[PATCH 2/2] iommu: debug-pagealloc: Use page_ext_get_phys()

Mostafa Saleh
2026-01-19T14:22:54Z

Instead of calling pfn_valid() and then getting the page, call
the newly added function page_ext_get_phys(), which would also
check for MMIO and offline memory and return NULL in that case.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/iommu-debug-pagealloc.c | 31 ++++++++++++---------------
1 file changed, 14 insertions(+), 17 deletions(-)

diff --git a/drivers/iommu/iommu-debug-pagealloc.c b/drivers/iommu/iommu-debug-pagealloc.c
index c080a38f45a4..9343af3bdbb6 100644
--- a/drivers/iommu/iommu-debug-pagealloc.c
+++ b/drivers/iommu/iommu-debug-pagealloc.c
@@ -30,14 +30,6 @@ struct page_ext_operations page_iommu_debug_ops = {
.need = need_iommu_debug,
};

-static struct page_ext *get_iommu_page_ext(phys_addr_t phys)
-{
- struct page *page = phys_to_page(phys);
- struct page_ext *page_ext = page_ext_get(page);
-
- return page_ext;
-}
-
static struct iommu_debug_metadata *get_iommu_data(struct page_ext *page_ext)
{
return page_ext_data(page_ext, &page_iommu_debug_ops);
@@ -45,18 +37,26 @@ static struct iommu_debug_metadata *get_iommu_data(struct page_ext *page_ext)

static void iommu_debug_inc_page(phys_addr_t phys)
{
- struct page_ext *page_ext = get_iommu_page_ext(phys);
- struct iommu_debug_metadata *d = get_iommu_data(page_ext);
+ struct page_ext *page_ext = page_ext_get_phys(phys);
+ struct iommu_debug_metadata *d;
+
+ if (!page_ext)
+ return;

+ d = get_iommu_data(page_ext);
WARN_ON(atomic_inc_return_relaxed(&d->ref) <= 0);
page_ext_put(page_ext);
}

static void iommu_debug_dec_page(phys_addr_t phys)
{
- struct page_ext *page_ext = get_iommu_page_ext(phys);
- struct iommu_debug_metadata *d = get_iommu_data(page_ext);
+ struct page_ext *page_ext = page_ext_get_phys(phys);
+ struct iommu_debug_metadata *d;
+
+ if (!page_ext)
+ return;

+ d = get_iommu_data(page_ext);
WARN_ON(atomic_dec_return_relaxed(&d->ref) < 0);
page_ext_put(page_ext);
}
@@ -104,11 +104,8 @@ void __iommu_debug_map(struct iommu_domain *domain, phys_addr_t phys, size_t siz
if (WARN_ON(!phys || check_add_overflow(phys, size, &end)))
return;

- for (off = 0 ; off < size ; off += page_size) {
- if (!pfn_valid(__phys_to_pfn(phys + off)))
- continue;
+ for (off = 0 ; off < size ; off += page_size)
iommu_debug_inc_page(phys + off);
- }
}

static void __iommu_debug_update_iova(struct iommu_domain *domain,
@@ -123,7 +120,7 @@ static void __iommu_debug_update_iova(struct iommu_domain *domain,
for (off = 0 ; off < size ; off += page_size) {
phys_addr_t phys = iommu_iova_to_phys(domain, iova + off);

- if (!phys || !pfn_valid(__phys_to_pfn(phys)))
+ if (!phys)
continue;

if (inc)
--
2.52.0.457.g6b5491de43-goog