block: cleanup tracing

A couple tweaks to the tracing code:

 - trace the request size for all requests
 - trace request sector and nr_sectors only for fs requests, enforced by
   helpers
 - drop SCSI CDB tracing - we have SCSI tracing for this and are going
   to me the CDB out of the generic struct request soon.

With this the tracing code stops to know about BLOCK_PC requests entirely,
it's just FS vs passthrough requests now, where the latter includes any
driver-private requests.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index e417f08..a143a67 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -110,16 +110,16 @@ struct compat_blk_user_trace_setup {
 
 #endif
 
-#if defined(CONFIG_EVENT_TRACING) && defined(CONFIG_BLOCK)
-
-static inline int blk_cmd_buf_len(struct request *rq)
-{
-	return (rq->cmd_type == REQ_TYPE_BLOCK_PC) ? rq->cmd_len * 3 : 1;
-}
-
-extern void blk_dump_cmd(char *buf, struct request *rq);
 extern void blk_fill_rwbs(char *rwbs, unsigned int op, int bytes);
 
-#endif /* CONFIG_EVENT_TRACING && CONFIG_BLOCK */
+static inline sector_t blk_rq_trace_sector(struct request *rq)
+{
+	return (rq->cmd_type != REQ_TYPE_FS) ? 0 : blk_rq_pos(rq);
+}
+
+static inline unsigned int blk_rq_trace_nr_sectors(struct request *rq)
+{
+	return (rq->cmd_type != REQ_TYPE_FS) ? 0 : blk_rq_sectors(rq);
+}
 
 #endif