[PATCH 3.11 76/93] kvm: free resources after canceling async_pf

[Luis Henriques]

3.11.10.12 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar at redhat.com>

commit 28b441e24088081c1e213139d1303b451a34a4f4 upstream.

When we cancel 'async_pf_execute()', we should behave as if the work was
never scheduled in 'kvm_setup_async_pf()'.
Fixes a bug when we can't unload module because the vm wasn't destroyed.

Signed-off-by: Radim Krčmář <rkrcmar at redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini at redhat.com>
Reviewed-by: Gleb Natapov <gleb at redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 virt/kvm/async_pf.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index ea475cd03511..8a39dda7a325 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -101,8 +101,11 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 				   typeof(*work), queue);
 		cancel_work_sync(&work->work);
 		list_del(&work->queue);
-		if (!work->done) /* work was canceled */
+		if (!work->done) { /* work was canceled */
+			mmdrop(work->mm);
+			kvm_put_kvm(vcpu->kvm); /* == work->vcpu->kvm */
 			kmem_cache_free(async_pf_cache, work);
+		}
 	}
 
 	spin_lock(&vcpu->async_pf.lock);
-- 
1.9.1