f2fs: ignore discard return value

__blkdev_issue_discard() always returns 0, making the error assignment
in __submit_discard_cmd() dead code.

Initialize err to 0 and remove the error assignment from the
__blkdev_issue_discard() call to err. Move fault injection code into
already present if branch where err is set to -EIO.

This preserves the fault injection behavior while removing dead error
handling.

Reviewed-by: Martin K. Petersen <[e-mail]>
Reviewed-by: Johannes Thumshirn <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Chao Yu <[e-mail]>
Signed-off-by: Chaitanya Kulkarni <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/segment.c

···
 
 		dc->di.len += len;
 
+		err = 0;
 		if (time_to_inject(sbi, FAULT_DISCARD)) {
 			err = -EIO;
-		} else {
-			err = __blkdev_issue_discard(bdev,
-					SECTOR_FROM_BLOCK(start),
-					SECTOR_FROM_BLOCK(len),
-					GFP_NOFS, &bio);
-		}
-		if (err) {
 			spin_lock_irqsave(&dc->lock, flags);
 			if (dc->state == D_PARTIAL)
 				dc->state = D_SUBMIT;
···
 			break;
 		}
 
+		__blkdev_issue_discard(bdev, SECTOR_FROM_BLOCK(start),
+				SECTOR_FROM_BLOCK(len), GFP_NOFS, &bio);
 		f2fs_bug_on(sbi, !bio);
 
 		/*