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Re: [Qemu-devel] [v5, 17/31] vhost-user: keep vhost_net after a disconne
From: |
Ilya Maximets |
Subject: |
Re: [Qemu-devel] [v5, 17/31] vhost-user: keep vhost_net after a disconnection |
Date: |
Mon, 25 Jul 2016 15:48:30 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 |
On 21.07.2016 11:57, Marc-André Lureau wrote:
> From: Marc-André Lureau <address@hidden>
>
> Many code paths assume get_vhost_net() returns non-null.
>
> Keep VhostUserState.vhost_net after a successful vhost_net_init(),
> instead of freeing it in vhost_net_cleanup().
>
> VhostUserState.vhost_net is thus freed before after being recreated or
> on final vhost_user_cleanup() and there is no need to save the acked
> features.
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
> hw/net/vhost_net.c | 1 -
> net/tap.c | 1 +
> net/vhost-user.c | 36 ++++++++++++++++--------------------
> 3 files changed, 17 insertions(+), 21 deletions(-)
>
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index c11f69c..7b76591 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -378,7 +378,6 @@ void vhost_net_stop(VirtIODevice *dev, NetClientState
> *ncs,
> void vhost_net_cleanup(struct vhost_net *net)
> {
> vhost_dev_cleanup(&net->dev);
> - g_free(net);
> }
>
> int vhost_net_notify_migration_done(struct vhost_net *net, char* mac_addr)
> diff --git a/net/tap.c b/net/tap.c
> index 40a8c74..6abb962 100644
> --- a/net/tap.c
> +++ b/net/tap.c
> @@ -312,6 +312,7 @@ static void tap_cleanup(NetClientState *nc)
>
> if (s->vhost_net) {
> vhost_net_cleanup(s->vhost_net);
> + g_free(s->vhost_net);
> s->vhost_net = NULL;
> }
>
> diff --git a/net/vhost-user.c b/net/vhost-user.c
> index 2af212b..60fab9a 100644
> --- a/net/vhost-user.c
> +++ b/net/vhost-user.c
> @@ -23,7 +23,6 @@ typedef struct VhostUserState {
> CharDriverState *chr;
> VHostNetState *vhost_net;
> guint watch;
> - uint64_t acked_features;
> } VhostUserState;
>
> typedef struct VhostUserChardevProps {
> @@ -42,12 +41,7 @@ uint64_t vhost_user_get_acked_features(NetClientState *nc)
> {
> VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
> assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
> - return s->acked_features;
> -}
> -
> -static int vhost_user_running(VhostUserState *s)
> -{
> - return (s->vhost_net) ? 1 : 0;
> + return s->vhost_net ? vhost_net_get_acked_features(s->vhost_net) : 0;
> }
>
> static void vhost_user_stop(int queues, NetClientState *ncs[])
> @@ -59,15 +53,9 @@ static void vhost_user_stop(int queues, NetClientState
> *ncs[])
> assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
>
> s = DO_UPCAST(VhostUserState, nc, ncs[i]);
> - if (!vhost_user_running(s)) {
> - continue;
> - }
>
> if (s->vhost_net) {
> - /* save acked features */
> - s->acked_features = vhost_net_get_acked_features(s->vhost_net);
> vhost_net_cleanup(s->vhost_net);
> - s->vhost_net = NULL;
> }
> }
> }
> @@ -75,6 +63,7 @@ static void vhost_user_stop(int queues, NetClientState
> *ncs[])
> static int vhost_user_start(int queues, NetClientState *ncs[])
> {
> VhostNetOptions options;
> + struct vhost_net *net = NULL;
> VhostUserState *s;
> int max_queues;
> int i;
> @@ -85,33 +74,39 @@ static int vhost_user_start(int queues, NetClientState
> *ncs[])
> assert(ncs[i]->info->type == NET_CLIENT_DRIVER_VHOST_USER);
>
> s = DO_UPCAST(VhostUserState, nc, ncs[i]);
> - if (vhost_user_running(s)) {
> - continue;
> - }
>
> options.net_backend = ncs[i];
> options.opaque = s->chr;
> options.busyloop_timeout = 0;
> - s->vhost_net = vhost_net_init(&options);
> - if (!s->vhost_net) {
> + net = vhost_net_init(&options);
> + if (!net) {
> error_report("failed to init vhost_net for queue %d", i);
> goto err;
> }
>
> if (i == 0) {
> - max_queues = vhost_net_get_max_queues(s->vhost_net);
> + max_queues = vhost_net_get_max_queues(net);
> if (queues > max_queues) {
> error_report("you are asking more queues than supported: %d",
> max_queues);
> goto err;
> }
> }
> +
> + if (s->vhost_net) {
> + vhost_net_cleanup(s->vhost_net);
> + g_free(s->vhost_net);
> + }
> + s->vhost_net = net;
> }
>
> return 0;
>
> err:
> - vhost_user_stop(i + 1, ncs);
> + if (net) {
> + vhost_net_cleanup(net);
> + }
> + vhost_user_stop(i, ncs);
> return -1;
> }
>
> @@ -150,6 +145,7 @@ static void vhost_user_cleanup(NetClientState *nc)
>
> if (s->vhost_net) {
> vhost_net_cleanup(s->vhost_net);
> + g_free(s->vhost_net);
> s->vhost_net = NULL;
> }
> if (s->chr) {
>
In patch number 7 of this patch set was introduced 'memset()' inside
'vhost_dev_cleanup()' which clears 'acked_features' field of 'vhost_dev'
structure. This patch uses already zeroed value of this field for
features restore after reconnection.
You should not remove 'acked_features' from 'struct VhostUserState' or
avoid cleaning of this field in 'vhost_dev'.
I'm suggesting following fixup (mainly, just a partial revert):
----------------------------------------------------------------------
diff --git a/net/vhost-user.c b/net/vhost-user.c
index 60fab9a..3100a5e 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -23,6 +23,7 @@ typedef struct VhostUserState {
CharDriverState *chr;
VHostNetState *vhost_net;
guint watch;
+ uint64_t acked_features;
} VhostUserState;
typedef struct VhostUserChardevProps {
@@ -41,7 +42,7 @@ uint64_t vhost_user_get_acked_features(NetClientState *nc)
{
VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_USER);
- return s->vhost_net ? vhost_net_get_acked_features(s->vhost_net) : 0;
+ return s->acked_features;
}
static void vhost_user_stop(int queues, NetClientState *ncs[])
@@ -55,6 +56,11 @@ static void vhost_user_stop(int queues, NetClientState
*ncs[])
s = DO_UPCAST(VhostUserState, nc, ncs[i]);
if (s->vhost_net) {
+ /* save acked features */
+ uint64_t features = vhost_net_get_acked_features(s->vhost_net);
+ if (features) {
+ s->acked_features = features;
+ }
vhost_net_cleanup(s->vhost_net);
}
}
----------------------------------------------------------------------
Best regards, Ilya Maximets.
- Re: [Qemu-devel] [v5, 09/31] vhost: fix calling vhost_dev_cleanup() after vhost_dev_init(), (continued)
[Qemu-devel] [PATCH v5 10/31] vhost: do not assert() on vhost_ops failure, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 11/31] vhost: add missing VHOST_OPS_DEBUG, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 12/31] vhost: use error_report() instead of fprintf(stderr, ...), marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 13/31] qemu-char: fix qemu_chr_fe_set_msgfds() crash when disconnected, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 15/31] vhost-user: check qemu_chr_fe_set_msgfds() return value, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 14/31] vhost-user: call set_msgfds unconditionally, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 16/31] vhost-user: check vhost_user_{read, write}() return value, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 17/31] vhost-user: keep vhost_net after a disconnection, marcandre . lureau, 2016/07/21
- Re: [Qemu-devel] [v5, 17/31] vhost-user: keep vhost_net after a disconnection,
Ilya Maximets <=
[Qemu-devel] [PATCH v5 18/31] vhost-user: add get_vhost_net() assertions, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 19/31] Revert "vhost-net: do not crash if backend is not present", marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 20/31] vhost-net: vhost_migration_done is vhost-user specific, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 21/31] vhost: add assert() to check runtime behaviour, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 22/31] char: add chr_wait_connected callback, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 23/31] char: add and use tcp_chr_wait_connected, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 24/31] vhost-user: wait until backend init is completed, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 25/31] tests: plug some leaks in virtio-net-test, marcandre . lureau, 2016/07/21
[Qemu-devel] [PATCH v5 26/31] tests: fix vhost-user-test leak, marcandre . lureau, 2016/07/21