block: add REQ_OP definitions and helpers

The following patches separate the operation (WRITE, READ, DISCARD,
etc) from the rq_flag_bits flags. This patch adds definitions for
request/bio operations (REQ_OPs) and adds request/bio accessors to
get/set the op.

In this patch the REQ_OPs match the REQ rq_flag_bits ones
for compat reasons while all the code is converted to use the
op accessors in the set. In the last patches the op will become a
number and the accessors and helpers in this patch will be dropped
or updated.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3d9cf326574f..49c2dbcad583 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -200,6 +200,13 @@ struct request {
         struct request *next_rq;
 };
 
+#define req_op(req)             (op_from_rq_bits((req)->cmd_flags))
+#define req_set_op(req, op)     ((req)->cmd_flags |= op)
+#define req_set_op_attrs(req, op, flags) do {   \
+        req_set_op(req, op);                    \
+        (req)->cmd_flags |= flags;              \
+} while (0)
+
 static inline unsigned short req_get_ioprio(struct request *req)
 {
         return req->ioprio;
@@ -597,7 +604,8 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 
 #define list_entry_rq(ptr)      list_entry((ptr), struct request, queuelist)
 
-#define rq_data_dir(rq)         ((int)((rq)->cmd_flags & 1))
+#define rq_data_dir(rq) \
+        (op_is_write(op_from_rq_bits(rq->cmd_flags)) ? WRITE : READ)
 
 /*
  * Driver can handle struct request, if it either has an old style