f2fs: trace __submit_discard_cmd

Add an even class f2fs_discard for introducing f2fs_queue_discard, then
use f2fs_{queue,issue}_discard to trace __{queue,submit}_discard_cmd.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/segment.c

@@ -763,6 +763,8 @@ static void __submit_discard_cmd(struct f2fs_sb_info *sbi,
 	if (dc->state != D_PREP)
 		return;
 
+	trace_f2fs_issue_discard(dc->bdev, dc->start, dc->len);
+
 	dc->error = __blkdev_issue_discard(dc->bdev,
 				SECTOR_FROM_BLOCK(dc->start),
 				SECTOR_FROM_BLOCK(dc->len),
@@ -942,7 +944,7 @@ static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
 {
 	block_t lblkstart = blkstart;
 
-	trace_f2fs_issue_discard(bdev, blkstart, blklen);
+	trace_f2fs_queue_discard(bdev, blkstart, blklen);
 
 	if (sbi->s_ndevs) {
 		int devi = f2fs_target_device_index(sbi, blkstart);

include/trace/events/f2fs.h

@@ -1129,7 +1129,7 @@ TRACE_EVENT(f2fs_write_checkpoint,
 		__entry->msg)
 );
 
-TRACE_EVENT(f2fs_issue_discard,
+DECLARE_EVENT_CLASS(f2fs_discard,
 
 	TP_PROTO(struct block_device *dev, block_t blkstart, block_t blklen),
 
@@ -1153,6 +1153,20 @@ TRACE_EVENT(f2fs_issue_discard,
 		(unsigned long long)__entry->blklen)
 );
 
+DEFINE_EVENT(f2fs_discard, f2fs_queue_discard,
+
+	TP_PROTO(struct block_device *dev, block_t blkstart, block_t blklen),
+
+	TP_ARGS(dev, blkstart, blklen)
+);
+
+DEFINE_EVENT(f2fs_discard, f2fs_issue_discard,
+
+	TP_PROTO(struct block_device *dev, block_t blkstart, block_t blklen),
+
+	TP_ARGS(dev, blkstart, blklen)
+);
+
 TRACE_EVENT(f2fs_issue_reset_zone,
 
 	TP_PROTO(struct block_device *dev, block_t blkstart),