Re: [Qemu-devel] [PATCH] net: remove all cleanup methods from NIC NetClientInfos

[Stefan Hajnoczi]

On Tue, Dec 23, 2014 at 05:53:19PM +0100, Paolo Bonzini wrote:
> All NICs have a cleanup function that, in most cases, zeroes the pointer
> to the NICState.  In some cases, it frees data belonging to the NIC.
> 
> However, this function is never called except when exiting from QEMU.
> It is not necessary to NULL pointers and free data here; the right place
> to do that would be in the device's unrealize function, after calling
> qemu_del_nic.  Zeroing the NIC multiple times is also wrong for multiqueue
> devices.
> 
> This cleanup function gets in the way of making the NetClientStates for
> the NIC hold an object_ref reference to the object, so get rid of it.

This patch does not drop NetClientInfo->cleanup() and clean up net.c.
Do you have plans for a follow-up patch?

> diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c
> index 7eab7ad..7ce13d2 100644
> --- a/hw/net/dp8393x.c
> +++ b/hw/net/dp8393x.c
> @@ -859,22 +859,11 @@ static void nic_reset(void *opaque)
>      dp8393x_update_irq(s);
>  }
>  
> -static void nic_cleanup(NetClientState *nc)
> -{
> -    dp8393xState *s = qemu_get_nic_opaque(nc);
> -
> -    timer_del(s->watchdog);
> -    timer_free(s->watchdog);
> -
> -    g_free(s);
> -}

How about moving code that frees resources to unrealize?

There are a couple of instances in this patch where we drop g_free() and
it's a shame to lose the resource management life cycle completely.

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