io_uring/rw: split io_read() into a helper

Commit a08d195b586a217d76b42062f88f375a3eedda4d upstream.

Add __io_read() which does the grunt of the work, leaving the completion
side to the new io_read(). No functional changes in this patch.

Reviewed-by: Gabriel Krisman Bertazi <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
(cherry picked from commit a08d195b586a217d76b42062f88f375a3eedda4d)
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: axboe

io_uring/rw.c

@@ -691,7 +691,7 @@ static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
 	return 0;
 }
 
-int io_read(struct io_kiocb *req, unsigned int issue_flags)
+static int __io_read(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
 	struct io_rw_state __s, *s = &__s;
@@ -836,7 +836,18 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags)
 	/* it's faster to check here then delegate to kfree */
 	if (iovec)
 		kfree(iovec);
-	return kiocb_done(req, ret, issue_flags);
+	return ret;
+}
+
+int io_read(struct io_kiocb *req, unsigned int issue_flags)
+{
+	int ret;
+
+	ret = __io_read(req, issue_flags);
+	if (ret >= 0)
+		return kiocb_done(req, ret, issue_flags);
+
+	return ret;
 }
 
 static bool io_kiocb_start_write(struct io_kiocb *req, struct kiocb *kiocb)