From: Michal Nazarewicz <mina86@mina86.com>
To: Felipe Balbi <felipe.balbi@linux.intel.com>, "Du\,
Changbin" <changbin.du@intel.com>,
Alan Stern <stern@rowland.harvard.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
"gregkh\@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"rui.silva\@linaro.org" <rui.silva@linaro.org>,
"k.opasiak\@samsung.com" <k.opasiak@samsung.com>,
"lars\@metafoo.de" <lars@metafoo.de>,
"linux-usb\@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] usb: gadget: f_fs: report error if excess data received
Date: Wed, 18 May 2016 15:39:11 +0200 [thread overview]
Message-ID: <xa1tmvnno58g.fsf@mina86.com> (raw)
In-Reply-To: <878tz7zn7y.fsf@linux.intel.com>
On Wed, May 18 2016, Felipe Balbi wrote:
> we've been through this before. This needs to be done at the gadget
> layer. Gadget driver can over-allocate ahead of time if
> gadget->quirk_ep_out_aligned_size is true, then we avoid memcpy() at
> the UDC driver level.
Right, all right, so let’s look at it from a regular USB function point
of view. If a USB function allocates a request which is not aligned,
UDC will align the buffer and *drop* excess data. Seeing how ugly
f_fs’s code is becoming, I’m now leaning to letting to f_fs do the same
thing: if user space makes an unaligned read, f_fs aligns the buffer and
then drops excess data.
Any arguments for f_fs to not drop the data apply to UDC, so they should
behave identically.
--
Best regards
ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ
«If at first you don’t succeed, give up skydiving»
next prev parent reply other threads:[~2016-05-18 13:39 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-11 10:19 [PATCH] usb: gadget: f_fs: report error if excess data received changbin.du
2016-05-11 10:59 ` Felipe Balbi
2016-05-11 12:30 ` Michal Nazarewicz
2016-05-12 4:25 ` Du, Changbin
2016-05-12 4:21 ` Du, Changbin
2016-05-12 6:52 ` Felipe Balbi
2016-05-12 7:30 ` Du, Changbin
2016-05-12 7:46 ` Felipe Balbi
2016-05-12 8:16 ` Du, Changbin
2016-05-12 9:15 ` Felipe Balbi
2016-05-12 9:22 ` Felipe Balbi
2016-05-12 9:51 ` Du, Changbin
2016-05-12 9:39 ` Du, Changbin
2016-05-12 10:13 ` Felipe Balbi
2016-05-12 10:14 ` Felipe Balbi
2016-05-12 10:45 ` Du, Changbin
2016-05-12 11:22 ` Felipe Balbi
2016-05-13 5:52 ` Du, Changbin
2016-05-13 6:36 ` Felipe Balbi
2016-05-13 10:32 ` Du, Changbin
2016-05-13 14:29 ` Alan Stern
2016-05-14 20:39 ` Michal Nazarewicz
2016-05-16 12:57 ` Felipe Balbi
2016-05-16 13:08 ` Michal Nazarewicz
2016-05-16 13:16 ` Felipe Balbi
2016-05-16 19:09 ` Michal Nazarewicz
2016-05-17 2:53 ` Du, Changbin
2016-05-18 9:45 ` Michal Nazarewicz
2016-05-18 10:15 ` Felipe Balbi
2016-05-18 13:39 ` Michal Nazarewicz [this message]
2016-05-19 2:54 ` Du, Changbin
2016-05-19 7:34 ` Michal Nazarewicz
2016-05-19 8:49 ` Du, Changbin
2016-05-19 2:31 ` Du, Changbin
2016-05-16 16:05 ` Michal Nazarewicz
2016-05-16 16:27 ` Lars-Peter Clausen
2016-05-16 16:48 ` Michal Nazarewicz
2016-05-16 16:35 ` Krzysztof Opasiak
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