static int get_all_floating_irqs()

in kvm/interrupt.c [2241:2329]

• 74 lines of code
• 20 McCabe index (conditional complexity)

static int get_all_floating_irqs(struct kvm *kvm, u8 __user *usrbuf, u64 len)
{
	struct kvm_s390_gisa_interrupt *gi = &kvm->arch.gisa_int;
	struct kvm_s390_interrupt_info *inti;
	struct kvm_s390_float_interrupt *fi;
	struct kvm_s390_irq *buf;
	struct kvm_s390_irq *irq;
	int max_irqs;
	int ret = 0;
	int n = 0;
	int i;

	if (len > KVM_S390_FLIC_MAX_BUFFER || len == 0)
		return -EINVAL;

	/*
	 * We are already using -ENOMEM to signal
	 * userspace it may retry with a bigger buffer,
	 * so we need to use something else for this case
	 */
	buf = vzalloc(len);
	if (!buf)
		return -ENOBUFS;

	max_irqs = len / sizeof(struct kvm_s390_irq);

	if (gi->origin && gisa_get_ipm(gi->origin)) {
		for (i = 0; i <= MAX_ISC; i++) {
			if (n == max_irqs) {
				/* signal userspace to try again */
				ret = -ENOMEM;
				goto out_nolock;
			}
			if (gisa_tac_ipm_gisc(gi->origin, i)) {
				irq = (struct kvm_s390_irq *) &buf[n];
				irq->type = KVM_S390_INT_IO(1, 0, 0, 0);
				irq->u.io.io_int_word = isc_to_int_word(i);
				n++;
			}
		}
	}
	fi = &kvm->arch.float_int;
	spin_lock(&fi->lock);
	for (i = 0; i < FIRQ_LIST_COUNT; i++) {
		list_for_each_entry(inti, &fi->lists[i], list) {
			if (n == max_irqs) {
				/* signal userspace to try again */
				ret = -ENOMEM;
				goto out;
			}
			inti_to_irq(inti, &buf[n]);
			n++;
		}
	}
	if (test_bit(IRQ_PEND_EXT_SERVICE, &fi->pending_irqs) ||
	    test_bit(IRQ_PEND_EXT_SERVICE_EV, &fi->pending_irqs)) {
		if (n == max_irqs) {
			/* signal userspace to try again */
			ret = -ENOMEM;
			goto out;
		}
		irq = (struct kvm_s390_irq *) &buf[n];
		irq->type = KVM_S390_INT_SERVICE;
		irq->u.ext = fi->srv_signal;
		n++;
	}
	if (test_bit(IRQ_PEND_MCHK_REP, &fi->pending_irqs)) {
		if (n == max_irqs) {
				/* signal userspace to try again */
				ret = -ENOMEM;
				goto out;
		}
		irq = (struct kvm_s390_irq *) &buf[n];
		irq->type = KVM_S390_MCHK;
		irq->u.mchk = fi->mchk;
		n++;
}

out:
	spin_unlock(&fi->lock);
out_nolock:
	if (!ret && n > 0) {
		if (copy_to_user(usrbuf, buf, sizeof(struct kvm_s390_irq) * n))
			ret = -EFAULT;
	}
	vfree(buf);

	return ret < 0 ? ret : n;
}