Commit d2450c69 authored by Peter Chen's avatar Peter Chen Committed by Greg Kroah-Hartman

usb: gadget: f_fs: set req->num_sgs as 0 for non-sg transfer

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). For f_fs async
io mode, it is not harm to initialize req->num_sgs as 0 either, in case,
the UDC driver doesn't zeroed request structure.

Cc: Jun Li <jun.li@nxp.com>
Cc: stable <stable@vger.kernel.org>
Fixes: 772a7a72 ("usb: gadget: f_fs: Allow scatter-gather buffers")
Signed-off-by: default avatarPeter Chen <peter.chen@nxp.com>
Signed-off-by: default avatarFelipe Balbi <balbi@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a0249703
......@@ -1062,6 +1062,7 @@ 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;
......@@ -1105,6 +1106,7 @@ 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;
......
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