From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Woodhouse Subject: Re: [PATCH v3 8/7] pppoatm: fix missing wakeup in pppoatm_send() Date: Sun, 11 Nov 2012 07:28:53 +0000 Message-ID: <1352618933.9449.113.camel@shinybook.infradead.org> References: <1352240222-363-1-git-send-email-krzysiek@podlesie.net> <1352292734.7340.35.camel@shinybook.infradead.org> <20121110202338.GA1749@shrek.podlesie.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="sha1"; protocol="application/x-pkcs7-signature"; boundary="=-JOy855DYwXVEZTlXzHji" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Chas Williams - CONTRACTOR , davem@davemloft.net To: Krzysztof Mazur Return-path: In-Reply-To: <20121110202338.GA1749@shrek.podlesie.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --=-JOy855DYwXVEZTlXzHji Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, 2012-11-10 at 21:23 +0100, Krzysztof Mazur wrote: > With this tasklet_schedule() we implement a "spin_lock" here, but in > this case both conditions (vcc not ready and socket locked) can be > true for a long time and we can spin here for a long time.=20 Reading this more carefully this morning... I hadn't realised it was these conditions, and not the sock_owned_by_user(), which had triggered. Yes, perhaps we should just return zero in that case and find another wakeup trigger... if indeed a wakeup is ever required in the VF_RELEASED and VF_CLOSE case. And if we've fixed things so that !VF_READY can never happen (have we?).... perhaps this one doesn't matter at all? It was the sock_owned_by_user() case I was most interested in, and I was expecting that lock would generally be held briefly enough that the tasklet would be fine. 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