From: Alexander Duyck <alexander.duyck@gmail.com>
To: Antoine Tenart <atenart@kernel.org>
Cc: David Miller <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH net-next v2 12/12] net-sysfs: move the xps cpus/rxqs retrieval in a common function
Date: Mon, 8 Feb 2021 14:45:32 -0800 [thread overview]
Message-ID: <CAKgT0UdP+1giTCzyfZ5x8q51otv2+KiPUN8djF=8XGcMOEZgEQ@mail.gmail.com> (raw)
In-Reply-To: <20210208171917.1088230-13-atenart@kernel.org>
On Mon, Feb 8, 2021 at 9:19 AM Antoine Tenart <atenart@kernel.org> wrote:
>
> Most of the xps_cpus_show and xps_rxqs_show functions share the same
> logic. Having it in two different functions does not help maintenance.
> This patch moves their common logic into a new function, xps_queue_show,
> to improve this.
>
> Signed-off-by: Antoine Tenart <atenart@kernel.org>
> ---
> net/core/net-sysfs.c | 98 ++++++++++++++------------------------------
> 1 file changed, 31 insertions(+), 67 deletions(-)
>
> diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
> index 6ce5772e799e..984c15248483 100644
> --- a/net/core/net-sysfs.c
> +++ b/net/core/net-sysfs.c
> @@ -1314,35 +1314,31 @@ static const struct attribute_group dql_group = {
> #endif /* CONFIG_BQL */
>
> #ifdef CONFIG_XPS
> -static ssize_t xps_cpus_show(struct netdev_queue *queue,
> - char *buf)
> +static ssize_t xps_queue_show(struct net_device *dev, unsigned int index,
> + char *buf, enum xps_map_type type)
> {
> - struct net_device *dev = queue->dev;
> struct xps_dev_maps *dev_maps;
> - unsigned int index, nr_ids;
> - int j, len, ret, tc = 0;
> unsigned long *mask;
> -
> - if (!netif_is_multiqueue(dev))
> - return -ENOENT;
> -
> - index = get_netdev_queue_index(queue);
> -
> - /* If queue belongs to subordinate dev use its map */
> - dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev;
> + unsigned int nr_ids;
> + int j, len, tc = 0;
>
> tc = netdev_txq_to_tc(dev, index);
> if (tc < 0)
> return -EINVAL;
>
> rcu_read_lock();
> - dev_maps = rcu_dereference(dev->xps_maps[XPS_CPUS]);
> - nr_ids = dev_maps ? dev_maps->nr_ids : nr_cpu_ids;
> + dev_maps = rcu_dereference(dev->xps_maps[type]);
> +
> + /* Default to nr_cpu_ids/dev->num_rx_queues and do not just return 0
> + * when dev_maps hasn't been allocated yet, to be backward compatible.
> + */
> + nr_ids = dev_maps ? dev_maps->nr_ids :
> + (type == XPS_CPUS ? nr_cpu_ids : dev->num_rx_queues);
>
> mask = bitmap_zalloc(nr_ids, GFP_KERNEL);
> if (!mask) {
> - ret = -ENOMEM;
> - goto err_rcu_unlock;
> + rcu_read_unlock();
> + return -ENOMEM;
> }
>
> if (!dev_maps || tc >= dev_maps->num_tc)
> @@ -1368,11 +1364,24 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue,
>
> len = bitmap_print_to_pagebuf(false, buf, mask, nr_ids);
> bitmap_free(mask);
> +
> return len < PAGE_SIZE ? len : -EINVAL;
> +}
>
> -err_rcu_unlock:
> - rcu_read_unlock();
> - return ret;
> +static ssize_t xps_cpus_show(struct netdev_queue *queue, char *buf)
> +{
> + struct net_device *dev = queue->dev;
> + unsigned int index;
> +
> + if (!netif_is_multiqueue(dev))
> + return -ENOENT;
> +
> + index = get_netdev_queue_index(queue);
> +
> + /* If queue belongs to subordinate dev use its map */
> + dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev;
> +
> + return xps_queue_show(dev, index, buf, XPS_CPUS);
> }
>
> static ssize_t xps_cpus_store(struct netdev_queue *queue,
So this patch has the same issue as the one that was removing the
rtnl_lock. Basically the sb_dev needs to still be protected by the
rtnl_lock. We might need to take the rtnl_lock and maybe make use of
the get_device/put_device logic to make certain the device cannot be
freed while you are passing it to xps_queue_show.
prev parent reply other threads:[~2021-02-08 22:46 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-08 17:19 [PATCH net-next v2 00/12] net: xps: improve the xps maps handling Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 01/12] net-sysfs: convert xps_cpus_show to bitmap_zalloc Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 02/12] net-sysfs: store the return of get_netdev_queue_index in an unsigned int Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 03/12] net-sysfs: make xps_cpus_show and xps_rxqs_show consistent Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 04/12] net: embed num_tc in the xps maps Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 05/12] net: embed nr_ids " Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 06/12] net: assert the rtnl lock is held when calling __netif_set_xps_queue Antoine Tenart
2021-02-23 6:27 ` [net] 81bb8ff453: assertion_failed kernel test robot
2021-02-08 17:19 ` [PATCH net-next v2 07/12] net: remove the xps possible_mask Antoine Tenart
2021-02-08 21:43 ` Alexander Duyck
2021-02-09 8:47 ` Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 08/12] net: move the xps maps to an array Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 09/12] net-sysfs: remove the rtnl lock when accessing the xps maps Antoine Tenart
2021-02-08 22:20 ` Alexander Duyck
2021-02-09 9:12 ` Antoine Tenart
2021-02-09 9:20 ` Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 10/12] net: add an helper to copy xps maps to the new dev_maps Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 11/12] net: improve queue removal readability in __netif_set_xps_queue Antoine Tenart
2021-02-08 17:19 ` [PATCH net-next v2 12/12] net-sysfs: move the xps cpus/rxqs retrieval in a common function Antoine Tenart
2021-02-08 22:45 ` Alexander Duyck [this message]
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