aboutsummaryrefslogtreecommitdiffstats
path: root/include
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-08-31 18:12:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-08-31 18:12:07 -0700
commit7073bc66126e3ab742cce9416ad6b4be8b03c4f7 (patch)
tree18f7d5f3de8a6070481d347e792d9d358813b6b7 /include
parentd4c90396ed7ef9b4e4d221e008e54be8bea8307f (diff)
parentf612a7b1a7f1b5139f228724ce340aac24720591 (diff)
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar: "The main RCU changes in this cycle are: - the combination of tree geometry-initialization simplifications and OS-jitter-reduction changes to expedited grace periods. These two are stacked due to the large number of conflicts that would otherwise result. - privatize smp_mb__after_unlock_lock(). This commit moves the definition of smp_mb__after_unlock_lock() to kernel/rcu/tree.h, in recognition of the fact that RCU is the only thing using this, that nothing else is likely to use it, and that it is likely to go away completely. - documentation updates. - torture-test updates. - misc fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits) rcu,locking: Privatize smp_mb__after_unlock_lock() rcu: Silence lockdep false positive for expedited grace periods rcu: Don't disable CPU hotplug during OOM notifiers scripts: Make checkpatch.pl warn on expedited RCU grace periods rcu: Update MAINTAINERS entry rcu: Clarify CONFIG_RCU_EQS_DEBUG help text rcu: Fix backwards RCU_LOCKDEP_WARN() in synchronize_rcu_tasks() rcu: Rename rcu_lockdep_assert() to RCU_LOCKDEP_WARN() rcu: Make rcu_is_watching() really notrace cpu: Wait for RCU grace periods concurrently rcu: Create a synchronize_rcu_mult() rcu: Fix obsolete priority-boosting comment rcu: Use WRITE_ONCE in RCU_INIT_POINTER rcu: Hide RCU_NOCB_CPU behind RCU_EXPERT rcu: Add RCU-sched flavors of get-state and cond-sync rcu: Add fastpath bypassing funnel locking rcu: Rename RCU_GP_DONE_FQS to RCU_GP_DOING_FQS rcu: Pull out wait_event*() condition into helper function documentation: Describe new expedited stall warnings rcu: Add stall warnings to synchronize_sched_expedited() ...
Diffstat (limited to 'include')
-rw-r--r--include/linux/fdtable.h4
-rw-r--r--include/linux/rcupdate.h144
-rw-r--r--include/linux/rcutiny.h10
-rw-r--r--include/linux/rcutree.h2
-rw-r--r--include/linux/spinlock.h10
-rw-r--r--include/linux/types.h3
-rw-r--r--include/trace/events/rcu.h1
7 files changed, 95 insertions, 79 deletions
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index fbb88740634a..674e3e226465 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -86,8 +86,8 @@ static inline struct file *__fcheck_files(struct files_struct *files, unsigned i
static inline struct file *fcheck_files(struct files_struct *files, unsigned int fd)
{
- rcu_lockdep_assert(rcu_read_lock_held() ||
- lockdep_is_held(&files->file_lock),
+ RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&
+ !lockdep_is_held(&files->file_lock),
"suspicious rcu_dereference_check() usage");
return __fcheck_files(files, fd);
}
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 4cf5f51b4c9c..ff476515f716 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -226,6 +226,37 @@ struct rcu_synchronize {
};
void wakeme_after_rcu(struct rcu_head *head);
+void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
+ struct rcu_synchronize *rs_array);
+
+#define _wait_rcu_gp(checktiny, ...) \
+do { \
+ call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
+ const int __n = ARRAY_SIZE(__crcu_array); \
+ struct rcu_synchronize __rs_array[__n]; \
+ \
+ __wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
+} while (0)
+
+#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
+
+/**
+ * synchronize_rcu_mult - Wait concurrently for multiple grace periods
+ * @...: List of call_rcu() functions for the flavors to wait on.
+ *
+ * This macro waits concurrently for multiple flavors of RCU grace periods.
+ * For example, synchronize_rcu_mult(call_rcu, call_rcu_bh) would wait
+ * on concurrent RCU and RCU-bh grace periods. Waiting on a give SRCU
+ * domain requires you to write a wrapper function for that SRCU domain's
+ * call_srcu() function, supplying the corresponding srcu_struct.
+ *
+ * If Tiny RCU, tell _wait_rcu_gp() not to bother waiting for RCU
+ * or RCU-bh, given that anywhere synchronize_rcu_mult() can be called
+ * is automatically a grace period.
+ */
+#define synchronize_rcu_mult(...) \
+ _wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__)
+
/**
* call_rcu_tasks() - Queue an RCU for invocation task-based grace period
* @head: structure to be used for queueing the RCU updates.
@@ -309,7 +340,7 @@ static inline void rcu_sysrq_end(void)
}
#endif /* #else #ifdef CONFIG_RCU_STALL_COMMON */
-#ifdef CONFIG_RCU_USER_QS
+#ifdef CONFIG_NO_HZ_FULL
void rcu_user_enter(void);
void rcu_user_exit(void);
#else
@@ -317,7 +348,7 @@ static inline void rcu_user_enter(void) { }
static inline void rcu_user_exit(void) { }
static inline void rcu_user_hooks_switch(struct task_struct *prev,
struct task_struct *next) { }
-#endif /* CONFIG_RCU_USER_QS */
+#endif /* CONFIG_NO_HZ_FULL */
#ifdef CONFIG_RCU_NOCB_CPU
void rcu_init_nohz(void);
@@ -392,10 +423,6 @@ bool __rcu_is_watching(void);
* TREE_RCU and rcu_barrier_() primitives in TINY_RCU.
*/
-typedef void call_rcu_func_t(struct rcu_head *head,
- void (*func)(struct rcu_head *head));
-void wait_rcu_gp(call_rcu_func_t crf);
-
#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)
#include <linux/rcutree.h>
#elif defined(CONFIG_TINY_RCU)
@@ -469,46 +496,10 @@ int rcu_read_lock_bh_held(void);
* If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an
* RCU-sched read-side critical section. In absence of
* CONFIG_DEBUG_LOCK_ALLOC, this assumes we are in an RCU-sched read-side
- * critical section unless it can prove otherwise. Note that disabling
- * of preemption (including disabling irqs) counts as an RCU-sched
- * read-side critical section. This is useful for debug checks in functions
- * that required that they be called within an RCU-sched read-side
- * critical section.
- *
- * Check debug_lockdep_rcu_enabled() to prevent false positives during boot
- * and while lockdep is disabled.
- *
- * Note that if the CPU is in the idle loop from an RCU point of
- * view (ie: that we are in the section between rcu_idle_enter() and
- * rcu_idle_exit()) then rcu_read_lock_held() returns false even if the CPU
- * did an rcu_read_lock(). The reason for this is that RCU ignores CPUs
- * that are in such a section, considering these as in extended quiescent
- * state, so such a CPU is effectively never in an RCU read-side critical
- * section regardless of what RCU primitives it invokes. This state of
- * affairs is required --- we need to keep an RCU-free window in idle
- * where the CPU may possibly enter into low power mode. This way we can
- * notice an extended quiescent state to other CPUs that started a grace
- * period. Otherwise we would delay any grace period as long as we run in
- * the idle task.
- *
- * Similarly, we avoid claiming an SRCU read lock held if the current
- * CPU is offline.
+ * critical section unless it can prove otherwise.
*/
#ifdef CONFIG_PREEMPT_COUNT
-static inline int rcu_read_lock_sched_held(void)
-{
- int lockdep_opinion = 0;
-
- if (!debug_lockdep_rcu_enabled())
- return 1;
- if (!rcu_is_watching())
- return 0;
- if (!rcu_lockdep_current_cpu_online())
- return 0;
- if (debug_locks)
- lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
- return lockdep_opinion || preempt_count() != 0 || irqs_disabled();
-}
+int rcu_read_lock_sched_held(void);
#else /* #ifdef CONFIG_PREEMPT_COUNT */
static inline int rcu_read_lock_sched_held(void)
{
@@ -545,6 +536,11 @@ static inline int rcu_read_lock_sched_held(void)
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
+/* Deprecate rcu_lockdep_assert(): Use RCU_LOCKDEP_WARN() instead. */
+static inline void __attribute((deprecated)) deprecate_rcu_lockdep_assert(void)
+{
+}
+
#ifdef CONFIG_PROVE_RCU
/**
@@ -555,17 +551,32 @@ static inline int rcu_read_lock_sched_held(void)
#define rcu_lockdep_assert(c, s) \
do { \
static bool __section(.data.unlikely) __warned; \
+ deprecate_rcu_lockdep_assert(); \
if (debug_lockdep_rcu_enabled() && !__warned && !(c)) { \
__warned = true; \
lockdep_rcu_suspicious(__FILE__, __LINE__, s); \
} \
} while (0)
+/**
+ * RCU_LOCKDEP_WARN - emit lockdep splat if specified condition is met
+ * @c: condition to check
+ * @s: informative message
+ */
+#define RCU_LOCKDEP_WARN(c, s) \
+ do { \
+ static bool __section(.data.unlikely) __warned; \
+ if (debug_lockdep_rcu_enabled() && !__warned && (c)) { \
+ __warned = true; \
+ lockdep_rcu_suspicious(__FILE__, __LINE__, s); \
+ } \
+ } while (0)
+
#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
static inline void rcu_preempt_sleep_check(void)
{
- rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
- "Illegal context switch in RCU read-side critical section");
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_lock_map),
+ "Illegal context switch in RCU read-side critical section");
}
#else /* #ifdef CONFIG_PROVE_RCU */
static inline void rcu_preempt_sleep_check(void)
@@ -576,15 +587,16 @@ static inline void rcu_preempt_sleep_check(void)
#define rcu_sleep_check() \
do { \
rcu_preempt_sleep_check(); \
- rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map), \
- "Illegal context switch in RCU-bh read-side critical section"); \
- rcu_lockdep_assert(!lock_is_held(&rcu_sched_lock_map), \
- "Illegal context switch in RCU-sched read-side critical section"); \
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map), \
+ "Illegal context switch in RCU-bh read-side critical section"); \
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map), \
+ "Illegal context switch in RCU-sched read-side critical section"); \
} while (0)
#else /* #ifdef CONFIG_PROVE_RCU */
-#define rcu_lockdep_assert(c, s) do { } while (0)
+#define rcu_lockdep_assert(c, s) deprecate_rcu_lockdep_assert()
+#define RCU_LOCKDEP_WARN(c, s) do { } while (0)
#define rcu_sleep_check() do { } while (0)
#endif /* #else #ifdef CONFIG_PROVE_RCU */
@@ -615,13 +627,13 @@ static inline void rcu_preempt_sleep_check(void)
({ \
/* Dependency order vs. p above. */ \
typeof(*p) *________p1 = (typeof(*p) *__force)lockless_dereference(p); \
- rcu_lockdep_assert(c, "suspicious rcu_dereference_check() usage"); \
+ RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_check() usage"); \
rcu_dereference_sparse(p, space); \
((typeof(*p) __force __kernel *)(________p1)); \
})
#define __rcu_dereference_protected(p, c, space) \
({ \
- rcu_lockdep_assert(c, "suspicious rcu_dereference_protected() usage"); \
+ RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_protected() usage"); \
rcu_dereference_sparse(p, space); \
((typeof(*p) __force __kernel *)(p)); \
})
@@ -845,8 +857,8 @@ static inline void rcu_read_lock(void)
__rcu_read_lock();
__acquire(RCU);
rcu_lock_acquire(&rcu_lock_map);
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_lock() used illegally while idle");
+ RCU_LOCKDEP_WARN(!rcu_is_watching(),
+ "rcu_read_lock() used illegally while idle");
}
/*
@@ -896,8 +908,8 @@ static inline void rcu_read_lock(void)
*/
static inline void rcu_read_unlock(void)
{
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_unlock() used illegally while idle");
+ RCU_LOCKDEP_WARN(!rcu_is_watching(),
+ "rcu_read_unlock() used illegally while idle");
__release(RCU);
__rcu_read_unlock();
rcu_lock_release(&rcu_lock_map); /* Keep acq info for rls diags. */
@@ -925,8 +937,8 @@ static inline void rcu_read_lock_bh(void)
local_bh_disable();
__acquire(RCU_BH);
rcu_lock_acquire(&rcu_bh_lock_map);
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_lock_bh() used illegally while idle");
+ RCU_LOCKDEP_WARN(!rcu_is_watching(),
+ "rcu_read_lock_bh() used illegally while idle");
}
/*
@@ -936,8 +948,8 @@ static inline void rcu_read_lock_bh(void)
*/
static inline void rcu_read_unlock_bh(void)
{
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_unlock_bh() used illegally while idle");
+ RCU_LOCKDEP_WARN(!rcu_is_watching(),
+ "rcu_read_unlock_bh() used illegally while idle");
rcu_lock_release(&rcu_bh_lock_map);
__release(RCU_BH);
local_bh_enable();
@@ -961,8 +973,8 @@ static inline void rcu_read_lock_sched(void)
preempt_disable();
__acquire(RCU_SCHED);
rcu_lock_acquire(&rcu_sched_lock_map);
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_lock_sched() used illegally while idle");
+ RCU_LOCKDEP_WARN(!rcu_is_watching(),
+ "rcu_read_lock_sched() used illegally while idle");
}
/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
@@ -979,8 +991,8 @@ static inline notrace void rcu_read_lock_sched_notrace(void)
*/
static inline void rcu_read_unlock_sched(void)
{
- rcu_lockdep_assert(rcu_is_watching(),
- "rcu_read_unlock_sched() used illegally while idle");
+ RCU_LOCKDEP_WARN(!rcu_is_watching(),
+ "rcu_read_unlock_sched() used illegally while idle");
rcu_lock_release(&rcu_sched_lock_map);
__release(RCU_SCHED);
preempt_enable();
@@ -1031,7 +1043,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
#define RCU_INIT_POINTER(p, v) \
do { \
rcu_dereference_sparse(p, __rcu); \
- p = RCU_INITIALIZER(v); \
+ WRITE_ONCE(p, RCU_INITIALIZER(v)); \
} while (0)
/**
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 3df6c1ec4e25..ff968b7af3a4 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -37,6 +37,16 @@ static inline void cond_synchronize_rcu(unsigned long oldstate)
might_sleep();
}
+static inline unsigned long get_state_synchronize_sched(void)
+{
+ return 0;
+}
+
+static inline void cond_synchronize_sched(unsigned long oldstate)
+{
+ might_sleep();
+}
+
static inline void rcu_barrier_bh(void)
{
wait_rcu_gp(call_rcu_bh);
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 456879143f89..5abec82f325e 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -76,6 +76,8 @@ void rcu_barrier_bh(void);
void rcu_barrier_sched(void);
unsigned long get_state_synchronize_rcu(void);
void cond_synchronize_rcu(unsigned long oldstate);
+unsigned long get_state_synchronize_sched(void);
+void cond_synchronize_sched(unsigned long oldstate);
extern unsigned long rcutorture_testseq;
extern unsigned long rcutorture_vernum;
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index 0063b24b4f36..16c5ed5a627c 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -130,16 +130,6 @@ do { \
#define smp_mb__before_spinlock() smp_wmb()
#endif
-/*
- * Place this after a lock-acquisition primitive to guarantee that
- * an UNLOCK+LOCK pair act as a full barrier. This guarantee applies
- * if the UNLOCK and LOCK are executed by the same CPU or if the
- * UNLOCK and LOCK operate on the same lock variable.
- */
-#ifndef smp_mb__after_unlock_lock
-#define smp_mb__after_unlock_lock() do { } while (0)
-#endif
-
/**
* raw_spin_unlock_wait - wait until the spinlock gets unlocked
* @lock: the spinlock in question.
diff --git a/include/linux/types.h b/include/linux/types.h
index 8715287c3b1f..c314989d9158 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -212,6 +212,9 @@ struct callback_head {
};
#define rcu_head callback_head
+typedef void (*rcu_callback_t)(struct rcu_head *head);
+typedef void (*call_rcu_func_t)(struct rcu_head *head, rcu_callback_t func);
+
/* clocksource cycle base type */
typedef u64 cycle_t;
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index c78e88ce5ea3..ef72c4aada56 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -661,7 +661,6 @@ TRACE_EVENT(rcu_torture_read,
* Tracepoint for _rcu_barrier() execution. The string "s" describes
* the _rcu_barrier phase:
* "Begin": _rcu_barrier() started.
- * "Check": _rcu_barrier() checking for piggybacking.
* "EarlyExit": _rcu_barrier() piggybacked, thus early exit.
* "Inc1": _rcu_barrier() piggyback check counter incremented.
* "OfflineNoCB": _rcu_barrier() found callback on never-online CPU

Privacy Policy