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Subject[PATCH 2/5] mmu_notifier: keep track of active invalidation ranges v2
Date
From: Jérôme Glisse <jglisse@redhat.com>

The mmu_notifier_invalidate_range_start() and mmu_notifier_invalidate_range_end()
can be considered as forming an "atomic" section for the cpu page table update
point of view. Between this two function the cpu page table content is unreliable
for the address range being invalidated.

Current user such as kvm need to know when they can trust the content of the cpu
page table. This becomes even more important to new users of the mmu_notifier
api (such as HMM or ODP).

This patch use a structure define at all call site to invalidate_range_start()
that is added to a list for the duration of the invalidation. It adds two new
helpers to allow querying if a range is being invalidated or to wait for a range
to become valid.

For proper synchronization, user must block new range invalidation from inside
there invalidate_range_start() callback, before calling the helper functions.
Otherwise there is no garanty that a new range invalidation will not be added
after the call to the helper function to query for existing range.

Changed since v1:
- Fix a possible deadlock in mmu_notifier_range_wait_valid()

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
---
drivers/gpu/drm/i915/i915_gem_userptr.c | 13 +++--
drivers/iommu/amd_iommu_v2.c | 8 +--
drivers/misc/sgi-gru/grutlbpurge.c | 15 +++---
drivers/xen/gntdev.c | 15 +++---
fs/proc/task_mmu.c | 12 +++--
include/linux/mmu_notifier.h | 60 ++++++++++++----------
kernel/events/uprobes.c | 13 +++--
mm/huge_memory.c | 78 +++++++++++++----------------
mm/hugetlb.c | 55 +++++++++++----------
mm/ksm.c | 28 +++++------
mm/memory.c | 78 ++++++++++++++++-------------
mm/migrate.c | 36 +++++++-------
mm/mmu_notifier.c | 88 ++++++++++++++++++++++++++++-----
mm/mprotect.c | 17 ++++---
mm/mremap.c | 14 +++---
mm/rmap.c | 15 +++---
virt/kvm/kvm_main.c | 10 ++--
17 files changed, 310 insertions(+), 245 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 20dbd26..10b0044 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -128,26 +128,25 @@ restart:

static void i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn,
struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ const struct mmu_notifier_range *range)
{
struct i915_mmu_notifier *mn = container_of(_mn, struct i915_mmu_notifier, mn);
struct interval_tree_node *it = NULL;
- unsigned long next = start;
+ unsigned long next = range->start;
unsigned long serial = 0;
+ /* interval ranges are inclusive, but invalidate range is exclusive */
+ unsigned long end = range->end - 1;

- end--; /* interval ranges are inclusive, but invalidate range is exclusive */
while (next < end) {
struct drm_i915_gem_object *obj = NULL;

spin_lock(&mn->lock);
if (mn->has_linear)
- it = invalidate_range__linear(mn, mm, start, end);
+ it = invalidate_range__linear(mn, mm, range->start, end);
else if (serial == mn->serial)
it = interval_tree_iter_next(it, next, end);
else
- it = interval_tree_iter_first(&mn->objects, start, end);
+ it = interval_tree_iter_first(&mn->objects, range->start, end);
if (it != NULL) {
obj = container_of(it, struct i915_mmu_object, it)->obj;
drm_gem_object_reference(&obj->base);
diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 57d2acf..9b7f32d 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -421,9 +421,7 @@ static void mn_invalidate_page(struct mmu_notifier *mn,

static void mn_invalidate_range_start(struct mmu_notifier *mn,
struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ const struct mmu_notifier_range *range)
{
struct pasid_state *pasid_state;
struct device_state *dev_state;
@@ -444,9 +442,7 @@ static void mn_invalidate_range_start(struct mmu_notifier *mn,

static void mn_invalidate_range_end(struct mmu_notifier *mn,
struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ const struct mmu_notifier_range *range)
{
struct pasid_state *pasid_state;
struct device_state *dev_state;
diff --git a/drivers/misc/sgi-gru/grutlbpurge.c b/drivers/misc/sgi-gru/grutlbpurge.c
index e67fed1..44b41b7 100644
--- a/drivers/misc/sgi-gru/grutlbpurge.c
+++ b/drivers/misc/sgi-gru/grutlbpurge.c
@@ -221,8 +221,7 @@ void gru_flush_all_tlb(struct gru_state *gru)
*/
static void gru_invalidate_range_start(struct mmu_notifier *mn,
struct mm_struct *mm,
- unsigned long start, unsigned long end,
- enum mmu_event event)
+ const struct mmu_notifier_range *range)
{
struct gru_mm_struct *gms = container_of(mn, struct gru_mm_struct,
ms_notifier);
@@ -230,14 +229,13 @@ static void gru_invalidate_range_start(struct mmu_notifier *mn,
STAT(mmu_invalidate_range);
atomic_inc(&gms->ms_range_active);
gru_dbg(grudev, "gms %p, start 0x%lx, end 0x%lx, act %d\n", gms,
- start, end, atomic_read(&gms->ms_range_active));
- gru_flush_tlb_range(gms, start, end - start);
+ range->start, range->end, atomic_read(&gms->ms_range_active));
+ gru_flush_tlb_range(gms, range->start, range->end - range->start);
}

static void gru_invalidate_range_end(struct mmu_notifier *mn,
- struct mm_struct *mm, unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ struct mm_struct *mm,
+ const struct mmu_notifier_range *range)
{
struct gru_mm_struct *gms = container_of(mn, struct gru_mm_struct,
ms_notifier);
@@ -246,7 +244,8 @@ static void gru_invalidate_range_end(struct mmu_notifier *mn,
(void)atomic_dec_and_test(&gms->ms_range_active);

wake_up_all(&gms->ms_wait_queue);
- gru_dbg(grudev, "gms %p, start 0x%lx, end 0x%lx\n", gms, start, end);
+ gru_dbg(grudev, "gms %p, start 0x%lx, end 0x%lx\n", gms,
+ range->start, range->end);
}

static void gru_invalidate_page(struct mmu_notifier *mn, struct mm_struct *mm,
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index fe9da94..db5c2cad 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -428,19 +428,17 @@ static void unmap_if_in_range(struct grant_map *map,

static void mn_invl_range_start(struct mmu_notifier *mn,
struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ const struct mmu_notifier_range *range)
{
struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
struct grant_map *map;

spin_lock(&priv->lock);
list_for_each_entry(map, &priv->maps, next) {
- unmap_if_in_range(map, start, end);
+ unmap_if_in_range(map, range->start, range->end);
}
list_for_each_entry(map, &priv->freeable_maps, next) {
- unmap_if_in_range(map, start, end);
+ unmap_if_in_range(map, range->start, range->end);
}
spin_unlock(&priv->lock);
}
@@ -450,7 +448,12 @@ static void mn_invl_page(struct mmu_notifier *mn,
unsigned long address,
enum mmu_event event)
{
- mn_invl_range_start(mn, mm, address, address + PAGE_SIZE, event);
+ struct mmu_notifier_range range;
+
+ range.start = address;
+ range.end = address + PAGE_SIZE;
+ range.event = event;
+ mn_invl_range_start(mn, mm, &range);
}

static void mn_release(struct mmu_notifier *mn,
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e75a848..ce57739 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -855,6 +855,12 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
.mm = mm,
.private = &cp,
};
+ struct mmu_notifier_range range = {
+ .start = 0,
+ .end = -1UL,
+ .event = MMU_ISDIRTY,
+ };
+
down_read(&mm->mmap_sem);
if (type == CLEAR_REFS_SOFT_DIRTY) {
for (vma = mm->mmap; vma; vma = vma->vm_next) {
@@ -869,8 +875,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
downgrade_write(&mm->mmap_sem);
break;
}
- mmu_notifier_invalidate_range_start(mm, 0,
- -1, MMU_ISDIRTY);
+ mmu_notifier_invalidate_range_start(mm, &range);
}
for (vma = mm->mmap; vma; vma = vma->vm_next) {
cp.vma = vma;
@@ -895,8 +900,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
&clear_refs_walk);
}
if (type == CLEAR_REFS_SOFT_DIRTY)
- mmu_notifier_invalidate_range_end(mm, 0,
- -1, MMU_ISDIRTY);
+ mmu_notifier_invalidate_range_end(mm, &range);
flush_tlb_mm(mm);
up_read(&mm->mmap_sem);
mmput(mm);
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index ac2a121..d20eeb1 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -69,6 +69,13 @@ enum mmu_event {
MMU_WRITE_PROTECT,
};

+struct mmu_notifier_range {
+ struct list_head list;
+ unsigned long start;
+ unsigned long end;
+ enum mmu_event event;
+};
+
#ifdef CONFIG_MMU_NOTIFIER

/*
@@ -82,6 +89,12 @@ struct mmu_notifier_mm {
struct hlist_head list;
/* to serialize the list modifications and hlist_unhashed */
spinlock_t lock;
+ /* List of all active range invalidations. */
+ struct list_head ranges;
+ /* Number of active range invalidations. */
+ int nranges;
+ /* For threads waiting on range invalidations. */
+ wait_queue_head_t wait_queue;
};

struct mmu_notifier_ops {
@@ -202,14 +215,10 @@ struct mmu_notifier_ops {
*/
void (*invalidate_range_start)(struct mmu_notifier *mn,
struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event);
+ const struct mmu_notifier_range *range);
void (*invalidate_range_end)(struct mmu_notifier *mn,
struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event);
+ const struct mmu_notifier_range *range);

/*
* invalidate_range() is either called between
@@ -279,15 +288,17 @@ extern void __mmu_notifier_invalidate_page(struct mm_struct *mm,
unsigned long address,
enum mmu_event event);
extern void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event);
+ struct mmu_notifier_range *range);
extern void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event);
+ struct mmu_notifier_range *range);
extern void __mmu_notifier_invalidate_range(struct mm_struct *mm,
unsigned long start, unsigned long end);
+extern bool mmu_notifier_range_is_valid(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end);
+extern void mmu_notifier_range_wait_valid(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end);

static inline void mmu_notifier_release(struct mm_struct *mm)
{
@@ -330,21 +341,22 @@ static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,
}

static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ struct mmu_notifier_range *range)
{
+ /*
+ * Initialize list no matter what in case a mmu_notifier register after
+ * a range_start but before matching range_end.
+ */
+ INIT_LIST_HEAD(&range->list);
if (mm_has_notifiers(mm))
- __mmu_notifier_invalidate_range_start(mm, start, end, event);
+ __mmu_notifier_invalidate_range_start(mm, range);
}

static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ struct mmu_notifier_range *range)
{
if (mm_has_notifiers(mm))
- __mmu_notifier_invalidate_range_end(mm, start, end, event);
+ __mmu_notifier_invalidate_range_end(mm, range);
}

static inline void mmu_notifier_invalidate_range(struct mm_struct *mm,
@@ -486,16 +498,12 @@ static inline void mmu_notifier_invalidate_page(struct mm_struct *mm,
}

static inline void mmu_notifier_invalidate_range_start(struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ struct mmu_notifier_range *range)
{
}

static inline void mmu_notifier_invalidate_range_end(struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ struct mmu_notifier_range *range)
{
}

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index f7d79d9..3cfe7ae 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -164,9 +164,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
spinlock_t *ptl;
pte_t *ptep;
int err;
- /* For mmu_notifiers */
- const unsigned long mmun_start = addr;
- const unsigned long mmun_end = addr + PAGE_SIZE;
+ struct mmu_notifier_range range;
struct mem_cgroup *memcg;

err = mem_cgroup_try_charge(kpage, vma->vm_mm, GFP_KERNEL, &memcg);
@@ -176,8 +174,10 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
/* For try_to_free_swap() and munlock_vma_page() below */
lock_page(page);

- mmu_notifier_invalidate_range_start(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ range.start = addr;
+ range.end = addr + PAGE_SIZE;
+ range.event = MMU_MIGRATE;
+ mmu_notifier_invalidate_range_start(mm, &range);
err = -EAGAIN;
ptep = page_check_address(page, mm, addr, &ptl, 0);
if (!ptep)
@@ -211,8 +211,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
err = 0;
unlock:
mem_cgroup_cancel_charge(kpage, memcg);
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);
unlock_page(page);
return err;
}
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 49d0cec..7f56188 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -987,8 +987,7 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
pmd_t _pmd;
int ret = 0, i;
struct page **pages;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;

pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR,
GFP_KERNEL);
@@ -1026,10 +1025,10 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
cond_resched();
}

- mmun_start = haddr;
- mmun_end = haddr + HPAGE_PMD_SIZE;
- mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end,
- MMU_MIGRATE);
+ range.start = haddr;
+ range.end = haddr + HPAGE_PMD_SIZE;
+ range.event = MMU_MIGRATE;
+ mmu_notifier_invalidate_range_start(mm, &range);

ptl = pmd_lock(mm, pmd);
if (unlikely(!pmd_same(*pmd, orig_pmd)))
@@ -1063,8 +1062,7 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
page_remove_rmap(page);
spin_unlock(ptl);

- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);

ret |= VM_FAULT_WRITE;
put_page(page);
@@ -1074,8 +1072,7 @@ out:

out_free_pages:
spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);
for (i = 0; i < HPAGE_PMD_NR; i++) {
memcg = (void *)page_private(pages[i]);
set_page_private(pages[i], 0);
@@ -1094,8 +1091,7 @@ int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page *page = NULL, *new_page;
struct mem_cgroup *memcg;
unsigned long haddr;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;

ptl = pmd_lockptr(mm, pmd);
VM_BUG_ON_VMA(!vma->anon_vma, vma);
@@ -1165,10 +1161,10 @@ alloc:
copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR);
__SetPageUptodate(new_page);

- mmun_start = haddr;
- mmun_end = haddr + HPAGE_PMD_SIZE;
- mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end,
- MMU_MIGRATE);
+ range.start = haddr;
+ range.end = haddr + HPAGE_PMD_SIZE;
+ range.event = MMU_MIGRATE;
+ mmu_notifier_invalidate_range_start(mm, &range);

spin_lock(ptl);
if (page)
@@ -1200,8 +1196,7 @@ alloc:
}
spin_unlock(ptl);
out_mn:
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);
out:
return ret;
out_unlock:
@@ -1633,12 +1628,12 @@ static int __split_huge_page_splitting(struct page *page,
spinlock_t *ptl;
pmd_t *pmd;
int ret = 0;
- /* For mmu_notifiers */
- const unsigned long mmun_start = address;
- const unsigned long mmun_end = address + HPAGE_PMD_SIZE;
+ struct mmu_notifier_range range;

- mmu_notifier_invalidate_range_start(mm, mmun_start,
- mmun_end, MMU_HSPLIT);
+ range.start = address;
+ range.end = address + HPAGE_PMD_SIZE;
+ range.event = MMU_HSPLIT;
+ mmu_notifier_invalidate_range_start(mm, &range);
pmd = page_check_address_pmd(page, mm, address,
PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG, &ptl);
if (pmd) {
@@ -1654,8 +1649,7 @@ static int __split_huge_page_splitting(struct page *page,
ret = 1;
spin_unlock(ptl);
}
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_HSPLIT);
+ mmu_notifier_invalidate_range_end(mm, &range);

return ret;
}
@@ -2433,8 +2427,7 @@ static void collapse_huge_page(struct mm_struct *mm,
int isolated;
unsigned long hstart, hend;
struct mem_cgroup *memcg;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;

VM_BUG_ON(address & ~HPAGE_PMD_MASK);

@@ -2474,10 +2467,10 @@ static void collapse_huge_page(struct mm_struct *mm,
pte = pte_offset_map(pmd, address);
pte_ptl = pte_lockptr(mm, pmd);

- mmun_start = address;
- mmun_end = address + HPAGE_PMD_SIZE;
- mmu_notifier_invalidate_range_start(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ range.start = address;
+ range.end = address + HPAGE_PMD_SIZE;
+ range.event = MMU_MIGRATE;
+ mmu_notifier_invalidate_range_start(mm, &range);
pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
/*
* After this gup_fast can't run anymore. This also removes
@@ -2487,8 +2480,7 @@ static void collapse_huge_page(struct mm_struct *mm,
*/
_pmd = pmdp_clear_flush(vma, address, pmd);
spin_unlock(pmd_ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);

spin_lock(pte_ptl);
isolated = __collapse_huge_page_isolate(vma, address, pte);
@@ -2871,36 +2863,32 @@ void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
struct page *page;
struct mm_struct *mm = vma->vm_mm;
unsigned long haddr = address & HPAGE_PMD_MASK;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;

BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE);

- mmun_start = haddr;
- mmun_end = haddr + HPAGE_PMD_SIZE;
+ range.start = haddr;
+ range.end = haddr + HPAGE_PMD_SIZE;
+ range.event = MMU_MIGRATE;
again:
- mmu_notifier_invalidate_range_start(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_start(mm, &range);
ptl = pmd_lock(mm, pmd);
if (unlikely(!pmd_trans_huge(*pmd))) {
spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);
return;
}
if (is_huge_zero_pmd(*pmd)) {
__split_huge_zero_page_pmd(vma, haddr, pmd);
spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);
return;
}
page = pmd_page(*pmd);
VM_BUG_ON_PAGE(!page_count(page), page);
get_page(page);
spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);

split_huge_page(page);

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 652feac..3486d84 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2551,17 +2551,16 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
int cow;
struct hstate *h = hstate_vma(vma);
unsigned long sz = huge_page_size(h);
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;
int ret = 0;

cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;

- mmun_start = vma->vm_start;
- mmun_end = vma->vm_end;
+ range.start = vma->vm_start;
+ range.end = vma->vm_end;
+ range.event = MMU_MIGRATE;
if (cow)
- mmu_notifier_invalidate_range_start(src, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_start(src, &range);

for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
spinlock_t *src_ptl, *dst_ptl;
@@ -2601,8 +2600,8 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
} else {
if (cow) {
huge_ptep_set_wrprotect(src, addr, src_pte);
- mmu_notifier_invalidate_range(src, mmun_start,
- mmun_end);
+ mmu_notifier_invalidate_range(src, range.start,
+ range.end);
}
entry = huge_ptep_get(src_pte);
ptepage = pte_page(entry);
@@ -2615,8 +2614,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
}

if (cow)
- mmu_notifier_invalidate_range_end(src, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(src, &range);

return ret;
}
@@ -2634,16 +2632,17 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
struct page *page;
struct hstate *h = hstate_vma(vma);
unsigned long sz = huge_page_size(h);
- const unsigned long mmun_start = start; /* For mmu_notifiers */
- const unsigned long mmun_end = end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;

WARN_ON(!is_vm_hugetlb_page(vma));
BUG_ON(start & ~huge_page_mask(h));
BUG_ON(end & ~huge_page_mask(h));

+ range.start = start;
+ range.end = end;
+ range.event = MMU_MIGRATE;
tlb_start_vma(tlb, vma);
- mmu_notifier_invalidate_range_start(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_start(mm, &range);
address = start;
again:
for (; address < end; address += sz) {
@@ -2716,8 +2715,7 @@ unlock:
if (address < end && !ref_page)
goto again;
}
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);
tlb_end_vma(tlb, vma);
}

@@ -2814,8 +2812,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
struct hstate *h = hstate_vma(vma);
struct page *old_page, *new_page;
int ret = 0, outside_reserve = 0;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;

old_page = pte_page(pte);

@@ -2893,10 +2890,11 @@ retry_avoidcopy:
pages_per_huge_page(h));
__SetPageUptodate(new_page);

- mmun_start = address & huge_page_mask(h);
- mmun_end = mmun_start + huge_page_size(h);
- mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end,
- MMU_MIGRATE);
+ range.start = address & huge_page_mask(h);
+ range.end = range.start + huge_page_size(h);
+ range.event = MMU_MIGRATE;
+ mmu_notifier_invalidate_range_start(mm, &range);
+
/*
* Retake the page table lock to check for racing updates
* before the page tables are altered
@@ -2908,7 +2906,7 @@ retry_avoidcopy:

/* Break COW */
huge_ptep_clear_flush(vma, address, ptep);
- mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
+ mmu_notifier_invalidate_range(mm, range.start, range.end);
set_huge_pte_at(mm, address, ptep,
make_huge_pte(vma, new_page, 1));
page_remove_rmap(old_page);
@@ -2917,8 +2915,7 @@ retry_avoidcopy:
new_page = old_page;
}
spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end,
- MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);
out_release_all:
page_cache_release(new_page);
out_release_old:
@@ -3352,11 +3349,15 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
pte_t pte;
struct hstate *h = hstate_vma(vma);
unsigned long pages = 0;
+ struct mmu_notifier_range range;

BUG_ON(address >= end);
flush_cache_range(vma, address, end);

- mmu_notifier_invalidate_range_start(mm, start, end, MMU_MPROT);
+ range.start = start;
+ range.end = end;
+ range.event = MMU_MPROT;
+ mmu_notifier_invalidate_range_start(mm, &range);
i_mmap_lock_write(vma->vm_file->f_mapping);
for (; address < end; address += huge_page_size(h)) {
spinlock_t *ptl;
@@ -3387,7 +3388,7 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
flush_tlb_range(vma, start, end);
mmu_notifier_invalidate_range(mm, start, end);
i_mmap_unlock_write(vma->vm_file->f_mapping);
- mmu_notifier_invalidate_range_end(mm, start, end, MMU_MPROT);
+ mmu_notifier_invalidate_range_end(mm, &range);

return pages << h->order;
}
diff --git a/mm/ksm.c b/mm/ksm.c
index 8c3a892..3667d98 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -855,14 +855,13 @@ static inline int pages_identical(struct page *page1, struct page *page2)
static int write_protect_page(struct vm_area_struct *vma, struct page *page,
pte_t *orig_pte)
{
+ struct mmu_notifier_range range;
struct mm_struct *mm = vma->vm_mm;
unsigned long addr;
pte_t *ptep;
spinlock_t *ptl;
int swapped;
int err = -EFAULT;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */

addr = page_address_in_vma(page, vma);
if (addr == -EFAULT)
@@ -870,10 +869,10 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,

BUG_ON(PageTransCompound(page));

- mmun_start = addr;
- mmun_end = addr + PAGE_SIZE;
- mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end,
- MMU_WRITE_PROTECT);
+ range.start = addr;
+ range.end = addr + PAGE_SIZE;
+ range.event = MMU_WRITE_PROTECT;
+ mmu_notifier_invalidate_range_start(mm, &range);

ptep = page_check_address(page, mm, addr, &ptl, 0);
if (!ptep)
@@ -913,8 +912,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
out_unlock:
pte_unmap_unlock(ptep, ptl);
out_mn:
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end,
- MMU_WRITE_PROTECT);
+ mmu_notifier_invalidate_range_end(mm, &range);
out:
return err;
}
@@ -937,8 +935,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
spinlock_t *ptl;
unsigned long addr;
int err = -EFAULT;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;

addr = page_address_in_vma(page, vma);
if (addr == -EFAULT)
@@ -948,10 +945,10 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
if (!pmd)
goto out;

- mmun_start = addr;
- mmun_end = addr + PAGE_SIZE;
- mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end,
- MMU_MIGRATE);
+ range.start = addr;
+ range.end = addr + PAGE_SIZE;
+ range.event = MMU_MIGRATE;
+ mmu_notifier_invalidate_range_start(mm, &range);

ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
if (!pte_same(*ptep, orig_pte)) {
@@ -976,8 +973,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
pte_unmap_unlock(ptep, ptl);
err = 0;
out_mn:
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end,
- MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);
out:
return err;
}
diff --git a/mm/memory.c b/mm/memory.c
index 187f844..6c44dd7 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1011,8 +1011,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
unsigned long next;
unsigned long addr = vma->vm_start;
unsigned long end = vma->vm_end;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;
bool is_cow;
int ret;

@@ -1048,11 +1047,11 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
* is_cow_mapping() returns true.
*/
is_cow = is_cow_mapping(vma->vm_flags);
- mmun_start = addr;
- mmun_end = end;
+ range.start = addr;
+ range.end = end;
+ range.event = MMU_MIGRATE;
if (is_cow)
- mmu_notifier_invalidate_range_start(src_mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_start(src_mm, &range);

ret = 0;
dst_pgd = pgd_offset(dst_mm, addr);
@@ -1069,8 +1068,7 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
} while (dst_pgd++, src_pgd++, addr = next, addr != end);

if (is_cow)
- mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end,
- MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(src_mm, &range);
return ret;
}

@@ -1374,13 +1372,16 @@ void unmap_vmas(struct mmu_gather *tlb,
unsigned long end_addr)
{
struct mm_struct *mm = vma->vm_mm;
+ struct mmu_notifier_range range = {
+ .start = start_addr,
+ .end = end_addr,
+ .event = MMU_MUNMAP,
+ };

- mmu_notifier_invalidate_range_start(mm, start_addr,
- end_addr, MMU_MUNMAP);
+ mmu_notifier_invalidate_range_start(mm, &range);
for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
unmap_single_vma(tlb, vma, start_addr, end_addr, NULL);
- mmu_notifier_invalidate_range_end(mm, start_addr,
- end_addr, MMU_MUNMAP);
+ mmu_notifier_invalidate_range_end(mm, &range);
}

/**
@@ -1397,16 +1398,20 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long start,
{
struct mm_struct *mm = vma->vm_mm;
struct mmu_gather tlb;
- unsigned long end = start + size;
+ struct mmu_notifier_range range = {
+ .start = start,
+ .end = start + size,
+ .event = MMU_MIGRATE,
+ };

lru_add_drain();
- tlb_gather_mmu(&tlb, mm, start, end);
+ tlb_gather_mmu(&tlb, mm, start, range.end);
update_hiwater_rss(mm);
- mmu_notifier_invalidate_range_start(mm, start, end, MMU_MIGRATE);
- for ( ; vma && vma->vm_start < end; vma = vma->vm_next)
- unmap_single_vma(&tlb, vma, start, end, details);
- mmu_notifier_invalidate_range_end(mm, start, end, MMU_MIGRATE);
- tlb_finish_mmu(&tlb, start, end);
+ mmu_notifier_invalidate_range_start(mm, &range);
+ for ( ; vma && vma->vm_start < range.end; vma = vma->vm_next)
+ unmap_single_vma(&tlb, vma, start, range.end, details);
+ mmu_notifier_invalidate_range_end(mm, &range);
+ tlb_finish_mmu(&tlb, start, range.end);
}

/**
@@ -1423,15 +1428,19 @@ static void zap_page_range_single(struct vm_area_struct *vma, unsigned long addr
{
struct mm_struct *mm = vma->vm_mm;
struct mmu_gather tlb;
- unsigned long end = address + size;
+ struct mmu_notifier_range range = {
+ .start = address,
+ .end = address + size,
+ .event = MMU_MUNMAP,
+ };

lru_add_drain();
- tlb_gather_mmu(&tlb, mm, address, end);
+ tlb_gather_mmu(&tlb, mm, address, range.end);
update_hiwater_rss(mm);
- mmu_notifier_invalidate_range_start(mm, address, end, MMU_MUNMAP);
- unmap_single_vma(&tlb, vma, address, end, details);
- mmu_notifier_invalidate_range_end(mm, address, end, MMU_MUNMAP);
- tlb_finish_mmu(&tlb, address, end);
+ mmu_notifier_invalidate_range_start(mm, &range);
+ unmap_single_vma(&tlb, vma, address, range.end, details);
+ mmu_notifier_invalidate_range_end(mm, &range);
+ tlb_finish_mmu(&tlb, address, range.end);
}

/**
@@ -2051,10 +2060,12 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
int ret = 0;
int page_mkwrite = 0;
struct page *dirty_page = NULL;
- unsigned long mmun_start = 0; /* For mmu_notifiers */
- unsigned long mmun_end = 0; /* For mmu_notifiers */
+ struct mmu_notifier_range range;
struct mem_cgroup *memcg;

+ range.start = 0;
+ range.end = 0;
+
old_page = vm_normal_page(vma, address, orig_pte);
if (!old_page) {
/*
@@ -2213,10 +2224,10 @@ gotten:
if (mem_cgroup_try_charge(new_page, mm, GFP_KERNEL, &memcg))
goto oom_free_new;

- mmun_start = address & PAGE_MASK;
- mmun_end = mmun_start + PAGE_SIZE;
- mmu_notifier_invalidate_range_start(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ range.start = address & PAGE_MASK;
+ range.end = range.start + PAGE_SIZE;
+ range.event = MMU_MIGRATE;
+ mmu_notifier_invalidate_range_start(mm, &range);

/*
* Re-check the pte - we dropped the lock
@@ -2286,9 +2297,8 @@ gotten:
page_cache_release(new_page);
unlock:
pte_unmap_unlock(page_table, ptl);
- if (mmun_end > mmun_start)
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ if (range.end > range.start)
+ mmu_notifier_invalidate_range_end(mm, &range);
if (old_page) {
/*
* Don't let another task, with possibly unlocked vma,
diff --git a/mm/migrate.c b/mm/migrate.c
index b5279b8..1b5b9ab 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1776,10 +1776,13 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
int isolated = 0;
struct page *new_page = NULL;
int page_lru = page_is_file_cache(page);
- unsigned long mmun_start = address & HPAGE_PMD_MASK;
- unsigned long mmun_end = mmun_start + HPAGE_PMD_SIZE;
+ struct mmu_notifier_range range;
pmd_t orig_entry;

+ range.start = address & HPAGE_PMD_MASK;
+ range.end = range.start + HPAGE_PMD_SIZE;
+ range.event = MMU_MIGRATE;
+
/*
* Rate-limit the amount of data that is being migrated to a node.
* Optimal placement is no good if the memory bus is saturated and
@@ -1801,7 +1804,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
}

if (mm_tlb_flush_pending(mm))
- flush_tlb_range(vma, mmun_start, mmun_end);
+ flush_tlb_range(vma, range.start, range.end);

/* Prepare a page as a migration target */
__set_page_locked(new_page);
@@ -1814,14 +1817,12 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
WARN_ON(PageLRU(new_page));

/* Recheck the target PMD */
- mmu_notifier_invalidate_range_start(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_start(mm, &range);
ptl = pmd_lock(mm, pmd);
if (unlikely(!pmd_same(*pmd, entry) || page_count(page) != 2)) {
fail_putback:
spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);

/* Reverse changes made by migrate_page_copy() */
if (TestClearPageActive(new_page))
@@ -1854,17 +1855,17 @@ fail_putback:
* The SetPageUptodate on the new page and page_add_new_anon_rmap
* guarantee the copy is visible before the pagetable update.
*/
- flush_cache_range(vma, mmun_start, mmun_end);
- page_add_anon_rmap(new_page, vma, mmun_start);
- pmdp_clear_flush_notify(vma, mmun_start, pmd);
- set_pmd_at(mm, mmun_start, pmd, entry);
- flush_tlb_range(vma, mmun_start, mmun_end);
+ flush_cache_range(vma, range.start, range.end);
+ page_add_anon_rmap(new_page, vma, range.start);
+ pmdp_clear_flush_notify(vma, range.start, pmd);
+ set_pmd_at(mm, range.start, pmd, entry);
+ flush_tlb_range(vma, range.start, range.end);
update_mmu_cache_pmd(vma, address, &entry);

if (page_count(page) != 2) {
- set_pmd_at(mm, mmun_start, pmd, orig_entry);
- flush_tlb_range(vma, mmun_start, mmun_end);
- mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
+ set_pmd_at(mm, range.start, pmd, orig_entry);
+ flush_tlb_range(vma, range.start, range.end);
+ mmu_notifier_invalidate_range(mm, range.start, range.end);
update_mmu_cache_pmd(vma, address, &entry);
page_remove_rmap(new_page);
goto fail_putback;
@@ -1875,8 +1876,7 @@ fail_putback:
page_remove_rmap(page);

spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(mm, &range);

/* Take an "isolate" reference and put new page on the LRU. */
get_page(new_page);
@@ -1901,7 +1901,7 @@ out_dropref:
ptl = pmd_lock(mm, pmd);
if (pmd_same(*pmd, entry)) {
entry = pmd_mknonnuma(entry);
- set_pmd_at(mm, mmun_start, pmd, entry);
+ set_pmd_at(mm, range.start, pmd, entry);
update_mmu_cache_pmd(vma, address, &entry);
}
spin_unlock(ptl);
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index e51ea02..8d48bc4 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -174,9 +174,7 @@ void __mmu_notifier_invalidate_page(struct mm_struct *mm,
}

void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ struct mmu_notifier_range *range)

{
struct mmu_notifier *mn;
@@ -185,21 +183,36 @@ void __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
if (mn->ops->invalidate_range_start)
- mn->ops->invalidate_range_start(mn, mm, start,
- end, event);
+ mn->ops->invalidate_range_start(mn, mm, range);
}
srcu_read_unlock(&srcu, id);
+
+ /*
+ * This must happen after the callback so that subsystem can block on
+ * new invalidation range to synchronize itself.
+ */
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ list_add_tail(&range->list, &mm->mmu_notifier_mm->ranges);
+ mm->mmu_notifier_mm->nranges++;
+ spin_unlock(&mm->mmu_notifier_mm->lock);
}
EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range_start);

void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ struct mmu_notifier_range *range)
{
struct mmu_notifier *mn;
int id;

+ /*
+ * This must happen before the callback so that subsystem can unblock
+ * when range invalidation end.
+ */
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ list_del_init(&range->list);
+ mm->mmu_notifier_mm->nranges--;
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
/*
@@ -211,12 +224,18 @@ void __mmu_notifier_invalidate_range_end(struct mm_struct *mm,
* (besides the pointer check).
*/
if (mn->ops->invalidate_range)
- mn->ops->invalidate_range(mn, mm, start, end);
+ mn->ops->invalidate_range(mn, mm,
+ range->start, range->end);
if (mn->ops->invalidate_range_end)
- mn->ops->invalidate_range_end(mn, mm, start,
- end, event);
+ mn->ops->invalidate_range_end(mn, mm, range);
}
srcu_read_unlock(&srcu, id);
+
+ /*
+ * Wakeup after callback so they can do their job before any of the
+ * waiters resume.
+ */
+ wake_up(&mm->mmu_notifier_mm->wait_queue);
}
EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range_end);

@@ -235,6 +254,50 @@ void __mmu_notifier_invalidate_range(struct mm_struct *mm,
}
EXPORT_SYMBOL_GPL(__mmu_notifier_invalidate_range);

+static bool mmu_notifier_range_is_valid_locked(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ struct mmu_notifier_range *range;
+
+ list_for_each_entry(range, &mm->mmu_notifier_mm->ranges, list) {
+ if (!(range->end <= start || range->start >= end)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+bool mmu_notifier_range_is_valid(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ bool valid;
+
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ valid = mmu_notifier_range_is_valid_locked(mm, start, end);
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+ return valid;
+}
+EXPORT_SYMBOL_GPL(mmu_notifier_range_is_valid);
+
+void mmu_notifier_range_wait_valid(struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ while (!mmu_notifier_range_is_valid_locked(mm, start, end)) {
+ int nranges = mm->mmu_notifier_mm->nranges;
+
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+ wait_event(mm->mmu_notifier_mm->wait_queue,
+ nranges != mm->mmu_notifier_mm->nranges);
+ spin_lock(&mm->mmu_notifier_mm->lock);
+ }
+ spin_unlock(&mm->mmu_notifier_mm->lock);
+}
+EXPORT_SYMBOL_GPL(mmu_notifier_range_wait_valid);
+
static int do_mmu_notifier_register(struct mmu_notifier *mn,
struct mm_struct *mm,
int take_mmap_sem)
@@ -264,6 +327,9 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn,
if (!mm_has_notifiers(mm)) {
INIT_HLIST_HEAD(&mmu_notifier_mm->list);
spin_lock_init(&mmu_notifier_mm->lock);
+ INIT_LIST_HEAD(&mmu_notifier_mm->ranges);
+ mmu_notifier_mm->nranges = 0;
+ init_waitqueue_head(&mmu_notifier_mm->wait_queue);

mm->mmu_notifier_mm = mmu_notifier_mm;
mmu_notifier_mm = NULL;
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 2302721..c88f770 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -139,7 +139,9 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
unsigned long next;
unsigned long pages = 0;
unsigned long nr_huge_updates = 0;
- unsigned long mni_start = 0;
+ struct mmu_notifier_range range = {
+ .start = 0,
+ };

pmd = pmd_offset(pud, addr);
do {
@@ -150,10 +152,11 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
continue;

/* invoke the mmu notifier if the pmd is populated */
- if (!mni_start) {
- mni_start = addr;
- mmu_notifier_invalidate_range_start(mm, mni_start,
- end, MMU_MPROT);
+ if (!range.start) {
+ range.start = addr;
+ range.end = end;
+ range.event = MMU_MPROT;
+ mmu_notifier_invalidate_range_start(mm, &range);
}

if (pmd_trans_huge(*pmd)) {
@@ -180,8 +183,8 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,
pages += this_pages;
} while (pmd++, addr = next, addr != end);

- if (mni_start)
- mmu_notifier_invalidate_range_end(mm, mni_start, end, MMU_MPROT);
+ if (range.start)
+ mmu_notifier_invalidate_range_end(mm, &range);

if (nr_huge_updates)
count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates);
diff --git a/mm/mremap.c b/mm/mremap.c
index 1ede220..5556f51 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -167,18 +167,17 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
bool need_rmap_locks)
{
unsigned long extent, next, old_end;
+ struct mmu_notifier_range range;
pmd_t *old_pmd, *new_pmd;
bool need_flush = false;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */

old_end = old_addr + len;
flush_cache_range(vma, old_addr, old_end);

- mmun_start = old_addr;
- mmun_end = old_end;
- mmu_notifier_invalidate_range_start(vma->vm_mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ range.start = old_addr;
+ range.end = old_end;
+ range.event = MMU_MIGRATE;
+ mmu_notifier_invalidate_range_start(vma->vm_mm, &range);

for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
cond_resched();
@@ -230,8 +229,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
if (likely(need_flush))
flush_tlb_range(vma, old_end-len, old_addr);

- mmu_notifier_invalidate_range_end(vma->vm_mm, mmun_start,
- mmun_end, MMU_MIGRATE);
+ mmu_notifier_invalidate_range_end(vma->vm_mm, &range);

return len + old_addr - old_end; /* how much done */
}
diff --git a/mm/rmap.c b/mm/rmap.c
index 367f882..ff79815 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1316,15 +1316,14 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
spinlock_t *ptl;
struct page *page;
unsigned long address;
- unsigned long mmun_start; /* For mmu_notifiers */
- unsigned long mmun_end; /* For mmu_notifiers */
+ struct mmu_notifier_range range;
unsigned long end;
int ret = SWAP_AGAIN;
int locked_vma = 0;
- enum mmu_event event = MMU_MIGRATE;

+ range.event = MMU_MIGRATE;
if (flags & TTU_MUNLOCK)
- event = MMU_MUNLOCK;
+ range.event = MMU_MUNLOCK;

address = (vma->vm_start + cursor) & CLUSTER_MASK;
end = address + CLUSTER_SIZE;
@@ -1337,9 +1336,9 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
if (!pmd)
return ret;

- mmun_start = address;
- mmun_end = end;
- mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end, event);
+ range.start = address;
+ range.end = end;
+ mmu_notifier_invalidate_range_start(mm, &range);

/*
* If we can acquire the mmap_sem for read, and vma is VM_LOCKED,
@@ -1408,7 +1407,7 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
(*mapcount)--;
}
pte_unmap_unlock(pte - 1, ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end, event);
+ mmu_notifier_invalidate_range_end(mm, &range);
if (locked_vma)
up_read(&vma->vm_mm->mmap_sem);
return ret;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 08bc07c..4ab31de 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -322,9 +322,7 @@ static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,

static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ const struct mmu_notifier_range *range)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
int need_tlb_flush = 0, idx;
@@ -337,7 +335,7 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
* count is also read inside the mmu_lock critical section.
*/
kvm->mmu_notifier_count++;
- need_tlb_flush = kvm_unmap_hva_range(kvm, start, end);
+ need_tlb_flush = kvm_unmap_hva_range(kvm, range->start, range->end);
need_tlb_flush |= kvm->tlbs_dirty;
/* we've to flush the tlb before the pages can be freed */
if (need_tlb_flush)
@@ -349,9 +347,7 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,

static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
struct mm_struct *mm,
- unsigned long start,
- unsigned long end,
- enum mmu_event event)
+ const struct mmu_notifier_range *range)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);

--
1.9.3
--
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