sysctl: define proc_do_static_key()

Convert proc_dointvec_minmax_bpf_stats() into a more generic
helper, since we are going to use jump labels more often.

Note that sysctl_bpf_stats_enabled is removed, since
it is no longer needed/used.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 21 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 7d1008be6173..1beca96fb625 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -230,11 +230,6 @@ static int proc_dostring_coredump(struct ctl_table *table, int write,
 #endif
 static int proc_dopipe_max_size(struct ctl_table *table, int write,
                 void __user *buffer, size_t *lenp, loff_t *ppos);
-#ifdef CONFIG_BPF_SYSCALL
-static int proc_dointvec_minmax_bpf_stats(struct ctl_table *table, int write,
-                                          void __user *buffer, size_t *lenp,
-                                          loff_t *ppos);
-#endif
 
 #ifdef CONFIG_MAGIC_SYSRQ
 /* Note: sysrq code uses its own private copy */
@@ -1253,12 +1248,10 @@ static struct ctl_table kern_table[] = {
         },
         {
                 .procname       = "bpf_stats_enabled",
-                .data           = &sysctl_bpf_stats_enabled,
-                .maxlen         = sizeof(sysctl_bpf_stats_enabled),
+                .data           = &bpf_stats_enabled_key.key,
+                .maxlen         = sizeof(bpf_stats_enabled_key),
                 .mode           = 0644,
-                .proc_handler   = proc_dointvec_minmax_bpf_stats,
-                .extra1         = &zero,
-                .extra2         = &one,
+                .proc_handler   = proc_do_static_key,
         },
 #endif
 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)
@@ -3374,26 +3367,35 @@ int proc_do_large_bitmap(struct ctl_table *table, int write,
 
 #endif /* CONFIG_PROC_SYSCTL */
 
-#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_SYSCTL)
-static int proc_dointvec_minmax_bpf_stats(struct ctl_table *table, int write,
-                                          void __user *buffer, size_t *lenp,
-                                          loff_t *ppos)
+#if defined(CONFIG_SYSCTL)
+int proc_do_static_key(struct ctl_table *table, int write,
+                       void __user *buffer, size_t *lenp,
+                       loff_t *ppos)
 {
-        int ret, bpf_stats = *(int *)table->data;
-        struct ctl_table tmp = *table;
+        struct static_key *key = (struct static_key *)table->data;
+        static DEFINE_MUTEX(static_key_mutex);
+        int val, ret;
+        struct ctl_table tmp = {
+                .data   = &val,
+                .maxlen = sizeof(val),
+                .mode   = table->mode,
+                .extra1 = &zero,
+                .extra2 = &one,
+        };
 
         if (write && !capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
-        tmp.data = &bpf_stats;
+        mutex_lock(&static_key_mutex);
+        val = static_key_enabled(key);
         ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
         if (write && !ret) {
-                *(int *)table->data = bpf_stats;
-                if (bpf_stats)
-                        static_branch_enable(&bpf_stats_enabled_key);
+                if (val)
+                        static_key_enable(key);
                 else
-                        static_branch_disable(&bpf_stats_enabled_key);
+                        static_key_disable(key);
         }
+        mutex_unlock(&static_key_mutex);
         return ret;
 }
 #endif