XDP hardware hints discussion mail archive
 help / color / mirror / Atom feed
From: Martin KaFai Lau <martin.lau@linux.dev>
To: Stanislav Fomichev <sdf@google.com>
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
	song@kernel.org, yhs@fb.com, john.fastabend@gmail.com,
	kpsingh@kernel.org, haoluo@google.com, jolsa@kernel.org,
	David Ahern <dsahern@gmail.com>, Jakub Kicinski <kuba@kernel.org>,
	Willem de Bruijn <willemb@google.com>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Anatoly Burakov <anatoly.burakov@intel.com>,
	Alexander Lobakin <alexandr.lobakin@intel.com>,
	Magnus Karlsson <magnus.karlsson@gmail.com>,
	Maryam Tahhan <mtahhan@redhat.com>,
	xdp-hints@xdp-project.net, netdev@vger.kernel.org,
	bpf@vger.kernel.org
Subject: [xdp-hints] Re: [PATCH bpf-next v5 05/17] bpf: Introduce device-bound XDP programs
Date: Thu, 22 Dec 2022 16:19:15 -0800	[thread overview]
Message-ID: <04e1406b-0a31-0109-9a1b-f016e8f23603@linux.dev> (raw)
In-Reply-To: <20221220222043.3348718-6-sdf@google.com>

On 12/20/22 2:20 PM, Stanislav Fomichev wrote:
> -int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
> +int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr)
>   {
>   	struct bpf_offload_netdev *ondev;
>   	struct bpf_prog_offload *offload;
> @@ -199,7 +197,7 @@ int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
>   	    attr->prog_type != BPF_PROG_TYPE_XDP)
>   		return -EINVAL;
>   
> -	if (attr->prog_flags)
> +	if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY)
>   		return -EINVAL;
>   
>   	offload = kzalloc(sizeof(*offload), GFP_USER);
> @@ -214,11 +212,23 @@ int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr)
>   	if (err)
>   		goto err_maybe_put;
>   
> +	prog->aux->offload_requested = !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY);

Just noticed bpf_prog_dev_bound_init() takes BPF_PROG_TYPE_SCHED_CLS.  Not sure 
if there is device match check when attaching BPF_PROG_TYPE_SCHED_CLS.  If not, 
does it make sense to reject dev bound only BPF_PROG_TYPE_SCHED_CLS?

> +
>   	down_write(&bpf_devs_lock);
>   	ondev = bpf_offload_find_netdev(offload->netdev);
>   	if (!ondev) {
> -		err = -EINVAL;
> -		goto err_unlock;
> +		if (bpf_prog_is_offloaded(prog->aux)) {
> +			err = -EINVAL;
> +			goto err_unlock;
> +		}
> +
> +		/* When only binding to the device, explicitly
> +		 * create an entry in the hashtable.
> +		 */
> +		err = __bpf_offload_dev_netdev_register(NULL, offload->netdev);
> +		if (err)
> +			goto err_unlock;
> +		ondev = bpf_offload_find_netdev(offload->netdev);
>   	}
>   	offload->offdev = ondev->offdev;
>   	prog->aux->offload = offload;
> @@ -321,12 +331,41 @@ bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
>   	up_read(&bpf_devs_lock);
>   }
>   
> -void bpf_prog_offload_destroy(struct bpf_prog *prog)
> +static void __bpf_prog_dev_bound_destroy(struct bpf_prog *prog)
> +{
> +	struct bpf_prog_offload *offload = prog->aux->offload;
> +
> +	if (offload->dev_state)
> +		offload->offdev->ops->destroy(prog);
> +
> +	/* Make sure BPF_PROG_GET_NEXT_ID can't find this dead program */
> +	bpf_prog_free_id(prog, true);
> +
> +	kfree(offload);
> +	prog->aux->offload = NULL;
> +}
> +
> +void bpf_prog_dev_bound_destroy(struct bpf_prog *prog)
>   {
> +	struct bpf_offload_netdev *ondev;
> +	struct net_device *netdev;
> +
> +	rtnl_lock();
>   	down_write(&bpf_devs_lock);
> -	if (prog->aux->offload)
> -		__bpf_prog_offload_destroy(prog);
> +	if (prog->aux->offload) {
> +		list_del_init(&prog->aux->offload->offloads);
> +
> +		netdev = prog->aux->offload->netdev;

After saving the netdev, would it work to call __bpf_prog_offload_destroy() here 
instead of creating an almost identical __bpf_prog_dev_bound_destroy().  The 
idea is to call list_del_init() first but does not need the "offload" around to 
do the __bpf_offload_dev_netdev_unregister()?

> +		if (netdev) {

I am thinking offload->netdev cannot be NULL.  Did I overlook places that reset 
offload->netdev back to NULL?  eg. In bpf_prog_offload_info_fill_ns(), it is not 
checking offload->netdev.

> +			ondev = bpf_offload_find_netdev(netdev);

and ondev should not be NULL too?

I am trying to ensure my understanding that all offload->netdev and ondev should 
be protected by bpf_devs_lock.

> +			if (ondev && !ondev->offdev && list_empty(&ondev->progs))
> +				__bpf_offload_dev_netdev_unregister(NULL, netdev);
> +		}
> +
> +		__bpf_prog_dev_bound_destroy(prog);
> +	}
>   	up_write(&bpf_devs_lock);
> +	rtnl_unlock();
>   }


  reply	other threads:[~2022-12-23  0:19 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-20 22:20 [xdp-hints] [PATCH bpf-next v5 00/17] xdp: hints via kfuncs Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 01/17] bpf: Document XDP RX metadata Stanislav Fomichev
2022-12-28 17:25   ` [xdp-hints] " David Vernet
2023-01-03 22:23     ` Stanislav Fomichev
2023-01-04 16:02       ` David Vernet
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 02/17] bpf: Rename bpf_{prog,map}_is_dev_bound to is_offloaded Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 03/17] bpf: Move offload initialization into late_initcall Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 04/17] bpf: Reshuffle some parts of bpf/offload.c Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 05/17] bpf: Introduce device-bound XDP programs Stanislav Fomichev
2022-12-23  0:19   ` Martin KaFai Lau [this message]
2022-12-23  4:06     ` [xdp-hints] " Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 06/17] selftests/bpf: Update expected test_offload.py messages Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 07/17] bpf: XDP metadata RX kfuncs Stanislav Fomichev
2022-12-21  5:43   ` [xdp-hints] " kernel test robot
2022-12-21 17:49     ` Stanislav Fomichev
2022-12-23  0:31   ` Martin KaFai Lau
2022-12-23  4:06     ` Stanislav Fomichev
2022-12-27 20:33   ` David Vernet
2023-01-03 22:23     ` Stanislav Fomichev
2023-01-03 22:35       ` David Vernet
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 09/17] veth: Introduce veth_xdp_buff wrapper for xdp_buff Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 10/17] veth: Support RX XDP metadata Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 11/17] selftests/bpf: Verify xdp_metadata xdp->af_xdp path Stanislav Fomichev
2022-12-23  0:40   ` [xdp-hints] " Martin KaFai Lau
2022-12-23  4:06     ` Stanislav Fomichev
2023-01-04  2:05       ` Martin KaFai Lau
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 12/17] net/mlx4_en: Introduce wrapper for xdp_buff Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 13/17] net/mlx4_en: Support RX XDP metadata Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 14/17] xsk: Add cb area to struct xdp_buff_xsk Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 15/17] net/mlx5e: Introduce wrapper for xdp_buff Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 16/17] net/mlx5e: Support RX XDP metadata Stanislav Fomichev
2022-12-20 22:20 ` [xdp-hints] [PATCH bpf-next v5 17/17] selftests/bpf: Simple program to dump XDP RX metadata Stanislav Fomichev
2022-12-23  0:53   ` [xdp-hints] " Martin KaFai Lau
2022-12-23  4:07     ` Stanislav Fomichev

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://lists.xdp-project.net/postorius/lists/xdp-hints.xdp-project.net/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=04e1406b-0a31-0109-9a1b-f016e8f23603@linux.dev \
    --to=martin.lau@linux.dev \
    --cc=alexandr.lobakin@intel.com \
    --cc=anatoly.burakov@intel.com \
    --cc=andrii@kernel.org \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=brouer@redhat.com \
    --cc=daniel@iogearbox.net \
    --cc=dsahern@gmail.com \
    --cc=haoluo@google.com \
    --cc=john.fastabend@gmail.com \
    --cc=jolsa@kernel.org \
    --cc=kpsingh@kernel.org \
    --cc=kuba@kernel.org \
    --cc=magnus.karlsson@gmail.com \
    --cc=mtahhan@redhat.com \
    --cc=netdev@vger.kernel.org \
    --cc=sdf@google.com \
    --cc=song@kernel.org \
    --cc=willemb@google.com \
    --cc=xdp-hints@xdp-project.net \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox