[PATCH] vfio/type1: avoid redundant PageReserved checking

[Ben Luo]

currently, if the page is not a tail of compound page, it will be
checked twice for the same thing.

Signed-off-by: Ben Luo <luoben@xxxxxxxxxxxxxxxxx>
---
 drivers/vfio/vfio_iommu_type1.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 054391f..cbe0d88 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -291,11 +291,10 @@ static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
 static bool is_invalid_reserved_pfn(unsigned long pfn)
 {
 	if (pfn_valid(pfn)) {
-		bool reserved;
 		struct page *tail = pfn_to_page(pfn);
 		struct page *head = compound_head(tail);
-		reserved = !!(PageReserved(head));
 		if (head != tail) {
+			bool reserved = !!(PageReserved(head));
 			/*
 			 * "head" is not a dangling pointer
 			 * (compound_head takes care of that)
@@ -310,7 +309,7 @@ static bool is_invalid_reserved_pfn(unsigned long pfn)
 			if (PageTail(tail))
 				return reserved;
 		}
-		return PageReserved(tail);
+		return !!(PageReserved(tail));
 	}
 
 	return true;
-- 
1.8.3.1