Re: [PATCH v5 1/3] NFSD: convert write_threads to netlink command

Jeff Layton
2023-11-29T18:13:36Z

On Wed, 2023-11-29 at 18:12 +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(+)
>
> 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 d6eeee149370..130b3d937a79 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1699,6 +1699,64 @@ 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 3cd044edee5d..1b6fe1f9ed0e 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 360b6448c6e9..9768328a7751 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 */
> @@ -198,6 +209,87 @@ 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 989c6e209ced..e162a4f20d91 100644
> --- a/tools/net/ynl/generated/nfsd-user.h
> +++ b/tools/net/ynl/generated/nfsd-user.h
> @@ -64,4 +64,51 @@ nfsd_rpc_status_get_rsp_list_free(struct nfsd_rpc_status_get_rsp_list *rsp);
> struct nfsd_rpc_status_get_rsp_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 */

Ok, Uncle! I'll relent on the quest for a single netlink command to
start the server. This patch looks reasonable to me.

Reviewed-by: Jeff Layton <jlayton@kernel.org>