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Salil Mehta authored
This patch fixes the problem of the spin locks, originally meant for the netpoll path of hns driver, causing deadlock in the normal NAPI poll path. The issue happened due to the presence of the stray leftover spin lock code related to the netpoll, whose support was earlier removed from the HNS[1], got activated due to enabling of NET_POLL_CONTROLLER switch. Earlier background: The netpoll handling code originally had this bug(as identified by Marc Zyngier[2]) of wrong spin lock API being used which did not disable the interrupts and hence could cause locking issues. i.e. if the lock were first acquired in context to thread like 'ip' util and this lock if ever got later acquired again in context to the interrupt context like TX/RX (Interrupts could always pre-empt the lock holding task and acquire the lock again) and hence could cause deadlock. Proposed Solution: 1. If the netpoll was enabled in the HNS driver, which is not right now, we could have simply used spin_[un]lock_irqsave() 2. But as netpoll is disabled, therefore, it is best to get rid of the existing locks and stray code for now. This should solve the problem reported by Marc. [1] https://git.kernel.org/torvalds/c/4bd2c03be7 [2] https://patchwork.ozlabs.org/patch/1189139/ Fixes: 4bd2c03b ("net: hns: remove ndo_poll_controller") Cc: lipeng <lipeng321@huawei.com> Cc: Yisen Zhuang <yisen.zhuang@huawei.com> Cc: Eric Dumazet <edumazet@google.com> Cc: David S. Miller <davem@davemloft.net> Reported-by:
Marc Zyngier <maz@kernel.org> Acked-by:
Marc Zyngier <maz@kernel.org> Tested-by:
Marc Zyngier <maz@kernel.org> Signed-off-by:
Salil Mehta <salil.mehta@huawei.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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