From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755077Ab3KEPG4 (ORCPT ); Tue, 5 Nov 2013 10:06:56 -0500 Received: from mga03.intel.com ([143.182.124.21]:24906 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754396Ab3KEPGy (ORCPT ); Tue, 5 Nov 2013 10:06:54 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.93,535,1378882800"; d="scan'208";a="384927253" Message-ID: <52790925.7040306@linux.intel.com> Date: Tue, 05 Nov 2013 07:05:09 -0800 From: David Cohen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20131005 Icedove/17.0.9 MIME-Version: 1.0 To: Alan Stern CC: balbi@ti.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 3/4] usb: ffs: check quirk to pad epout buf size when not aligned to maxpacketsize References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/05/2013 06:52 AM, Alan Stern wrote: > On Mon, 4 Nov 2013, David Cohen wrote: > >> 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: David Cohen >> --- >> drivers/usb/gadget/f_fs.c | 22 ++++++++++++++++++++++ >> 1 file changed, 22 insertions(+) >> >> diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c >> index 75e4b7846a8d..e7c3c3119552 100644 >> --- a/drivers/usb/gadget/f_fs.c >> +++ b/drivers/usb/gadget/f_fs.c >> @@ -755,10 +755,13 @@ 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; >> char *data = NULL; >> + size_t data_len = 0; >> ssize_t ret; >> int halt; >> + size_t orig_len = len; >> >> goto first_try; >> do { >> @@ -794,11 +797,30 @@ first_try: >> goto error; >> } >> >> + /* >> + * Controller requires buffer size to be aligned to >> + * maxpacketsize of an out endpoint. >> + */ >> + if (gadget->quirk_ep_out_aligned_size && read) { >> + /* >> + * We pass 'orig_len' to usp_ep_align_maxpacketsize() >> + * due to we're in a loop and 'len' may have been >> + * changed. >> + */ >> + len = usb_ep_align_maxpacketsize(ep->ep, orig_len); >> + if (data && len > data_len) { >> + kfree(data); >> + data = NULL; >> + data_len = 0; >> + } >> + } > > Since the value of orig_len never changes, there's no point calling > usb_ep_align_maxpacketsize() inside the loop. You should call it only > once, before the loop starts. Once you do that, you won't need > orig_len at all. orig_len doesn't change but ep->ep does. If USB specs say max packet size won't change even if ep does, than we can call it from outside the loop. Br, David