If can_send() fail, it should not update statistics in bcm_can_tx().
Add the result check for can_send() in bcm_can_tx().
Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol")
Signed-off-by: Ziyang Xuan <[email protected]>
---
net/can/bcm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/can/bcm.c b/net/can/bcm.c
index e2783156bfd1..8f5d704a409f 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -298,7 +298,8 @@ static void bcm_can_tx(struct bcm_op *op)
/* send with loopback */
skb->dev = dev;
can_skb_set_owner(skb, op->sk);
- can_send(skb, 1);
+ if (can_send(skb, 1))
+ goto out;
/* update statistics */
op->currframe++;
--
2.25.1
Sorry, but NACK.
The curr_frame counter handles the sequence counter of multiplex messages.
Even when this single send attempt failed the curr_frame counter has to
continue.
For that reason the comment about statistics *before* the curr_frame++
might be misleading.
A potential improvement could be:
if (!(can_send(skb, 1)))
op->frames_abs++;
op->currframe++;
But as op->frames_abs is a functional unused(!) value for tx ops and
only displayed via procfs I would NOT tag such improvement as a 'fix'
which might then be queued up for stable.
This could be something for the can-next tree ...
Best regards,
Oliver
On 08.09.22 05:04, Ziyang Xuan wrote:
> If can_send() fail, it should not update statistics in bcm_can_tx().
> Add the result check for can_send() in bcm_can_tx().
>
> Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol")
> Signed-off-by: Ziyang Xuan <[email protected]>
> ---
> net/can/bcm.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/can/bcm.c b/net/can/bcm.c
> index e2783156bfd1..8f5d704a409f 100644
> --- a/net/can/bcm.c
> +++ b/net/can/bcm.c
> @@ -298,7 +298,8 @@ static void bcm_can_tx(struct bcm_op *op)
> /* send with loopback */
> skb->dev = dev;
> can_skb_set_owner(skb, op->sk);
> - can_send(skb, 1);
> + if (can_send(skb, 1))
> + goto out;
>
> /* update statistics */
> op->currframe++;
> Sorry, but NACK.
>
> The curr_frame counter handles the sequence counter of multiplex messages.
>
> Even when this single send attempt failed the curr_frame counter has to continue.
>
> For that reason the comment about statistics *before* the curr_frame++ might be misleading.
>
> A potential improvement could be:
>
> if (!(can_send(skb, 1)))
> op->frames_abs++;
>
> op->currframe++;
>
> But as op->frames_abs is a functional unused(!) value for tx ops and only displayed via procfs I would NOT tag such improvement as a 'fix' which might then be queued up for stable.
>
I will modify and remove 'Fixes' tag in v2.
Thank you for your review.
> This could be something for the can-next tree ...
>
> Best regards,
> Oliver
>
>
> On 08.09.22 05:04, Ziyang Xuan wrote:
>> If can_send() fail, it should not update statistics in bcm_can_tx().
>> Add the result check for can_send() in bcm_can_tx().
>>
>> Fixes: ffd980f976e7 ("[CAN]: Add broadcast manager (bcm) protocol")
>> Signed-off-by: Ziyang Xuan <[email protected]>
>> ---
>> net/can/bcm.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/can/bcm.c b/net/can/bcm.c
>> index e2783156bfd1..8f5d704a409f 100644
>> --- a/net/can/bcm.c
>> +++ b/net/can/bcm.c
>> @@ -298,7 +298,8 @@ static void bcm_can_tx(struct bcm_op *op)
>> /* send with loopback */
>> skb->dev = dev;
>> can_skb_set_owner(skb, op->sk);
>> - can_send(skb, 1);
>> + if (can_send(skb, 1))
>> + goto out;
>> /* update statistics */
>> op->currframe++;
> .
On 08.09.2022 08:47:57, Oliver Hartkopp wrote:
> Sorry, but NACK.
>
> The curr_frame counter handles the sequence counter of multiplex messages.
>
> Even when this single send attempt failed the curr_frame counter has to
> continue.
>
> For that reason the comment about statistics *before* the curr_frame++ might
> be misleading.
>
> A potential improvement could be:
>
> if (!(can_send(skb, 1)))
Nitpick:
In the kernel we usually assign the return value to a variable first,
and evaluate this variable in the if ().
> op->frames_abs++;
>
> op->currframe++;
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
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