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In case of a resource shortage, i.e. the rx_offload queue will overflow
or a skb fails to be allocated (due to OOM),
can_rx_offload_offload_one() will call mailbox_read() to discard the
mailbox and return an ERR_PTR.
If the hardware FIFO is empty can_rx_offload_offload_one() will return
NULL.
In case a CAN frame was read from the hardware,
can_rx_offload_offload_one() returns the skb containing it.
Without this patch can_rx_offload_irq_offload_fifo() bails out if no skb
returned, regardless of the reason.
Similar to can_rx_offload_irq_offload_timestamp() in case of a resource
shortage the whole FIFO should be discarded, to avoid an IRQ storm and
give the system some time to recover. However if the FIFO is empty the
loop can be left.
With this patch the loop is left in case of empty FIFO, but not on
errors.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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In case of a resource shortage, i.e. the rx_offload queue will overflow
or a skb fails to be allocated (due to OOM),
can_rx_offload_offload_one() will call mailbox_read() to discard the
mailbox and return an ERR_PTR.
However can_rx_offload_irq_offload_timestamp() bails out in the error
case. In case of a resource shortage all mailboxes should be discarded,
to avoid an IRQ storm and give the system some time to recover.
Since can_rx_offload_irq_offload_timestamp() is typically called from a
while loop, all message will eventually be discarded. So let's continue
on error instead to discard them directly.
Signed-off-by: Jeroen Hofstee <jhofstee@victronenergy.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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error value in case of errors
Before this patch can_rx_offload_offload_one() returns a pointer to a
skb containing the read CAN frame or a NULL pointer.
However the meaning of the NULL pointer is ambiguous, it can either mean
the requested mailbox is empty or there was an error.
This patch fixes this situation by returning:
- pointer to skb on success
- NULL pointer if mailbox is empty
- ERR_PTR() in case of an error
All users of can_rx_offload_offload_one() have been adopted, no
functional change intended.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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queue overflow or OOM
If the rx-offload skb_queue is full or the skb allocation fails (due to OOM),
the mailbox contents is discarded.
This patch adds the incrementing of the rx_fifo_errors statistics counter.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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beyond skb_queue_len_max
The skb_queue is a linked list, holding the skb to be processed in the
next NAPI call.
Without this patch, the queue length in can_rx_offload_offload_one() is
limited to skb_queue_len_max + 1. As the skb_queue is a linked list, no
array or other resources are accessed out-of-bound, however this
behaviour is counterintuitive.
This patch limits the rx-offload skb_queue length to skb_queue_len_max.
Fixes: d254586c3453 ("can: rx-offload: Add support for HW fifo based irq offloading")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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mem leak
If the rx-offload skb_queue is full can_rx_offload_queue_tail() will not
queue the skb and return with an error.
This patch frees the skb in case of a full queue, which brings
can_rx_offload_queue_tail() in line with the
can_rx_offload_queue_sorted() function, which has been adjusted in the
previous patch.
The return value is adjusted to -ENOBUFS to better reflect the actual
problem.
The device stats handling is left to the caller.
Fixes: d254586c3453 ("can: rx-offload: Add support for HW fifo based irq offloading")
Reported-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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skb mem leak
If the rx-offload skb_queue is full can_rx_offload_queue_sorted() will
not queue the skb and return with an error.
None of the callers of this function, issue a kfree_skb() to free the
not queued skb. This results in a memory leak.
This patch fixes the problem by freeing the skb in case of a full queue.
The return value is adjusted to -ENOBUFS to better reflect the actual
problem.
The device stats handling is left to the callers, as this function might
be used in both the rx and tx path.
Fixes: 55059f2b7f86 ("can: rx-offload: introduce can_rx_offload_get_echo_skb() and can_rx_offload_queue_sorted() functions")
Cc: linux-stable <stable@vger.kernel.org>
Cc: Martin Hundebøll <martin@geanix.com>
Reported-by: Martin Hundebøll <martin@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the version 2 of the gnu general public
license as published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 15 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000437.427740574@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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can_rx_offload_queue_tail()
This function has nothing todo with error.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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can_rx_offload_queue_sorted() functions
Current CAN framework can't guarantee proper/chronological order
of RX and TX-ECHO messages. To make this possible, drivers should use
this functions instead of can_get_echo_skb().
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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Eliminate code which assumes that SKBs and skb_queue_head objects
can be cast to eachother during list processing.
Signed-off-by: David S. Miller <davem@davemloft.net>
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return statement
This patch removes the duplicate semicolon at the end of the return
statement.
Suggested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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Some CAN controllers don't implement a FIFO in hardware, but fill their
mailboxes in a particular order (from lowest to highest or highest to lowest).
This makes problems to read the frames in the correct order from the hardware,
as new frames might be filled into just read (low) mailboxes. This gets worse,
when following new frames are received into not read (higher) mailboxes.
On the bright side some these CAN controllers put a timestamp on each received
CAN frame. This patch adds support to offload CAN frames in interrupt context,
order them by timestamp and then transmitted in a NAPI context.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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Some CAN controllers have a usable FIFO already but can still benefit
from off-loading the CAN controller FIFO. The CAN frames of the FIFO are
read and put into a skb queue during interrupt and then transmitted in a
NAPI context.
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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