block/drbd: Use the enum req_op and blk_opf_t types

Improve static type checking by using the enum req_op type for variables
that represent a request operation and the new blk_opf_t type for
variables that represent request flags.

Reviewed-by: Christoph Böhmwalder <[e-mail]>
Cc: Lars Ellenberg <[e-mail]>
Cc: Philipp Reisner <[e-mail]>
Signed-off-by: Bart Van Assche <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/block/drbd/drbd_actlog.c

···
 
 static int _drbd_md_sync_page_io(struct drbd_device *device,
 				 struct drbd_backing_dev *bdev,
-				 sector_t sector, int op)
+				 sector_t sector, enum req_op op)
 {
 	struct bio *bio;
 	/* we do all our meta data IO in aligned 4k blocks. */
 	const int size = 4096;
-	int err, op_flags = 0;
+	int err;
+	blk_opf_t op_flags = 0;
 
 	device->md_io.done = 0;
 	device->md_io.error = -ENODEV;
···
 }
 
 int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bdev,
-			 sector_t sector, int op)
+			 sector_t sector, enum req_op op)
 {
 	int err;
 	D_ASSERT(device, atomic_read(&device->md_io.in_use) == 1);
···
 		write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
 		rcu_read_unlock();
 		if (write_al_updates) {
-			if (drbd_md_sync_page_io(device, device->ldev, sector, WRITE)) {
+			if (drbd_md_sync_page_io(device, device->ldev, sector, REQ_OP_WRITE)) {
 				err = -EIO;
 				drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
 			} else {

drivers/block/drbd/drbd_bitmap.c

···
 static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_hold(local)
 {
 	struct drbd_device *device = ctx->device;
-	unsigned int op = (ctx->flags & BM_AIO_READ) ? REQ_OP_READ : REQ_OP_WRITE;
+	enum req_op op = ctx->flags & BM_AIO_READ ? REQ_OP_READ : REQ_OP_WRITE;
 	struct bio *bio = bio_alloc_bioset(device->ldev->md_bdev, 1, op,
 					   GFP_NOIO, &drbd_md_io_bio_set);
 	struct drbd_bitmap *b = device->bitmap;

drivers/block/drbd/drbd_int.h

···
 extern void *drbd_md_get_buffer(struct drbd_device *device, const char *intent);
 extern void drbd_md_put_buffer(struct drbd_device *device);
 extern int drbd_md_sync_page_io(struct drbd_device *device,
-		struct drbd_backing_dev *bdev, sector_t sector, int op);
+		struct drbd_backing_dev *bdev, sector_t sector, enum req_op op);
 extern void drbd_ov_out_of_sync_found(struct drbd_device *, sector_t, int);
 extern void wait_until_done_or_force_detached(struct drbd_device *device,
 		struct drbd_backing_dev *bdev, unsigned int *done);
···
 extern bool drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector,
 		bool throttle_if_app_is_waiting);
 extern int drbd_submit_peer_request(struct drbd_device *,
-				    struct drbd_peer_request *, const unsigned,
-				    const unsigned, const int);
+				    struct drbd_peer_request *, enum req_op,
+				    blk_opf_t, int);
 extern int drbd_free_peer_reqs(struct drbd_device *, struct list_head *);
 extern struct drbd_peer_request *drbd_alloc_peer_req(struct drbd_peer_device *, u64,
 						     sector_t, unsigned int,

drivers/block/drbd/drbd_receiver.c

···
 /* TODO allocate from our own bio_set. */
 int drbd_submit_peer_request(struct drbd_device *device,
 			     struct drbd_peer_request *peer_req,
-			     const unsigned op, const unsigned op_flags,
+			     const enum req_op op, const blk_opf_t op_flags,
 			     const int fault_type)
 {
 	struct bio *bios = NULL;
···
 /* see also bio_flags_to_wire()
  * DRBD_REQ_*, because we need to semantically map the flags to data packet
  * flags and back. We may replicate to other kernel versions. */
-static unsigned long wire_flags_to_bio_flags(u32 dpf)
+static blk_opf_t wire_flags_to_bio_flags(u32 dpf)
 {
 	return  (dpf & DP_RW_SYNC ? REQ_SYNC : 0) |
 		(dpf & DP_FUA ? REQ_FUA : 0) |
 		(dpf & DP_FLUSH ? REQ_PREFLUSH : 0);
 }
 
-static unsigned long wire_flags_to_bio_op(u32 dpf)
+static enum req_op wire_flags_to_bio_op(u32 dpf)
 {
 	if (dpf & DP_ZEROES)
 		return REQ_OP_WRITE_ZEROES;
···
 	struct drbd_peer_request *peer_req;
 	struct p_data *p = pi->data;
 	u32 peer_seq = be32_to_cpu(p->seq_num);
-	int op, op_flags;
+	enum req_op op;
+	blk_opf_t op_flags;
 	u32 dp_flags;
 	int err, tp;
 
···
 
 	if (get_ldev(device)) {
 		struct drbd_peer_request *peer_req;
-		const int op = REQ_OP_WRITE_ZEROES;
+		const enum req_op op = REQ_OP_WRITE_ZEROES;
 
 		peer_req = drbd_alloc_peer_req(peer_device, ID_SYNCER, sector,
 					       size, 0, GFP_NOIO);