The UDC core uses req->num_sgs to judge if scatter buffer list is used.
Eg: usb_gadget_map_request_by_dev. For f_fs sync io mode, the request
is re-used for each request, so if the 1st request->length > PAGE_SIZE,
and the 2nd request->length is < PAGE_SIZE, the f_fs uses the 1st
req->num_sgs for the 2nd request, it causes the UDC core get the wrong
req->num_sgs value (The 2nd request doesn't use sg).
We set req->num_sgs as 0 for each request at non-sg transfer case to
fix it.
Cc: Jun Li <jun.li@xxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Fixes: 772a7a724f69 ("usb: gadget: f_fs: Allow scatter-gather buffers")
Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
---
drivers/usb/gadget/function/f_fs.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index eedd926cc578..b5a1bfc2fc7e 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1106,7 +1106,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
req->num_sgs = io_data->sgt.nents;
} else {
req->buf = data;
- req->num_sgs = 0;
}
req->length = data_len;
--
2.17.1
