Re: [Qemu-devel] [Qemu-block] [PATCH 2/6] curl: Keep *socket until the end of curl_sock_cb()

[John Snow <jsnow@redhat.com>]

On 8/27/19 12:34 PM, Max Reitz wrote:
> This does not really change anything, but it makes the code a bit easier
> to follow once we use @socket as the opaque pointer for
> aio_set_fd_handler().
> 
> (Also, this change stops us from creating new CURLSocket objects when
> the cURL library just wants to stop listening on an existing socket that
> we do not recognize.  With a well-behaving cURL, that should never
> happen anyway.)
> 
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/curl.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/block/curl.c b/block/curl.c
> index 92dc2f630e..8a45b371cc 100644
> --- a/block/curl.c
> +++ b/block/curl.c
> @@ -174,18 +174,16 @@ static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
>          if (socket->fd == fd) {
>              if (action == CURL_POLL_REMOVE) {
>                  QLIST_REMOVE(socket, next);
> -                g_free(socket);
>              }
>              break;
>          }
>      }

> -    if (!socket) {
> +    if (action != CURL_POLL_REMOVE && !socket) {
>          socket = g_new0(CURLSocket, 1);
>          socket->fd = fd;
>          socket->state = state;
>          QLIST_INSERT_HEAD(&state->sockets, socket, next);
>      }
> -    socket = NULL;
>  
>      trace_curl_sock_cb(action, (int)fd);
>      switch (action) {
> @@ -207,6 +205,9 @@ static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
>              break;
>      }
>  
> +    if (action == CURL_POLL_REMOVE) {
> +        g_free(socket);
> +    }
>      return 0;
>  }
>  
> 

Very naive question: why is CURL_POLL_REMOVE handled so early in the
function? Why not handle both QLIST_REMOVE and g_free under the
switch(action) construct entirely?