netvsc: handle select_queue when device is being removed

Move the send indirection table from the inner device (netvsc)
to the network device context.

It is possible that netvsc_device is not present (remove in progress).
This solves potential use after free issues when packet is being
created during MTU change, shutdown, or queue count changes.

Fixes: d8e18ee0fa96 ("netvsc: enhance transmit select_queue")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index d3e73ac..f9f3dba 100644 (file)
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -700,6 +700,8 @@ struct net_device_context {
 
        u32 tx_checksum_mask;
 
+       u32 tx_send_table[VRSS_SEND_TAB_SIZE];
+
        /* Ethtool settings */
        u8 duplex;
        u32 speed;
@@ -757,7 +759,6 @@ struct netvsc_device {
 
        struct nvsp_message revoke_packet;
 
-       u32 send_table[VRSS_SEND_TAB_SIZE];
        u32 max_chn;
        u32 num_chn;
        spinlock_t sc_lock; /* Protects num_sc_offered variable */

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index d35ebd9..4c1d8cc 100644 (file)
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -1136,15 +1136,11 @@ static void netvsc_receive(struct net_device *ndev,
 static void netvsc_send_table(struct hv_device *hdev,
                              struct nvsp_message *nvmsg)
 {
-       struct netvsc_device *nvscdev;
        struct net_device *ndev = hv_get_drvdata(hdev);
+       struct net_device_context *net_device_ctx = netdev_priv(ndev);
        int i;
        u32 count, *tab;
 
-       nvscdev = get_outbound_net_device(hdev);
-       if (!nvscdev)
-               return;
-
        count = nvmsg->msg.v5_msg.send_table.count;
        if (count != VRSS_SEND_TAB_SIZE) {
                netdev_err(ndev, "Received wrong send-table size:%u\n", count);
@@ -1155,7 +1151,7 @@ static void netvsc_send_table(struct hv_device *hdev,
                      nvmsg->msg.v5_msg.send_table.offset);
 
        for (i = 0; i < count; i++)
-               nvscdev->send_table[i] = tab[i];
+               net_device_ctx->tx_send_table[i] = tab[i];
 }
 
 static void netvsc_send_vf(struct net_device_context *net_device_ctx,

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index bc05c89..5ede87f 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -206,17 +206,15 @@ static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
                        void *accel_priv, select_queue_fallback_t fallback)
 {
        struct net_device_context *net_device_ctx = netdev_priv(ndev);
-       struct netvsc_device *nvsc_dev = net_device_ctx->nvdev;
+       unsigned int num_tx_queues = ndev->real_num_tx_queues;
        struct sock *sk = skb->sk;
        int q_idx = sk_tx_queue_get(sk);
 
-       if (q_idx < 0 || skb->ooo_okay ||
-           q_idx >= ndev->real_num_tx_queues) {
+       if (q_idx < 0 || skb->ooo_okay || q_idx >= num_tx_queues) {
                u16 hash = __skb_tx_hash(ndev, skb, VRSS_SEND_TAB_SIZE);
                int new_idx;
 
-               new_idx = nvsc_dev->send_table[hash]
-                       % nvsc_dev->num_chn;
+               new_idx = net_device_ctx->tx_send_table[hash] % num_tx_queues;
 
                if (q_idx != new_idx && sk &&
                    sk_fullsock(sk) && rcu_access_pointer(sk->sk_dst_cache))
@@ -225,9 +223,6 @@ static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
                q_idx = new_idx;
        }
 
-       if (unlikely(!nvsc_dev->chan_table[q_idx].channel))
-               q_idx = 0;
-
        return q_idx;
 }