0001-runtime-make-probe-locks-rt-safe.patch

From 6033075d73fb69e54653e97a8b0efff7af400c4a Mon Sep 17 00:00:00 2001
From: Sultan Alsawaf <sultan@openresty.com>
Date: Thu, 4 Feb 2021 14:00:24 -0800
Subject: [PATCH] runtime: make probe locks rt-safe

---
 runtime/linux/common_session_state.h |  2 +-
 runtime/linux/probe_lock.h           | 10 +++++-----
 runtime/stp_helper_lock.h            | 13 +++++++++++++
 translate.cxx                        |  2 +-
 4 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/runtime/linux/common_session_state.h b/runtime/linux/common_session_state.h
index 444349080..83e5f9a59 100644
--- a/runtime/linux/common_session_state.h
+++ b/runtime/linux/common_session_state.h
@@ -50,7 +50,7 @@ static struct stp_globals stp_global;
 #define global(name)		(stp_global.name)
 #define global_set(name, val)	(global(name) = (val))
 #define global_lock(name)	(&global(name ## _lock))
-#define global_lock_init(name)	rwlock_init(global_lock(name))
+#define global_lock_init(name)	stp_rwlock_init(global_lock(name))
 #ifdef STP_TIMING
 #define global_skipped(name)	(&global(name ## _lock_skip_count))
 #define global_contended(name)	(&global(name ## _lock_contention_count))
diff --git a/runtime/linux/probe_lock.h b/runtime/linux/probe_lock.h
index 847f0d457..de53e65ee 100644
--- a/runtime/linux/probe_lock.h
+++ b/runtime/linux/probe_lock.h
@@ -22,7 +22,7 @@ struct stp_probe_lock {
 	atomic_t *skipped;
 	atomic_t *contention;
 	#endif
-	rwlock_t *lock;
+	stp_rwlock_t *lock;
 	unsigned write_p;
 };
 
@@ -34,9 +34,9 @@ stp_unlock_probe(const struct stp_probe_lock *locks, unsigned num_locks)
 	if (num_locks == 0) return; /* defeat a gcc9 warning */
 	for (i = num_locks; i-- > 0;) {
 		if (locks[i].write_p)
-			write_unlock(locks[i].lock);
+			stp_write_unlock(locks[i].lock);
 		else
-			read_unlock(locks[i].lock);
+			stp_read_unlock(locks[i].lock);
 	}
 }
 
@@ -47,7 +47,7 @@ stp_lock_probe(const struct stp_probe_lock *locks, unsigned num_locks)
 	unsigned i, retries = 0;
 	for (i = 0; i < num_locks; ++i) {
 		if (locks[i].write_p)
-			while (!write_trylock(locks[i].lock)) {
+			while (!stp_write_trylock(locks[i].lock)) {
 #if !defined(STAP_SUPPRESS_TIME_LIMITS_ENABLE)
 				if (++retries > MAXTRYLOCK)
 					goto skip;
@@ -58,7 +58,7 @@ stp_lock_probe(const struct stp_probe_lock *locks, unsigned num_locks)
 				udelay (TRYLOCKDELAY);
 			}
 		else
-			while (!read_trylock(locks[i].lock)) {
+			while (!stp_read_trylock(locks[i].lock)) {
 #if !defined(STAP_SUPPRESS_TIME_LIMITS_ENABLE)
 				if (++retries > MAXTRYLOCK)
 					goto skip;
diff --git a/runtime/stp_helper_lock.h b/runtime/stp_helper_lock.h
index 81e6a1644..d2961b74c 100644
--- a/runtime/stp_helper_lock.h
+++ b/runtime/stp_helper_lock.h
@@ -31,14 +31,20 @@ static inline void stp_spin_unlock(raw_spinlock_t *lock)	{ raw_spin_unlock(lock)
 #define stp_spin_lock_irqsave(lock, flags)		raw_spin_lock_irqsave(lock, flags)
 #define stp_spin_unlock_irqrestore(lock, flags)		raw_spin_unlock_irqrestore(lock, flags)
 
+#define stp_rwlock_t raw_spinlock_t
 
 #define STP_DEFINE_RWLOCK(lock)		DEFINE_RAW_SPINLOCK(lock)
 
+static inline void stp_rwlock_init(raw_spinlock_t *lock)	{ raw_spin_lock_init(lock); }
+
 static inline void stp_read_lock(raw_spinlock_t *lock)		{ raw_spin_lock(lock); }
 static inline void stp_read_unlock(raw_spinlock_t *lock)	{ raw_spin_unlock(lock); }
 static inline void stp_write_lock(raw_spinlock_t *lock)		{ raw_spin_lock(lock); }
 static inline void stp_write_unlock(raw_spinlock_t *lock)	{ raw_spin_unlock(lock); }
 
+static inline int stp_read_trylock(raw_spinlock_t *lock)	{ return raw_spin_trylock(lock); }
+static inline int stp_write_trylock(raw_spinlock_t *lock)	{ return raw_spin_trylock(lock); }
+
 #define stp_read_lock_irqsave(lock, flags)		raw_spin_lock_irqsave(lock, flags)
 #define stp_read_unlock_irqrestore(lock, flags)		raw_spin_unlock_irqrestore(lock, flags)
 #define stp_write_lock_irqsave(lock, flags)		raw_spin_lock_irqsave(lock, flags)
@@ -58,13 +64,20 @@ static inline void stp_spin_unlock(spinlock_t *lock)		{ spin_unlock(lock); }
 #define stp_spin_lock_irqsave(lock, flags)		spin_lock_irqsave(lock, flags)
 #define stp_spin_unlock_irqrestore(lock, flags)		spin_unlock_irqrestore(lock, flags)
 
+#define stp_rwlock_t rwlock_t
+
 #define STP_DEFINE_RWLOCK(lock)				DEFINE_RWLOCK(lock)
 
+static inline void stp_rwlock_init(rwlock_t *lock)	{ rwlock_init(lock); }
+
 static inline void stp_read_lock(rwlock_t *lock)	{ read_lock(lock); }
 static inline void stp_read_unlock(rwlock_t *lock)	{ read_unlock(lock); }
 static inline void stp_write_lock(rwlock_t *lock)	{ write_lock(lock); }
 static inline void stp_write_unlock(rwlock_t *lock)	{ write_unlock(lock); }
 
+static inline int stp_read_trylock(rwlock_t *lock)	{ return read_trylock(lock); }
+static inline int stp_write_trylock(rwlock_t *lock)	{ return write_trylock(lock); }
+
 #define stp_read_lock_irqsave(lock, flags)		read_lock_irqsave(lock, flags)
 #define stp_read_unlock_irqrestore(lock, flags)		read_unlock_irqrestore(lock, flags)
 #define stp_write_lock_irqsave(lock, flags)		write_lock_irqsave(lock, flags)
diff --git a/translate.cxx b/translate.cxx
index d7fe1e3b2..e7d4e9f99 100644
--- a/translate.cxx
+++ b/translate.cxx
@@ -1710,7 +1710,7 @@ c_unparser::emit_global (vardecl *v)
   else
     o->newline() << type << " " << vn << ";";
 
-  o->newline() << "rwlock_t " << vn << "_lock;";
+  o->newline() << "stp_rwlock_t " << vn << "_lock;";
   o->newline() << "#ifdef STP_TIMING";
   o->newline() << "atomic_t " << vn << "_lock_skip_count;";
   o->newline() << "atomic_t " << vn << "_lock_contention_count;";
-- 
2.30.0