Trace zone write plugging operations on block devices.

As tracing of zoned block commands needs the upper 32bit of the widened
64bit action, only add traces to blktrace if user-space has requested
version 2 of the blktrace protocol.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 include/uapi/linux/blktrace_api.h |  5 ++++
 kernel/trace/blktrace.c           | 39 +++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/include/uapi/linux/blktrace_api.h b/include/uapi/linux/blktrace_api.h
index 074c4de62c3e..dc1aa8e4d787 100644
--- a/include/uapi/linux/blktrace_api.h
+++ b/include/uapi/linux/blktrace_api.h
@@ -64,6 +64,8 @@ enum blktrace_act {
 	__BLK_TA_REMAP,			/* bio was remapped */
 	__BLK_TA_ABORT,			/* request aborted */
 	__BLK_TA_DRV_DATA,		/* driver-specific binary data */
+	__BLK_TA_ZONE_PLUG,		/* zone write plug was plugged */
+	__BLK_TA_ZONE_UNPLUG,		/* zone write plug was unplugged */
 	__BLK_TA_ZONE_MGMT,		/* zone management command was issued */
 	__BLK_TA_CGROUP = 1 << 8,	/* from a cgroup*/
 };
@@ -103,6 +105,9 @@ enum blktrace_notify {
 #define BLK_TA_ZONE_APPEND	(__BLK_TA_COMPLETE |\
 				 BLK_TC_ACT2(BLK_TC_ZONE_APPEND))
 #define BLK_TA_ZONE_MGMT	__BLK_TA_ZONE_MGMT
+#define BLK_TA_ZONE_PLUG	(__BLK_TA_ZONE_PLUG | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_ZONE_UNPLUG	(__BLK_TA_ZONE_UNPLUG |\
+				 BLK_TC_ACT(BLK_TC_QUEUE))
 
 #define BLK_TN_PROCESS		(__BLK_TN_PROCESS | BLK_TC_ACT(BLK_TC_NOTIFY))
 #define BLK_TN_TIMESTAMP	(__BLK_TN_TIMESTAMP | BLK_TC_ACT(BLK_TC_NOTIFY))
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 13424efbb2f6..3e7cd8f46c0c 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1094,6 +1094,37 @@ static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
 	rcu_read_unlock();
 }
 
+static void blk_add_trace_zone_plug(void *ignore, struct request_queue *q,
+				    unsigned int zno, sector_t sector,
+				    unsigned int sectors)
+{
+	struct blk_trace *bt;
+
+	rcu_read_lock();
+	bt = rcu_dereference(q->blk_trace);
+	if (bt && bt->version >= 2)
+		__blk_add_trace(bt, sector, sectors << SECTOR_SHIFT, 0,
+				BLK_TA_ZONE_PLUG, 0, 0, NULL, 0);
+	rcu_read_unlock();
+
+	return;
+}
+
+static void blk_add_trace_zone_unplug(void *ignore, struct request_queue *q,
+				      unsigned int zno, sector_t sector,
+				      unsigned int sectors)
+{
+	struct blk_trace *bt;
+
+	rcu_read_lock();
+	bt = rcu_dereference(q->blk_trace);
+	if (bt && bt->version >= 2)
+		__blk_add_trace(bt, sector, sectors << SECTOR_SHIFT, 0,
+				BLK_TA_ZONE_UNPLUG, 0, 0, NULL, 0);
+	rcu_read_unlock();
+	return;
+}
+
 static void blk_add_trace_split(void *ignore, struct bio *bio, unsigned int pdu)
 {
 	struct request_queue *q = bio->bi_bdev->bd_disk->queue;
@@ -1240,6 +1271,12 @@ static void blk_register_tracepoints(void)
 	ret = register_trace_blkdev_zone_mgmt(blk_add_trace_blkdev_zone_mgmt,
 					      NULL);
 	WARN_ON(ret);
+	ret = register_trace_disk_zone_wplug_add_bio(blk_add_trace_zone_plug,
+						     NULL);
+	WARN_ON(ret);
+	ret = register_trace_blk_zone_wplug_bio(blk_add_trace_zone_unplug,
+						NULL);
+	WARN_ON(ret);
 	ret = register_trace_block_plug(blk_add_trace_plug, NULL);
 	WARN_ON(ret);
 	ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
@@ -1259,6 +1296,8 @@ static void blk_unregister_tracepoints(void)
 	unregister_trace_block_split(blk_add_trace_split, NULL);
 	unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
 	unregister_trace_block_plug(blk_add_trace_plug, NULL);
+	unregister_trace_blk_zone_wplug_bio(blk_add_trace_zone_unplug, NULL);
+	unregister_trace_disk_zone_wplug_add_bio(blk_add_trace_zone_plug, NULL);
 	unregister_trace_blkdev_zone_mgmt(blk_add_trace_blkdev_zone_mgmt, NULL);
 	unregister_trace_blk_zone_append_update_request_bio(
 		blk_add_trace_zone_update_request, NULL);
-- 
2.51.0