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can: replace timestamp as unique skb attribute

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Commit 514ac99c64 "can: fix multiple delivery of a single CAN frame for
overlapping CAN filters" requires the skb->tstamp to be set to check for
identical CAN skbs.

Without timestamping to be required by user space applications this timestamp
was not generated which lead to commit 36c01245eb "can: fix loss of CAN frames
in raw_rcv" - which forces the timestamp to be set in all CAN related skbuffs
by introducing several __net_timestamp() calls.

This forces e.g. out of tree drivers which are not using alloc_can{,fd}_skb()
to add __net_timestamp() after skbuff creation to prevent the frame loss fixed
in mainline Linux.

This patch removes the timestamp dependency and uses an atomic counter to
create an unique identifier together with the skbuff pointer.

Btw: the new skbcnt element introduced in struct can_skb_priv has to be
initialized with zero in out-of-tree drivers which are not using
alloc_can{,fd}_skb() too.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Oliver Hartkopp
2015-06-26 11:58:19 +02:00
committed by Marc Kleine-Budde
parent 2acb5c301e
commit d3b58c47d3
7 changed files with 18 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
net/can/af_can.c
View File

@@ -89,6 +89,8 @@ struct timer_list can_stattimer; /* timer for statistics update */
struct s_stats can_stats; /* packet statistics */
struct s_pstats can_pstats; /* receive list statistics */
static atomic_t skbcounter = ATOMIC_INIT(0);
/*
* af_can socket functions
*/
@@ -310,12 +312,8 @@ int can_send(struct sk_buff *skb, int loop)
return err;
}
if (newskb) {
if (!(newskb->tstamp.tv64))
__net_timestamp(newskb);
if (newskb)
netif_rx_ni(newskb);
}
/* update statistics */
can_stats.tx_frames++;
@@ -683,6 +681,10 @@ static void can_receive(struct sk_buff *skb, struct net_device *dev)
can_stats.rx_frames++;
can_stats.rx_frames_delta++;
/* create non-zero unique skb identifier together with *skb */
while (!(can_skb_prv(skb)->skbcnt))
can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
rcu_read_lock();
/* deliver the packet to sockets listening on all devices */

2
net/can/bcm.c
View File

@@ -261,6 +261,7 @@ static void bcm_can_tx(struct bcm_op *op)
can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
can_skb_prv(skb)->skbcnt = 0;
memcpy(skb_put(skb, CFSIZ), cf, CFSIZ);
@@ -1217,6 +1218,7 @@ static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk)
}
can_skb_prv(skb)->ifindex = dev->ifindex;
can_skb_prv(skb)->skbcnt = 0;
skb->dev = dev;
can_skb_set_owner(skb, sk);
err = can_send(skb, 1); /* send with loopback */

7
net/can/raw.c
View File

@@ -75,7 +75,7 @@ MODULE_ALIAS("can-proto-1");
*/
struct uniqframe {
ktime_t tstamp;
int skbcnt;
const struct sk_buff *skb;
unsigned int join_rx_count;
};
@@ -133,7 +133,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
/* eliminate multiple filter matches for the same skb */
if (this_cpu_ptr(ro->uniq)->skb == oskb &&
ktime_equal(this_cpu_ptr(ro->uniq)->tstamp, oskb->tstamp)) {
this_cpu_ptr(ro->uniq)->skbcnt == can_skb_prv(oskb)->skbcnt) {
if (ro->join_filters) {
this_cpu_inc(ro->uniq->join_rx_count);
/* drop frame until all enabled filters matched */
@@ -144,7 +144,7 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
}
} else {
this_cpu_ptr(ro->uniq)->skb = oskb;
this_cpu_ptr(ro->uniq)->tstamp = oskb->tstamp;
this_cpu_ptr(ro->uniq)->skbcnt = can_skb_prv(oskb)->skbcnt;
this_cpu_ptr(ro->uniq)->join_rx_count = 1;
/* drop first frame to check all enabled filters? */
if (ro->join_filters && ro->count > 1)
@@ -749,6 +749,7 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
can_skb_reserve(skb);
can_skb_prv(skb)->ifindex = dev->ifindex;
can_skb_prv(skb)->skbcnt = 0;
err = memcpy_from_msg(skb_put(skb, size), msg, size);
if (err < 0)