xen: use bio op accessors

Separate the op from the rq_flag_bits and have xen
set/get the bio using bio_set_op_attrs/bio_op.

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

drivers/block/xen-blkback/blkback.c

@@ -501,7 +501,7 @@ static int xen_vbd_translate(struct phys_req *req, struct xen_blkif *blkif,
 	struct xen_vbd *vbd = &blkif->vbd;
 	int rc = -EACCES;
 
-	if ((operation != READ) && vbd->readonly)
+	if ((operation != REQ_OP_READ) && vbd->readonly)
 		goto out;
 
 	if (likely(req->nr_sects)) {
@@ -1014,7 +1014,7 @@ static int dispatch_discard_io(struct xen_blkif_ring *ring,
 	preq.sector_number = req->u.discard.sector_number;
 	preq.nr_sects      = req->u.discard.nr_sectors;
 
-	err = xen_vbd_translate(&preq, blkif, WRITE);
+	err = xen_vbd_translate(&preq, blkif, REQ_OP_WRITE);
 	if (err) {
 		pr_warn("access denied: DISCARD [%llu->%llu] on dev=%04x\n",
 			preq.sector_number,
@@ -1229,6 +1229,7 @@ static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
 	struct bio **biolist = pending_req->biolist;
 	int i, nbio = 0;
 	int operation;
+	int operation_flags = 0;
 	struct blk_plug plug;
 	bool drain = false;
 	struct grant_page **pages = pending_req->segments;
@@ -1247,17 +1248,19 @@ static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
 	switch (req_operation) {
 	case BLKIF_OP_READ:
 		ring->st_rd_req++;
-		operation = READ;
+		operation = REQ_OP_READ;
 		break;
 	case BLKIF_OP_WRITE:
 		ring->st_wr_req++;
-		operation = WRITE_ODIRECT;
+		operation = REQ_OP_WRITE;
+		operation_flags = WRITE_ODIRECT;
 		break;
 	case BLKIF_OP_WRITE_BARRIER:
 		drain = true;
 	case BLKIF_OP_FLUSH_DISKCACHE:
 		ring->st_f_req++;
-		operation = WRITE_FLUSH;
+		operation = REQ_OP_WRITE;
+		operation_flags = WRITE_FLUSH;
 		break;
 	default:
 		operation = 0; /* make gcc happy */
@@ -1269,7 +1272,7 @@ static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
 	nseg = req->operation == BLKIF_OP_INDIRECT ?
 	       req->u.indirect.nr_segments : req->u.rw.nr_segments;
 
-	if (unlikely(nseg == 0 && operation != WRITE_FLUSH) ||
+	if (unlikely(nseg == 0 && operation_flags != WRITE_FLUSH) ||
 	    unlikely((req->operation != BLKIF_OP_INDIRECT) &&
 		     (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) ||
 	    unlikely((req->operation == BLKIF_OP_INDIRECT) &&
@@ -1310,7 +1313,7 @@ static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
 
 	if (xen_vbd_translate(&preq, ring->blkif, operation) != 0) {
 		pr_debug("access denied: %s of [%llu,%llu] on dev=%04x\n",
-			 operation == READ ? "read" : "write",
+			 operation == REQ_OP_READ ? "read" : "write",
 			 preq.sector_number,
 			 preq.sector_number + preq.nr_sects,
 			 ring->blkif->vbd.pdevice);
@@ -1369,15 +1372,15 @@ static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
 			bio->bi_private = pending_req;
 			bio->bi_end_io  = end_block_io_op;
 			bio->bi_iter.bi_sector  = preq.sector_number;
-			bio->bi_rw	= operation;
+			bio_set_op_attrs(bio, operation, operation_flags);
 		}
 
 		preq.sector_number += seg[i].nsec;
 	}
 
 	/* This will be hit if the operation was a flush or discard. */
 	if (!bio) {
-		BUG_ON(operation != WRITE_FLUSH);
+		BUG_ON(operation_flags != WRITE_FLUSH);
 
 		bio = bio_alloc(GFP_KERNEL, 0);
 		if (unlikely(bio == NULL))
@@ -1387,7 +1390,7 @@ static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
 		bio->bi_bdev    = preq.bdev;
 		bio->bi_private = pending_req;
 		bio->bi_end_io  = end_block_io_op;
-		bio->bi_rw	= operation;
+		bio_set_op_attrs(bio, operation, operation_flags);
 	}
 
 	atomic_set(&pending_req->pendcnt, nbio);
@@ -1399,9 +1402,9 @@ static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
 	/* Let the I/Os go.. */
 	blk_finish_plug(&plug);
 
-	if (operation == READ)
+	if (operation == REQ_OP_READ)
 		ring->st_rd_sect += preq.nr_sects;
-	else if (operation & WRITE)
+	else if (operation == REQ_OP_WRITE)
 		ring->st_wr_sect += preq.nr_sects;
 
 	return 0;