KVM: async_pf: Cleanup kvm_setup_async_pf() (7863e346) · Commits · 戴 / test

schedule_work() returns 'false' only when the work is already on the queue and this can't happen as kvm_setup_async_pf() always allocates a new one. Also, to avoid potential race, it makes sense to to schedule_work() at the very end after we've added it to the queue. While on it, do some minor cleanup. gfn_to_pfn_async() mentioned in a comment does not currently exist and, moreover, we can check kvm_is_error_hva() at the very beginning, before we try to allocate work so 'retry_sync' label can go away completely. Signed-off-by:

Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200610175532.779793-1-vkuznets@redhat.com> Reviewed-by:

Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:

Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/async_pf.c

+6 −13

Original line number	Diff line number	Diff line
		@@ -164,7 +164,9 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
		if (vcpu->async_pf.queued >= ASYNC_PF_PER_VCPU)
		return 0;

		/* setup delayed work */
		/* Arch specific code should not do async PF in this case */
		if (unlikely(kvm_is_error_hva(hva)))
		return 0;

		/*
		* do alloc nowait since if we are going to sleep anyway we
		@@ -183,24 +185,15 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
		mmget(work->mm);
		kvm_get_kvm(work->vcpu->kvm);

		/* this can't really happen otherwise gfn_to_pfn_async
		would succeed */
		if (unlikely(kvm_is_error_hva(work->addr)))
		goto retry_sync;

		INIT_WORK(&work->work, async_pf_execute);
		if (!schedule_work(&work->work))
		goto retry_sync;

		list_add_tail(&work->queue, &vcpu->async_pf.queue);
		vcpu->async_pf.queued++;
		kvm_arch_async_page_not_present(vcpu, work);

		schedule_work(&work->work);

		return 1;
		retry_sync:
		kvm_put_kvm(work->vcpu->kvm);
		mmput(work->mm);
		kmem_cache_free(async_pf_cache, work);
		return 0;
		}

		int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)

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