From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andre Naujoks Subject: Re: [PATCH net/stable] can bcm: fix tx_setup off-by-one errors Date: Tue, 27 Sep 2011 23:09:16 +0200 Message-ID: <4E823B7C.4040906@gmail.com> References: <4E7CCEB3.4050408@hartkopp.net> Reply-To: nautsch@gmail.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: David Miller , Linux Netdev List , stable@kernel.org To: Oliver Hartkopp Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:44333 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751747Ab1I0VJV (ORCPT ); Tue, 27 Sep 2011 17:09:21 -0400 Received: by fxe4 with SMTP id 4so7549398fxe.19 for ; Tue, 27 Sep 2011 14:09:20 -0700 (PDT) In-Reply-To: <4E7CCEB3.4050408@hartkopp.net> Sender: netdev-owner@vger.kernel.org List-ID: Am 23.09.2011 20:23, schrieb Oliver Hartkopp: > This patch fixes two off-by-one errors that canceled each other out. > Checking for the same condition two times in bcm_tx_timeout_tsklet() reduced > the count of frames to be sent by one. This did not show up the first time > tx_setup is invoked as an additional frame is sent due to TX_ANNONCE. > Invoking a second tx_setup on the same item led to a reduced (by 1) number of > sent frames. > > Reported-by: Andre Naujoks > Signed-off-by: Oliver Hartkopp Tested by: Andre Naujoks > > --- > > diff --git a/net/can/bcm.c b/net/can/bcm.c > index d6c8ae5..c9cdb8d 100644 > --- a/net/can/bcm.c > +++ b/net/can/bcm.c > @@ -365,9 +365,6 @@ static void bcm_tx_timeout_tsklet(unsigned long data) > > bcm_send_to_user(op, &msg_head, NULL, 0); > } > - } > - > - if (op->kt_ival1.tv64 && (op->count > 0)) { > > /* send (next) frame */ > bcm_can_tx(op); > @@ -970,8 +967,9 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, > /* spec: send can_frame when starting timer */ > op->flags |= TX_ANNOUNCE; > > - if (op->kt_ival1.tv64 && (op->count > 0)) { > - /* op->count-- is done in bcm_tx_timeout_handler */ > + /* only start timer when having more frames than sent below */ > + if (op->kt_ival1.tv64 && (op->count > 1)) { > + /* op->count-- is done in bcm_tx_timeout_tsklet */ > hrtimer_start(&op->timer, op->kt_ival1, > HRTIMER_MODE_REL); > } else > @@ -979,8 +977,11 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, > HRTIMER_MODE_REL); > } > > - if (op->flags & TX_ANNOUNCE) > + if (op->flags & TX_ANNOUNCE) { > bcm_can_tx(op); > + if (op->kt_ival1.tv64 && (op->count > 0)) > + op->count--; > + } > > return msg_head->nframes * CFSIZ + MHSIZ; > } >