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Now that KVM does NOT gift async #PF workers a "struct kvm" reference,
don't bother skipping "done" workers when flushing/canceling queued
workers, as the deadlock that was being fudged around can no longer occur.
When workers, i.e. async_pf_execute(), were gifted a referenced, it was
possible for a worker to put the last reference and trigger VM destruction,
i.e. trigger flushing of a workqueue from a worker in said workqueue.
Note, there is no actual lock, the deadlock was that a worker will be
stuck waiting for itself (the workqueue code simulates a lock/unlock via
lock_map_{acquire,release}()).
Skipping "done" workers isn't problematic per se, but using work->vcpu as
a "done" flag is confusing, e.g. it's not clear that async_pf.lock is
acquired to protect the work->vcpu, NOT the processing of async_pf.queue
(which is protected by vcpu->mutex).
This reverts commit
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|---|---|---|
| .. | ||
| async_pf.c | ||
| async_pf.h | ||
| binary_stats.c | ||
| coalesced_mmio.c | ||
| coalesced_mmio.h | ||
| dirty_ring.c | ||
| eventfd.c | ||
| guest_memfd.c | ||
| irqchip.c | ||
| Kconfig | ||
| kvm_main.c | ||
| kvm_mm.h | ||
| Makefile.kvm | ||
| pfncache.c | ||
| vfio.c | ||
| vfio.h | ||