[tip:locking/core] locking/static_key: Add support for deferred static branches

From: tip-bot for Jakub Kicinski
Date: Mon Apr 29 2019 - 02:40:52 EST


Commit-ID: ad282a8117d5048398f506f20b092c14b3b3c43f
Gitweb: https://git.kernel.org/tip/ad282a8117d5048398f506f20b092c14b3b3c43f
Author: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
AuthorDate: Fri, 29 Mar 2019 17:08:52 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 29 Apr 2019 08:29:20 +0200

locking/static_key: Add support for deferred static branches

Add deferred static branches. We can't unfortunately use the
nice trick of encapsulating the entire structure in true/false
variants, because the inside has to be either struct static_key_true
or struct static_key_false. Use defines to pass the appropriate
members to the helpers separately.

Signed-off-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: alexei.starovoitov@xxxxxxxxx
Cc: ard.biesheuvel@xxxxxxxxxx
Cc: oss-drivers@xxxxxxxxxxxxx
Cc: yamada.masahiro@xxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20190330000854.30142-2-jakub.kicinski@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/jump_label_ratelimit.h | 64 ++++++++++++++++++++++++++++++++++--
kernel/jump_label.c | 17 ++++++----
2 files changed, 71 insertions(+), 10 deletions(-)

diff --git a/include/linux/jump_label_ratelimit.h b/include/linux/jump_label_ratelimit.h
index a49f2b45b3f0..42710d5949ba 100644
--- a/include/linux/jump_label_ratelimit.h
+++ b/include/linux/jump_label_ratelimit.h
@@ -12,21 +12,79 @@ struct static_key_deferred {
struct delayed_work work;
};

-extern void static_key_slow_dec_deferred(struct static_key_deferred *key);
-extern void static_key_deferred_flush(struct static_key_deferred *key);
+struct static_key_true_deferred {
+ struct static_key_true key;
+ unsigned long timeout;
+ struct delayed_work work;
+};
+
+struct static_key_false_deferred {
+ struct static_key_false key;
+ unsigned long timeout;
+ struct delayed_work work;
+};
+
+#define static_key_slow_dec_deferred(x) \
+ __static_key_slow_dec_deferred(&(x)->key, &(x)->work, (x)->timeout)
+#define static_branch_slow_dec_deferred(x) \
+ __static_key_slow_dec_deferred(&(x)->key.key, &(x)->work, (x)->timeout)
+
+#define static_key_deferred_flush(x) \
+ __static_key_deferred_flush((x), &(x)->work)
+
+extern void
+__static_key_slow_dec_deferred(struct static_key *key,
+ struct delayed_work *work,
+ unsigned long timeout);
+extern void __static_key_deferred_flush(void *key, struct delayed_work *work);
extern void
jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl);

+extern void jump_label_update_timeout(struct work_struct *work);
+
+#define DEFINE_STATIC_KEY_DEFERRED_TRUE(name, rl) \
+ struct static_key_true_deferred name = { \
+ .key = { STATIC_KEY_INIT_TRUE }, \
+ .timeout = (rl), \
+ .work = __DELAYED_WORK_INITIALIZER((name).work, \
+ jump_label_update_timeout, \
+ 0), \
+ }
+
+#define DEFINE_STATIC_KEY_DEFERRED_FALSE(name, rl) \
+ struct static_key_false_deferred name = { \
+ .key = { STATIC_KEY_INIT_FALSE }, \
+ .timeout = (rl), \
+ .work = __DELAYED_WORK_INITIALIZER((name).work, \
+ jump_label_update_timeout, \
+ 0), \
+ }
+
+#define static_branch_deferred_inc(x) static_branch_inc(&(x)->key)
+
#else /* !CONFIG_JUMP_LABEL */
struct static_key_deferred {
struct static_key key;
};
+struct static_key_true_deferred {
+ struct static_key_true key;
+};
+struct static_key_false_deferred {
+ struct static_key_false key;
+};
+#define DEFINE_STATIC_KEY_DEFERRED_TRUE(name, rl) \
+ struct static_key_true_deferred name = { STATIC_KEY_TRUE_INIT }
+#define DEFINE_STATIC_KEY_DEFERRED_FALSE(name, rl) \
+ struct static_key_false_deferred name = { STATIC_KEY_FALSE_INIT }
+
+#define static_branch_slow_dec_deferred(x) static_branch_dec(&(x)->key)
+
static inline void static_key_slow_dec_deferred(struct static_key_deferred *key)
{
STATIC_KEY_CHECK_USE(key);
static_key_slow_dec(&key->key);
}
-static inline void static_key_deferred_flush(struct static_key_deferred *key)
+static inline void static_key_deferred_flush(void *key)
{
STATIC_KEY_CHECK_USE(key);
}
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index a799b1ac6b2f..73bbbaddbd9c 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -244,12 +244,13 @@ static void __static_key_slow_dec(struct static_key *key,
cpus_read_unlock();
}

-static void jump_label_update_timeout(struct work_struct *work)
+void jump_label_update_timeout(struct work_struct *work)
{
struct static_key_deferred *key =
container_of(work, struct static_key_deferred, work.work);
__static_key_slow_dec(&key->key, 0, NULL);
}
+EXPORT_SYMBOL_GPL(jump_label_update_timeout);

void static_key_slow_dec(struct static_key *key)
{
@@ -264,19 +265,21 @@ void static_key_slow_dec_cpuslocked(struct static_key *key)
__static_key_slow_dec_cpuslocked(key, 0, NULL);
}

-void static_key_slow_dec_deferred(struct static_key_deferred *key)
+void __static_key_slow_dec_deferred(struct static_key *key,
+ struct delayed_work *work,
+ unsigned long timeout)
{
STATIC_KEY_CHECK_USE(key);
- __static_key_slow_dec(&key->key, key->timeout, &key->work);
+ __static_key_slow_dec(key, timeout, work);
}
-EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
+EXPORT_SYMBOL_GPL(__static_key_slow_dec_deferred);

-void static_key_deferred_flush(struct static_key_deferred *key)
+void __static_key_deferred_flush(void *key, struct delayed_work *work)
{
STATIC_KEY_CHECK_USE(key);
- flush_delayed_work(&key->work);
+ flush_delayed_work(work);
}
-EXPORT_SYMBOL_GPL(static_key_deferred_flush);
+EXPORT_SYMBOL_GPL(__static_key_deferred_flush);

void jump_label_rate_limit(struct static_key_deferred *key,
unsigned long rl)