| Message ID | 20190219200430.11130-9-jglisse@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mmu notifier provide context informations | expand |
On 2/19/19 12:04 PM, jglisse@redhat.com wrote: > From: Jérôme Glisse <jglisse@redhat.com> > > Helper to test if a range is updated to read only (it is still valid > to read from the range). This is useful for device driver or anyone > who wish to optimize out update when they know that they already have > the range map read only. > > Signed-off-by: Jérôme Glisse <jglisse@redhat.com> > Cc: Christian König <christian.koenig@amd.com> > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> > Cc: Jani Nikula <jani.nikula@linux.intel.com> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> > Cc: Jan Kara <jack@suse.cz> > Cc: Andrea Arcangeli <aarcange@redhat.com> > Cc: Peter Xu <peterx@redhat.com> > Cc: Felix Kuehling <Felix.Kuehling@amd.com> > Cc: Jason Gunthorpe <jgg@mellanox.com> > Cc: Ross Zwisler <zwisler@kernel.org> > Cc: Dan Williams <dan.j.williams@intel.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Radim Krčmář <rkrcmar@redhat.com> > Cc: Michal Hocko <mhocko@kernel.org> > Cc: Christian Koenig <christian.koenig@amd.com> > Cc: Ralph Campbell <rcampbell@nvidia.com> > Cc: John Hubbard <jhubbard@nvidia.com> > Cc: kvm@vger.kernel.org > Cc: dri-devel@lists.freedesktop.org > Cc: linux-rdma@vger.kernel.org > Cc: Arnd Bergmann <arnd@arndb.de> > --- > include/linux/mmu_notifier.h | 4 ++++ > mm/mmu_notifier.c | 10 ++++++++++ > 2 files changed, 14 insertions(+) > > diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h > index 0379956fff23..b6c004bd9f6a 100644 > --- a/include/linux/mmu_notifier.h > +++ b/include/linux/mmu_notifier.h > @@ -259,6 +259,8 @@ extern void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *r, > bool only_end); > extern void __mmu_notifier_invalidate_range(struct mm_struct *mm, > unsigned long start, unsigned long end); > +extern bool > +mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range); > > static inline bool > mmu_notifier_range_blockable(const struct mmu_notifier_range *range) > @@ -568,6 +570,8 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) > { > } > > +#define mmu_notifier_range_update_to_read_only(r) false > + > #define ptep_clear_flush_young_notify ptep_clear_flush_young > #define pmdp_clear_flush_young_notify pmdp_clear_flush_young > #define ptep_clear_young_notify ptep_test_and_clear_young > diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c > index abd88c466eb2..ee36068077b6 100644 > --- a/mm/mmu_notifier.c > +++ b/mm/mmu_notifier.c > @@ -395,3 +395,13 @@ void mmu_notifier_unregister_no_release(struct mmu_notifier *mn, > mmdrop(mm); > } > EXPORT_SYMBOL_GPL(mmu_notifier_unregister_no_release); > + > +bool > +mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range) > +{ > + if (!range->vma || range->event != MMU_NOTIFY_PROTECTION_VMA) > + return false; > + /* Return true if the vma still have the read flag set. */ > + return range->vma->vm_flags & VM_READ; > +} > +EXPORT_SYMBOL_GPL(mmu_notifier_range_update_to_read_only); > Don't you have to check for !WRITE & READ? mprotect() can change the permissions from R/O to RW and end up calling mmu_notifier_range_init() and mmu_notifier_invalidate_range_start()/end(). I'm not sure how useful this is since only applies to the MMU_NOTIFY_PROTECTION_VMA case. Anyway, you can add Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index 0379956fff23..b6c004bd9f6a 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -259,6 +259,8 @@ extern void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *r, bool only_end); extern void __mmu_notifier_invalidate_range(struct mm_struct *mm, unsigned long start, unsigned long end); +extern bool +mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range); static inline bool mmu_notifier_range_blockable(const struct mmu_notifier_range *range) @@ -568,6 +570,8 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm) { } +#define mmu_notifier_range_update_to_read_only(r) false + #define ptep_clear_flush_young_notify ptep_clear_flush_young #define pmdp_clear_flush_young_notify pmdp_clear_flush_young #define ptep_clear_young_notify ptep_test_and_clear_young diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index abd88c466eb2..ee36068077b6 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -395,3 +395,13 @@ void mmu_notifier_unregister_no_release(struct mmu_notifier *mn, mmdrop(mm); } EXPORT_SYMBOL_GPL(mmu_notifier_unregister_no_release); + +bool +mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range) +{ + if (!range->vma || range->event != MMU_NOTIFY_PROTECTION_VMA) + return false; + /* Return true if the vma still have the read flag set. */ + return range->vma->vm_flags & VM_READ; +} +EXPORT_SYMBOL_GPL(mmu_notifier_range_update_to_read_only);