KVM: s390: Fix for error codes

- return the proper error to userspace when a signal interrupts the
   KSM unsharing operation
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Merge tag 'kvm-s390-next-5.7-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390: Fix for error codes

- return the proper error to userspace when a signal interrupts the
  KSM unsharing operation

Documentation/virt/kvm/api.rst

@@ -4666,6 +4666,12 @@ KVM_PV_ENABLE
   command has succeeded, any CPU added via hotplug will become
   protected during its creation as well.
 
+  Errors:
+
+  =====      =============================
+  EINTR      an unmasked signal is pending
+  =====      =============================
+
 KVM_PV_DISABLE
 
   Deregister the VM from the Ultravisor and reclaim the memory that

arch/s390/mm/gmap.c

@@ -2552,12 +2552,13 @@ int gmap_mark_unmergeable(void)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
+	int ret;
 
 	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
-				MADV_UNMERGEABLE, &vma->vm_flags)) {
-			return -ENOMEM;
-		}
+		ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
+				  MADV_UNMERGEABLE, &vma->vm_flags);
+		if (ret)
+			return ret;
 	}
 	mm->def_flags &= ~VM_MERGEABLE;
 	return 0;