[PATCH v2 0/2] iommu: debug-pagealloc: Remove pfn_valid() usage

[Mostafa Saleh <smostafa@google.com>]

This is a small fix for the new config IOMMU_DEBUG_PAGEALLOC based
on the discussion:
https://lore.kernel.org/linux-iommu/CAFgf54pBAUm3ao-UJksiuGKtvv4wzRyFq_uKwLe0H1ettO4DLQ@mail.gmail.com/

Where it was concluded that pfn_valid() is not enough to validate
physical addresses before access to page_ext.

The first patch introduces a new function in page_ext that takes a
physical address as an argument, and the second patch uses it instead
of calling pfn_valid() and phys_to_page()

Benchmarks with the new implementation can be found in:
https://lore.kernel.org/linux-iommu/20260114164322.787125-1-smostafa@google.com/

This series applies to iommu/core tree.

Changes on v2:
v1: https://lore.kernel.org/linux-iommu/20260119142246.3821052-1-smostafa@google.com/
- Rename page_ext_phys() to page_ext_from_phys()
- Reword comment and commit messages.

Mostafa Saleh (2):
  mm/page_ext: Add page_ext_get_from_phys()
  iommu: debug-pagealloc: Use page_ext_get_from_phys()

 drivers/iommu/iommu-debug-pagealloc.c | 31 ++++++++++++---------------
 include/linux/page_ext.h              |  6 ++++++
 mm/page_ext.c                         | 23 ++++++++++++++++++++
 3 files changed, 43 insertions(+), 17 deletions(-)

-- 
2.52.0.457.g6b5491de43-goog