Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 4 Feb 2021 09:54:37 -0800 | Subject | Re: [PATCH v2 3/4] mm: Introduce page_needs_cow_for_dma() for deciding whether cow |
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On Thu, Feb 4, 2021 at 6:50 AM Peter Xu <peterx@redhat.com> wrote: > > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1291,6 +1291,27 @@ static inline bool page_maybe_dma_pinned(struct page *page) > GUP_PIN_COUNTING_BIAS; > } > > +static inline bool is_cow_mapping(vm_flags_t flags) > +{ > + return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; > +}
Oh, and I just realized: moving this to <linux/mm.h> means that this patch could/should also get rid of
- manual copy of this in mm/hugetlb.c:
cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
- private #define for the same thing in fs/proc/task_mmu.c
#define is_cow_mapping(flags) (((flags) & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE)
- manual copy in drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c:
bool is_cow_mapping = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
I guess it could be a later cleanup patch too, but maybe best done in this series just to not forget about it.
Linus
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