From: Andre Naujoks <nautsch@gmail.com>
To: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: David Miller <davem@davemloft.net>,
Linux Netdev List <netdev@vger.kernel.org>,
stable@kernel.org
Subject: Re: [PATCH net/stable] can bcm: fix tx_setup off-by-one errors
Date: Tue, 27 Sep 2011 23:09:16 +0200 [thread overview]
Message-ID: <4E823B7C.4040906@gmail.com> (raw)
In-Reply-To: <4E7CCEB3.4050408@hartkopp.net>
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 <nautsch@gmail.com>
> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested by: Andre Naujoks <nautsch@gmail.com>
>
> ---
>
> 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;
> }
>
next prev parent reply other threads:[~2011-09-27 21:09 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-23 18:23 [PATCH net/stable] can bcm: fix tx_setup off-by-one errors Oliver Hartkopp
2011-09-27 21:09 ` Andre Naujoks [this message]
2011-09-29 4:33 ` David Miller
2011-09-29 7:46 ` Oliver Hartkopp
2011-09-29 7:58 ` David Miller
2011-09-29 8:04 ` Oliver Hartkopp
2011-09-29 8:24 ` David Miller
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