diff mbox series

[v6,19/26] proc/task_mmu: Mark devdax and fsdax pages as always unpinned

Message ID d7a6c9822ddc945daaf4f9db34d3f2b1c0454447.1736488799.git-series.apopple@nvidia.com (mailing list archive)
State New
Headers show
Series fs/dax: Fix ZONE_DEVICE page reference counts | expand

Commit Message

Alistair Popple Jan. 10, 2025, 6 a.m. UTC 
The procfs mmu files such as smaps and pagemap currently ignore devdax and
fsdax pages because these pages are considered special. A future change
will start treating these as normal pages, meaning they can be exposed via
smaps and pagemap.

The only difference is that devdax and fsdax pages can never be pinned for
DMA via FOLL_LONGTERM, so add an explicit check in pte_is_pinned() to
reflect that.

Signed-off-by: Alistair Popple <apopple@nvidia.com>

---

Changes for v5:

 - After discussion with David remove the checks for DAX pages for
   smaps and pagemap walkers. This means DAX pages will now appear in
   those procfs files.
---
 fs/proc/task_mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 38a5a3e..9a8a7d3 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1378,7 +1378,7 @@  static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr,
 	if (likely(!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)))
 		return false;
 	folio = vm_normal_folio(vma, addr, pte);
-	if (!folio)
+	if (!folio || folio_is_devdax(folio) || folio_is_fsdax(folio))
 		return false;
 	return folio_maybe_dma_pinned(folio);
 }