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| author | John Stultz <john.stultz@linaro.org> | 2013-10-07 15:51:59 -0700 |
|---|---|---|
| committer | Chanho Park <chanho61.park@samsung.com> | 2014-11-21 19:12:26 +0900 |
| commit | 66d2009169bb981072c32c618aca2b203d6bf897 (patch) | |
| tree | 0d180c395bdba6c5d19e1d025e2d015e15cd0442 /arch | |
| parent | 384b43ecf124f8f0959e92252b0a0c1b4996fe0c (diff) | |
| download | linux-3.10-66d2009169bb981072c32c618aca2b203d6bf897.tar.gz linux-3.10-66d2009169bb981072c32c618aca2b203d6bf897.tar.bz2 linux-3.10-66d2009169bb981072c32c618aca2b203d6bf897.zip | |
seqcount: Add lockdep functionality to seqcount/seqlock structures
Currently seqlocks and seqcounts don't support lockdep.
After running across a seqcount related deadlock in the timekeeping
code, I used a less-refined and more focused variant of this patch
to narrow down the cause of the issue.
This is a first-pass attempt to properly enable lockdep functionality
on seqlocks and seqcounts.
Since seqcounts are used in the vdso gettimeofday code, I've provided
non-lockdep accessors for those needs.
I've also handled one case where there were nested seqlock writers
and there may be more edge cases.
Comments and feedback would be appreciated!
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/1381186321-4906-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/vdso/vclock_gettime.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c index c74436e687b..fe8a77a32c2 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(>od->seq); + seq = read_seqcount_begin_no_lockdep(>od->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(>od->seq); + seq = read_seqcount_begin_no_lockdep(>od->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(>od->seq); + seq = read_seqcount_begin_no_lockdep(>od->seq); ts->tv_sec = gtod->wall_time_coarse.tv_sec; ts->tv_nsec = gtod->wall_time_coarse.tv_nsec; } while (unlikely(read_seqcount_retry(>od->seq, seq))); @@ -225,7 +225,7 @@ notrace static int do_monotonic_coarse(struct timespec *ts) { unsigned long seq; do { - seq = read_seqcount_begin(>od->seq); + seq = read_seqcount_begin_no_lockdep(>od->seq); ts->tv_sec = gtod->monotonic_time_coarse.tv_sec; ts->tv_nsec = gtod->monotonic_time_coarse.tv_nsec; } while (unlikely(read_seqcount_retry(>od->seq, seq))); |