multi: remove PENDING + MSGSENT handles from the main linked list

As they are not driving transfers or any socket activity, the main loop
does not need to iterate over these handles. A performance improvement.

They are instead only held in their own separate lists.

'data->multi' is kept a pointer to the multi handle as long as the easy
handle is actually part of it even when the handle is moved to the
pending/msgsent lists. It needs to know which multi handle it belongs
to, if for example curl_easy_cleanup() is called before the handle is
removed from the multi handle.

Alll 'data->multi' pointers of handles still part of the multi handle
gets cleared by curl_multi_cleanup() which "orphans" all previously
attached easy handles.

This is take 2. The first version was reverted for the 8.0.1 release.

Assisted-by: Stefan Eissing
Closes #10801

1 files changed, 1 insertions, 3 deletions

diff --git a/lib/url.c b/lib/url.c
index f7b4bbbe9..c1fdd1d67 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -346,7 +346,6 @@ static void up_free(struct Curl_easy *data)
 
 CURLcode Curl_close(struct Curl_easy **datap)
 {
-  struct Curl_multi *m;
   struct Curl_easy *data;
 
   if(!datap || !*datap)
@@ -360,8 +359,7 @@ CURLcode Curl_close(struct Curl_easy **datap)
   /* Detach connection if any is left. This should not be normal, but can be
      the case for example with CONNECT_ONLY + recv/send (test 556) */
   Curl_detach_connection(data);
-  m = data->multi;
-  if(m)
+  if(data->multi)
     /* This handle is still part of a multi handle, take care of this first
        and detach this handle from there. */
     curl_multi_remove_handle(data->multi, data);