Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5f32b265 authored by Jérôme Glisse's avatar Jérôme Glisse Committed by Linus Torvalds
Browse files

mm/mmu_notifier: kill invalidate_page 



The invalidate_page callback suffered from two pitfalls.  First it used
to happen after the page table lock was release and thus a new page
might have setup before the call to invalidate_page() happened.

This is in a weird way fixed by commit c7ab0d2f ("mm: convert
try_to_unmap_one() to use page_vma_mapped_walk()") that moved the
callback under the page table lock but this also broke several existing
users of the mmu_notifier API that assumed they could sleep inside this
callback.

The second pitfall was invalidate_page() being the only callback not
taking a range of address in respect to invalidation but was giving an
address and a page.  Lots of the callback implementers assumed this
could never be THP and thus failed to invalidate the appropriate range
for THP.

By killing this callback we unify the mmu_notifier callback API to
always take a virtual address range as input.

Finally this also simplifies the end user life as there is now two clear
choices:
  - invalidate_range_start()/end() callback (which allow you to sleep)
  - invalidate_range() where you can not sleep but happen right after
    page table update under page table lock

Signed-off-by: default avatarJérôme Glisse <jglisse@redhat.com>
Cc: Bernhard Held <berny156@gmx.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: axie <axie@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fb1522e0

include/linux/mmu_notifier.h

+0 −25
Original line number Diff line number Diff line
@@ -94,17 +94,6 @@ struct mmu_notifier_ops { 
			   unsigned long address,

			   pte_t pte);



	/*

	 * Before this is invoked any secondary MMU is still ok to

	 * read/write to the page previously pointed to by the Linux

	 * pte because the page hasn't been freed yet and it won't be

	 * freed until this returns. If required set_page_dirty has to

	 * be called internally to this method.

	 */

	void (*invalidate_page)(struct mmu_notifier *mn,

				struct mm_struct *mm,

				unsigned long address);



	/*

	 * invalidate_range_start() and invalidate_range_end() must be

	 * paired and are called only when the mmap_sem and/or the
@@ -220,8 +209,6 @@ extern int __mmu_notifier_test_young(struct mm_struct *mm, 
				     unsigned long address);

extern void __mmu_notifier_change_pte(struct mm_struct *mm,

				      unsigned long address, pte_t pte);

extern void __mmu_notifier_invalidate_page(struct mm_struct *mm,

					  unsigned long address);

extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,

				  unsigned long start, unsigned long end);

extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
@@ -268,13 +255,6 @@ static inline void mmu_notifier_change_pte(struct mm_struct *mm, 
		__mmu_notifier_change_pte(mm, address, pte);

}



static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,

					  unsigned long address)

{

	if (mm_has_notifiers(mm))

		__mmu_notifier_invalidate_page(mm, address);

}



static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,

				  unsigned long start, unsigned long end)

{
@@ -442,11 +422,6 @@ static inline void mmu_notifier_change_pte(struct mm_struct *mm, 
{

}



static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,

					  unsigned long address)

{

}



static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,

				  unsigned long start, unsigned long end)

{

mm/mmu_notifier.c

+0 −14
Original line number Diff line number Diff line
@@ -174,20 +174,6 @@ void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address, 
	srcu_read_unlock(&srcu, id);

}



void __mmu_notifier_invalidate_page(struct mm_struct *mm,

					  unsigned long address)

{

	struct mmu_notifier *mn;

	int id;



	id = srcu_read_lock(&srcu);

	hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {

		if (mn->ops->invalidate_page)

			mn->ops->invalidate_page(mn, mm, address);

	}

	srcu_read_unlock(&srcu, id);

}



void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,

				  unsigned long start, unsigned long end)

{