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authorLinus Torvalds <torvalds@linux-foundation.org>2017-12-15 11:44:59 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-12-15 11:44:59 -0800
commit1f76a75561a006fc03559f665c835e0e69c9014d (patch)
tree013179ea7e602ee4a0666142d91e8ad45b505c10 /include
parenta58653cc1e8b329fe786d103dcd3048115b65a55 (diff)
parent92ccc262e485781ff4c0fb3b7c77a619282df49a (diff)
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar: "Misc fixes: - Fix a S390 boot hang that was caused by the lock-break logic. Remove lock-break to begin with, as review suggested it was unreasonably fragile and our confidence in its continued good health is lower than our confidence in its removal. - Remove the lockdep cross-release checking code for now, because of unresolved false positive warnings. This should make lockdep work well everywhere again. - Get rid of the final (and single) ACCESS_ONCE() straggler and remove the API from v4.15. - Fix a liblockdep build warning" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tools/lib/lockdep: Add missing declaration of 'pr_cont()' checkpatch: Remove ACCESS_ONCE() warning compiler.h: Remove ACCESS_ONCE() tools/include: Remove ACCESS_ONCE() tools/perf: Convert ACCESS_ONCE() to READ_ONCE() locking/lockdep: Remove the cross-release locking checks locking/core: Remove break_lock field when CONFIG_GENERIC_LOCKBREAK=y locking/core: Fix deadlock during boot on systems with GENERIC_LOCKBREAK
Diffstat (limited to 'include')
-rw-r--r--include/linux/compiler.h47
-rw-r--r--include/linux/completion.h45
-rw-r--r--include/linux/lockdep.h125
-rw-r--r--include/linux/rwlock_types.h3
-rw-r--r--include/linux/sched.h11
-rw-r--r--include/linux/spinlock.h5
-rw-r--r--include/linux/spinlock_types.h3
7 files changed, 11 insertions, 228 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 188ed9f65517..52e611ab9a6c 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -220,21 +220,21 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
/*
* Prevent the compiler from merging or refetching reads or writes. The
* compiler is also forbidden from reordering successive instances of
- * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
- * compiler is aware of some particular ordering. One way to make the
- * compiler aware of ordering is to put the two invocations of READ_ONCE,
- * WRITE_ONCE or ACCESS_ONCE() in different C statements.
+ * READ_ONCE and WRITE_ONCE, but only when the compiler is aware of some
+ * particular ordering. One way to make the compiler aware of ordering is to
+ * put the two invocations of READ_ONCE or WRITE_ONCE in different C
+ * statements.
*
- * In contrast to ACCESS_ONCE these two macros will also work on aggregate
- * data types like structs or unions. If the size of the accessed data
- * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
- * READ_ONCE() and WRITE_ONCE() will fall back to memcpy(). There's at
- * least two memcpy()s: one for the __builtin_memcpy() and then one for
- * the macro doing the copy of variable - '__u' allocated on the stack.
+ * These two macros will also work on aggregate data types like structs or
+ * unions. If the size of the accessed data type exceeds the word size of
+ * the machine (e.g., 32 bits or 64 bits) READ_ONCE() and WRITE_ONCE() will
+ * fall back to memcpy(). There's at least two memcpy()s: one for the
+ * __builtin_memcpy() and then one for the macro doing the copy of variable
+ * - '__u' allocated on the stack.
*
* Their two major use cases are: (1) Mediating communication between
* process-level code and irq/NMI handlers, all running on the same CPU,
- * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
+ * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
* mutilate accesses that either do not require ordering or that interact
* with an explicit memory barrier or atomic instruction that provides the
* required ordering.
@@ -327,29 +327,4 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
compiletime_assert(__native_word(t), \
"Need native word sized stores/loads for atomicity.")
-/*
- * Prevent the compiler from merging or refetching accesses. The compiler
- * is also forbidden from reordering successive instances of ACCESS_ONCE(),
- * but only when the compiler is aware of some particular ordering. One way
- * to make the compiler aware of ordering is to put the two invocations of
- * ACCESS_ONCE() in different C statements.
- *
- * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
- * on a union member will work as long as the size of the member matches the
- * size of the union and the size is smaller than word size.
- *
- * The major use cases of ACCESS_ONCE used to be (1) Mediating communication
- * between process-level code and irq/NMI handlers, all running on the same CPU,
- * and (2) Ensuring that the compiler does not fold, spindle, or otherwise
- * mutilate accesses that either do not require ordering or that interact
- * with an explicit memory barrier or atomic instruction that provides the
- * required ordering.
- *
- * If possible use READ_ONCE()/WRITE_ONCE() instead.
- */
-#define __ACCESS_ONCE(x) ({ \
- __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
- (volatile typeof(x) *)&(x); })
-#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
-
#endif /* __LINUX_COMPILER_H */
diff --git a/include/linux/completion.h b/include/linux/completion.h
index 0662a417febe..94a59ba7d422 100644
--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -10,9 +10,6 @@
*/
#include <linux/wait.h>
-#ifdef CONFIG_LOCKDEP_COMPLETIONS
-#include <linux/lockdep.h>
-#endif
/*
* struct completion - structure used to maintain state for a "completion"
@@ -29,58 +26,16 @@
struct completion {
unsigned int done;
wait_queue_head_t wait;
-#ifdef CONFIG_LOCKDEP_COMPLETIONS
- struct lockdep_map_cross map;
-#endif
};
-#ifdef CONFIG_LOCKDEP_COMPLETIONS
-static inline void complete_acquire(struct completion *x)
-{
- lock_acquire_exclusive((struct lockdep_map *)&x->map, 0, 0, NULL, _RET_IP_);
-}
-
-static inline void complete_release(struct completion *x)
-{
- lock_release((struct lockdep_map *)&x->map, 0, _RET_IP_);
-}
-
-static inline void complete_release_commit(struct completion *x)
-{
- lock_commit_crosslock((struct lockdep_map *)&x->map);
-}
-
-#define init_completion_map(x, m) \
-do { \
- lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map, \
- (m)->name, (m)->key, 0); \
- __init_completion(x); \
-} while (0)
-
-#define init_completion(x) \
-do { \
- static struct lock_class_key __key; \
- lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map, \
- "(completion)" #x, \
- &__key, 0); \
- __init_completion(x); \
-} while (0)
-#else
#define init_completion_map(x, m) __init_completion(x)
#define init_completion(x) __init_completion(x)
static inline void complete_acquire(struct completion *x) {}
static inline void complete_release(struct completion *x) {}
static inline void complete_release_commit(struct completion *x) {}
-#endif
-#ifdef CONFIG_LOCKDEP_COMPLETIONS
-#define COMPLETION_INITIALIZER(work) \
- { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait), \
- STATIC_CROSS_LOCKDEP_MAP_INIT("(completion)" #work, &(work)) }
-#else
#define COMPLETION_INITIALIZER(work) \
{ 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
-#endif
#define COMPLETION_INITIALIZER_ONSTACK_MAP(work, map) \
(*({ init_completion_map(&(work), &(map)); &(work); }))
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index a842551fe044..2e75dc34bff5 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -158,12 +158,6 @@ struct lockdep_map {
int cpu;
unsigned long ip;
#endif
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
- /*
- * Whether it's a crosslock.
- */
- int cross;
-#endif
};
static inline void lockdep_copy_map(struct lockdep_map *to,
@@ -267,96 +261,9 @@ struct held_lock {
unsigned int hardirqs_off:1;
unsigned int references:12; /* 32 bits */
unsigned int pin_count;
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
- /*
- * Generation id.
- *
- * A value of cross_gen_id will be stored when holding this,
- * which is globally increased whenever each crosslock is held.
- */
- unsigned int gen_id;
-#endif
-};
-
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
-#define MAX_XHLOCK_TRACE_ENTRIES 5
-
-/*
- * This is for keeping locks waiting for commit so that true dependencies
- * can be added at commit step.
- */
-struct hist_lock {
- /*
- * Id for each entry in the ring buffer. This is used to
- * decide whether the ring buffer was overwritten or not.
- *
- * For example,
- *
- * |<----------- hist_lock ring buffer size ------->|
- * pppppppppppppppppppppiiiiiiiiiiiiiiiiiiiiiiiiiiiii
- * wrapped > iiiiiiiiiiiiiiiiiiiiiiiiiii.......................
- *
- * where 'p' represents an acquisition in process
- * context, 'i' represents an acquisition in irq
- * context.
- *
- * In this example, the ring buffer was overwritten by
- * acquisitions in irq context, that should be detected on
- * rollback or commit.
- */
- unsigned int hist_id;
-
- /*
- * Seperate stack_trace data. This will be used at commit step.
- */
- struct stack_trace trace;
- unsigned long trace_entries[MAX_XHLOCK_TRACE_ENTRIES];
-
- /*
- * Seperate hlock instance. This will be used at commit step.
- *
- * TODO: Use a smaller data structure containing only necessary
- * data. However, we should make lockdep code able to handle the
- * smaller one first.
- */
- struct held_lock hlock;
};
/*
- * To initialize a lock as crosslock, lockdep_init_map_crosslock() should
- * be called instead of lockdep_init_map().
- */
-struct cross_lock {
- /*
- * When more than one acquisition of crosslocks are overlapped,
- * we have to perform commit for them based on cross_gen_id of
- * the first acquisition, which allows us to add more true
- * dependencies.
- *
- * Moreover, when no acquisition of a crosslock is in progress,
- * we should not perform commit because the lock might not exist
- * any more, which might cause incorrect memory access. So we
- * have to track the number of acquisitions of a crosslock.
- */
- int nr_acquire;
-
- /*
- * Seperate hlock instance. This will be used at commit step.
- *
- * TODO: Use a smaller data structure containing only necessary
- * data. However, we should make lockdep code able to handle the
- * smaller one first.
- */
- struct held_lock hlock;
-};
-
-struct lockdep_map_cross {
- struct lockdep_map map;
- struct cross_lock xlock;
-};
-#endif
-
-/*
* Initialization, self-test and debugging-output methods:
*/
extern void lockdep_info(void);
@@ -560,37 +467,6 @@ enum xhlock_context_t {
XHLOCK_CTX_NR,
};
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
-extern void lockdep_init_map_crosslock(struct lockdep_map *lock,
- const char *name,
- struct lock_class_key *key,
- int subclass);
-extern void lock_commit_crosslock(struct lockdep_map *lock);
-
-/*
- * What we essencially have to initialize is 'nr_acquire'. Other members
- * will be initialized in add_xlock().
- */
-#define STATIC_CROSS_LOCK_INIT() \
- { .nr_acquire = 0,}
-
-#define STATIC_CROSS_LOCKDEP_MAP_INIT(_name, _key) \
- { .map.name = (_name), .map.key = (void *)(_key), \
- .map.cross = 1, .xlock = STATIC_CROSS_LOCK_INIT(), }
-
-/*
- * To initialize a lockdep_map statically use this macro.
- * Note that _name must not be NULL.
- */
-#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
- { .name = (_name), .key = (void *)(_key), .cross = 0, }
-
-extern void crossrelease_hist_start(enum xhlock_context_t c);
-extern void crossrelease_hist_end(enum xhlock_context_t c);
-extern void lockdep_invariant_state(bool force);
-extern void lockdep_init_task(struct task_struct *task);
-extern void lockdep_free_task(struct task_struct *task);
-#else /* !CROSSRELEASE */
#define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)
/*
* To initialize a lockdep_map statically use this macro.
@@ -604,7 +480,6 @@ static inline void crossrelease_hist_end(enum xhlock_context_t c) {}
static inline void lockdep_invariant_state(bool force) {}
static inline void lockdep_init_task(struct task_struct *task) {}
static inline void lockdep_free_task(struct task_struct *task) {}
-#endif /* CROSSRELEASE */
#ifdef CONFIG_LOCK_STAT
diff --git a/include/linux/rwlock_types.h b/include/linux/rwlock_types.h
index cc0072e93e36..857a72ceb794 100644
--- a/include/linux/rwlock_types.h
+++ b/include/linux/rwlock_types.h
@@ -10,9 +10,6 @@
*/
typedef struct {
arch_rwlock_t raw_lock;
-#ifdef CONFIG_GENERIC_LOCKBREAK
- unsigned int break_lock;
-#endif
#ifdef CONFIG_DEBUG_SPINLOCK
unsigned int magic, owner_cpu;
void *owner;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5124ba709830..d2588263a989 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -849,17 +849,6 @@ struct task_struct {
struct held_lock held_locks[MAX_LOCK_DEPTH];
#endif
-#ifdef CONFIG_LOCKDEP_CROSSRELEASE
-#define MAX_XHLOCKS_NR 64UL
- struct hist_lock *xhlocks; /* Crossrelease history locks */
- unsigned int xhlock_idx;
- /* For restoring at history boundaries */
- unsigned int xhlock_idx_hist[XHLOCK_CTX_NR];
- unsigned int hist_id;
- /* For overwrite check at each context exit */
- unsigned int hist_id_save[XHLOCK_CTX_NR];
-#endif
-
#ifdef CONFIG_UBSAN
unsigned int in_ubsan;
#endif
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index a39186194cd6..3bf273538840 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -107,16 +107,11 @@ do { \
#define raw_spin_is_locked(lock) arch_spin_is_locked(&(lock)->raw_lock)
-#ifdef CONFIG_GENERIC_LOCKBREAK
-#define raw_spin_is_contended(lock) ((lock)->break_lock)
-#else
-
#ifdef arch_spin_is_contended
#define raw_spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock)
#else
#define raw_spin_is_contended(lock) (((void)(lock), 0))
#endif /*arch_spin_is_contended*/
-#endif
/*
* This barrier must provide two things:
diff --git a/include/linux/spinlock_types.h b/include/linux/spinlock_types.h
index 73548eb13a5d..24b4e6f2c1a2 100644
--- a/include/linux/spinlock_types.h
+++ b/include/linux/spinlock_types.h
@@ -19,9 +19,6 @@
typedef struct raw_spinlock {
arch_spinlock_t raw_lock;
-#ifdef CONFIG_GENERIC_LOCKBREAK
- unsigned int break_lock;
-#endif
#ifdef CONFIG_DEBUG_SPINLOCK
unsigned int magic, owner_cpu;
void *owner;