From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752056Ab3KJQu6 (ORCPT ); Sun, 10 Nov 2013 11:50:58 -0500 Received: from mail-ea0-f169.google.com ([209.85.215.169]:61439 "EHLO mail-ea0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751851Ab3KJQuu (ORCPT ); Sun, 10 Nov 2013 11:50:50 -0500 From: Michal Nazarewicz To: David Cohen , Alan Stern Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Nazarewicz Subject: [PATCH 2/2] check quirk to pad epout buf size when not aligned to maxpacketsize Date: Sun, 10 Nov 2013 17:50:37 +0100 Message-Id: <1384102237-19784-2-git-send-email-mpn@google.com> X-Mailer: git-send-email 1.8.4.1 In-Reply-To: <1384102237-19784-1-git-send-email-mpn@google.com> References: <1384102237-19784-1-git-send-email-mpn@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michal Nazarewicz Check gadget.quirk_ep_out_aligned_size to decide if buffer size requires to be aligned to maxpacketsize of an out endpoint. ffs_epfile_io() needs to pad epout buffer to match above condition if quirk is found. Signed-off-by: Michal Nazarewicz --- I'm wondering whether the len should be aligned down rather then up. This would have it's own problems, but maybe better then a possibility of silently dropping data. drivers/usb/gadget/f_fs.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c index f875f26..ea0b8ba 100644 --- a/drivers/usb/gadget/f_fs.c +++ b/drivers/usb/gadget/f_fs.c @@ -753,8 +753,9 @@ static ssize_t ffs_epfile_io(struct file *file, char __user *buf, size_t len, int read) { struct ffs_epfile *epfile = file->private_data; + struct usb_gadget *gadget = epfile->ffs->gadget; struct ffs_ep *ep; - ssize_t ret; + ssize_t ret, data_len; char *data; int halt; @@ -787,6 +788,13 @@ static ssize_t ffs_epfile_io(struct file *file, /* Allocate & copy */ if (!halt) { + /* + * Controller requires buffer size to be aligned to + * maxpacketsize of an out endpoint. + */ + data_len = read && gadget->quirk_ep_out_aligned_size ? + usb_ep_align_maxpacketsize(ep->ep, len) : len; + data = kmalloc(len, GFP_KERNEL); if (unlikely(!data)) return -ENOMEM; @@ -824,7 +832,7 @@ static ssize_t ffs_epfile_io(struct file *file, req->context = &done; req->complete = ffs_epfile_io_complete; req->buf = data; - req->length = len; + req->length = data_len; ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC); @@ -836,9 +844,16 @@ static ssize_t ffs_epfile_io(struct file *file, ret = -EINTR; usb_ep_dequeue(ep->ep, req); } else { + /* + * XXX We may end up silently droping data here. + * Since data_len (i.e. req->length) may be bigger + * than len (after being rounded up to maxpacketsize), + * we may end up with more data then user space has + * space for. + */ ret = ep->status; if (read && ret > 0 && - unlikely(copy_to_user(buf, data, ret))) + unlikely(copy_to_user(buf, data, min(ret, len)))) ret = -EFAULT; } } -- 1.8.3.2