btrfs: Sink find_lock_delalloc_range's 'max_bytes' argument

All callers of this function pass BTRFS_MAX_EXTENT_SIZE (128M) so let's
reduce the argument count and make that a local variable. No functional
changes.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -1559,8 +1559,9 @@ static noinline int lock_delalloc_pages(struct inode *inode,
 static noinline_for_stack u64 find_lock_delalloc_range(struct inode *inode,
 				    struct extent_io_tree *tree,
 				    struct page *locked_page, u64 *start,
-				    u64 *end, u64 max_bytes)
+				    u64 *end)
 {
+	u64 max_bytes = BTRFS_MAX_EXTENT_SIZE;
 	u64 delalloc_start;
 	u64 delalloc_end;
 	u64 found;
@@ -1640,10 +1641,9 @@ out_failed:
 u64 btrfs_find_lock_delalloc_range(struct inode *inode,
 				    struct extent_io_tree *tree,
 				    struct page *locked_page, u64 *start,
-				    u64 *end, u64 max_bytes)
+				    u64 *end)
 {
-	return find_lock_delalloc_range(inode, tree, locked_page, start, end,
-			max_bytes);
+	return find_lock_delalloc_range(inode, tree, locked_page, start, end);
 }
 #endif
 
@@ -3217,8 +3217,7 @@ static noinline_for_stack int writepage_delalloc(struct inode *inode,
 		nr_delalloc = find_lock_delalloc_range(inode, tree,
 					       page,
 					       &delalloc_start,
-					       &delalloc_end,
-					       BTRFS_MAX_EXTENT_SIZE);
+					       &delalloc_end);
 		if (nr_delalloc == 0) {
 			delalloc_start = delalloc_end + 1;
 			continue;

fs/btrfs/extent_io.h

@@ -525,7 +525,7 @@ int free_io_failure(struct extent_io_tree *failure_tree,
 u64 btrfs_find_lock_delalloc_range(struct inode *inode,
 				      struct extent_io_tree *tree,
 				      struct page *locked_page, u64 *start,
-				      u64 *end, u64 max_bytes);
+				      u64 *end);
 #endif
 struct extent_buffer *alloc_test_extent_buffer(struct btrfs_fs_info *fs_info,
 					       u64 start);

fs/btrfs/tests/extent-io-tests.c

@@ -108,7 +108,7 @@ static int test_find_delalloc(u32 sectorsize)
 	start = 0;
 	end = 0;
 	found = btrfs_find_lock_delalloc_range(inode, &tmp, locked_page, &start,
-					 &end, max_bytes);
+					 &end);
 	if (!found) {
 		test_err("should have found at least one delalloc");
 		goto out_bits;
@@ -139,7 +139,7 @@ static int test_find_delalloc(u32 sectorsize)
 	start = test_start;
 	end = 0;
 	found = btrfs_find_lock_delalloc_range(inode, &tmp, locked_page, &start,
-					 &end, max_bytes);
+					 &end);
 	if (!found) {
 		test_err("couldn't find delalloc in our range");
 		goto out_bits;
@@ -173,7 +173,7 @@ static int test_find_delalloc(u32 sectorsize)
 	start = test_start;
 	end = 0;
 	found = btrfs_find_lock_delalloc_range(inode, &tmp, locked_page, &start,
-					 &end, max_bytes);
+					 &end);
 	if (found) {
 		test_err("found range when we shouldn't have");
 		goto out_bits;
@@ -194,7 +194,7 @@ static int test_find_delalloc(u32 sectorsize)
 	start = test_start;
 	end = 0;
 	found = btrfs_find_lock_delalloc_range(inode, &tmp, locked_page, &start,
-					 &end, max_bytes);
+					 &end);
 	if (!found) {
 		test_err("didn't find our range");
 		goto out_bits;
@@ -235,7 +235,7 @@ static int test_find_delalloc(u32 sectorsize)
 	 * tests expected behavior.
 	 */
 	found = btrfs_find_lock_delalloc_range(inode, &tmp, locked_page, &start,
-					 &end, max_bytes);
+					 &end);
 	if (!found) {
 		test_err("didn't find our range");
 		goto out_bits;