio = btrfs_io_bio(bio);
@@ -2801,8 +2799,7 @@ static int submit_extent_page(int op, int op_flags, struct extent_io_tree *tree,
 		}
 	}
 
-	bio = btrfs_bio_alloc(bdev, sector, BIO_MAX_PAGES,
-			GFP_NOFS | __GFP_HIGH);
+	bio = btrfs_bio_alloc(bdev, sector);
 	bio_add_page(bio, page, page_size, offset);
 	bio->bi_end_io = end_io_func;
 	bio->bi_private = tree;

fs/btrfs/extent_io.h

@@ -462,9 +462,7 @@ void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
 				 u64 delalloc_end, struct page *locked_page,
 				 unsigned bits_to_clear,
 				 unsigned long page_ops);
-struct bio *
-btrfs_bio_alloc(struct block_device *bdev, u64 first_sector, int nr_vecs,
-		gfp_t gfp_flags);
+struct bio *btrfs_bio_alloc(struct block_device *bdev, u64 first_sector);
 struct bio *btrfs_io_bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs);
 struct bio *btrfs_bio_clone(struct bio *bio);
 struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size);