btrfs: split waiting from read_extent_buffer_pages(), drop parameter wait

There are only 2 WAIT_* values left for wait parameter, we can encode
this to the function name if the waiting functionality is split.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: kdave

fs/btrfs/disk-io.c

@@ -226,7 +226,7 @@ int btrfs_read_extent_buffer(struct extent_buffer *eb,
 
 	while (1) {
 		clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
-		ret = read_extent_buffer_pages(eb, WAIT_COMPLETE, mirror_num, check);
+		ret = read_extent_buffer_pages(eb, mirror_num, check);
 		if (!ret)
 			break;
 

fs/btrfs/extent_io.c

@@ -3479,8 +3479,8 @@ static void end_bbio_meta_read(struct btrfs_bio *bbio)
 	bio_put(&bbio->bio);
 }
 
-int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
-			     const struct btrfs_tree_parent_check *check)
+int read_extent_buffer_pages_nowait(struct extent_buffer *eb, int mirror_num,
+				    const struct btrfs_tree_parent_check *check)
 {
 	struct btrfs_bio *bbio;
 	bool ret;
@@ -3498,7 +3498,7 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
 
 	/* Someone else is already reading the buffer, just wait for it. */
 	if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags))
-		goto done;
+		return 0;
 
 	/*
 	 * Between the initial test_bit(EXTENT_BUFFER_UPTODATE) and the above
@@ -3538,14 +3538,21 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
 		}
 	}
 	btrfs_submit_bbio(bbio, mirror_num);
+	return 0;
+}
 
-done:
-	if (wait == WAIT_COMPLETE) {
-		wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_READING, TASK_UNINTERRUPTIBLE);
-		if (!test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
-			return -EIO;
-	}
+int read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num,
+			     const struct btrfs_tree_parent_check *check)
+{
+	int ret;
 
+	ret = read_extent_buffer_pages_nowait(eb, mirror_num, check);
+	if (ret < 0)
+		return ret;
+
+	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_READING, TASK_UNINTERRUPTIBLE);
+	if (!test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
+		return -EIO;
 	return 0;
 }
 
@@ -4276,7 +4283,7 @@ void btrfs_readahead_tree_block(struct btrfs_fs_info *fs_info,
 		return;
 	}
 
-	ret = read_extent_buffer_pages(eb, WAIT_NONE, 0, &check);
+	ret = read_extent_buffer_pages_nowait(eb, 0, &check);
 	if (ret < 0)
 		free_extent_buffer_stale(eb);
 	else

fs/btrfs/extent_io.h

@@ -261,10 +261,11 @@ struct extent_buffer *find_extent_buffer(struct btrfs_fs_info *fs_info,
 					 u64 start);
 void free_extent_buffer(struct extent_buffer *eb);
 void free_extent_buffer_stale(struct extent_buffer *eb);
-#define WAIT_NONE	0
-#define WAIT_COMPLETE	1
-int read_extent_buffer_pages(struct extent_buffer *eb, int wait, int mirror_num,
+int read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num,
 			     const struct btrfs_tree_parent_check *parent_check);
+int read_extent_buffer_pages_nowait(struct extent_buffer *eb, int mirror_num,
+				    const struct btrfs_tree_parent_check *parent_check);
+
 static inline void wait_on_extent_buffer_writeback(struct extent_buffer *eb)
 {
 	wait_on_bit_io(&eb->bflags, EXTENT_BUFFER_WRITEBACK,