[PATCH] blktrace: correct remap names

[Alan D . Brunelle]

This attempts to clarify names utilized during block I/O remap operations
(partition, volume manager). It correctly matches up the /from/ information for both device & sector. This takes in the concept from osaki Motohiro and extends it to include better naming for the "device_from" field.

Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Alan D. Brunelle <alan.brunelle@xxxxxx>
---
 include/linux/blktrace_api.h |    4 ++--
 include/trace/block.h        |    4 ++--
 kernel/trace/blktrace.c      |   21 +++++++++++----------
 3 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index d960889..da1a14e 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -116,9 +116,9 @@ struct blk_io_trace {
  * The remap event
  */
 struct blk_io_trace_remap {
-	__be32 device;
 	__be32 device_from;
-	__be64 sector;
+	__be32 device_to;
+	__be64 sector_from;
 };
 
 enum {
diff --git a/include/trace/block.h b/include/trace/block.h
index 8ac945b..5b12efa 100644
--- a/include/trace/block.h
+++ b/include/trace/block.h
@@ -70,7 +70,7 @@ DECLARE_TRACE(block_split,
 
 DECLARE_TRACE(block_remap,
 	TP_PROTO(struct request_queue *q, struct bio *bio, dev_t dev,
-		 sector_t to),
-	      TP_ARGS(q, bio, dev, to));
+		 sector_t from),
+	      TP_ARGS(q, bio, dev, from));
 
 #endif
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 6eaef3b..1492d50 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -817,7 +817,7 @@ static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
  *
  **/
 static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
-				       dev_t dev, sector_t to)
+				       dev_t dev, sector_t from)
 {
 	struct blk_trace *bt = q->blk_trace;
 	struct blk_io_trace_remap r;
@@ -825,9 +825,9 @@ static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
 	if (likely(!bt))
 		return;
 
-	r.device = cpu_to_be32(dev);
-	r.device_from = cpu_to_be32(bio->bi_bdev->bd_dev);
-	r.sector = cpu_to_be64(to);
+	r.device_from = cpu_to_be32(dev);
+	r.device_to   = cpu_to_be32(bio->bi_bdev->bd_dev);
+	r.sector_from = cpu_to_be64(from);
 
 	__blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
 			BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
@@ -997,11 +997,11 @@ static void get_pdu_remap(const struct trace_entry *ent,
 			  struct blk_io_trace_remap *r)
 {
 	const struct blk_io_trace_remap *__r = pdu_start(ent);
-	__u64 sector = __r->sector;
+	__u64 sector_from = __r->sector_from;
 
-	r->device = be32_to_cpu(__r->device);
 	r->device_from = be32_to_cpu(__r->device_from);
-	r->sector = be64_to_cpu(sector);
+	r->device_to   = be32_to_cpu(__r->device_to);
+	r->sector_from = be64_to_cpu(sector_from);
 }
 
 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
@@ -1055,13 +1055,14 @@ static int blk_log_with_error(struct trace_seq *s,
 
 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
 {
-	struct blk_io_trace_remap r = { .device = 0, };
+	struct blk_io_trace_remap r = { .device_from = 0, };
 
 	get_pdu_remap(ent, &r);
 	return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
 			       t_sector(ent),
-			       t_sec(ent), MAJOR(r.device), MINOR(r.device),
-			       (unsigned long long)r.sector);
+			       t_sec(ent), MAJOR(r.device_from),
+			       MINOR(r.device_from),
+			       (unsigned long long)r.sector_from);
 }
 
 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
-- 
1.6.0.4


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