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authorIzik Eidus <izike@qumranet.com>2008-03-30 16:01:25 +0300
committerAvi Kivity <avi@qumranet.com>2008-04-27 12:00:56 +0300
commitd39f13b0da7fa7f705fbe6c80995205d0380bc7a (patch)
treefebc1458c6225c70ca4c435047acf279fd77b019 /virt
parent9c20456a32ce9e82ccda55e12c10016b181d85e5 (diff)
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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 <izike@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 41d4b651913..93ed78b015c 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;
}