Commit 195ed8cb authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

qemu/queue.h: add QLIST_SAFE_REMOVE() 



QLIST_REMOVE() assumes the element is in a list.  It also leaves the
element's linked list pointers dangling.

Introduce a safe version of QLIST_REMOVE() and convert open-coded
instances of this pattern.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarSergio Lopez <slp@redhat.com>
Message-id: 20200214171712.541358-4-stefanha@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent ca8c6b22

block.c

+1 −4
Original line number Diff line number Diff line
@@ -2636,10 +2636,7 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, 


static void bdrv_detach_child(BdrvChild *child)

{

    if (child->next.le_prev) {

        QLIST_REMOVE(child, next);

        child->next.le_prev = NULL;

    }

    QLIST_SAFE_REMOVE(child, next);



    bdrv_replace_child(child, NULL);

chardev/spice.c

+1 −3
Original line number Diff line number Diff line
@@ -216,9 +216,7 @@ static void char_spice_finalize(Object *obj) 


    vmc_unregister_interface(s);



    if (s->next.le_prev) {

        QLIST_REMOVE(s, next);

    }

    QLIST_SAFE_REMOVE(s, next);



    g_free((char *)s->sin.subtype);

    g_free((char *)s->sin.portname);

include/qemu/queue.h

+14 −0
Original line number Diff line number Diff line
@@ -144,6 +144,20 @@ struct { \ 
        *(elm)->field.le_prev = (elm)->field.le_next;                   \

} while (/*CONSTCOND*/0)



/*

 * Like QLIST_REMOVE() but safe to call when elm is not in a list

 */

#define QLIST_SAFE_REMOVE(elm, field) do {                              \

        if ((elm)->field.le_prev != NULL) {                             \

                if ((elm)->field.le_next != NULL)                       \

                        (elm)->field.le_next->field.le_prev =           \

                            (elm)->field.le_prev;                       \

                *(elm)->field.le_prev = (elm)->field.le_next;           \

                (elm)->field.le_next = NULL;                            \

                (elm)->field.le_prev = NULL;                            \

        }                                                               \

} while (/*CONSTCOND*/0)



#define QLIST_FOREACH(var, head, field)                                 \

        for ((var) = ((head)->lh_first);                                \

                (var);                                                  \