Silence NETLINK when in S3
Pulling in ABT's fix to silence the NETLINK messaging to healthd which keeps
waking the system from S3 once the last CPU is pushed to offline. This is
based upon ABT patches Id705dc790eaa07651cce1e807ccbbb39e27d869b and
I459d561d55388ab8642d4ffed09d0d443db9de0e.
Change-Id: I3664caf063e7b32dd58eb26079f3b2f7a9700c63
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 5f72767..7ed6eec 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -24,6 +24,7 @@
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
+#include <linux/suspend.h>
#include <net/sock.h>
#include <net/net_namespace.h>
@@ -41,6 +42,21 @@
/* This lock protects uevent_seqnum and uevent_sock_list */
static DEFINE_MUTEX(uevent_sock_mutex);
+#ifdef CONFIG_PM_SLEEP
+struct uevent_buffered {
+ struct kobject *kobj;
+ struct kobj_uevent_env *env;
+ const char *action;
+ char *devpath;
+ char *subsys;
+ struct list_head buffer_list;
+};
+
+static DEFINE_MUTEX(uevent_buffer_mutex);
+static bool uevent_buffer;
+static LIST_HEAD(uevent_buffer_list);
+#endif
+
/* the strings here must match the enum in include/linux/kobject.h */
static const char *kobject_actions[] = {
[KOBJ_ADD] = "add",
@@ -124,6 +140,89 @@
return 0;
}
+static int kobject_deliver_uevent(struct kobject *kobj,
+ struct kobj_uevent_env *env,
+ const char *action_string,
+ const char *devpath,
+ const char *subsystem)
+{
+ int retval, i;
+#ifdef CONFIG_NET
+ struct uevent_sock *ue_sk;
+#endif
+
+ mutex_lock(&uevent_sock_mutex);
+ /* we will send an event, so request a new sequence number */
+ retval = add_uevent_var(env, "SEQNUM=%llu",
+ (unsigned long long) ++uevent_seqnum);
+ if (retval) {
+ mutex_unlock(&uevent_sock_mutex);
+ return -1;
+ }
+
+#if defined(CONFIG_NET)
+ /* send netlink message */
+ list_for_each_entry(ue_sk, &uevent_sock_list, list) {
+ struct sock *uevent_sock = ue_sk->sk;
+ struct sk_buff *skb;
+ size_t len;
+
+ if (!netlink_has_listeners(uevent_sock, 1))
+ continue;
+
+ /* allocate message with the maximum possible size */
+ len = strlen(action_string) + strlen(devpath) + 2;
+ skb = alloc_skb(len + env->buflen, GFP_KERNEL);
+ if (skb) {
+ char *scratch;
+
+ /* add header */
+ scratch = skb_put(skb, len);
+ sprintf(scratch, "%s@%s", action_string, devpath);
+
+ /* copy keys to our continuous event payload buffer */
+ for (i = 0; i < env->envp_idx; i++) {
+ len = strlen(env->envp[i]) + 1;
+ scratch = skb_put(skb, len);
+ strcpy(scratch, env->envp[i]);
+ }
+
+ NETLINK_CB(skb).dst_group = 1;
+ retval = netlink_broadcast_filtered(uevent_sock, skb,
+ 0, 1, GFP_KERNEL,
+ kobj_bcast_filter,
+ kobj);
+ /* ENOBUFS should be handled in userspace */
+ if (retval == -ENOBUFS || retval == -ESRCH)
+ retval = 0;
+ } else
+ retval = -ENOMEM;
+ }
+#endif
+ mutex_unlock(&uevent_sock_mutex);
+
+ /* call uevent_helper, usually only enabled during early boot */
+ if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
+ char *argv[3];
+
+ argv[0] = uevent_helper;
+ argv[1] = (char *) subsystem;
+ argv[2] = NULL;
+ retval = add_uevent_var(env, "HOME=/");
+ if (retval)
+ return -1;
+ retval = add_uevent_var(env,
+ "PATH=/sbin:/bin:/user/sbin:/usr/bin");
+ if (retval)
+ return -1;
+
+ retval = call_usermodehelper(argv[0], argv,
+ env->envp, UMH_WAIT_EXEC);
+ }
+
+ return 0;
+}
+
/**
* kobject_uevent_env - send an uevent with environmental data
*
@@ -146,9 +245,6 @@
const struct kset_uevent_ops *uevent_ops;
int i = 0;
int retval = 0;
-#ifdef CONFIG_NET
- struct uevent_sock *ue_sk;
-#endif
pr_debug("kobject: '%s' (%p): %s\n",
kobject_name(kobj), kobj, __func__);
@@ -250,73 +346,48 @@
else if (action == KOBJ_REMOVE)
kobj->state_remove_uevent_sent = 1;
- mutex_lock(&uevent_sock_mutex);
- /* we will send an event, so request a new sequence number */
- retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum);
- if (retval) {
- mutex_unlock(&uevent_sock_mutex);
- goto exit;
- }
+#ifdef CONFIG_PM_SLEEP
+ /*
+ * Delivery of skb's to userspace processes waiting via
+ * EPOLLWAKEUP will abort suspend. Buffer events emitted when
+ * there is no unfrozen userspace to receive them.
+ */
+ mutex_lock(&uevent_buffer_mutex);
+ if (uevent_buffer) {
+ struct uevent_buffered *ub;
+ ub = kmalloc(sizeof(*ub), GFP_KERNEL);
+ if (!ub) {
+ mutex_unlock(&uevent_buffer_mutex);
+ goto exit;
+ }
-#if defined(CONFIG_NET)
- /* send netlink message */
- list_for_each_entry(ue_sk, &uevent_sock_list, list) {
- struct sock *uevent_sock = ue_sk->sk;
- struct sk_buff *skb;
- size_t len;
+ ub->kobj = kobj;
+ ub->env = env;
+ ub->action = action_string;
+ ub->devpath = kstrdup(devpath, GFP_KERNEL);
+ ub->subsys = kstrdup(subsystem, GFP_KERNEL);
- if (!netlink_has_listeners(uevent_sock, 1))
- continue;
-
- /* allocate message with the maximum possible size */
- len = strlen(action_string) + strlen(devpath) + 2;
- skb = alloc_skb(len + env->buflen, GFP_KERNEL);
- if (skb) {
- char *scratch;
-
- /* add header */
- scratch = skb_put(skb, len);
- sprintf(scratch, "%s@%s", action_string, devpath);
-
- /* copy keys to our continuous event payload buffer */
- for (i = 0; i < env->envp_idx; i++) {
- len = strlen(env->envp[i]) + 1;
- scratch = skb_put(skb, len);
- strcpy(scratch, env->envp[i]);
- }
-
- NETLINK_CB(skb).dst_group = 1;
- retval = netlink_broadcast_filtered(uevent_sock, skb,
- 0, 1, GFP_KERNEL,
- kobj_bcast_filter,
- kobj);
- /* ENOBUFS should be handled in userspace */
- if (retval == -ENOBUFS || retval == -ESRCH)
- retval = 0;
- } else
+ if (!ub->devpath || !ub->subsys) {
+ kfree(ub->devpath);
+ /* kfree(ub->action); not free'd as action_string is on the stack */
+ kfree(ub->subsys);
+ kfree(ub);
retval = -ENOMEM;
+ mutex_unlock(&uevent_buffer_mutex);
+ goto exit;
+ }
+
+ kobject_get(kobj);
+ list_add(&ub->buffer_list, &uevent_buffer_list);
+ env = NULL;
}
+ mutex_unlock(&uevent_buffer_mutex);
#endif
- mutex_unlock(&uevent_sock_mutex);
- /* call uevent_helper, usually only enabled during early boot */
- if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
- char *argv [3];
-
- argv [0] = uevent_helper;
- argv [1] = (char *)subsystem;
- argv [2] = NULL;
- retval = add_uevent_var(env, "HOME=/");
- if (retval)
+ if (env)
+ if (kobject_deliver_uevent(kobj, env, action_string, devpath,
+ subsystem))
goto exit;
- retval = add_uevent_var(env,
- "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
- if (retval)
- goto exit;
-
- retval = call_usermodehelper(argv[0], argv,
- env->envp, UMH_WAIT_EXEC);
- }
exit:
kfree(devpath);
@@ -421,6 +492,34 @@
kfree(ue_sk);
}
+#ifdef CONFIG_PM_SLEEP
+int uevent_buffer_pm_notify(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ mutex_lock(&uevent_buffer_mutex);
+ if (action == PM_SUSPEND_PREPARE) {
+ uevent_buffer = true;
+ } else if (action == PM_POST_SUSPEND) {
+ struct uevent_buffered *ub, *tmp;
+ list_for_each_entry_safe(ub, tmp, &uevent_buffer_list,
+ buffer_list) {
+ kobject_deliver_uevent(ub->kobj, ub->env, ub->action,
+ ub->devpath, ub->subsys);
+ list_del(&ub->buffer_list);
+ kobject_put(ub->kobj);
+ kfree(ub->env);
+ kfree(ub->devpath);
+ kfree(ub->subsys);
+ kfree(ub);
+ }
+
+ uevent_buffer = false;
+ }
+ mutex_unlock(&uevent_buffer_mutex);
+ return 0;
+}
+#endif
+
static struct pernet_operations uevent_net_ops = {
.init = uevent_net_init,
.exit = uevent_net_exit,
@@ -428,6 +527,9 @@
static int __init kobject_uevent_init(void)
{
+#ifdef CONFIG_PM_SLEEP
+ pm_notifier(uevent_buffer_pm_notify, 0);
+#endif
return register_pernet_subsys(&uevent_net_ops);
}
