[qemu-xen stable-4.13] curl: Report only ready sockets

[patchbot@xxxxxxx]

commit 18e1b71937a37bde173e3d9b2f8f97ee92fedd16
Author:     Max Reitz <mreitz@xxxxxxxxxx>
AuthorDate: Tue Sep 10 14:41:34 2019 +0200
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Wed Oct 30 11:34:26 2019 -0500

    curl: Report only ready sockets
    
    Instead of reporting all sockets to cURL, only report the one that has
    caused curl_multi_do_locked() to be called.  This lets us get rid of the
    QLIST_FOREACH_SAFE() list, which was actually wrong: SAFE foreaches are
    only safe when the current element is removed in each iteration.  If it
    possible for the list to be concurrently modified, we cannot guarantee
    that only the current element will be removed.  Therefore, we must not
    use QLIST_FOREACH_SAFE() here.
    
    Fixes: ff5ca1664af85b24a4180d595ea6873fd3deac57
    Cc: qemu-stable@xxxxxxxxxx
    Signed-off-by: Max Reitz <mreitz@xxxxxxxxxx>
    Message-id: 20190910124136.10565-6-mreitz@xxxxxxxxxx
    Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
    Reviewed-by: John Snow <jsnow@xxxxxxxxxx>
    Signed-off-by: Max Reitz <mreitz@xxxxxxxxxx>
    (cherry picked from commit 9abaf9fc474c3dd53e8e119326abc774c977c331)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 block/curl.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/block/curl.c b/block/curl.c
index cf2686218d..fd70f1ebc4 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -392,24 +392,19 @@ static void curl_multi_check_completion(BDRVCURLState *s)
 }
 
 /* Called with s->mutex held.  */
-static void curl_multi_do_locked(CURLSocket *ready_socket)
+static void curl_multi_do_locked(CURLSocket *socket)
 {
-    CURLSocket *socket, *next_socket;
-    CURLState *s = ready_socket->state;
+    BDRVCURLState *s = socket->state->s;
     int running;
     int r;
 
-    if (!s->s->multi) {
+    if (!s->multi) {
         return;
     }
 
-    /* Need to use _SAFE because curl_multi_socket_action() may trigger
-     * curl_sock_cb() which might modify this list */
-    QLIST_FOREACH_SAFE(socket, &s->sockets, next, next_socket) {
-        do {
-            r = curl_multi_socket_action(s->s->multi, socket->fd, 0, &running);
-        } while (r == CURLM_CALL_MULTI_PERFORM);
-    }
+    do {
+        r = curl_multi_socket_action(s->multi, socket->fd, 0, &running);
+    } while (r == CURLM_CALL_MULTI_PERFORM);
 }
 
 static void curl_multi_do(void *arg)
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.13