[PATCH]netfront: need release all resources after adding and removing NICs time and again

[liuyingdong]

Hello Roger,
	Sorry, I am a freshman. I ran the following command to git kernel source of freebsd 10.2.0:
		git clone https://github.com/freebsd/freebsd.git
		git checkout origin/release/10.2.0
	On the base of the above, I make a patch file as fellows:

diff --git a/sys/dev/xen/netfront/netfront.c b/sys/dev/xen/netfront/netfront.c
index d89c0e0..903eb98 100644
--- a/sys/dev/xen/netfront/netfront.c
+++ b/sys/dev/xen/netfront/netfront.c
@@ -2172,6 +2172,46 @@ netfront_detach(device_t dev)
 }

 static void
+netif_release_rx_bufs_copy(struct netfront_info *np)
+{
+	struct mbuf *m;
+	int i, ref;
+	int busy = 0, inuse = 0;
+
+	XN_RX_LOCK(np);
+
+	for (i = 0; i < NET_RX_RING_SIZE; i++) {
+		ref = np->grant_rx_ref[i];
+
+		if (ref == GRANT_REF_INVALID)
+			continue;
+
+		inuse++;
+
+		m = np->rx_mbufs[i];
+
+		if (!gnttab_end_foreign_access_ref(ref))
+		{
+			busy++;
+			continue;
+		}
+
+		gnttab_release_grant_reference(&np->gref_rx_head, ref);
+		np->grant_rx_ref[i] = GRANT_REF_INVALID;
+		add_id_to_freelist(np->rx_mbufs, i);
+
+		m_freem(m);
+	}
+
+	if (busy)
+		device_printf(np->xbdev, "Unable to release %d of %d "
+			"inuse grant references out of %ld total.\n",
+			busy, inuse, NET_RX_RING_SIZE);
+	
+	XN_RX_UNLOCK(np);
+}
+
+static void
 netif_free(struct netfront_info *info)
 {
 	XN_LOCK(info);
@@ -2185,6 +2225,13 @@ netif_free(struct netfront_info *info)
 		info->xn_ifp = NULL;
 	}
 	ifmedia_removeall(&info->sc_media);
+	
+	netif_release_tx_bufs(info);
+	if (info->copying_receiver)
+		netif_release_rx_bufs_copy(info);
+
+	gnttab_free_grant_references(info->gref_tx_head);
+	gnttab_free_grant_references(info->gref_rx_head);
 }

 static void


Yours Yingdong Liu


-----邮件原件-----
发件人: roger.pau at citrix.com [mailto:roger.pau at citrix.com]
发送时间: 2016年11月8日 21:05
收件人: Liuyingdong
抄送: freebsd-xen at freebsd.org; Zhaojun (Euler); Suoben
主题: Re: [PATCH]netfront: need release all resources after adding and removing NICs time and again

On Fri, Nov 04, 2016 at 07:43:41AM +0000, Liuyingdong wrote:
> On xen,freebsd 10.2 virtual machines hang after adding and removing NICs time and again(more than 30 times).
> I found error log is as follows:
> "netfront can't alloc tx grant refs"

Hello,

Thanks for the patch, although I'm not able to import it, git complain with:

patch: **** malformed patch at line 7: }

Could you please resend it using git send-email?

I also have a couple of comments below regarding style.

>
> Signed-off-by: Yingdong Liu<liuyingdong at huawei.com>
>
> diff --git a/dev/xen/netfront/netfront.c b/dev/xen/netfront/netfront.c
> index 5497139..e96bbba 100644
> --- a/dev/xen/netfront/netfront.c
> +++ b/dev/xen/netfront/netfront.c
> @@ -790,6 +790,44 @@ netif_release_tx_bufs(struct netfront_info *np)
>        }
> }

Missing new line.

> +static void
netif_release_rx_bufs_copy(struct netfront_info *np)

This needs to be on a new line.

> +{
> +       struct mbuf *m;
> +       int i, ref;
> +       int busy = 0, inuse = 0;
> +
> +       XN_RX_LOCK(np);
> +
> +       for (i = 0; i < NET_RX_RING_SIZE; i++) {
> +                ref = np->grant_rx_ref[i];
> +
> +                if (ref == GRANT_REF_INVALID)
> +                          continue;
> +
> +                inuse++;
> +
> +                m = np->rx_mbufs[i];
> +
> +                if (!gnttab_end_foreign_access_ref(ref))
> +                {
> +                          busy++;
> +                          continue;
> +                }
> +
> +                gnttab_release_grant_reference(&np->gref_rx_head, ref);
> +                np->grant_rx_ref[i] = GRANT_REF_INVALID;
> +                add_id_to_freelist(np->rx_mbufs, i);
> +
> +                m_freem(m);
> +       }
> +
> +       if (busy)
> +                DPRINTK("%s: Unable to release %d of %d inuse grant references out of %ld total.\n",
> +                          __FUNCTION__, busy, inuse,
> + NET_RX_RING_SIZE);

Please use device_printf for this instead of the function name. Also, could you align the string so it doesn't extend past 80 characters?

Roger.