[PATCH 05/11] Protect irq_sources_bitmap by kvm->lock instead of kvm->irq_lock

[Gleb Natapov]

It is already protected by kvm->lock on device assignment path. Just
take the same lock in the PIT code.

Signed-off-by: Gleb Natapov <g...@redhat.com>
---
 arch/x86/kvm/i8254.c |    2 ++
 virt/kvm/irq_comm.c  |    8 ++++----
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 472653c..59021da 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -611,7 +611,9 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
        if (!pit)
                return NULL;
 
+       mutex_lock(&kvm->lock);
        pit->irq_source_id = kvm_request_irq_source_id(kvm);
+       mutex_unlock(&kvm->lock);
        if (pit->irq_source_id < 0) {
                kfree(pit);
                return NULL;
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 6c57e46..ce8fcd3 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -210,7 +210,8 @@ int kvm_request_irq_source_id(struct kvm *kvm)
        unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
        int irq_source_id;
 
-       mutex_lock(&kvm->irq_lock);
+       WARN_ON(!mutex_is_locked(&kvm->lock));
+
        irq_source_id = find_first_zero_bit(bitmap,
                                sizeof(kvm->arch.irq_sources_bitmap));
 
@@ -221,7 +222,6 @@ int kvm_request_irq_source_id(struct kvm *kvm)
 
        ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
        set_bit(irq_source_id, bitmap);
-       mutex_unlock(&kvm->irq_lock);
 
        return irq_source_id;
 }
@@ -230,9 +230,10 @@ void kvm_free_irq_source_id(struct kvm *kvm, int 
irq_source_id)
 {
        int i;
 
+       /* during vm destruction this function is called without locking */
+       WARN_ON(!mutex_is_locked(&kvm->lock) && atomic_read(&kvm->users_count));
        ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
 
-       mutex_lock(&kvm->irq_lock);
        if (irq_source_id < 0 ||
            irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) {
                printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
@@ -241,7 +242,6 @@ void kvm_free_irq_source_id(struct kvm *kvm, int 
irq_source_id)
        for (i = 0; i < KVM_IOAPIC_NUM_PINS; i++)
                clear_bit(irq_source_id, &kvm->arch.irq_states[i]);
        clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
-       mutex_unlock(&kvm->irq_lock);
 }
 
 void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
-- 
1.6.2.1

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