f2fs: make FAULT_DISCARD obsolete

__blkdev_issue_discard() in __submit_discard_cmd() will never fail, so
let's make FAULT_DISCARD fault injection obsolete.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Author: chaseyu

Documentation/ABI/testing/sysfs-fs-f2fs

@@ -732,7 +732,7 @@ Description:	Support configuring fault injection type, should be
 		FAULT_TRUNCATE                   0x00000400
 		FAULT_READ_IO                    0x00000800
 		FAULT_CHECKPOINT                 0x00001000
-		FAULT_DISCARD                    0x00002000
+		FAULT_DISCARD                    0x00002000 (obsolete)
 		FAULT_WRITE_IO                   0x00004000
 		FAULT_SLAB_ALLOC                 0x00008000
 		FAULT_DQUOT_INIT                 0x00010000

Documentation/filesystems/f2fs.rst

@@ -206,7 +206,7 @@ fault_type=%d		 Support configuring fault injection type, should be
 			     FAULT_TRUNCATE                   0x00000400
 			     FAULT_READ_IO                    0x00000800
 			     FAULT_CHECKPOINT                 0x00001000
-			     FAULT_DISCARD                    0x00002000
+			     FAULT_DISCARD                    0x00002000 (obsolete)
 			     FAULT_WRITE_IO                   0x00004000
 			     FAULT_SLAB_ALLOC                 0x00008000
 			     FAULT_DQUOT_INIT                 0x00010000

fs/f2fs/f2fs.h

@@ -54,7 +54,7 @@ enum {
 	FAULT_TRUNCATE,
 	FAULT_READ_IO,
 	FAULT_CHECKPOINT,
-	FAULT_DISCARD,
+	FAULT_DISCARD,		/* it's obsolete due to __blkdev_issue_discard() will never fail */
 	FAULT_WRITE_IO,
 	FAULT_SLAB_ALLOC,
 	FAULT_DQUOT_INIT,

fs/f2fs/segment.c

@@ -1287,7 +1287,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
 					&(dcc->fstrim_list) : &(dcc->wait_list);
 	blk_opf_t flag = dpolicy->sync ? REQ_SYNC : 0;
 	block_t lstart, start, len, total_len;
-	int err = 0;
 
 	if (dc->state != D_PREP)
 		return 0;
@@ -1328,7 +1327,7 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
 
 	dc->di.len = 0;
 
-	while (total_len && *issued < dpolicy->max_requests && !err) {
+	while (total_len && *issued < dpolicy->max_requests) {
 		struct bio *bio = NULL;
 		unsigned long flags;
 		bool last = true;
@@ -1344,17 +1343,6 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
 
 		dc->di.len += len;
 
-		err = 0;
-		if (time_to_inject(sbi, FAULT_DISCARD)) {
-			err = -EIO;
-			spin_lock_irqsave(&dc->lock, flags);
-			if (dc->state == D_PARTIAL)
-				dc->state = D_SUBMIT;
-			spin_unlock_irqrestore(&dc->lock, flags);
-
-			break;
-		}
-
 		__blkdev_issue_discard(bdev, SECTOR_FROM_BLOCK(start),
 				SECTOR_FROM_BLOCK(len), GFP_NOFS, &bio);
 		f2fs_bug_on(sbi, !bio);
@@ -1393,11 +1381,11 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
 		len = total_len;
 	}
 
-	if (!err && len) {
+	if (len) {
 		dcc->undiscard_blks -= len;
 		__update_discard_tree_range(sbi, bdev, lstart, start, len);
 	}
-	return err;
+	return 0;
 }
 
 static void __insert_discard_cmd(struct f2fs_sb_info *sbi,