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Message-ID: <20171226224210.dl6h5jdunqk6ygfz@ast-mbp>
Date: Tue, 26 Dec 2017 14:42:12 -0800
From: Alexei Starovoitov <alexei.starovoitov@...il.com>
To: Jakub Kicinski <jakub.kicinski@...ronome.com>,
ebiederm@...ssion.com
Cc: netdev@...r.kernel.org, daniel@...earbox.net, ktkhai@...tuozzo.com,
oss-drivers@...ronome.com
Subject: Re: [PATCH bpf-next v2 6/8] bpf: offload: report device information
for offloaded programs
On Thu, Dec 21, 2017 at 01:01:18PM -0800, Jakub Kicinski wrote:
> Report to the user ifindex and namespace information of offloaded
> programs. If device has disappeared return -ENODEV. Specify the
> namespace using dev/inode combination.
>
> CC: Eric W. Biederman <ebiederm@...ssion.com>
> Signed-off-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
> Reviewed-by: Quentin Monnet <quentin.monnet@...ronome.com>
> ---
> v2:
> - take RTNL lock to grab a coherent snapshot of device state
> (ifindex vs name space) and avoid races with name space
> moves (based on Eric's comment on Kirill's patch to
> peernet2id_alloc()).
Eric, could you please review this patch.
The whole set is blocked on it.
Thanks
> ---
> fs/nsfs.c | 2 +-
> include/linux/bpf.h | 2 ++
> include/linux/proc_ns.h | 1 +
> include/uapi/linux/bpf.h | 3 +++
> kernel/bpf/offload.c | 44 ++++++++++++++++++++++++++++++++++++++++++
> kernel/bpf/syscall.c | 6 ++++++
> tools/include/uapi/linux/bpf.h | 3 +++
> 7 files changed, 60 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nsfs.c b/fs/nsfs.c
> index 7c6f76d29f56..e50628675935 100644
> --- a/fs/nsfs.c
> +++ b/fs/nsfs.c
> @@ -51,7 +51,7 @@ static void nsfs_evict(struct inode *inode)
> ns->ops->put(ns);
> }
>
> -static void *__ns_get_path(struct path *path, struct ns_common *ns)
> +void *__ns_get_path(struct path *path, struct ns_common *ns)
> {
> struct vfsmount *mnt = nsfs_mnt;
> struct dentry *dentry;
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 9a916ab34299..7810ae57b357 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -531,6 +531,8 @@ static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
>
> int bpf_prog_offload_compile(struct bpf_prog *prog);
> void bpf_prog_offload_destroy(struct bpf_prog *prog);
> +int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
> + struct bpf_prog *prog);
>
> #if defined(CONFIG_NET) && defined(CONFIG_BPF_SYSCALL)
> int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr);
> diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
> index 2ff18c9840a7..1733359cf713 100644
> --- a/include/linux/proc_ns.h
> +++ b/include/linux/proc_ns.h
> @@ -76,6 +76,7 @@ static inline int ns_alloc_inum(struct ns_common *ns)
>
> extern struct file *proc_ns_fget(int fd);
> #define get_proc_ns(inode) ((struct ns_common *)(inode)->i_private)
> +extern void *__ns_get_path(struct path *path, struct ns_common *ns);
> extern void *ns_get_path(struct path *path, struct task_struct *task,
> const struct proc_ns_operations *ns_ops);
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index d01f1cb3cfc0..72b37fc3bc0c 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -921,6 +921,9 @@ struct bpf_prog_info {
> __u32 nr_map_ids;
> __aligned_u64 map_ids;
> char name[BPF_OBJ_NAME_LEN];
> + __u32 ifindex;
> + __u64 netns_dev;
> + __u64 netns_ino;
> } __attribute__((aligned(8)));
>
> struct bpf_map_info {
> diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
> index 1e6064ea3609..4d50000bd1e3 100644
> --- a/kernel/bpf/offload.c
> +++ b/kernel/bpf/offload.c
> @@ -16,9 +16,11 @@
> #include <linux/bpf.h>
> #include <linux/bpf_verifier.h>
> #include <linux/bug.h>
> +#include <linux/kdev_t.h>
> #include <linux/list.h>
> #include <linux/netdevice.h>
> #include <linux/printk.h>
> +#include <linux/proc_ns.h>
> #include <linux/rtnetlink.h>
> #include <linux/rwsem.h>
>
> @@ -181,6 +183,48 @@ int bpf_prog_offload_compile(struct bpf_prog *prog)
> return bpf_prog_offload_translate(prog);
> }
>
> +int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
> + struct bpf_prog *prog)
> +{
> + struct bpf_dev_offload *offload;
> + struct inode *ns_inode;
> + struct path ns_path;
> + int ifindex, err;
> + struct net *net;
> +
> +again:
> + rtnl_lock();
> + down_read(&bpf_devs_lock);
> +
> + offload = prog->aux->offload;
> + if (!offload) {
> + up_read(&bpf_devs_lock);
> + rtnl_unlock();
> + return -ENODEV;
> + }
> +
> + ifindex = offload->netdev->ifindex;
> + net = dev_net(offload->netdev);
> + get_net(net); /* __ns_get_path() drops the reference */
> +
> + up_read(&bpf_devs_lock);
> + rtnl_unlock();
> +
> + err = PTR_ERR_OR_ZERO(__ns_get_path(&ns_path, &net->ns));
> + if (err) {
> + if (err == -EAGAIN)
> + goto again;
> + return err;
> + }
> + ns_inode = ns_path.dentry->d_inode;
> +
> + info->ifindex = ifindex;
> + info->netns_dev = new_encode_dev(ns_inode->i_sb->s_dev);
> + info->netns_ino = ns_inode->i_ino;
> +
> + return 0;
> +}
> +
> const struct bpf_prog_ops bpf_offload_prog_ops = {
> };
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 7d9f5b0f0e49..20444fd678d0 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -1624,6 +1624,12 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
> return -EFAULT;
> }
>
> + if (bpf_prog_is_dev_bound(prog->aux)) {
> + err = bpf_prog_offload_info_fill(&info, prog);
> + if (err)
> + return err;
> + }
> +
> done:
> if (copy_to_user(uinfo, &info, info_len) ||
> put_user(info_len, &uattr->info.info_len))
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index db1b0923a308..4e8c60acfa32 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -921,6 +921,9 @@ struct bpf_prog_info {
> __u32 nr_map_ids;
> __aligned_u64 map_ids;
> char name[BPF_OBJ_NAME_LEN];
> + __u32 ifindex;
> + __u64 netns_dev;
> + __u64 netns_ino;
> } __attribute__((aligned(8)));
>
> struct bpf_map_info {
> --
> 2.15.1
>
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