usb: gadget: f_fs: Limit the maximum length of data transferring

When the ffs daemons request transfer with large size buffer, the usb
subsystems below cannot filled the buffer at once and then the request
is stalled in f_fs_epfile_io function. In order to prevent this
situation, this limits maximum length of data as PAGE_SIZE.

Change-Id: Ib84b3493a56b21f33a07cf0533f8df71580b7540
Signed-off-by: Dongwoo Lee <dwoo08.lee@samsung.com>

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 6e9ef35..ebe7126 100644 (file)
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1000,6 +1000,8 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
                        goto error_lock;
                }
                data_len = iov_iter_count(&io_data->data);
+               data_len = data_len > PAGE_SIZE ? PAGE_SIZE : data_len;
+
                /*
                 * Controller may require buffer size to be aligned to
                 * maxpacketsize of an out endpoint.