KVM: ia64: cleanup kvm_ia64_sync_dirty_log()

kvm_ia64_sync_dirty_log() is a helper function for kvm_vm_ioctl_get_dirty_log()
which copies ia64's arch specific dirty bitmap to general one in memslot.
So doing sanity checks in this function is unnatural. We move these checks
outside of this and change the prototype appropriately.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/ia64/kvm/kvm-ia64.c

@@ -1795,25 +1795,15 @@ void kvm_arch_exit(void)
 	kvm_vmm_info = NULL;
 }
 
-static int kvm_ia64_sync_dirty_log(struct kvm *kvm,
-		struct kvm_dirty_log *log)
+static void kvm_ia64_sync_dirty_log(struct kvm *kvm,
+				    struct kvm_memory_slot *memslot)
 {
-	struct kvm_memory_slot *memslot;
-	int r, i;
+	int i;
 	long base;
 	unsigned long n;
 	unsigned long *dirty_bitmap = (unsigned long *)(kvm->arch.vm_base +
 			offsetof(struct kvm_vm_data, kvm_mem_dirty_log));
 
-	r = -EINVAL;
-	if (log->slot >= KVM_MEMORY_SLOTS)
-		goto out;
-
-	memslot = &kvm->memslots->memslots[log->slot];
-	r = -ENOENT;
-	if (!memslot->dirty_bitmap)
-		goto out;
-
 	n = kvm_dirty_bitmap_bytes(memslot);
 	base = memslot->base_gfn / BITS_PER_LONG;
 
@@ -1823,9 +1813,6 @@ static int kvm_ia64_sync_dirty_log(struct kvm *kvm,
 		dirty_bitmap[base + i] = 0;
 	}
 	spin_unlock(&kvm->arch.dirty_log_lock);
-	r = 0;
-out:
-	return r;
 }
 
 int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
@@ -1838,10 +1825,16 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
 
 	mutex_lock(&kvm->slots_lock);
 
-	r = kvm_ia64_sync_dirty_log(kvm, log);
-	if (r)
+	r = -EINVAL;
+	if (log->slot >= KVM_MEMORY_SLOTS)
+		goto out;
+
+	memslot = &kvm->memslots->memslots[log->slot];
+	r = -ENOENT;
+	if (!memslot->dirty_bitmap)
 		goto out;
 
+	kvm_ia64_sync_dirty_log(kvm, memslot);
 	r = kvm_get_dirty_log(kvm, log, &is_dirty);
 	if (r)
 		goto out;
@@ -1849,7 +1842,6 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
 	/* If nothing is dirty, don't bother messing with page tables. */
 	if (is_dirty) {
 		kvm_flush_remote_tlbs(kvm);
-		memslot = &kvm->memslots->memslots[log->slot];
 		n = kvm_dirty_bitmap_bytes(memslot);
 		memset(memslot->dirty_bitmap, 0, n);
 	}