The lost message handling is broken in several ways.
1) Clearing the message lost flag is done by writing 0 to the
message control register of the object.
#define IF_MCONT_CLR_MSGLST (0 << 14)
That clears the object buffer configuration in the worst case,
which results in a loss of the EOB flag. That leaves the FIFO chain
without a limit and causes a complete lockup of the HW
2) In case that the error skb allocation fails, the code happily
claims that it handed down a packet. Just an accounting bug, but ....
3) The code adds a lot of pointless overhead to that error case, where
we need to get stuff done as fast as possible to avoid more packet
loss.
- printk an annoying error message
- reread the object buffer for nothing
Fix is simple again:
- Use the already known MSGCTRL content and only clear the MSGLST bit
- Fix the buffer accounting by adding a proper return code
- Remove the pointless operations
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
07c7b6f616