From d39f13b0da7fa7f705fbe6c80995205d0380bc7a Mon Sep 17 00:00:00 2001 From: Izik Eidus Date: Sun, 30 Mar 2008 16:01:25 +0300 Subject: KVM: add vm refcounting the main purpose of adding this functions is the abilaty to release the spinlock that protect the kvm list while still be able to do operations on a specific kvm in a safe way. Signed-off-by: Izik Eidus Signed-off-by: Avi Kivity --- virt/kvm/kvm_main.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) (limited to 'virt/kvm') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 41d4b6519136..93ed78b015c0 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -193,6 +193,7 @@ static struct kvm *kvm_create_vm(void) mutex_init(&kvm->lock); kvm_io_bus_init(&kvm->mmio_bus); init_rwsem(&kvm->slots_lock); + atomic_set(&kvm->users_count, 1); spin_lock(&kvm_lock); list_add(&kvm->vm_list, &vm_list); spin_unlock(&kvm_lock); @@ -242,11 +243,25 @@ static void kvm_destroy_vm(struct kvm *kvm) mmdrop(mm); } +void kvm_get_kvm(struct kvm *kvm) +{ + atomic_inc(&kvm->users_count); +} +EXPORT_SYMBOL_GPL(kvm_get_kvm); + +void kvm_put_kvm(struct kvm *kvm) +{ + if (atomic_dec_and_test(&kvm->users_count)) + kvm_destroy_vm(kvm); +} +EXPORT_SYMBOL_GPL(kvm_put_kvm); + + static int kvm_vm_release(struct inode *inode, struct file *filp) { struct kvm *kvm = filp->private_data; - kvm_destroy_vm(kvm); + kvm_put_kvm(kvm); return 0; } -- cgit v1.2.1