Re: [Qemu-block] [PATCH 3/6] curl: Pass CURLSocket to curl_multi_{do, read}()

[Max Reitz]

On 09.09.19 22:10, John Snow wrote:
> 
> 
> On 8/27/19 12:34 PM, Max Reitz wrote:
>> curl_multi_do_locked() currently marks all sockets as ready.  That is
>> not only inefficient, but in fact unsafe (the loop is).  A follow-up
>> patch will change that, but to do so, curl_multi_do_locked() needs to
>> know exactly which socket is ready; and that is accomplished by this
>> patch here.
>>
>> Cc: address@hidden
>> Signed-off-by: Max Reitz <address@hidden>
>> ---
>>  block/curl.c | 29 ++++++++++++++++-------------
>>  1 file changed, 16 insertions(+), 13 deletions(-)
>>
>> diff --git a/block/curl.c b/block/curl.c
>> index 8a45b371cc..05f77a38c2 100644
>> --- a/block/curl.c
>> +++ b/block/curl.c
>> @@ -189,15 +189,15 @@ static int curl_sock_cb(CURL *curl, curl_socket_t fd, 
>> int action,
>>      switch (action) {
>>          case CURL_POLL_IN:
>>              aio_set_fd_handler(s->aio_context, fd, false,
>> -                               curl_multi_read, NULL, NULL, state);
>> +                               curl_multi_read, NULL, NULL, socket);
>>              break;
>>          case CURL_POLL_OUT:
>>              aio_set_fd_handler(s->aio_context, fd, false,
>> -                               NULL, curl_multi_do, NULL, state);
>> +                               NULL, curl_multi_do, NULL, socket);
>>              break;
>>          case CURL_POLL_INOUT:
>>              aio_set_fd_handler(s->aio_context, fd, false,
>> -                               curl_multi_read, curl_multi_do, NULL, state);
>> +                               curl_multi_read, curl_multi_do, NULL, 
>> socket);
>>              break;
>>          case CURL_POLL_REMOVE:
>>              aio_set_fd_handler(s->aio_context, fd, false,
>> @@ -394,9 +394,10 @@ static void curl_multi_check_completion(BDRVCURLState 
>> *s)
>>  }
>>  
>>  /* Called with s->mutex held.  */
>> -static void curl_multi_do_locked(CURLState *s)
>> +static void curl_multi_do_locked(CURLSocket *ready_socket)
>>  {
>>      CURLSocket *socket, *next_socket;
>> +    CURLState *s = socket->state;
> 
> Did you mean to use ready_socket here instead?

Oops...  Yes, I suppose so.

(An artifact from pulling apart one large patch, sorry.)

Max

>>      int running;
>>      int r;
>>  
>> @@ -415,21 +416,23 @@ static void curl_multi_do_locked(CURLState *s)
>>  
>>  static void curl_multi_do(void *arg)
>>  {
>> -    CURLState *s = (CURLState *)arg;
>> +    CURLSocket *socket = arg;
>> +    BDRVCURLState *s = socket->state->s;
>>  
>> -    qemu_mutex_lock(&s->s->mutex);
>> -    curl_multi_do_locked(s);
>> -    qemu_mutex_unlock(&s->s->mutex);
>> +    qemu_mutex_lock(&s->mutex);
>> +    curl_multi_do_locked(socket);
>> +    qemu_mutex_unlock(&s->mutex);
>>  }
>>  
>>  static void curl_multi_read(void *arg)
>>  {
>> -    CURLState *s = (CURLState *)arg;
>> +    CURLSocket *socket = arg;
>> +    BDRVCURLState *s = socket->state->s;
>>  
>> -    qemu_mutex_lock(&s->s->mutex);
>> -    curl_multi_do_locked(s);
>> -    curl_multi_check_completion(s->s);
>> -    qemu_mutex_unlock(&s->s->mutex);
> 
> bye bye &s->s->mutex ! you're very nasty !!
> 
>> +    qemu_mutex_lock(&s->mutex);
>> +    curl_multi_do_locked(socket);
>> +    curl_multi_check_completion(s);
>> +    qemu_mutex_unlock(&s->mutex);
>>  }
>>  
>>  static void curl_multi_timeout_do(void *arg)
>>

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