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authorLinus Torvalds <torvalds@linux-foundation.org>2014-01-16 08:31:55 +0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-16 08:31:55 +0700
commit9b6c4ea95ff87464e012f70b119601de9e94deac (patch)
tree5dc1d4c9ea990bdf01a9f3c42965f9bc5bf0d47d
parent93a11c8f5cc642571071a1609a83998db1373077 (diff)
parent7a06c41cbec33c6dbe7eec575c61986122617408 (diff)
downloadlinux-9b6c4ea95ff87464e012f70b119601de9e94deac.tar.gz
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar: "Two fixes from lockdep coverage of seqlocks, which fix deadlocks on lockdep-enabled ARM systems" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched_clock: Disable seqlock lockdep usage in sched_clock() seqlock: Use raw_ prefix instead of _no_lockdep
-rw-r--r--arch/x86/vdso/vclock_gettime.c8
-rw-r--r--include/linux/seqlock.h27
-rw-r--r--kernel/time/sched_clock.c6
3 files changed, 26 insertions, 15 deletions
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 2ada505067c..eb5d7a56f8d 100644
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -178,7 +178,7 @@ notrace static int __always_inline do_realtime(struct timespec *ts)
ts->tv_nsec = 0;
do {
- seq = read_seqcount_begin_no_lockdep(&gtod->seq);
+ seq = raw_read_seqcount_begin(&gtod->seq);
mode = gtod->clock.vclock_mode;
ts->tv_sec = gtod->wall_time_sec;
ns = gtod->wall_time_snsec;
@@ -198,7 +198,7 @@ notrace static int do_monotonic(struct timespec *ts)
ts->tv_nsec = 0;
do {
- seq = read_seqcount_begin_no_lockdep(&gtod->seq);
+ seq = raw_read_seqcount_begin(&gtod->seq);
mode = gtod->clock.vclock_mode;
ts->tv_sec = gtod->monotonic_time_sec;
ns = gtod->monotonic_time_snsec;
@@ -214,7 +214,7 @@ notrace static int do_realtime_coarse(struct timespec *ts)
{
unsigned long seq;
do {
- seq = read_seqcount_begin_no_lockdep(&gtod->seq);
+ seq = raw_read_seqcount_begin(&gtod->seq);
ts->tv_sec = gtod->wall_time_coarse.tv_sec;
ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
@@ -225,7 +225,7 @@ notrace static int do_monotonic_coarse(struct timespec *ts)
{
unsigned long seq;
do {
- seq = read_seqcount_begin_no_lockdep(&gtod->seq);
+ seq = raw_read_seqcount_begin(&gtod->seq);
ts->tv_sec = gtod->monotonic_time_coarse.tv_sec;
ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec;
} while (unlikely(read_seqcount_retry(&gtod->seq, seq)));
diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index cf87a24c0f9..535f158977b 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -117,15 +117,15 @@ repeat:
}
/**
- * read_seqcount_begin_no_lockdep - start seq-read critical section w/o lockdep
+ * raw_read_seqcount_begin - start seq-read critical section w/o lockdep
* @s: pointer to seqcount_t
* Returns: count to be passed to read_seqcount_retry
*
- * read_seqcount_begin_no_lockdep opens a read critical section of the given
+ * raw_read_seqcount_begin opens a read critical section of the given
* seqcount, but without any lockdep checking. Validity of the critical
* section is tested by checking read_seqcount_retry function.
*/
-static inline unsigned read_seqcount_begin_no_lockdep(const seqcount_t *s)
+static inline unsigned raw_read_seqcount_begin(const seqcount_t *s)
{
unsigned ret = __read_seqcount_begin(s);
smp_rmb();
@@ -144,7 +144,7 @@ static inline unsigned read_seqcount_begin_no_lockdep(const seqcount_t *s)
static inline unsigned read_seqcount_begin(const seqcount_t *s)
{
seqcount_lockdep_reader_access(s);
- return read_seqcount_begin_no_lockdep(s);
+ return raw_read_seqcount_begin(s);
}
/**
@@ -206,14 +206,26 @@ static inline int read_seqcount_retry(const seqcount_t *s, unsigned start)
}
+
+static inline void raw_write_seqcount_begin(seqcount_t *s)
+{
+ s->sequence++;
+ smp_wmb();
+}
+
+static inline void raw_write_seqcount_end(seqcount_t *s)
+{
+ smp_wmb();
+ s->sequence++;
+}
+
/*
* Sequence counter only version assumes that callers are using their
* own mutexing.
*/
static inline void write_seqcount_begin_nested(seqcount_t *s, int subclass)
{
- s->sequence++;
- smp_wmb();
+ raw_write_seqcount_begin(s);
seqcount_acquire(&s->dep_map, subclass, 0, _RET_IP_);
}
@@ -225,8 +237,7 @@ static inline void write_seqcount_begin(seqcount_t *s)
static inline void write_seqcount_end(seqcount_t *s)
{
seqcount_release(&s->dep_map, 1, _RET_IP_);
- smp_wmb();
- s->sequence++;
+ raw_write_seqcount_end(s);
}
/**
diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index 68b79937598..0abb3646428 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -74,7 +74,7 @@ unsigned long long notrace sched_clock(void)
return cd.epoch_ns;
do {
- seq = read_seqcount_begin(&cd.seq);
+ seq = raw_read_seqcount_begin(&cd.seq);
epoch_cyc = cd.epoch_cyc;
epoch_ns = cd.epoch_ns;
} while (read_seqcount_retry(&cd.seq, seq));
@@ -99,10 +99,10 @@ static void notrace update_sched_clock(void)
cd.mult, cd.shift);
raw_local_irq_save(flags);
- write_seqcount_begin(&cd.seq);
+ raw_write_seqcount_begin(&cd.seq);
cd.epoch_ns = ns;
cd.epoch_cyc = cyc;
- write_seqcount_end(&cd.seq);
+ raw_write_seqcount_end(&cd.seq);
raw_local_irq_restore(flags);
}