netdev - Re: [PATCH][net-next][v2] virtio_net: s/raw_smp_processor_id/smp_processor_id/ in virtnet_xdp_get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20210913181040-mutt-send-email-mst@kernel.org>
Date:   Mon, 13 Sep 2021 18:10:49 -0400
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     Li RongQing <lirongqing@...du.com>
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH][net-next][v2] virtio_net:
 s/raw_smp_processor_id/smp_processor_id/ in virtnet_xdp_get_sq

On Thu, Sep 09, 2021 at 03:49:31PM +0800, Li RongQing wrote:
> virtnet_xdp_get_sq() is called in non-preemptible context, so
> it's safe to call the function smp_processor_id(), and keep
> smp_processor_id(), and remove the calling of raw_smp_processor_id(),
> this way we'll get a warning if this is ever called in a preemptible
> context in the future
> 
> Signed-off-by: Li RongQing <lirongqing@...du.com>

Acked-by: Michael S. Tsirkin <mst@...hat.com>

> ---
> diff with v1: change log based on Michael S. Tsirkin's suggestion
> 
>  drivers/net/virtio_net.c |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 2e42210..2a7b368 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -528,19 +528,20 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi,
>   * functions to perfectly solve these three problems at the same time.
>   */
>  #define virtnet_xdp_get_sq(vi) ({                                       \
> +	int cpu = smp_processor_id();                                   \
>  	struct netdev_queue *txq;                                       \
>  	typeof(vi) v = (vi);                                            \
>  	unsigned int qp;                                                \
>  									\
>  	if (v->curr_queue_pairs > nr_cpu_ids) {                         \
>  		qp = v->curr_queue_pairs - v->xdp_queue_pairs;          \
> -		qp += smp_processor_id();                               \
> +		qp += cpu;                                              \
>  		txq = netdev_get_tx_queue(v->dev, qp);                  \
>  		__netif_tx_acquire(txq);                                \
>  	} else {                                                        \
> -		qp = smp_processor_id() % v->curr_queue_pairs;          \
> +		qp = cpu % v->curr_queue_pairs;                         \
>  		txq = netdev_get_tx_queue(v->dev, qp);                  \
> -		__netif_tx_lock(txq, raw_smp_processor_id());           \
> +		__netif_tx_lock(txq, cpu);                              \
>  	}                                                               \
>  	v->sq + qp;                                                     \
>  })
> -- 
> 1.7.1