diff mbox

[FFmpeg-devel,3/3,v2] avfilter: use a mutex instead of atomics in avfilter_register()

Message ID 20180105014252.10048-1-jamrial@gmail.com
State Accepted
Commit 167e659b289f6c2236c905ee7b8c50857457c858
Headers show

Commit Message

James Almer Jan. 5, 2018, 1:42 a.m. UTC 
Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavfilter/avfilter.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

Comments

wm4 Jan. 5, 2018, 4:04 p.m. UTC | #1 
On Thu,  4 Jan 2018 22:42:52 -0300
James Almer <jamrial@gmail.com> wrote:

> Signed-off-by: James Almer <jamrial@gmail.com>
> ---
>  libavfilter/avfilter.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
> index b98b32bacb..ff7df672fd 100644
> --- a/libavfilter/avfilter.c
> +++ b/libavfilter/avfilter.c
> @@ -19,7 +19,6 @@
>   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
>   */
>  
> -#include "libavutil/atomic.h"
>  #include "libavutil/avassert.h"
>  #include "libavutil/avstring.h"
>  #include "libavutil/buffer.h"
> @@ -33,6 +32,7 @@
>  #include "libavutil/pixdesc.h"
>  #include "libavutil/rational.h"
>  #include "libavutil/samplefmt.h"
> +#include "libavutil/thread.h"
>  
>  #define FF_INTERNAL_FIELDS 1
>  #include "framequeue.h"
> @@ -590,19 +590,26 @@ const AVFilter *avfilter_get_by_name(const char *name)
>      return NULL;
>  }
>  
> +static AVMutex filter_register_mutex = AV_MUTEX_INITIALIZER;
> +
>  int avfilter_register(AVFilter *filter)
>  {
> -    AVFilter **f = last_filter;
> +    AVFilter **f;
>  
>      /* the filter must select generic or internal exclusively */
>      av_assert0((filter->flags & AVFILTER_FLAG_SUPPORT_TIMELINE) != AVFILTER_FLAG_SUPPORT_TIMELINE);
>  
> -    filter->next = NULL;
> +    ff_mutex_lock(&filter_register_mutex);
> +    f = last_filter;
>  
> -    while(*f || avpriv_atomic_ptr_cas((void * volatile *)f, NULL, filter))
> +    while (*f)
>          f = &(*f)->next;
> +    *f = filter;
> +    filter->next = NULL;
>      last_filter = &filter->next;
>  
> +    ff_mutex_unlock(&filter_register_mutex);
> +
>      return 0;
>  }
>  

Also seems good.
James Almer Jan. 5, 2018, 4:31 p.m. UTC | #2 
On 1/5/2018 1:04 PM, wm4 wrote:
> On Thu,  4 Jan 2018 22:42:52 -0300
> James Almer <jamrial@gmail.com> wrote:
> 
>> Signed-off-by: James Almer <jamrial@gmail.com>
>> ---
>>  libavfilter/avfilter.c | 15 +++++++++++----
>>  1 file changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
>> index b98b32bacb..ff7df672fd 100644
>> --- a/libavfilter/avfilter.c
>> +++ b/libavfilter/avfilter.c
>> @@ -19,7 +19,6 @@
>>   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
>>   */
>>  
>> -#include "libavutil/atomic.h"
>>  #include "libavutil/avassert.h"
>>  #include "libavutil/avstring.h"
>>  #include "libavutil/buffer.h"
>> @@ -33,6 +32,7 @@
>>  #include "libavutil/pixdesc.h"
>>  #include "libavutil/rational.h"
>>  #include "libavutil/samplefmt.h"
>> +#include "libavutil/thread.h"
>>  
>>  #define FF_INTERNAL_FIELDS 1
>>  #include "framequeue.h"
>> @@ -590,19 +590,26 @@ const AVFilter *avfilter_get_by_name(const char *name)
>>      return NULL;
>>  }
>>  
>> +static AVMutex filter_register_mutex = AV_MUTEX_INITIALIZER;
>> +
>>  int avfilter_register(AVFilter *filter)
>>  {
>> -    AVFilter **f = last_filter;
>> +    AVFilter **f;
>>  
>>      /* the filter must select generic or internal exclusively */
>>      av_assert0((filter->flags & AVFILTER_FLAG_SUPPORT_TIMELINE) != AVFILTER_FLAG_SUPPORT_TIMELINE);
>>  
>> -    filter->next = NULL;
>> +    ff_mutex_lock(&filter_register_mutex);
>> +    f = last_filter;
>>  
>> -    while(*f || avpriv_atomic_ptr_cas((void * volatile *)f, NULL, filter))
>> +    while (*f)
>>          f = &(*f)->next;
>> +    *f = filter;
>> +    filter->next = NULL;
>>      last_filter = &filter->next;
>>  
>> +    ff_mutex_unlock(&filter_register_mutex);
>> +
>>      return 0;
>>  }
>>  
> 
> Also seems good.

Pushed.
diff mbox

Patch

diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c
index b98b32bacb..ff7df672fd 100644
--- a/libavfilter/avfilter.c
+++ b/libavfilter/avfilter.c
@@ -19,7 +19,6 @@ 
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#include "libavutil/atomic.h"
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/buffer.h"
@@ -33,6 +32,7 @@ 
 #include "libavutil/pixdesc.h"
 #include "libavutil/rational.h"
 #include "libavutil/samplefmt.h"
+#include "libavutil/thread.h"
 
 #define FF_INTERNAL_FIELDS 1
 #include "framequeue.h"
@@ -590,19 +590,26 @@  const AVFilter *avfilter_get_by_name(const char *name)
     return NULL;
 }
 
+static AVMutex filter_register_mutex = AV_MUTEX_INITIALIZER;
+
 int avfilter_register(AVFilter *filter)
 {
-    AVFilter **f = last_filter;
+    AVFilter **f;
 
     /* the filter must select generic or internal exclusively */
     av_assert0((filter->flags & AVFILTER_FLAG_SUPPORT_TIMELINE) != AVFILTER_FLAG_SUPPORT_TIMELINE);
 
-    filter->next = NULL;
+    ff_mutex_lock(&filter_register_mutex);
+    f = last_filter;
 
-    while(*f || avpriv_atomic_ptr_cas((void * volatile *)f, NULL, filter))
+    while (*f)
         f = &(*f)->next;
+    *f = filter;
+    filter->next = NULL;
     last_filter = &filter->next;
 
+    ff_mutex_unlock(&filter_register_mutex);
+
     return 0;
 }