dm io: remove code duplication between sync_io and aysnc_io

The only difference between the code to setup and dispatch the io in
sync_io() and async_io() is the sync argument to dispatch_io(), which
is used to update the opf argument.

Update the opf argument direcly in sync_io(), and remove the sync
argument from dispatch_io(). Then, make sync_io() call async_io()
instead of duplicting all of its code.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

drivers/md/dm-io.c

@@ -384,16 +384,13 @@ static void do_region(const blk_opf_t opf, unsigned int region,
 
 static void dispatch_io(blk_opf_t opf, unsigned int num_regions,
 			struct dm_io_region *where, struct dpages *dp,
-			struct io *io, int sync, unsigned short ioprio)
+			struct io *io, unsigned short ioprio)
 {
 	int i;
 	struct dpages old_pages = *dp;
 
 	BUG_ON(num_regions > DM_IO_MAX_REGIONS);
 
-	if (sync)
-		opf |= REQ_SYNC;
-
 	/*
 	 * For multiple regions we need to be careful to rewind
 	 * the dp object for each call to do_region.
@@ -411,6 +408,26 @@ static void dispatch_io(blk_opf_t opf, unsigned int num_regions,
 	dec_count(io, 0, 0);
 }
 
+static void async_io(struct dm_io_client *client, unsigned int num_regions,
+		     struct dm_io_region *where, blk_opf_t opf,
+		     struct dpages *dp, io_notify_fn fn, void *context,
+		     unsigned short ioprio)
+{
+	struct io *io;
+
+	io = mempool_alloc(&client->pool, GFP_NOIO);
+	io->error_bits = 0;
+	atomic_set(&io->count, 1); /* see dispatch_io() */
+	io->client = client;
+	io->callback = fn;
+	io->context = context;
+
+	io->vma_invalidate_address = dp->vma_invalidate_address;
+	io->vma_invalidate_size = dp->vma_invalidate_size;
+
+	dispatch_io(opf, num_regions, where, dp, io, ioprio);
+}
+
 struct sync_io {
 	unsigned long error_bits;
 	struct completion wait;
@@ -428,22 +445,12 @@ static int sync_io(struct dm_io_client *client, unsigned int num_regions,
 		   struct dm_io_region *where, blk_opf_t opf, struct dpages *dp,
 		   unsigned long *error_bits, unsigned short ioprio)
 {
-	struct io *io;
 	struct sync_io sio;
 
 	init_completion(&sio.wait);
 
-	io = mempool_alloc(&client->pool, GFP_NOIO);
-	io->error_bits = 0;
-	atomic_set(&io->count, 1); /* see dispatch_io() */
-	io->client = client;
-	io->callback = sync_io_complete;
-	io->context = &sio;
-
-	io->vma_invalidate_address = dp->vma_invalidate_address;
-	io->vma_invalidate_size = dp->vma_invalidate_size;
-
-	dispatch_io(opf, num_regions, where, dp, io, 1, ioprio);
+	async_io(client, num_regions, where, opf | REQ_SYNC, dp,
+		 sync_io_complete, &sio, ioprio);
 
 	wait_for_completion_io(&sio.wait);
 
@@ -453,26 +460,6 @@ static int sync_io(struct dm_io_client *client, unsigned int num_regions,
 	return sio.error_bits ? -EIO : 0;
 }
 
-static void async_io(struct dm_io_client *client, unsigned int num_regions,
-		     struct dm_io_region *where, blk_opf_t opf,
-		     struct dpages *dp, io_notify_fn fn, void *context,
-		     unsigned short ioprio)
-{
-	struct io *io;
-
-	io = mempool_alloc(&client->pool, GFP_NOIO);
-	io->error_bits = 0;
-	atomic_set(&io->count, 1); /* see dispatch_io() */
-	io->client = client;
-	io->callback = fn;
-	io->context = context;
-
-	io->vma_invalidate_address = dp->vma_invalidate_address;
-	io->vma_invalidate_size = dp->vma_invalidate_size;
-
-	dispatch_io(opf, num_regions, where, dp, io, 0, ioprio);
-}
-
 static int dp_init(struct dm_io_request *io_req, struct dpages *dp,
 		   unsigned long size)
 {