[PATCH] iommu/vt-d: fix constant-out-of-range warning

From: Arnd Bergmann
Date: Tue Feb 13 2024 - 05:00:47 EST


From: Arnd Bergmann <arnd@xxxxxxxx>

On 32-bit builds, the vt-d driver causes a warning with clang:

drivers/iommu/intel/nested.c:112:13: error: result of comparison of constant 18446744073709551615 with expression of type 'unsigned long' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
112 | if (npages == U64_MAX)
| ~~~~~~ ^ ~~~~~~~

This can be easily avoided by making the variable a 64-bit type, which matches
both the caller and the use anyway.

Fixes: f6f3721244a8 ("iommu/vt-d: Add iotlb flush for nested domain")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/iommu/intel/nested.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/intel/nested.c b/drivers/iommu/intel/nested.c
index f26c7f1c46cc..77a09c982979 100644
--- a/drivers/iommu/intel/nested.c
+++ b/drivers/iommu/intel/nested.c
@@ -95,7 +95,7 @@ static void nested_flush_dev_iotlb(struct dmar_domain *domain, u64 addr,
}

static void intel_nested_flush_cache(struct dmar_domain *domain, u64 addr,
- unsigned long npages, bool ih)
+ u64 npages, bool ih)
{
struct iommu_domain_info *info;
unsigned int mask;
--
2.39.2