[XEN PATCH][for-4.19 8/9] xen/types: address Rule 10.1 for DECLARE_BITMAP use

[Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>]

Given its use in the declaration
'DECLARE_BITMAP(features, IOMMU_FEAT_count)' the argument
'bits' has essential type 'enum iommu_feature', which is not
allowed by the Rule as an operand to the addition operator
in macro 'BITS_TO_LONGS'.

A comment in BITS_TO_LONGS is added to make it clear that
values passed are meant to be positive.

Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
---
 xen/include/xen/iommu.h | 2 +-
 xen/include/xen/types.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 0e747b0bbc1c..34aa0b9b5b81 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -360,7 +360,7 @@ struct domain_iommu {
 #endif
 
     /* Features supported by the IOMMU */
-    DECLARE_BITMAP(features, IOMMU_FEAT_count);
+    DECLARE_BITMAP(features, (int)IOMMU_FEAT_count);
 
     /* Does the guest share HAP mapping with the IOMMU? */
     bool hap_pt_share;
diff --git a/xen/include/xen/types.h b/xen/include/xen/types.h
index aea259db1ef2..936e83d333a0 100644
--- a/xen/include/xen/types.h
+++ b/xen/include/xen/types.h
@@ -22,6 +22,7 @@ typedef signed long ssize_t;
 
 typedef __PTRDIFF_TYPE__ ptrdiff_t;
 
+/* Users of this macro are expected to pass a positive value */
 #define BITS_TO_LONGS(bits) \
     (((bits)+BITS_PER_LONG-1)/BITS_PER_LONG)
 #define DECLARE_BITMAP(name,bits) \
-- 
2.34.1