net: add IFF_SKB_TX_SHARED flag to priv_flags

Pktgen attempts to transmit shared skbs to net devices, which can't be used by
some drivers as they keep state information in skbs.  This patch adds a flag
marking drivers as being able to handle shared skbs in their tx path.  Drivers
are defaulted to being unable to do so, but calling ether_setup enables this
flag, as 90% of the drivers calling ether_setup touch real hardware and can
handle shared skbs.  A subsequent patch will audit drivers to ensure that the
flag is set properly

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Jiri Pirko <jpirko@redhat.com>
CC: Robert Olsson <robert.olsson@its.uu.se>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Alexey Dobriyan <adobriyan@gmail.com>
CC: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/if.h b/include/linux/if.h
index 3bc63e6..03489ca 100644 (file)
--- a/include/linux/if.h
+++ b/include/linux/if.h
@@ -76,6 +76,8 @@
 #define IFF_BRIDGE_PORT        0x4000          /* device used as bridge port */
 #define IFF_OVS_DATAPATH       0x8000  /* device used as Open vSwitch
                                         * datapath port */
+#define IFF_TX_SKB_SHARING     0x10000 /* The interface supports sharing
+                                        * skbs on transmit */
 
 #define IF_GET_IFACE   0x0001          /* for querying only */
 #define IF_GET_PROTO   0x0002

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index f76079c..e35a6fb 100644 (file)
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -1070,7 +1070,9 @@ static ssize_t pktgen_if_write(struct file *file,
                len = num_arg(&user_buffer[i], 10, &value);
                if (len < 0)
                        return len;
-
+               if ((value > 0) &&
+                   (!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))
+                       return -ENOTSUPP;
                i += len;
                pkt_dev->clone_skb = value;
 
@@ -3555,7 +3557,6 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname)
        pkt_dev->min_pkt_size = ETH_ZLEN;
        pkt_dev->max_pkt_size = ETH_ZLEN;
        pkt_dev->nfrags = 0;
-       pkt_dev->clone_skb = pg_clone_skb_d;
        pkt_dev->delay = pg_delay_d;
        pkt_dev->count = pg_count_d;
        pkt_dev->sofar = 0;
@@ -3563,7 +3564,6 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname)
        pkt_dev->udp_src_max = 9;
        pkt_dev->udp_dst_min = 9;
        pkt_dev->udp_dst_max = 9;
-
        pkt_dev->vlan_p = 0;
        pkt_dev->vlan_cfi = 0;
        pkt_dev->vlan_id = 0xffff;
@@ -3575,6 +3575,8 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname)
        err = pktgen_setup_dev(pkt_dev, ifname);
        if (err)
                goto out1;
+       if (pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)
+               pkt_dev->clone_skb = pg_clone_skb_d;
 
        pkt_dev->entry = proc_create_data(ifname, 0600, pg_proc_dir,
                                          &pktgen_if_fops, pkt_dev);

diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index b8453bd..27997d3 100644 (file)
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -340,6 +340,7 @@ void ether_setup(struct net_device *dev)
        dev->addr_len           = ETH_ALEN;
        dev->tx_queue_len       = 1000; /* Ethernet wants good queues */
        dev->flags              = IFF_BROADCAST|IFF_MULTICAST;
+       dev->priv_flags         = IFF_TX_SKB_SHARING;
 
        memset(dev->broadcast, 0xFF, ETH_ALEN);