KVM: Consolidate load/save temporary buffer allocation and freeing

Instead of three temporary variables and three free calls, have one temporary
variable (with four names) and one free call.

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 32 insertions, 30 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d918cb15e5b5..8e60b6c9c0b0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2436,25 +2436,29 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
         struct kvm_vcpu *vcpu = filp->private_data;
         void __user *argp = (void __user *)arg;
         int r;
-        struct kvm_lapic_state *lapic = NULL;
-        struct kvm_xsave *xsave = NULL;
-        struct kvm_xcrs *xcrs = NULL;
+        union {
+                struct kvm_lapic_state *lapic;
+                struct kvm_xsave *xsave;
+                struct kvm_xcrs *xcrs;
+                void *buffer;
+        } u;
 
+        u.buffer = NULL;
         switch (ioctl) {
         case KVM_GET_LAPIC: {
                 r = -EINVAL;
                 if (!vcpu->arch.apic)
                         goto out;
-                lapic = kzalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
+                u.lapic = kzalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
 
                 r = -ENOMEM;
-                if (!lapic)
+                if (!u.lapic)
                         goto out;
-                r = kvm_vcpu_ioctl_get_lapic(vcpu, lapic);
+                r = kvm_vcpu_ioctl_get_lapic(vcpu, u.lapic);
                 if (r)
                         goto out;
                 r = -EFAULT;
-                if (copy_to_user(argp, lapic, sizeof(struct kvm_lapic_state)))
+                if (copy_to_user(argp, u.lapic, sizeof(struct kvm_lapic_state)))
                         goto out;
                 r = 0;
                 break;
@@ -2463,14 +2467,14 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                 r = -EINVAL;
                 if (!vcpu->arch.apic)
                         goto out;
-                lapic = kmalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
+                u.lapic = kmalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);
                 r = -ENOMEM;
-                if (!lapic)
+                if (!u.lapic)
                         goto out;
                 r = -EFAULT;
-                if (copy_from_user(lapic, argp, sizeof(struct kvm_lapic_state)))
+                if (copy_from_user(u.lapic, argp, sizeof(struct kvm_lapic_state)))
                         goto out;
-                r = kvm_vcpu_ioctl_set_lapic(vcpu, lapic);
+                r = kvm_vcpu_ioctl_set_lapic(vcpu, u.lapic);
                 if (r)
                         goto out;
                 r = 0;
@@ -2634,68 +2638,66 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
                 break;
         }
         case KVM_GET_XSAVE: {
-                xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);
+                u.xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);
                 r = -ENOMEM;
-                if (!xsave)
+                if (!u.xsave)
                         break;
 
-                kvm_vcpu_ioctl_x86_get_xsave(vcpu, xsave);
+                kvm_vcpu_ioctl_x86_get_xsave(vcpu, u.xsave);
 
                 r = -EFAULT;
-                if (copy_to_user(argp, xsave, sizeof(struct kvm_xsave)))
+                if (copy_to_user(argp, u.xsave, sizeof(struct kvm_xsave)))
                         break;
                 r = 0;
                 break;
         }
         case KVM_SET_XSAVE: {
-                xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);
+                u.xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);
                 r = -ENOMEM;
-                if (!xsave)
+                if (!u.xsave)
                         break;
 
                 r = -EFAULT;
-                if (copy_from_user(xsave, argp, sizeof(struct kvm_xsave)))
+                if (copy_from_user(u.xsave, argp, sizeof(struct kvm_xsave)))
                         break;
 
-                r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, xsave);
+                r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, u.xsave);
                 break;
         }
         case KVM_GET_XCRS: {
-                xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);
+                u.xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);
                 r = -ENOMEM;
-                if (!xcrs)
+                if (!u.xcrs)
                         break;
 
-                kvm_vcpu_ioctl_x86_get_xcrs(vcpu, xcrs);
+                kvm_vcpu_ioctl_x86_get_xcrs(vcpu, u.xcrs);
 
                 r = -EFAULT;
-                if (copy_to_user(argp, xcrs,
+                if (copy_to_user(argp, u.xcrs,
                                  sizeof(struct kvm_xcrs)))
                         break;
                 r = 0;
                 break;
         }
         case KVM_SET_XCRS: {
-                xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);
+                u.xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);
                 r = -ENOMEM;
-                if (!xcrs)
+                if (!u.xcrs)
                         break;
 
                 r = -EFAULT;
-                if (copy_from_user(xcrs, argp,
+                if (copy_from_user(u.xcrs, argp,
                                    sizeof(struct kvm_xcrs)))
                         break;
 
-                r = kvm_vcpu_ioctl_x86_set_xcrs(vcpu, xcrs);
+                r = kvm_vcpu_ioctl_x86_set_xcrs(vcpu, u.xcrs);
                 break;
         }
         default:
                 r = -EINVAL;
         }
 out:
-        kfree(lapic);
-        kfree(xsave);
-        kfree(xcrs);
+        kfree(u.buffer);
         return r;
 }