Subject: Re: [PATCH 2/6] NFC: add nfc generic netlink interface
From: Johannes Berg <johannes@sipsolutions.net>
To: Aloisio Almeida <aloisio.almeida@openbossa.org>
Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org>,
	"John W. Linville" <linville@tuxdriver.com>,
	linux-wireless@vger.kernel.org, marcio.macedo@openbossa.org,
	sameo@linux.intel.com, Waldemar.Rymarkiewicz@tieto.com
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Date: Fri, 03 Jun 2011 23:39:08 +0200
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On Fri, 2011-06-03 at 18:35 -0300, Aloisio Almeida wrote:
> On Fri, Jun 3, 2011 at 5:38 PM, Johannes Berg <johannes@sipsolutions.net> wrote:
> > On Fri, 2011-06-03 at 17:18 -0300, Lauro Ramos Venancio wrote:
> >> We don't need a generation counter here because we have the events
> >> NFC_EVENT_DEVICE_ADDED and NFC_EVENT_DEVICE_REMOVED. So, it is
> >> possible to keep the device list consistency listening for these
> >> events.
> >
> > That may be true, but it complicates coding in userspace. Much easier to
> > check a generation counter (in both cases) to see if data is consistent
> > than to listen to multiple events concurrently with receiving a dump.
> 
> The userspace must listen to these events anyway. In addition, the
> application needs to get the list of devices only once (on its
> initialization).
> 
> In the target list case, the userspace application would have to
> orderly call start_poll before receive the dump in order to create the
> "invalid list" situation.

I think you're considering only the current applications, and new ones
might be developed, but whatever, I'll let it rest since I don't
particularly care anyway.

johannes