p54pci: prevent stuck rx-ring on slow system
This patch fixes an old problem, which - under certain circumstances - could cause the device to become unresponsive. most of p54pci's rx-ring management is implemented in just two distinct standalone functions. p54p_check_rx_ring takes care of processing incoming data, while p54p_refill_rx_ring tries to replenish all depleted communication buffers. This has always worked fine on my fast machine, but now I know there is a hidden race... The most likely candidate here is ring_control->device_idx. Quintin Pitts had already analyzed the culprit and posted a patch back in Oct 2009. But sadly, no one's picked up on this. ( https://patchwork.kernel.org/patch/53079/ [2 & 3] ). This patch does the same way, except that it also prioritize rx data processing, simply because tx routines *can* wait. Reported-by: Sean Young <sean@mess.org> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=11386Reported-by: Quintin Pitts <geek4linux@gmail.com> Signed-off-by: Quintin Pitts <geek4linux@gmail.com> Signed-off-by: Christian Lamparter <chunkeey@googlemail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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