blktrace: add support for driver data

This patch adds the new api call blk_add_driver_data() to blktrace.
It allows to trace device driver-specific binary data.

Signed-off-by: Stefan Raspl <raspl@linux.vnet.ibm.com>
Signed-off-by: Martin Peschke <mp3@de.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index 3a31eb506164a814a2b9599d11d709f9915ed1cc..bdf505d33e77c1ded7d9008b3f0bf6e3421d9890 100644 (file)
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -24,6 +24,7 @@ enum blktrace_cat {
        BLK_TC_AHEAD    = 1 << 11,      /* readahead */
        BLK_TC_META     = 1 << 12,      /* metadata */
        BLK_TC_DISCARD  = 1 << 13,      /* discard requests */
+       BLK_TC_DRV_DATA = 1 << 14,      /* binary per-driver data */
 
        BLK_TC_END      = 1 << 15,      /* only 16-bits, reminder */
 };
@@ -51,6 +52,7 @@ enum blktrace_act {
        __BLK_TA_BOUNCE,                /* bio was bounced */
        __BLK_TA_REMAP,                 /* bio was remapped */
        __BLK_TA_ABORT,                 /* request aborted */
+       __BLK_TA_DRV_DATA,              /* driver-specific binary data */
 };
 
 /*
@@ -82,6 +84,7 @@ enum blktrace_notify {
 #define BLK_TA_BOUNCE          (__BLK_TA_BOUNCE)
 #define BLK_TA_REMAP           (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
 #define BLK_TA_ABORT           (__BLK_TA_ABORT | BLK_TC_ACT(BLK_TC_QUEUE))
+#define BLK_TA_DRV_DATA        (__BLK_TA_DRV_DATA | BLK_TC_ACT(BLK_TC_DRV_DATA))
 
 #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))
@@ -317,6 +320,34 @@ static inline void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
        __blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
 }
 
+/**
+ * blk_add_driver_data - Add binary message with driver-specific data
+ * @q:         queue the io is for
+ * @rq:                io request
+ * @data:      driver-specific data
+ * @len:       length of driver-specific data
+ *
+ * Description:
+ *     Some drivers might want to write driver-specific data per request.
+ *
+ **/
+static inline void blk_add_driver_data(struct request_queue *q,
+                                      struct request *rq,
+                                      void *data, size_t len)
+{
+       struct blk_trace *bt = q->blk_trace;
+
+       if (likely(!bt))
+               return;
+
+       if (blk_pc_request(rq))
+               __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
+                               rq->errors, len, data);
+       else
+               __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
+                               0, BLK_TA_DRV_DATA, rq->errors, len, data);
+}
+
 extern int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
                           char __user *arg);
 extern int blk_trace_startstop(struct request_queue *q, int start);
@@ -330,6 +361,7 @@ extern int blk_trace_remove(struct request_queue *q);
 #define blk_add_trace_generic(q, rq, rw, what) do { } while (0)
 #define blk_add_trace_pdu_int(q, what, bio, pdu)       do { } while (0)
 #define blk_add_trace_remap(q, bio, dev, f, t) do {} while (0)
+#define blk_add_driver_data(q, rq, data, len)  do {} while (0)
 #define do_blk_trace_setup(q, name, dev, buts) (-ENOTTY)
 #define blk_trace_setup(q, name, dev, arg)     (-ENOTTY)
 #define blk_trace_startstop(q, start)          (-ENOTTY)