block: kill off q->flush_flags

Now that we converted everything to the newer block write cache
interface, kill off the queue flush_flags and queueable flush
entries.

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 4b1ffc0..626a5ec 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1348,13 +1348,13 @@
 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
 				sector_t start, sector_t len, void *data)
 {
-	unsigned flush = (*(unsigned *)data);
+	unsigned long flush = (unsigned long) data;
 	struct request_queue *q = bdev_get_queue(dev->bdev);
 
-	return q && (q->flush_flags & flush);
+	return q && (q->queue_flags & flush);
 }
 
-static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
+static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
 {
 	struct dm_target *ti;
 	unsigned i = 0;
@@ -1375,7 +1375,7 @@
 			return true;
 
 		if (ti->type->iterate_devices &&
-		    ti->type->iterate_devices(ti, device_flush_capable, &flush))
+		    ti->type->iterate_devices(ti, device_flush_capable, (void *) flush))
 			return true;
 	}
 
@@ -1518,9 +1518,9 @@
 	else
 		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
 
-	if (dm_table_supports_flush(t, REQ_FLUSH)) {
+	if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) {
 		wc = true;
-		if (dm_table_supports_flush(t, REQ_FUA))
+		if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA)))
 			fua = true;
 	}
 	blk_queue_write_cache(q, wc, fua);