block: better op and flags encoding

Now that we don't need the common flags to overflow outside the range
of a 32-bit type we can encode them the same way for both the bio and
request fields.  This in addition allows us to place the operation
first (and make some room for more ops while we're at it) and to
stop having to shift around the operation values.

In addition this allows passing around only one value in the block layer
instead of two (and eventuall also in the file systems, but we can do
that later) and thus clean up a lot of code.

Last but not least this allows decreasing the size of the cmd_flags
field in struct request to 32-bits.  Various functions passing this
value could also be updated, but I'd like to avoid the churn for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index e7f358d2e5fc..f219c9aed360 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -30,7 +30,7 @@ typedef int (elevator_dispatch_fn) (struct request_queue *, int);
 typedef void (elevator_add_req_fn) (struct request_queue *, struct request *);
 typedef struct request *(elevator_request_list_fn) (struct request_queue *, struct request *);
 typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
-typedef int (elevator_may_queue_fn) (struct request_queue *, int, int);
+typedef int (elevator_may_queue_fn) (struct request_queue *, unsigned int);
 
 typedef void (elevator_init_icq_fn) (struct io_cq *);
 typedef void (elevator_exit_icq_fn) (struct io_cq *);
@@ -139,7 +139,7 @@ extern struct request *elv_former_request(struct request_queue *, struct request
 extern struct request *elv_latter_request(struct request_queue *, struct request *);
 extern int elv_register_queue(struct request_queue *q);
 extern void elv_unregister_queue(struct request_queue *q);
-extern int elv_may_queue(struct request_queue *, int, int);
+extern int elv_may_queue(struct request_queue *, unsigned int);
 extern void elv_completed_request(struct request_queue *, struct request *);
 extern int elv_set_request(struct request_queue *q, struct request *rq,
                            struct bio *bio, gfp_t gfp_mask);