The patch titled
Subject: proc/task_mmu: mark devdax and fsdax pages as always unpinned
has been added to the -mm mm-unstable branch. Its filename is
proc-task_mmu-mark-devdax-and-fsdax-pages-as-always-unpinned.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/proc-task_mmu-mark-devdax-and-fsdax-pages-as-always-unpinned.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Alistair Popple <apopple@xxxxxxxxxx>
Subject: proc/task_mmu: mark devdax and fsdax pages as always unpinned
Date: Tue, 7 Jan 2025 14:42:35 +1100
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.
Link: https://lkml.kernel.org/r/e17a04cf8feaa838e62d0c7d1de97444222b7956.1736221254.git-series.apopple@xxxxxxxxxx
Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/proc/task_mmu.c~proc-task_mmu-mark-devdax-and-fsdax-pages-as-always-unpinned
+++ a/fs/proc/task_mmu.c
@@ -1378,7 +1378,7 @@ static inline bool pte_is_pinned(struct
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);
}
_
Patches currently in -mm which might be from apopple@xxxxxxxxxx are
fuse-fix-dax-truncate-punch_hole-fault-path.patch
fs-dax-return-unmapped-busy-pages-from-dax_layout_busy_page_range.patch
fs-dax-dont-skip-locked-entries-when-scanning-entries.patch
fs-dax-refactor-wait-for-dax-idle-page.patch
fs-dax-create-a-common-implementation-to-break-dax-layouts.patch
fs-dax-always-remove-dax-page-cache-entries-when-breaking-layouts.patch
fs-dax-ensure-all-pages-are-idle-prior-to-filesystem-unmount.patch
fs-dax-remove-page_mapping_dax_shared-mapping-flag.patch
mm-gup-remove-redundant-check-for-pci-p2pdma-page.patch
mm-mm_init-move-p2pdma-page-refcount-initialisation-to-p2pdma.patch
mm-allow-compound-zone-device-pages.patch
mm-memory-enhance-insert_page_into_pte_locked-to-create-writable-mappings.patch
mm-memory-add-vmf_insert_page_mkwrite.patch
rmap-add-support-for-pud-sized-mappings-to-rmap.patch
huge_memory-add-vmf_insert_folio_pud.patch
huge_memory-add-vmf_insert_folio_pmd.patch
memremap-add-is_devdax_page-and-is_fsdax_page-helpers.patch
mm-gup-dont-allow-foll_longterm-pinning-of-fs-dax-pages.patch
proc-task_mmu-mark-devdax-and-fsdax-pages-as-always-unpinned.patch
mm-mlock-skip-zone_device-pmds-during-mlock.patch
fs-dax-properly-refcount-fs-dax-pages.patch
device-dax-properly-refcount-device-dax-pages-when-mapping.patch
mm-remove-pxx_devmap-callers.patch
mm-remove-devmap-related-functions-and-page-table-bits.patch
revert-riscv-mm-add-support-for-zone_device.patch
