The patch titled
Subject: mm: allow a NULL fn callback in apply_to_page_range
has been added to the -mm tree. Its filename is
mm-allow-a-null-fn-callback-in-apply_to_page_range.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-allow-a-null-fn-callback-in-apply_to_page_range.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-allow-a-null-fn-callback-in-apply_to_page_range.patch
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: mm: allow a NULL fn callback in apply_to_page_range
Besides calling the callback on each page, apply_to_page_range also has
the effect of pre-faulting all PTEs for the range. To support callers
that only need the pre-faulting, make the callback optional.
Based on a patch from Minchan Kim <minchan@xxxxxxxxxx>.
Link: https://lkml.kernel.org/r/20200930175133.1252382-5-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
--- a/mm/memory.c~mm-allow-a-null-fn-callback-in-apply_to_page_range
+++ a/mm/memory.c
@@ -2421,13 +2421,15 @@ static int apply_to_pte_range(struct mm_
arch_enter_lazy_mmu_mode();
- do {
- if (create || !pte_none(*pte)) {
- err = fn(pte++, addr, data);
- if (err)
- break;
- }
- } while (addr += PAGE_SIZE, addr != end);
+ if (fn) {
+ do {
+ if (create || !pte_none(*pte)) {
+ err = fn(pte++, addr, data);
+ if (err)
+ break;
+ }
+ } while (addr += PAGE_SIZE, addr != end);
+ }
*mask |= PGTBL_PTE_MODIFIED;
arch_leave_lazy_mmu_mode();
_
Patches currently in -mm which might be from hch@xxxxxx are
mm-add-a-vm_map_put_pages-flag-for-vmap.patch
mm-add-a-vmap_pfn-function.patch
mm-allow-a-null-fn-callback-in-apply_to_page_range.patch
zsmalloc-switch-from-alloc_vm_area-to-get_vm_area.patch
drm-i915-use-vmap-in-shmem_pin_map.patch
drm-i915-use-vmap-in-i915_gem_object_map.patch
xen-xenbus-use-apply_to_page_range-directly-in-xenbus_map_ring_pv.patch
x86-xen-open-code-alloc_vm_area-in-arch_gnttab_valloc.patch
mm-remove-alloc_vm_area.patch
