fs: get rid of the res2 iocb->ki_complete argument

The second argument was only used by the USB gadget code, yet everyone
pays the overhead of passing a zero to be passed into aio, where it
ends up being part of the aio res2 value.

Now that everybody is passing in zero, kill off the extra argument.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
index fac2e8e..effe37e 100644
--- a/fs/cachefiles/io.c
+++ b/fs/cachefiles/io.c
@@ -37,11 +37,11 @@ static inline void cachefiles_put_kiocb(struct cachefiles_kiocb *ki)
 /*
  * Handle completion of a read from the cache.
  */
-static void cachefiles_read_complete(struct kiocb *iocb, long ret, long ret2)
+static void cachefiles_read_complete(struct kiocb *iocb, long ret)
 {
 	struct cachefiles_kiocb *ki = container_of(iocb, struct cachefiles_kiocb, iocb);
 
-	_enter("%ld,%ld", ret, ret2);
+	_enter("%ld", ret);
 
 	if (ki->term_func) {
 		if (ret >= 0)
@@ -139,7 +139,7 @@ static int cachefiles_read(struct netfs_cache_resources *cres,
 		fallthrough;
 	default:
 		ki->was_async = false;
-		cachefiles_read_complete(&ki->iocb, ret, 0);
+		cachefiles_read_complete(&ki->iocb, ret);
 		if (ret > 0)
 			ret = 0;
 		break;
@@ -159,12 +159,12 @@ static int cachefiles_read(struct netfs_cache_resources *cres,
 /*
  * Handle completion of a write to the cache.
  */
-static void cachefiles_write_complete(struct kiocb *iocb, long ret, long ret2)
+static void cachefiles_write_complete(struct kiocb *iocb, long ret)
 {
 	struct cachefiles_kiocb *ki = container_of(iocb, struct cachefiles_kiocb, iocb);
 	struct inode *inode = file_inode(ki->iocb.ki_filp);
 
-	_enter("%ld,%ld", ret, ret2);
+	_enter("%ld", ret);
 
 	/* Tell lockdep we inherited freeze protection from submission thread */
 	__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
@@ -244,7 +244,7 @@ static int cachefiles_write(struct netfs_cache_resources *cres,
 		fallthrough;
 	default:
 		ki->was_async = false;
-		cachefiles_write_complete(&ki->iocb, ret, 0);
+		cachefiles_write_complete(&ki->iocb, ret);
 		if (ret > 0)
 			ret = 0;
 		break;