f2fs: avoid duplicated codes for cleanup

f2fs_segment_has_free_slot() was copied and modified from
__next_free_blkoff(), they are almost the same, clean up to
reuse common code as much as possible.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -2635,22 +2635,20 @@ static void new_curseg(struct f2fs_sb_info *sbi, int type, bool new_sec)
 	curseg->alloc_type = LFS;
 }
 
-static void __next_free_blkoff(struct f2fs_sb_info *sbi,
-			struct curseg_info *seg, block_t start)
+static int __next_free_blkoff(struct f2fs_sb_info *sbi,
+					int segno, block_t start)
 {
-	struct seg_entry *se = get_seg_entry(sbi, seg->segno);
+	struct seg_entry *se = get_seg_entry(sbi, segno);
 	int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
 	unsigned long *target_map = SIT_I(sbi)->tmp_map;
 	unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
 	unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
-	int i, pos;
+	int i;
 
 	for (i = 0; i < entries; i++)
 		target_map[i] = ckpt_map[i] | cur_map[i];
 
-	pos = __find_rev_next_zero_bit(target_map, sbi->blocks_per_seg, start);
-
-	seg->next_blkoff = pos;
+	return __find_rev_next_zero_bit(target_map, sbi->blocks_per_seg, start);
 }
 
 /*
@@ -2662,26 +2660,16 @@ static void __refresh_next_blkoff(struct f2fs_sb_info *sbi,
 				struct curseg_info *seg)
 {
 	if (seg->alloc_type == SSR)
-		__next_free_blkoff(sbi, seg, seg->next_blkoff + 1);
+		seg->next_blkoff =
+			__next_free_blkoff(sbi, seg->segno,
+						seg->next_blkoff + 1);
 	else
 		seg->next_blkoff++;
 }
 
 bool f2fs_segment_has_free_slot(struct f2fs_sb_info *sbi, int segno)
 {
-	struct seg_entry *se = get_seg_entry(sbi, segno);
-	int entries = SIT_VBLOCK_MAP_SIZE / sizeof(unsigned long);
-	unsigned long *target_map = SIT_I(sbi)->tmp_map;
-	unsigned long *ckpt_map = (unsigned long *)se->ckpt_valid_map;
-	unsigned long *cur_map = (unsigned long *)se->cur_valid_map;
-	int i, pos;
-
-	for (i = 0; i < entries; i++)
-		target_map[i] = ckpt_map[i] | cur_map[i];
-
-	pos = __find_rev_next_zero_bit(target_map, sbi->blocks_per_seg, 0);
-
-	return pos < sbi->blocks_per_seg;
+	return __next_free_blkoff(sbi, segno, 0) < sbi->blocks_per_seg;
 }
 
 /*
@@ -2709,7 +2697,7 @@ static void change_curseg(struct f2fs_sb_info *sbi, int type, bool flush)
 
 	reset_curseg(sbi, type, 1);
 	curseg->alloc_type = SSR;
-	__next_free_blkoff(sbi, curseg, 0);
+	curseg->next_blkoff = __next_free_blkoff(sbi, curseg->segno, 0);
 
 	sum_page = f2fs_get_sum_page(sbi, new_segno);
 	if (IS_ERR(sum_page)) {