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>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d918cb15e5b5f7061962a951c38415aab1c82bb8..8e60b6c9c0b08c1c0ca4be5a51edf93ffe275da9 100644 (file)
--- 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;
 }