Re: [PATCH v4 1/3] NFSD: convert write_threads to netlink command

[Chuck Lever <chuck.lever@oracle.com>]

On Sat, Nov 04, 2023 at 12:13:45PM +0100, Lorenzo Bianconi wrote:
> Introduce write_threads netlink command similar to the ones available
> through the procfs.
> 
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---
>  Documentation/netlink/specs/nfsd.yaml | 23 +++++++
>  fs/nfsd/netlink.c                     | 17 +++++
>  fs/nfsd/netlink.h                     |  2 +
>  fs/nfsd/nfsctl.c                      | 58 +++++++++++++++++
>  include/uapi/linux/nfsd_netlink.h     |  9 +++
>  tools/net/ynl/generated/nfsd-user.c   | 92 +++++++++++++++++++++++++++
>  tools/net/ynl/generated/nfsd-user.h   | 47 ++++++++++++++
>  7 files changed, 248 insertions(+)

Hi Lorenzo -

This doesn't apply to my private nfsd-next branch. I don't believe
that's your fault... We've got some things in flight here that
conflict with what is in net-next.

Jakub tells me there is some ynl churn coming in v6.7-rc1 that
might resolve the conflicts.

I plan to rebase my private nfsd-next on v6.7-rc1 and push the first
set of patches on Monday or Tuesday. Please rebase this series on
top of that, regen the ynl code, and then send a v5. I will then
apply that to nfsd-next for more testing and review.


> diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlink/specs/nfsd.yaml
> index 05acc73e2e33..c92e1425d316 100644
> --- a/Documentation/netlink/specs/nfsd.yaml
> +++ b/Documentation/netlink/specs/nfsd.yaml
> @@ -62,6 +62,12 @@ attribute-sets:
>          name: compound-ops
>          type: u32
>          multi-attr: true
> +  -
> +    name: server-worker
> +    attributes:
> +      -
> +        name: threads
> +        type: u32
>  
>  operations:
>    list:
> @@ -87,3 +93,20 @@ operations:
>              - sport
>              - dport
>              - compound-ops
> +    -
> +      name: threads-set
> +      doc: set the number of running threads
> +      attribute-set: server-worker
> +      flags: [ admin-perm ]
> +      do:
> +        request:
> +          attributes:
> +            - threads
> +    -
> +      name: threads-get
> +      doc: get the number of running threads
> +      attribute-set: server-worker
> +      do:
> +        reply:
> +          attributes:
> +            - threads
> diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c
> index 0e1d635ec5f9..1a59a8e6c7e2 100644
> --- a/fs/nfsd/netlink.c
> +++ b/fs/nfsd/netlink.c
> @@ -10,6 +10,11 @@
>  
>  #include <uapi/linux/nfsd_netlink.h>
>  
> +/* NFSD_CMD_THREADS_SET - do */
> +static const struct nla_policy nfsd_threads_set_nl_policy[NFSD_A_SERVER_WORKER_THREADS + 1] = {
> +	[NFSD_A_SERVER_WORKER_THREADS] = { .type = NLA_U32, },
> +};
> +
>  /* Ops table for nfsd */
>  static const struct genl_split_ops nfsd_nl_ops[] = {
>  	{
> @@ -19,6 +24,18 @@ static const struct genl_split_ops nfsd_nl_ops[] = {
>  		.done	= nfsd_nl_rpc_status_get_done,
>  		.flags	= GENL_CMD_CAP_DUMP,
>  	},
> +	{
> +		.cmd		= NFSD_CMD_THREADS_SET,
> +		.doit		= nfsd_nl_threads_set_doit,
> +		.policy		= nfsd_threads_set_nl_policy,
> +		.maxattr	= NFSD_A_SERVER_WORKER_THREADS,
> +		.flags		= GENL_ADMIN_PERM | GENL_CMD_CAP_DO,
> +	},
> +	{
> +		.cmd	= NFSD_CMD_THREADS_GET,
> +		.doit	= nfsd_nl_threads_get_doit,
> +		.flags	= GENL_CMD_CAP_DO,
> +	},
>  };
>  
>  struct genl_family nfsd_nl_family __ro_after_init = {
> diff --git a/fs/nfsd/netlink.h b/fs/nfsd/netlink.h
> index d83dd6bdee92..4137fac477e4 100644
> --- a/fs/nfsd/netlink.h
> +++ b/fs/nfsd/netlink.h
> @@ -16,6 +16,8 @@ int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb);
>  
>  int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
>  				  struct netlink_callback *cb);
> +int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info);
> +int nfsd_nl_threads_get_doit(struct sk_buff *skb, struct genl_info *info);
>  
>  extern struct genl_family nfsd_nl_family;
>  
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index 739ed5bf71cd..0d0394887506 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1693,6 +1693,64 @@ int nfsd_nl_rpc_status_get_done(struct netlink_callback *cb)
>  	return 0;
>  }
>  
> +/**
> + * nfsd_nl_threads_set_doit - set the number of running threads
> + * @skb: reply buffer
> + * @info: netlink metadata and command arguments
> + *
> + * Return 0 on success or a negative errno.
> + */
> +int nfsd_nl_threads_set_doit(struct sk_buff *skb, struct genl_info *info)
> +{
> +	u32 nthreads;
> +	int ret;
> +
> +	if (GENL_REQ_ATTR_CHECK(info, NFSD_A_SERVER_WORKER_THREADS))
> +		return -EINVAL;
> +
> +	nthreads = nla_get_u32(info->attrs[NFSD_A_SERVER_WORKER_THREADS]);
> +	ret = nfsd_svc(nthreads, genl_info_net(info), get_current_cred());
> +
> +	return ret == nthreads ? 0 : ret;
> +}
> +
> +/**
> + * nfsd_nl_threads_get_doit - get the number of running threads
> + * @skb: reply buffer
> + * @info: netlink metadata and command arguments
> + *
> + * Return 0 on success or a negative errno.
> + */
> +int nfsd_nl_threads_get_doit(struct sk_buff *skb, struct genl_info *info)
> +{
> +	void *hdr;
> +	int err;
> +
> +	skb = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
> +	if (!skb)
> +		return -ENOMEM;
> +
> +	hdr = genlmsg_iput(skb, info);
> +	if (!hdr) {
> +		err = -EMSGSIZE;
> +		goto err_free_msg;
> +	}
> +
> +	if (nla_put_u32(skb, NFSD_A_SERVER_WORKER_THREADS,
> +			nfsd_nrthreads(genl_info_net(info)))) {
> +		err = -EINVAL;
> +		goto err_free_msg;
> +	}
> +
> +	genlmsg_end(skb, hdr);
> +
> +	return genlmsg_reply(skb, info);
> +
> +err_free_msg:
> +	nlmsg_free(skb);
> +	return err;
> +}
> +
>  /**
>   * nfsd_net_init - Prepare the nfsd_net portion of a new net namespace
>   * @net: a freshly-created network namespace
> diff --git a/include/uapi/linux/nfsd_netlink.h b/include/uapi/linux/nfsd_netlink.h
> index c8ae72466ee6..99f7855852a1 100644
> --- a/include/uapi/linux/nfsd_netlink.h
> +++ b/include/uapi/linux/nfsd_netlink.h
> @@ -29,8 +29,17 @@ enum {
>  	NFSD_A_RPC_STATUS_MAX = (__NFSD_A_RPC_STATUS_MAX - 1)
>  };
>  
> +enum {
> +	NFSD_A_SERVER_WORKER_THREADS = 1,
> +
> +	__NFSD_A_SERVER_WORKER_MAX,
> +	NFSD_A_SERVER_WORKER_MAX = (__NFSD_A_SERVER_WORKER_MAX - 1)
> +};
> +
>  enum {
>  	NFSD_CMD_RPC_STATUS_GET = 1,
> +	NFSD_CMD_THREADS_SET,
> +	NFSD_CMD_THREADS_GET,
>  
>  	__NFSD_CMD_MAX,
>  	NFSD_CMD_MAX = (__NFSD_CMD_MAX - 1)
> diff --git a/tools/net/ynl/generated/nfsd-user.c b/tools/net/ynl/generated/nfsd-user.c
> index fec6828680ce..342a00b0474a 100644
> --- a/tools/net/ynl/generated/nfsd-user.c
> +++ b/tools/net/ynl/generated/nfsd-user.c
> @@ -15,6 +15,8 @@
>  /* Enums */
>  static const char * const nfsd_op_strmap[] = {
>  	[NFSD_CMD_RPC_STATUS_GET] = "rpc-status-get",
> +	[NFSD_CMD_THREADS_SET] = "threads-set",
> +	[NFSD_CMD_THREADS_GET] = "threads-get",
>  };
>  
>  const char *nfsd_op_str(int op)
> @@ -47,6 +49,15 @@ struct ynl_policy_nest nfsd_rpc_status_nest = {
>  	.table = nfsd_rpc_status_policy,
>  };
>  
> +struct ynl_policy_attr nfsd_server_worker_policy[NFSD_A_SERVER_WORKER_MAX + 1] = {
> +	[NFSD_A_SERVER_WORKER_THREADS] = { .name = "threads", .type = YNL_PT_U32, },
> +};
> +
> +struct ynl_policy_nest nfsd_server_worker_nest = {
> +	.max_attr = NFSD_A_SERVER_WORKER_MAX,
> +	.table = nfsd_server_worker_policy,
> +};
> +
>  /* Common nested types */
>  /* ============== NFSD_CMD_RPC_STATUS_GET ============== */
>  /* NFSD_CMD_RPC_STATUS_GET - dump */
> @@ -90,6 +101,87 @@ struct nfsd_rpc_status_get_list *nfsd_rpc_status_get_dump(struct ynl_sock *ys)
>  	return NULL;
>  }
>  
> +/* ============== NFSD_CMD_THREADS_SET ============== */
> +/* NFSD_CMD_THREADS_SET - do */
> +void nfsd_threads_set_req_free(struct nfsd_threads_set_req *req)
> +{
> +	free(req);
> +}
> +
> +int nfsd_threads_set(struct ynl_sock *ys, struct nfsd_threads_set_req *req)
> +{
> +	struct nlmsghdr *nlh;
> +	int err;
> +
> +	nlh = ynl_gemsg_start_req(ys, ys->family_id, NFSD_CMD_THREADS_SET, 1);
> +	ys->req_policy = &nfsd_server_worker_nest;
> +
> +	if (req->_present.threads)
> +		mnl_attr_put_u32(nlh, NFSD_A_SERVER_WORKER_THREADS, req->threads);
> +
> +	err = ynl_exec(ys, nlh, NULL);
> +	if (err < 0)
> +		return -1;
> +
> +	return 0;
> +}
> +
> +/* ============== NFSD_CMD_THREADS_GET ============== */
> +/* NFSD_CMD_THREADS_GET - do */
> +void nfsd_threads_get_rsp_free(struct nfsd_threads_get_rsp *rsp)
> +{
> +	free(rsp);
> +}
> +
> +int nfsd_threads_get_rsp_parse(const struct nlmsghdr *nlh, void *data)
> +{
> +	struct ynl_parse_arg *yarg = data;
> +	struct nfsd_threads_get_rsp *dst;
> +	const struct nlattr *attr;
> +
> +	dst = yarg->data;
> +
> +	mnl_attr_for_each(attr, nlh, sizeof(struct genlmsghdr)) {
> +		unsigned int type = mnl_attr_get_type(attr);
> +
> +		if (type == NFSD_A_SERVER_WORKER_THREADS) {
> +			if (ynl_attr_validate(yarg, attr))
> +				return MNL_CB_ERROR;
> +			dst->_present.threads = 1;
> +			dst->threads = mnl_attr_get_u32(attr);
> +		}
> +	}
> +
> +	return MNL_CB_OK;
> +}
> +
> +struct nfsd_threads_get_rsp *nfsd_threads_get(struct ynl_sock *ys)
> +{
> +	struct ynl_req_state yrs = { .yarg = { .ys = ys, }, };
> +	struct nfsd_threads_get_rsp *rsp;
> +	struct nlmsghdr *nlh;
> +	int err;
> +
> +	nlh = ynl_gemsg_start_req(ys, ys->family_id, NFSD_CMD_THREADS_GET, 1);
> +	ys->req_policy = &nfsd_server_worker_nest;
> +	yrs.yarg.rsp_policy = &nfsd_server_worker_nest;
> +
> +	rsp = calloc(1, sizeof(*rsp));
> +	yrs.yarg.data = rsp;
> +	yrs.cb = nfsd_threads_get_rsp_parse;
> +	yrs.rsp_cmd = NFSD_CMD_THREADS_GET;
> +
> +	err = ynl_exec(ys, nlh, &yrs);
> +	if (err < 0)
> +		goto err_free;
> +
> +	return rsp;
> +
> +err_free:
> +	nfsd_threads_get_rsp_free(rsp);
> +	return NULL;
> +}
> +
>  const struct ynl_family ynl_nfsd_family =  {
>  	.name		= "nfsd",
>  };
> diff --git a/tools/net/ynl/generated/nfsd-user.h b/tools/net/ynl/generated/nfsd-user.h
> index b6b69501031a..4c11119217f1 100644
> --- a/tools/net/ynl/generated/nfsd-user.h
> +++ b/tools/net/ynl/generated/nfsd-user.h
> @@ -30,4 +30,51 @@ void nfsd_rpc_status_get_list_free(struct nfsd_rpc_status_get_list *rsp);
>  
>  struct nfsd_rpc_status_get_list *nfsd_rpc_status_get_dump(struct ynl_sock *ys);
>  
> +/* ============== NFSD_CMD_THREADS_SET ============== */
> +/* NFSD_CMD_THREADS_SET - do */
> +struct nfsd_threads_set_req {
> +	struct {
> +		__u32 threads:1;
> +	} _present;
> +
> +	__u32 threads;
> +};
> +
> +static inline struct nfsd_threads_set_req *nfsd_threads_set_req_alloc(void)
> +{
> +	return calloc(1, sizeof(struct nfsd_threads_set_req));
> +}
> +void nfsd_threads_set_req_free(struct nfsd_threads_set_req *req);
> +
> +static inline void
> +nfsd_threads_set_req_set_threads(struct nfsd_threads_set_req *req,
> +				 __u32 threads)
> +{
> +	req->_present.threads = 1;
> +	req->threads = threads;
> +}
> +
> +/*
> + * set the number of running threads
> + */
> +int nfsd_threads_set(struct ynl_sock *ys, struct nfsd_threads_set_req *req);
> +
> +/* ============== NFSD_CMD_THREADS_GET ============== */
> +/* NFSD_CMD_THREADS_GET - do */
> +
> +struct nfsd_threads_get_rsp {
> +	struct {
> +		__u32 threads:1;
> +	} _present;
> +
> +	__u32 threads;
> +};
> +
> +void nfsd_threads_get_rsp_free(struct nfsd_threads_get_rsp *rsp);
> +
> +/*
> + * get the number of running threads
> + */
> +struct nfsd_threads_get_rsp *nfsd_threads_get(struct ynl_sock *ys);
> +
>  #endif /* _LINUX_NFSD_GEN_H */
> -- 
> 2.41.0
> 

-- 
Chuck Lever