diff options
author | Alex Shi <alex.shi@linaro.org> | 2018-02-28 12:01:09 +0800 |
---|---|---|
committer | Alex Shi <alex.shi@linaro.org> | 2018-02-28 12:01:09 +0800 |
commit | 6e49b7fa3083c30688b7fff1b37ed891cd1c30af (patch) | |
tree | 3054864f2e58bcd86000567ce99e25753ddc794a /kernel/trace/blktrace.c | |
parent | 2ba51c6d36ee1b43c1f898c6c48ddf3d33e9ab30 (diff) | |
parent | be42cd02846a611af533103a3f4b6a7d8c592f49 (diff) |
Merge remote-tracking branch 'rt-stable/v4.9-rt' into linux-linaro-lsk-v4.9-rtlsk-v4.9-18.03-rt
Diffstat (limited to 'kernel/trace/blktrace.c')
-rw-r--r-- | kernel/trace/blktrace.c | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index dbafc5df03f3..4e17d55ba127 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -57,7 +57,8 @@ static struct tracer_flags blk_tracer_flags = { }; /* Global reference count of probes */ -static atomic_t blk_probes_ref = ATOMIC_INIT(0); +static DEFINE_MUTEX(blk_probe_mutex); +static int blk_probes_ref; static void blk_register_tracepoints(void); static void blk_unregister_tracepoints(void); @@ -306,11 +307,26 @@ static void blk_trace_free(struct blk_trace *bt) kfree(bt); } +static void get_probe_ref(void) +{ + mutex_lock(&blk_probe_mutex); + if (++blk_probes_ref == 1) + blk_register_tracepoints(); + mutex_unlock(&blk_probe_mutex); +} + +static void put_probe_ref(void) +{ + mutex_lock(&blk_probe_mutex); + if (!--blk_probes_ref) + blk_unregister_tracepoints(); + mutex_unlock(&blk_probe_mutex); +} + static void blk_trace_cleanup(struct blk_trace *bt) { blk_trace_free(bt); - if (atomic_dec_and_test(&blk_probes_ref)) - blk_unregister_tracepoints(); + put_probe_ref(); } int blk_trace_remove(struct request_queue *q) @@ -522,8 +538,7 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, if (cmpxchg(&q->blk_trace, NULL, bt)) goto err; - if (atomic_inc_return(&blk_probes_ref) == 1) - blk_register_tracepoints(); + get_probe_ref(); return 0; err: @@ -1469,9 +1484,7 @@ static int blk_trace_remove_queue(struct request_queue *q) if (bt == NULL) return -EINVAL; - if (atomic_dec_and_test(&blk_probes_ref)) - blk_unregister_tracepoints(); - + put_probe_ref(); blk_trace_free(bt); return 0; } @@ -1502,8 +1515,7 @@ static int blk_trace_setup_queue(struct request_queue *q, if (cmpxchg(&q->blk_trace, NULL, bt)) goto free_bt; - if (atomic_inc_return(&blk_probes_ref) == 1) - blk_register_tracepoints(); + get_probe_ref(); return 0; free_bt: |