blktrace: differentiate between blk_io_trace versions

Differentiate between blk_io_trace and blk_io_trace2 when relaying to
user-space depending on which version has been requested by the blktrace
utility.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 57 insertions, 1 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 185f19c9f772..5f8ecf88a196 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -91,7 +91,29 @@ static void record_blktrace_event(struct blk_io_trace *t, pid_t pid, int cpu,
 		memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
 }
 
-static void relay_blktrace_event(struct blk_trace *bt, unsigned long sequence,
+static void record_blktrace_event2(struct blk_io_trace2 *t2, pid_t pid, int cpu,
+				   sector_t sector, int bytes, u64 what,
+				   dev_t dev, int error, u64 cgid,
+				   ssize_t cgid_len, void *pdu_data,
+				   int pdu_len)
+{
+	t2->pid = pid;
+	t2->cpu = cpu;
+
+	t2->sector = sector;
+	t2->bytes = bytes;
+	t2->action = what;
+	t2->device = dev;
+	t2->error = error;
+	t2->pdu_len = pdu_len + cgid_len;
+
+	if (cgid_len)
+		memcpy((void *)t2 + sizeof(*t2), &cgid, cgid_len);
+	if (pdu_len)
+		memcpy((void *)t2 + sizeof(*t2) + cgid_len, pdu_data, pdu_len);
+}
+
+static void relay_blktrace_event1(struct blk_trace *bt, unsigned long sequence,
 				 pid_t pid, int cpu, sector_t sector, int bytes,
 				 u64 what, int error, u64 cgid,
 				 ssize_t cgid_len, void *pdu_data, int pdu_len)
@@ -111,6 +133,40 @@ static void relay_blktrace_event(struct blk_trace *bt, unsigned long sequence,
 			      cgid, cgid_len, pdu_data, pdu_len);
 }
 
+static void relay_blktrace_event2(struct blk_trace *bt, unsigned long sequence,
+				  pid_t pid, int cpu, sector_t sector,
+				  int bytes, u64 what, int error, u64 cgid,
+				  ssize_t cgid_len, void *pdu_data, int pdu_len)
+{
+	struct blk_io_trace2 *t;
+	size_t trace_len = sizeof(struct blk_io_trace2) + pdu_len + cgid_len;
+
+	t = relay_reserve(bt->rchan, trace_len);
+	if (!t)
+		return;
+
+	t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE2_VERSION;
+	t->sequence = sequence;
+	t->time = ktime_to_ns(ktime_get());
+
+	record_blktrace_event2(t, pid, cpu, sector, bytes, what, bt->dev, error,
+			       cgid, cgid_len, pdu_data, pdu_len);
+}
+
+static void relay_blktrace_event(struct blk_trace *bt, unsigned long sequence,
+				 pid_t pid, int cpu, sector_t sector, int bytes,
+				 u64 what, int error, u64 cgid,
+				 ssize_t cgid_len, void *pdu_data, int pdu_len)
+{
+	if (bt->version == 2)
+		return relay_blktrace_event2(bt, sequence, pid, cpu, sector,
+					     bytes, what, error, cgid, cgid_len,
+					     pdu_data, pdu_len);
+	return relay_blktrace_event1(bt, sequence, pid, cpu, sector, bytes,
+				     lower_32_bits(what), error, cgid, cgid_len,
+				     pdu_data, pdu_len);
+}
+
 /*
  * Send out a notify message.
  */