f2fs: do not use discard_map for hard disks

We don't need to keep discard_map, if disk does not support discard command.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index badd407..af69d6b 100644
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -154,7 +154,9 @@
 	si->base_mem += sizeof(struct sit_info);
 	si->base_mem += MAIN_SEGS(sbi) * sizeof(struct seg_entry);
 	si->base_mem += f2fs_bitmap_size(MAIN_SEGS(sbi));
-	si->base_mem += 3 * SIT_VBLOCK_MAP_SIZE * MAIN_SEGS(sbi);
+	si->base_mem += 2 * SIT_VBLOCK_MAP_SIZE * MAIN_SEGS(sbi);
+	if (f2fs_discard_en(sbi))
+		si->base_mem += SIT_VBLOCK_MAP_SIZE * MAIN_SEGS(sbi);
 	si->base_mem += SIT_VBLOCK_MAP_SIZE;
 	if (sbi->segs_per_sec > 1)
 		si->base_mem += MAIN_SECS(sbi) * sizeof(struct sec_entry);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 14f5fe2..f478cb6 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1072,6 +1072,13 @@
 	cp->ckpt_flags = cpu_to_le32(ckpt_flags);
 }
 
+static inline bool f2fs_discard_en(struct f2fs_sb_info *sbi)
+{
+	struct request_queue *q = bdev_get_queue(sbi->sb->s_bdev);
+
+	return blk_queue_discard(q);
+}
+
 static inline void f2fs_lock_op(struct f2fs_sb_info *sbi)
 {
 	down_read(&sbi->cp_rwsem);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index a46296f..59f578b 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -660,7 +660,7 @@
 	bool force = (cpc->reason == CP_DISCARD);
 	int i;
 
-	if (se->valid_blocks == max_blocks)
+	if (se->valid_blocks == max_blocks || !f2fs_discard_en(sbi))
 		return;
 
 	if (!force) {
@@ -818,12 +818,14 @@
 	if (del > 0) {
 		if (f2fs_test_and_set_bit(offset, se->cur_valid_map))
 			f2fs_bug_on(sbi, 1);
-		if (!f2fs_test_and_set_bit(offset, se->discard_map))
+		if (f2fs_discard_en(sbi) &&
+			!f2fs_test_and_set_bit(offset, se->discard_map))
 			sbi->discard_blks--;
 	} else {
 		if (!f2fs_test_and_clear_bit(offset, se->cur_valid_map))
 			f2fs_bug_on(sbi, 1);
-		if (f2fs_test_and_clear_bit(offset, se->discard_map))
+		if (f2fs_discard_en(sbi) &&
+			f2fs_test_and_clear_bit(offset, se->discard_map))
 			sbi->discard_blks++;
 	}
 	if (!f2fs_test_bit(offset, se->ckpt_valid_map))
@@ -2127,12 +2129,16 @@
 			= kzalloc(SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
 		sit_i->sentries[start].ckpt_valid_map
 			= kzalloc(SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
-		sit_i->sentries[start].discard_map
-			= kzalloc(SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
 		if (!sit_i->sentries[start].cur_valid_map ||
-				!sit_i->sentries[start].ckpt_valid_map ||
-				!sit_i->sentries[start].discard_map)
+				!sit_i->sentries[start].ckpt_valid_map)
 			return -ENOMEM;
+
+		if (f2fs_discard_en(sbi)) {
+			sit_i->sentries[start].discard_map
+				= kzalloc(SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
+			if (!sit_i->sentries[start].discard_map)
+				return -ENOMEM;
+		}
 	}
 
 	sit_i->tmp_map = kzalloc(SIT_VBLOCK_MAP_SIZE, GFP_KERNEL);
@@ -2276,8 +2282,12 @@
 			seg_info_from_raw_sit(se, &sit);
 
 			/* build discard map only one time */
-			memcpy(se->discard_map, se->cur_valid_map, SIT_VBLOCK_MAP_SIZE);
-			sbi->discard_blks += sbi->blocks_per_seg - se->valid_blocks;
+			if (f2fs_discard_en(sbi)) {
+				memcpy(se->discard_map, se->cur_valid_map,
+							SIT_VBLOCK_MAP_SIZE);
+				sbi->discard_blks += sbi->blocks_per_seg -
+							se->valid_blocks;
+			}
 
 			if (sbi->segs_per_sec > 1) {
 				struct sec_entry *e = get_sec_entry(sbi, start);