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Code Issues Releases Activity

lavfi: fix race when func rets holder is NULL

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If ret is NULL, a dummy common holder is created to hold *all* the
parallel function returns, which gets written concurrently. This commit
simplify the whole logic by simply not writing to that holder when not
set.
This commit is contained in:
Clément Bœsch
2017-03-28 18:00:02 +02:00
committed by Clément Bœsch
parent 77d2cb8874
commit 473f0f75a1
1 changed files with 6 additions and 11 deletions
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17
libavfilter/pthread.c
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@@ -43,7 +43,6 @@ typedef struct ThreadContext {
AVFilterContext *ctx; AVFilterContext *ctx;
void *arg; void *arg;
int *rets; int *rets;
int nb_rets;
int nb_jobs; int nb_jobs;
pthread_cond_t last_job_cond; pthread_cond_t last_job_cond;
@@ -60,10 +59,11 @@ static void* attribute_align_arg worker(void *v)
int our_job = c->nb_jobs; int our_job = c->nb_jobs;
int nb_threads = c->nb_threads; int nb_threads = c->nb_threads;
unsigned int last_execute = 0; unsigned int last_execute = 0;
int self_id; int ret, self_id;
pthread_mutex_lock(&c->current_job_lock); pthread_mutex_lock(&c->current_job_lock);
self_id = c->current_job++; self_id = c->current_job++;
for (;;) { for (;;) {
while (our_job >= c->nb_jobs) { while (our_job >= c->nb_jobs) {
if (c->current_job == nb_threads + c->nb_jobs) if (c->current_job == nb_threads + c->nb_jobs)
@@ -81,7 +81,9 @@ static void* attribute_align_arg worker(void *v)
} }
pthread_mutex_unlock(&c->current_job_lock); pthread_mutex_unlock(&c->current_job_lock);
c->rets[our_job % c->nb_rets] = c->func(c->ctx, c->arg, our_job, c->nb_jobs); ret = c->func(c->ctx, c->arg, our_job, c->nb_jobs);
if (c->rets)
c->rets[our_job % c->nb_jobs] = ret;
pthread_mutex_lock(&c->current_job_lock); pthread_mutex_lock(&c->current_job_lock);
our_job = c->current_job++; our_job = c->current_job++;
@@ -117,7 +119,6 @@ static int thread_execute(AVFilterContext *ctx, avfilter_action_func *func,
void *arg, int *ret, int nb_jobs) void *arg, int *ret, int nb_jobs)
{ {
ThreadContext *c = ctx->graph->internal->thread; ThreadContext *c = ctx->graph->internal->thread;
int dummy_ret;
if (nb_jobs <= 0) if (nb_jobs <= 0)
return 0; return 0;
@@ -129,13 +130,7 @@ static int thread_execute(AVFilterContext *ctx, avfilter_action_func *func,
c->ctx = ctx; c->ctx = ctx;
c->arg = arg; c->arg = arg;
c->func = func; c->func = func;
if (ret) { c->rets = ret;
c->rets = ret;
c->nb_rets = nb_jobs;
} else {
c->rets = &dummy_ret;
c->nb_rets = 1;
}
c->current_execute++; c->current_execute++;
pthread_cond_broadcast(&c->current_job_cond); pthread_cond_broadcast(&c->current_job_cond);