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Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
as correctly noted at bug #12454. Someone can lookup entry with NULL
->owner, thus not pinning enything, and release it later resulting
in module refcount underflow.

We can keep ->owner and supply it at registration time like ->proc_fops
and ->data.

But this leaves ->owner as easy-manipulative field (just one C assignment)
and somebody will forget to unpin previous/pin current module when
switching ->owner. ->proc_fops is declared as "const" which should give
some thoughts.

->read_proc/->write_proc were just fixed to not require ->owner for
protection.

rmmod'ed directories will be empty and return "." and ".." -- no harm.
And directories with tricky enough readdir and lookup shouldn't be modular.
We definitely don't want such modular code.

Removing ->owner will also make PDE smaller.

So, let's nuke it.

Kudos to Jeff Layton for reminding about this, let's say, oversight.

http://bugzilla.kernel.org/show_bug.cgi?id=12454

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

Due to the loopback functionality in can_send() we can not invoke it
from hardirq context which was done inside the
bcm_tx_timeout_handler() hrtimer callback:

[  700.361154]  [<c012228c>] warn_slowpath+0x80/0xb6
[  700.361163]  [<c013d559>] valid_state+0x125/0x136
[  700.361171]  [<c013d858>] mark_lock+0x18e/0x332
[  700.361180]  [<c013e300>] __lock_acquire+0x12e/0xb1e
[  700.361189]  [<f8ab5915>] bcm_tx_timeout_handler+0x0/0xbc [can_bcm]
[  700.361198]  [<c031e20a>] dev_queue_xmit+0x191/0x479
[  700.361206]  [<c01262a7>] __local_bh_disable+0x2b/0x64
[  700.361213]  [<c031e20a>] dev_queue_xmit+0x191/0x479
[  700.361225]  [<f8aa69a1>] can_send+0xd7/0x11a [can]
[  700.361235]  [<f8ab522b>] bcm_can_tx+0x9d/0xd9 [can_bcm]
[  700.361245]  [<f8ab597f>] bcm_tx_timeout_handler+0x6a/0xbc [can_bcm]
[  700.361255]  [<f8ab5915>] bcm_tx_timeout_handler+0x0/0xbc [can_bcm]
[  700.361263]  [<c0134143>] __run_hrtimer+0x5a/0x86
[  700.361273]  [<f8ab5915>] bcm_tx_timeout_handler+0x0/0xbc [can_bcm]
[  700.361282]  [<c0134a50>] hrtimer_interrupt+0xb9/0x110

This patch moves the rest of the functionality from the hrtimer
callback to the already existing tasklet to fix this slowpath problem.
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

The AF_CAN core delivered always cloned sk_buffs to the AF_CAN
protocols, although this was _only_ needed by the can-raw protocol.
With this (additionally documented) change, the AF_CAN core calls the
callback functions of the registered AF_CAN protocols with the original
(uncloned) sk_buff pointer and let's the can-raw protocol do the
skb_clone() itself which omits all unneeded skb_clone() calls for other
AF_CAN protocols.
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since commit ca109491

 ("hrtimer:
removing all ur callback modes") the hrtimer callbacks are processed
only in hardirq context.

This patch moves some functionality into tasklets to run in softirq
context.

Additionally some duplicated code was removed in bcm_rx_thr_flush()
and an avoidable memcpy was removed from bcm_rx_handler().
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Due to a wrong safety check in af_can.c it was not possible to filter
for SFF frames with a specific CAN identifier without getting the
same selected CAN identifier from a received EFF frame also.

This fix has a minimum (but user visible) impact on the CAN filter
API and therefore the CAN version is set to a new date.

Indeed the 'old' API is still working as-is. But when now setting
CAN_(EFF|RTR)_FLAG in can_filter.can_mask you might get less traffic
than before - but still the stuff that you expected to get for your
defined filter ...

Thanks to Kurt Van Dijck for pointing at this issue and for the review.
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

Without CONFIG_NET_NS, namespace is always &init_net.
Compiler will be able to omit namespace comparisons with this patch.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Even though the CAN netlayer only deals with CAN netdevices, the 
netlayer interface to the userspace and to the device layer should 
perform some sanity checks.

This patch adds several sanity checks that mainly prevent userspace apps 
to send broken content into the system that may be misinterpreted by 
some other userspace application.
Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>
Acked-by: Andre Naujoks <nautsch@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The helper function hrtimer_callback_running() is used in
kernel/hrtimer.c as well as in the updated net/can/bcm.c which now
supports hrtimers. Moving the helper function to hrtimer.h removes the
duplicate definition in the C-files.
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Make use of hrtimers to support high resolution capabilities, when
provided by the system clocksource.

The conversion to hrtimers additionally discovered and solved an
unlikely race condition that has been reproduced under (unrealistic)
massive receive load, which can only be produced on vcan software devices.

[ Fix printf format warnings on 64-bit -DaveM ]
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Introduce per-net_device inlines: dev_net(), dev_net_set().
Without CONFIG_NET_NS, no namespace other than &init_net exists.
Let's explicitly define them to help compiler optimizations.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

This patch adds the CAN broadcast manager (bcm) protocol.
Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>