mptcp: pm: in-kernel: reduce pernet struct size

All the 'unsigned int' variables from the 'pm_nl_pernet' structure are
bounded to MPTCP_PM_ADDR_MAX, currently set to 8. The endpoint ID is
also bounded by the protocol to 8-bit. MPTCP_PM_ADDR_MAX, if extended
later, will never over 8-bit.

So no need to use 'unsigned int' variables, 'u8' is enough.

Note that the exposed counters in MPTCP_INFO are already limited to
8-bit, same for pm->extra_subflows, and others. So it seems even better
to limit them to 8-bit.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250925-net-next-mptcp-c-flag-laminar-v1-13-ad126cc47c6b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mptcp/pm_kernel.c b/net/mptcp/pm_kernel.c
index 0e1e99e72950f2432b33610047bc4aa68c5e75af..117f842fe18e44f6e887d9044c7b0bb55cbb9084 100644 (file)
--- a/net/mptcp/pm_kernel.c
+++ b/net/mptcp/pm_kernel.c
@@ -18,12 +18,12 @@ struct pm_nl_pernet {
        /* protects pernet updates */
        spinlock_t              lock;
        struct list_head        endp_list;
-       unsigned int            endpoints;
-       unsigned int            endp_signal_max;
-       unsigned int            endp_subflow_max;
-       unsigned int            limit_add_addr_accepted;
-       unsigned int            limit_extra_subflows;
-       unsigned int            next_id;
+       u8                      endpoints;
+       u8                      endp_signal_max;
+       u8                      endp_subflow_max;
+       u8                      limit_add_addr_accepted;
+       u8                      limit_extra_subflows;
+       u8                      next_id;
        DECLARE_BITMAP(id_bitmap, MPTCP_PM_MAX_ADDR_ID + 1);
 };
 
@@ -45,7 +45,7 @@ static struct pm_nl_pernet *genl_info_pm_nl(struct genl_info *info)
        return pm_nl_get_pernet(genl_info_net(info));
 }
 
-unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
+u8 mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
 {
        const struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
@@ -53,7 +53,7 @@ unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_signal_max);
 
-unsigned int mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk)
+u8 mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk)
 {
        struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
@@ -61,7 +61,7 @@ unsigned int mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_endp_subflow_max);
 
-unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
+u8 mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
 {
        struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
@@ -69,7 +69,7 @@ unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk)
 }
 EXPORT_SYMBOL_GPL(mptcp_pm_get_limit_add_addr_accepted);
 
-unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk)
+u8 mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk)
 {
        struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
 
@@ -185,15 +185,13 @@ fill_remote_addresses_fullmesh(struct mptcp_sock *msk,
                               struct mptcp_addr_info *local,
                               struct mptcp_addr_info *addrs)
 {
+       u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
        bool deny_id0 = READ_ONCE(msk->pm.remote_deny_join_id0);
        DECLARE_BITMAP(unavail_id, MPTCP_PM_MAX_ADDR_ID + 1);
        struct sock *sk = (struct sock *)msk, *ssk;
        struct mptcp_subflow_context *subflow;
-       unsigned int limit_extra_subflows;
        int i = 0;
 
-       limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
-
        /* Forbid creation of new subflows matching existing ones, possibly
         * already created by incoming ADD_ADDR
         */
@@ -272,20 +270,14 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info)
 
 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 {
+       u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
+       struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+       u8 endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
+       u8 endp_signal_max = mptcp_pm_get_endp_signal_max(msk);
        struct sock *sk = (struct sock *)msk;
-       unsigned int limit_extra_subflows;
        bool signal_and_subflow = false;
-       unsigned int endp_subflow_max;
-       unsigned int endp_signal_max;
-       struct pm_nl_pernet *pernet;
        struct mptcp_pm_local local;
 
-       pernet = pm_nl_get_pernet(sock_net(sk));
-
-       endp_signal_max = mptcp_pm_get_endp_signal_max(msk);
-       endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
-       limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
-
        /* do lazy endpoint usage accounting for the MPC subflows */
        if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {
                struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(msk->first);
@@ -400,16 +392,15 @@ fill_local_addresses_vec_fullmesh(struct mptcp_sock *msk,
                                  struct mptcp_pm_local *locals,
                                  bool c_flag_case)
 {
+       u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
        struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
        struct sock *sk = (struct sock *)msk;
        struct mptcp_pm_addr_entry *entry;
-       unsigned int limit_extra_subflows;
        struct mptcp_addr_info mpc_addr;
        struct mptcp_pm_local *local;
        int i = 0;
 
        mptcp_local_address((struct sock_common *)msk, &mpc_addr);
-       limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
        rcu_read_lock();
        list_for_each_entry_rcu(entry, &pernet->endp_list, list) {
@@ -457,16 +448,15 @@ fill_local_addresses_vec_c_flag(struct mptcp_sock *msk,
                                struct mptcp_addr_info *remote,
                                struct mptcp_pm_local *locals)
 {
-       unsigned int endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
+       u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
        struct pm_nl_pernet *pernet = pm_nl_get_pernet_from_msk(msk);
+       u8 endp_subflow_max = mptcp_pm_get_endp_subflow_max(msk);
        struct sock *sk = (struct sock *)msk;
-       unsigned int limit_extra_subflows;
        struct mptcp_addr_info mpc_addr;
        struct mptcp_pm_local *local;
        int i = 0;
 
        mptcp_local_address((struct sock_common *)msk, &mpc_addr);
-       limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
 
        while (msk->pm.local_addr_used < endp_subflow_max) {
                local = &locals[i];
@@ -543,17 +533,14 @@ fill_local_addresses_vec(struct mptcp_sock *msk, struct mptcp_addr_info *remote,
 
 static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 {
+       u8 limit_add_addr_accepted = mptcp_pm_get_limit_add_addr_accepted(msk);
+       u8 limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
        struct mptcp_pm_local locals[MPTCP_PM_ADDR_MAX];
        struct sock *sk = (struct sock *)msk;
-       unsigned int limit_extra_subflows;
-       unsigned int limit_add_addr_accepted;
        struct mptcp_addr_info remote;
        bool sf_created = false;
        int i, nr;
 
-       limit_add_addr_accepted = mptcp_pm_get_limit_add_addr_accepted(msk);
-       limit_extra_subflows = mptcp_pm_get_limit_extra_subflows(msk);
-
        pr_debug("accepted %d:%d remote family %d\n",
                 msk->pm.add_addr_accepted, limit_add_addr_accepted,
                 msk->pm.remote.family);
@@ -595,7 +582,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 void mptcp_pm_nl_rm_addr(struct mptcp_sock *msk, u8 rm_id)
 {
        if (rm_id && WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)) {
-               unsigned int limit_add_addr_accepted =
+               u8 limit_add_addr_accepted =
                        mptcp_pm_get_limit_add_addr_accepted(msk);
 
                /* Note: if the subflow has been closed before, this
@@ -626,8 +613,8 @@ static int mptcp_pm_nl_append_new_local_addr(struct pm_nl_pernet *pernet,
                                             bool needs_id, bool replace)
 {
        struct mptcp_pm_addr_entry *cur, *del_entry = NULL;
-       unsigned int addr_max;
        int ret = -EINVAL;
+       u8 addr_max;
 
        spin_lock_bh(&pernet->lock);
        /* to keep the code simple, don't do IDR-like allocation for address ID,
@@ -1072,8 +1059,8 @@ int mptcp_pm_nl_del_addr_doit(struct sk_buff *skb, struct genl_info *info)
 {
        struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
        struct mptcp_pm_addr_entry addr, *entry;
-       unsigned int addr_max;
        struct nlattr *attr;
+       u8 addr_max;
        int ret;
 
        if (GENL_REQ_ATTR_CHECK(info, MPTCP_PM_ENDPOINT_ADDR))

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index df8f977039d0a716e5792e3ada7eee9e075f1581..0cd3333cafafad19a8c2c8ea302265af9f27a8bf 100644 (file)
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -1180,10 +1180,10 @@ void __init mptcp_pm_userspace_register(void);
 void __init mptcp_pm_nl_init(void);
 void mptcp_pm_worker(struct mptcp_sock *msk);
 void __mptcp_pm_kernel_worker(struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk);
-unsigned int mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_endp_signal_max(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_endp_subflow_max(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_limit_add_addr_accepted(const struct mptcp_sock *msk);
+u8 mptcp_pm_get_limit_extra_subflows(const struct mptcp_sock *msk);
 
 /* called under PM lock */
 static inline void __mptcp_pm_close_subflow(struct mptcp_sock *msk)