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author | Radim Krčmář <rkrcmar@redhat.com> | 2016-03-02 21:56:44 (GMT) |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-03-04 08:29:58 (GMT) |
commit | b39c90b6560c4458d46cb243abea0dcb7bc126d1 (patch) | |
tree | 0504d13b96b7006735826f3fbbfbb5ac21bd4dc0 /arch/x86/kvm/i8254.c | |
parent | 09edea72b7f9fd8a8d26c1f7504d989b9773ee5e (diff) | |
download | linux-b39c90b6560c4458d46cb243abea0dcb7bc126d1.tar.xz |
KVM: i8254: remove unnecessary uses of PIT state lock
- kvm_create_pit had to lock only because it exposed kvm->arch.vpit very
early, but initialization doesn't use kvm->arch.vpit since the last
patch, so we can drop locking.
- kvm_free_pit is only run after there are no users of KVM and therefore
is the sole actor.
- Locking in kvm_vm_ioctl_reinject doesn't do anything, because reinject
is only protected at that place.
- kvm_pit_reset isn't used anywhere and its locking can be dropped if we
hide it.
Removing useless locking allows to see what actually is being protected
by PIT state lock (values accessible from the guest).
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/i8254.c')
-rw-r--r-- | arch/x86/kvm/i8254.c | 9 |
1 files changed, 1 insertions, 8 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 2afe09b0..b8582fb 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -607,12 +607,11 @@ static int speaker_ioport_read(struct kvm_vcpu *vcpu, return 0; } -void kvm_pit_reset(struct kvm_pit *pit) +static void kvm_pit_reset(struct kvm_pit *pit) { int i; struct kvm_kpit_channel_state *c; - mutex_lock(&pit->pit_state.lock); pit->pit_state.flags = 0; for (i = 0; i < 3; i++) { c = &pit->pit_state.channels[i]; @@ -620,7 +619,6 @@ void kvm_pit_reset(struct kvm_pit *pit) c->gate = (i != 2); pit_load_count(pit, i, 0); } - mutex_unlock(&pit->pit_state.lock); kvm_pit_reset_reinject(pit); } @@ -663,7 +661,6 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags) } mutex_init(&pit->pit_state.lock); - mutex_lock(&pit->pit_state.lock); pid = get_pid(task_tgid(current)); pid_nr = pid_vnr(pid); @@ -673,7 +670,6 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags) pit->worker_task = kthread_run(kthread_worker_fn, &pit->worker, "kvm-pit/%d", pid_nr); if (IS_ERR(pit->worker_task)) { - mutex_unlock(&pit->pit_state.lock); kvm_free_irq_source_id(kvm, pit->irq_source_id); kfree(pit); return NULL; @@ -689,7 +685,6 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags) pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq; kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier); pit_state->reinject = true; - mutex_unlock(&pit->pit_state.lock); kvm_pit_reset(pit); @@ -737,13 +732,11 @@ void kvm_free_pit(struct kvm *kvm) &kvm->arch.vpit->mask_notifier); kvm_unregister_irq_ack_notifier(kvm, &kvm->arch.vpit->pit_state.irq_ack_notifier); - mutex_lock(&kvm->arch.vpit->pit_state.lock); timer = &kvm->arch.vpit->pit_state.timer; hrtimer_cancel(timer); flush_kthread_work(&kvm->arch.vpit->expired); kthread_stop(kvm->arch.vpit->worker_task); kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id); - mutex_unlock(&kvm->arch.vpit->pit_state.lock); kfree(kvm->arch.vpit); } } |