1 files changed, 97 insertions, 141 deletions

diff --git a/net/ipv4/tcp_memcontrol.c b/net/ipv4/tcp_memcontrol.c
index 49978788a9d..f7a2ec3ac58 100644
--- a/net/ipv4/tcp_memcontrol.c
+++ b/net/ipv4/tcp_memcontrol.c
@@ -6,50 +6,7 @@
 #include <linux/memcontrol.h>
 #include <linux/module.h>
 
-static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft);
-static int tcp_cgroup_write(struct cgroup *cont, struct cftype *cft,
-			    const char *buffer);
-static int tcp_cgroup_reset(struct cgroup *cont, unsigned int event);
-
-static struct cftype tcp_files[] = {
-	{
-		.name = "kmem.tcp.limit_in_bytes",
-		.write_string = tcp_cgroup_write,
-		.read_u64 = tcp_cgroup_read,
-		.private = RES_LIMIT,
-	},
-	{
-		.name = "kmem.tcp.usage_in_bytes",
-		.read_u64 = tcp_cgroup_read,
-		.private = RES_USAGE,
-	},
-	{
-		.name = "kmem.tcp.failcnt",
-		.private = RES_FAILCNT,
-		.trigger = tcp_cgroup_reset,
-		.read_u64 = tcp_cgroup_read,
-	},
-	{
-		.name = "kmem.tcp.max_usage_in_bytes",
-		.private = RES_MAX_USAGE,
-		.trigger = tcp_cgroup_reset,
-		.read_u64 = tcp_cgroup_read,
-	},
-};
-
-static inline struct tcp_memcontrol *tcp_from_cgproto(struct cg_proto *cg_proto)
-{
-	return container_of(cg_proto, struct tcp_memcontrol, cg_proto);
-}
-
-static void memcg_tcp_enter_memory_pressure(struct sock *sk)
-{
-	if (sk->sk_cgrp->memory_pressure)
-		*sk->sk_cgrp->memory_pressure = 1;
-}
-EXPORT_SYMBOL(memcg_tcp_enter_memory_pressure);
-
-int tcp_init_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
+int tcp_init_cgroup(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
 {
 	/*
 	 * The root cgroup does not use res_counters, but rather,
@@ -58,69 +15,44 @@ int tcp_init_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
 	 */
 	struct res_counter *res_parent = NULL;
 	struct cg_proto *cg_proto, *parent_cg;
-	struct tcp_memcontrol *tcp;
-	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
 	struct mem_cgroup *parent = parent_mem_cgroup(memcg);
-	struct net *net = current->nsproxy->net_ns;
 
 	cg_proto = tcp_prot.proto_cgroup(memcg);
 	if (!cg_proto)
-		goto create_files;
-
-	tcp = tcp_from_cgproto(cg_proto);
+		return 0;
 
-	tcp->tcp_prot_mem[0] = net->ipv4.sysctl_tcp_mem[0];
-	tcp->tcp_prot_mem[1] = net->ipv4.sysctl_tcp_mem[1];
-	tcp->tcp_prot_mem[2] = net->ipv4.sysctl_tcp_mem[2];
-	tcp->tcp_memory_pressure = 0;
+	cg_proto->sysctl_mem[0] = sysctl_tcp_mem[0];
+	cg_proto->sysctl_mem[1] = sysctl_tcp_mem[1];
+	cg_proto->sysctl_mem[2] = sysctl_tcp_mem[2];
+	cg_proto->memory_pressure = 0;
+	cg_proto->memcg = memcg;
 
 	parent_cg = tcp_prot.proto_cgroup(parent);
 	if (parent_cg)
-		res_parent = parent_cg->memory_allocated;
-
-	res_counter_init(&tcp->tcp_memory_allocated, res_parent);
-	percpu_counter_init(&tcp->tcp_sockets_allocated, 0);
+		res_parent = &parent_cg->memory_allocated;
 
-	cg_proto->enter_memory_pressure = memcg_tcp_enter_memory_pressure;
-	cg_proto->memory_pressure = &tcp->tcp_memory_pressure;
-	cg_proto->sysctl_mem = tcp->tcp_prot_mem;
-	cg_proto->memory_allocated = &tcp->tcp_memory_allocated;
-	cg_proto->sockets_allocated = &tcp->tcp_sockets_allocated;
-	cg_proto->memcg = memcg;
+	res_counter_init(&cg_proto->memory_allocated, res_parent);
+	percpu_counter_init(&cg_proto->sockets_allocated, 0);
 
-create_files:
-	return cgroup_add_files(cgrp, ss, tcp_files,
-				ARRAY_SIZE(tcp_files));
+	return 0;
 }
 EXPORT_SYMBOL(tcp_init_cgroup);
 
-void tcp_destroy_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
+void tcp_destroy_cgroup(struct mem_cgroup *memcg)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
 	struct cg_proto *cg_proto;
-	struct tcp_memcontrol *tcp;
-	u64 val;
 
 	cg_proto = tcp_prot.proto_cgroup(memcg);
 	if (!cg_proto)
 		return;
 
-	tcp = tcp_from_cgproto(cg_proto);
-	percpu_counter_destroy(&tcp->tcp_sockets_allocated);
-
-	val = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
-
-	if (val != RESOURCE_MAX)
-		jump_label_dec(&memcg_socket_limit_enabled);
+	percpu_counter_destroy(&cg_proto->sockets_allocated);
 }
 EXPORT_SYMBOL(tcp_destroy_cgroup);
 
 static int tcp_update_limit(struct mem_cgroup *memcg, u64 val)
 {
-	struct net *net = current->nsproxy->net_ns;
-	struct tcp_memcontrol *tcp;
 	struct cg_proto *cg_proto;
-	u64 old_lim;
 	int i;
 	int ret;
 
@@ -128,39 +60,61 @@ static int tcp_update_limit(struct mem_cgroup *memcg, u64 val)
 	if (!cg_proto)
 		return -EINVAL;
 
-	if (val > RESOURCE_MAX)
-		val = RESOURCE_MAX;
-
-	tcp = tcp_from_cgproto(cg_proto);
+	if (val > RES_COUNTER_MAX)
+		val = RES_COUNTER_MAX;
 
-	old_lim = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
-	ret = res_counter_set_limit(&tcp->tcp_memory_allocated, val);
+	ret = res_counter_set_limit(&cg_proto->memory_allocated, val);
 	if (ret)
 		return ret;
 
 	for (i = 0; i < 3; i++)
-		tcp->tcp_prot_mem[i] = min_t(long, val >> PAGE_SHIFT,
-					     net->ipv4.sysctl_tcp_mem[i]);
-
-	if (val == RESOURCE_MAX && old_lim != RESOURCE_MAX)
-		jump_label_dec(&memcg_socket_limit_enabled);
-	else if (old_lim == RESOURCE_MAX && val != RESOURCE_MAX)
-		jump_label_inc(&memcg_socket_limit_enabled);
+		cg_proto->sysctl_mem[i] = min_t(long, val >> PAGE_SHIFT,
+						sysctl_tcp_mem[i]);
+
+	if (val == RES_COUNTER_MAX)
+		clear_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
+	else if (val != RES_COUNTER_MAX) {
+		/*
+		 * The active bit needs to be written after the static_key
+		 * update. This is what guarantees that the socket activation
+		 * function is the last one to run. See sock_update_memcg() for
+		 * details, and note that we don't mark any socket as belonging
+		 * to this memcg until that flag is up.
+		 *
+		 * We need to do this, because static_keys will span multiple
+		 * sites, but we can't control their order. If we mark a socket
+		 * as accounted, but the accounting functions are not patched in
+		 * yet, we'll lose accounting.
+		 *
+		 * We never race with the readers in sock_update_memcg(),
+		 * because when this value change, the code to process it is not
+		 * patched in yet.
+		 *
+		 * The activated bit is used to guarantee that no two writers
+		 * will do the update in the same memcg. Without that, we can't
+		 * properly shutdown the static key.
+		 */
+		if (!test_and_set_bit(MEMCG_SOCK_ACTIVATED, &cg_proto->flags))
+			static_key_slow_inc(&memcg_socket_limit_enabled);
+		set_bit(MEMCG_SOCK_ACTIVE, &cg_proto->flags);
+	}
 
 	return 0;
 }
 
-static int tcp_cgroup_write(struct cgroup *cont, struct cftype *cft,
-			    const char *buffer)
+static ssize_t tcp_cgroup_write(struct kernfs_open_file *of,
+				char *buf, size_t nbytes, loff_t off)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+	struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
 	unsigned long long val;
 	int ret = 0;
 
-	switch (cft->private) {
+	buf = strstrip(buf);
+
+	switch (of_cft(of)->private) {
 	case RES_LIMIT:
 		/* see memcontrol.c */
-		ret = res_counter_memparse_write_strategy(buffer, &val);
+		ret = res_counter_memparse_write_strategy(buf, &val);
 		if (ret)
 			break;
 		ret = tcp_update_limit(memcg, val);
@@ -169,43 +123,39 @@ static int tcp_cgroup_write(struct cgroup *cont, struct cftype *cft,
 		ret = -EINVAL;
 		break;
 	}
-	return ret;
+	return ret ?: nbytes;
 }
 
 static u64 tcp_read_stat(struct mem_cgroup *memcg, int type, u64 default_val)
 {
-	struct tcp_memcontrol *tcp;
 	struct cg_proto *cg_proto;
 
 	cg_proto = tcp_prot.proto_cgroup(memcg);
 	if (!cg_proto)
 		return default_val;
 
-	tcp = tcp_from_cgproto(cg_proto);
-	return res_counter_read_u64(&tcp->tcp_memory_allocated, type);
+	return res_counter_read_u64(&cg_proto->memory_allocated, type);
 }
 
 static u64 tcp_read_usage(struct mem_cgroup *memcg)
 {
-	struct tcp_memcontrol *tcp;
 	struct cg_proto *cg_proto;
 
 	cg_proto = tcp_prot.proto_cgroup(memcg);
 	if (!cg_proto)
 		return atomic_long_read(&tcp_memory_allocated) << PAGE_SHIFT;
 
-	tcp = tcp_from_cgproto(cg_proto);
-	return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_USAGE);
+	return res_counter_read_u64(&cg_proto->memory_allocated, RES_USAGE);
 }
 
-static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft)
+static u64 tcp_cgroup_read(struct cgroup_subsys_state *css, struct cftype *cft)
 {
-	struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
 	u64 val;
 
 	switch (cft->private) {
 	case RES_LIMIT:
-		val = tcp_read_stat(memcg, RES_LIMIT, RESOURCE_MAX);
+		val = tcp_read_stat(memcg, RES_LIMIT, RES_COUNTER_MAX);
 		break;
 	case RES_USAGE:
 		val = tcp_read_usage(memcg);
@@ -220,53 +170,59 @@ static u64 tcp_cgroup_read(struct cgroup *cont, struct cftype *cft)
 	return val;
 }
 
-static int tcp_cgroup_reset(struct cgroup *cont, unsigned int event)
+static ssize_t tcp_cgroup_reset(struct kernfs_open_file *of,
+				char *buf, size_t nbytes, loff_t off)
 {
 	struct mem_cgroup *memcg;
-	struct tcp_memcontrol *tcp;
 	struct cg_proto *cg_proto;
 
-	memcg = mem_cgroup_from_cont(cont);
+	memcg = mem_cgroup_from_css(of_css(of));
 	cg_proto = tcp_prot.proto_cgroup(memcg);
 	if (!cg_proto)
-		return 0;
-	tcp = tcp_from_cgproto(cg_proto);
+		return nbytes;
 
-	switch (event) {
+	switch (of_cft(of)->private) {
 	case RES_MAX_USAGE:
-		res_counter_reset_max(&tcp->tcp_memory_allocated);
+		res_counter_reset_max(&cg_proto->memory_allocated);
 		break;
 	case RES_FAILCNT:
-		res_counter_reset_failcnt(&tcp->tcp_memory_allocated);
+		res_counter_reset_failcnt(&cg_proto->memory_allocated);
 		break;
 	}
 
-	return 0;
+	return nbytes;
 }
 
-unsigned long long tcp_max_memory(const struct mem_cgroup *memcg)
-{
-	struct tcp_memcontrol *tcp;
-	struct cg_proto *cg_proto;
-
-	cg_proto = tcp_prot.proto_cgroup((struct mem_cgroup *)memcg);
-	if (!cg_proto)
-		return 0;
-
-	tcp = tcp_from_cgproto(cg_proto);
-	return res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
-}
+static struct cftype tcp_files[] = {
+	{
+		.name = "kmem.tcp.limit_in_bytes",
+		.write = tcp_cgroup_write,
+		.read_u64 = tcp_cgroup_read,
+		.private = RES_LIMIT,
+	},
+	{
+		.name = "kmem.tcp.usage_in_bytes",
+		.read_u64 = tcp_cgroup_read,
+		.private = RES_USAGE,
+	},
+	{
+		.name = "kmem.tcp.failcnt",
+		.private = RES_FAILCNT,
+		.write = tcp_cgroup_reset,
+		.read_u64 = tcp_cgroup_read,
+	},
+	{
+		.name = "kmem.tcp.max_usage_in_bytes",
+		.private = RES_MAX_USAGE,
+		.write = tcp_cgroup_reset,
+		.read_u64 = tcp_cgroup_read,
+	},
+	{ }	/* terminate */
+};
 
-void tcp_prot_mem(struct mem_cgroup *memcg, long val, int idx)
+static int __init tcp_memcontrol_init(void)
 {
-	struct tcp_memcontrol *tcp;
-	struct cg_proto *cg_proto;
-
-	cg_proto = tcp_prot.proto_cgroup(memcg);
-	if (!cg_proto)
-		return;
-
-	tcp = tcp_from_cgproto(cg_proto);
-
-	tcp->tcp_prot_mem[idx] = val;
+	WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys, tcp_files));
+	return 0;
 }
+__initcall(tcp_memcontrol_init);