[RFC,v2,08/12] KVM: Allow kvm_device_ops to be const

Commit Message

Steven Price Dec. 12, 2018, 3:02 p.m. UTC

Currently a kvm_device_ops structure cannot be const without triggering
compiler warnings. However the structure doesn't need to be written to
and, by marking it const, it can be read-only in memory. Add some more
const keywords to allow this.

Signed-off-by: Steven Price <[e-mail]>
---
 include/linux/kvm_host.h | 4 ++--
 virt/kvm/kvm_main.c      | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

Patch

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c926698040e0..e87e4bae3a63 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1177,7 +1177,7 @@  extern unsigned int halt_poll_ns_grow;
 extern unsigned int halt_poll_ns_shrink;
 
 struct kvm_device {
-	struct kvm_device_ops *ops;
+	const struct kvm_device_ops *ops;
 	struct kvm *kvm;
 	void *private;
 	struct list_head vm_node;
@@ -1220,7 +1220,7 @@  struct kvm_device_ops {
 void kvm_device_get(struct kvm_device *dev);
 void kvm_device_put(struct kvm_device *dev);
 struct kvm_device *kvm_device_from_filp(struct file *filp);
-int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type);
+int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type);
 void kvm_unregister_device_ops(u32 type);
 
 extern struct kvm_device_ops kvm_mpic_ops;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2679e476b6c3..d2aebea09fe9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2855,14 +2855,14 @@  struct kvm_device *kvm_device_from_filp(struct file *filp)
 	return filp->private_data;
 }
 
-static struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
+static const struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
 #ifdef CONFIG_KVM_MPIC
 	[KVM_DEV_TYPE_FSL_MPIC_20]	= &kvm_mpic_ops,
 	[KVM_DEV_TYPE_FSL_MPIC_42]	= &kvm_mpic_ops,
 #endif
 };
 
-int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type)
+int kvm_register_device_ops(const struct kvm_device_ops *ops, u32 type)
 {
 	if (type >= ARRAY_SIZE(kvm_device_ops_table))
 		return -ENOSPC;
@@ -2883,7 +2883,7 @@  void kvm_unregister_device_ops(u32 type)
 static int kvm_ioctl_create_device(struct kvm *kvm,
 				   struct kvm_create_device *cd)
 {
-	struct kvm_device_ops *ops = NULL;
+	const struct kvm_device_ops *ops = NULL;
 	struct kvm_device *dev;
 	bool test = cd->flags & KVM_CREATE_DEVICE_TEST;
 	int ret;