[PATCH 5/7] mm: Use pudp_get() for accessing PUD entries

From: Anshuman Khandual
Date: Fri Sep 13 2024 - 04:47:05 EST

Convert PUD accesses via pudp_get() helper that defaults as READ_ONCE() but
also provides the platform an opportunity to override when required.

Cc: Dimitri Sivanich <dimitri.sivanich@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: "Jérôme Glisse" <jglisse@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Naoya Horiguchi <nao.horiguchi@xxxxxxxxx>
Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-perf-users@xxxxxxxxxxxxxxx
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
drivers/misc/sgi-gru/grufault.c | 2 +-
include/linux/huge_mm.h | 2 +-
include/linux/mm.h | 2 +-
include/linux/pgtable.h | 10 +++++-----
kernel/events/core.c | 2 +-
mm/gup.c | 12 ++++++------
mm/hmm.c | 2 +-
mm/huge_memory.c | 16 ++++++++--------
mm/hugetlb.c | 6 +++---
mm/kasan/init.c | 10 +++++-----
mm/kasan/shadow.c | 4 ++--
mm/mapping_dirty_helpers.c | 2 +-
mm/memory-failure.c | 4 ++--
mm/memory.c | 10 +++++-----
mm/page_table_check.c | 2 +-
mm/page_vma_mapped.c | 2 +-
mm/pgalloc-track.h | 2 +-
mm/pgtable-generic.c | 2 +-
mm/ptdump.c | 4 ++--
19 files changed, 48 insertions(+), 48 deletions(-)

diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index f3d6249b7dfb..0a06ec92f090 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -220,7 +220,7 @@ static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
goto err;

pudp = pud_offset(p4dp, vaddr);
- if (unlikely(pud_none(*pudp)))
+ if (unlikely(pud_none(pudp_get(pudp))))
goto err;

pmdp = pmd_offset(pudp, vaddr);
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 351d6c72af9e..17ee222e4004 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -378,7 +378,7 @@ static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
struct vm_area_struct *vma)
{
- if (pud_trans_huge(*pud) || pud_devmap(*pud))
+ if (pud_trans_huge(pudp_get(pud)) || pud_devmap(pudp_get(pud)))
return __pud_trans_huge_lock(pud, vma);
else
return NULL;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 258e49323306..1bb1599b5779 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2832,7 +2832,7 @@ static inline pud_t *pud_alloc(struct mm_struct *mm, p4d_t *p4d,

static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
{
- return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?
+ return (unlikely(pud_none(pudp_get(pud))) && __pmd_alloc(mm, pud, address)) ?
NULL: pmd_offset(pud, address);
}
#endif /* CONFIG_MMU */
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 188a183205b3..b25a0a505ce6 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -611,7 +611,7 @@ static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,
unsigned long address,
pud_t *pudp)
{
- pud_t pud = *pudp;
+ pud_t pud = pudp_get(pudp);

pud_clear(pudp);
page_table_check_pud_clear(mm, pud);
@@ -893,7 +893,7 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
static inline void pudp_set_wrprotect(struct mm_struct *mm,
unsigned long address, pud_t *pudp)
{
- pud_t old_pud = *pudp;
+ pud_t old_pud = pudp_get(pudp);

set_pud_at(mm, address, pudp, pud_wrprotect(old_pud));
}
@@ -1072,7 +1072,7 @@ static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)

#define set_pud_safe(pudp, pud) \
({ \
- WARN_ON_ONCE(pud_present(*pudp) && !pud_same(*pudp, pud)); \
+ WARN_ON_ONCE(pud_present(pudp_get(pudp)) && !pud_same(pudp_get(pudp), pud)); \
set_pud(pudp, pud); \
})

@@ -1259,9 +1259,9 @@ static inline int p4d_none_or_clear_bad(p4d_t *p4d)

static inline int pud_none_or_clear_bad(pud_t *pud)
{
- if (pud_none(*pud))
+ if (pud_none(pudp_get(pud)))
return 1;
- if (unlikely(pud_bad(*pud))) {
+ if (unlikely(pud_bad(pudp_get(pud)))) {
pud_clear_bad(pud);
return 1;
}
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8a6c6bbcd658..35e2f2789246 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7619,7 +7619,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
return p4d_leaf_size(p4d);

pudp = pud_offset_lockless(p4dp, p4d, addr);
- pud = READ_ONCE(*pudp);
+ pud = pudp_get(pudp);
if (!pud_present(pud))
return 0;

diff --git a/mm/gup.c b/mm/gup.c
index aeeac0a54944..300fc7eb306c 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -606,7 +606,7 @@ static struct page *follow_huge_pud(struct vm_area_struct *vma,
{
struct mm_struct *mm = vma->vm_mm;
struct page *page;
- pud_t pud = *pudp;
+ pud_t pud = pudp_get(pudp);
unsigned long pfn = pud_pfn(pud);
int ret;

@@ -989,7 +989,7 @@ static struct page *follow_pud_mask(struct vm_area_struct *vma,
struct mm_struct *mm = vma->vm_mm;

pudp = pud_offset(p4dp, address);
- pud = READ_ONCE(*pudp);
+ pud = pudp_get(pudp);
if (!pud_present(pud))
return no_page_table(vma, flags, address);
if (pud_leaf(pud)) {
@@ -1117,7 +1117,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
if (p4d_none(*p4d))
return -EFAULT;
pud = pud_offset(p4d, address);
- if (pud_none(*pud))
+ if (pud_none(pudp_get(pud)))
return -EFAULT;
pmd = pmd_offset(pud, address);
if (!pmd_present(pmdp_get(pmd)))
@@ -3025,7 +3025,7 @@ static int gup_fast_devmap_pud_leaf(pud_t orig, pud_t *pudp, unsigned long addr,
if (!gup_fast_devmap_leaf(fault_pfn, addr, end, flags, pages, nr))
return 0;

- if (unlikely(pud_val(orig) != pud_val(*pudp))) {
+ if (unlikely(pud_val(orig) != pud_val(pudp_get(pudp)))) {
gup_fast_undo_dev_pagemap(nr, nr_start, flags, pages);
return 0;
}
@@ -3118,7 +3118,7 @@ static int gup_fast_pud_leaf(pud_t orig, pud_t *pudp, unsigned long addr,
if (!folio)
return 0;

- if (unlikely(pud_val(orig) != pud_val(*pudp))) {
+ if (unlikely(pud_val(orig) != pud_val(pudp_get(pudp)))) {
gup_put_folio(folio, refs, flags);
return 0;
}
@@ -3219,7 +3219,7 @@ static int gup_fast_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr,

pudp = pud_offset_lockless(p4dp, p4d, addr);
do {
- pud_t pud = READ_ONCE(*pudp);
+ pud_t pud = pudp_get(pudp);

next = pud_addr_end(addr, end);
if (unlikely(!pud_present(pud)))
diff --git a/mm/hmm.c b/mm/hmm.c
index 7e0229ae4a5a..c1b093d670b8 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -423,7 +423,7 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end,
/* Normally we don't want to split the huge page */
walk->action = ACTION_CONTINUE;

- pud = READ_ONCE(*pudp);
+ pud = pudp_get(pudp);
if (!pud_present(pud)) {
spin_unlock(ptl);
return hmm_vma_walk_hole(start, end, -1, walk);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 3545142a5dc9..994babaca75f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1247,13 +1247,13 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
spinlock_t *ptl;

ptl = pud_lock(mm, pud);
- if (!pud_none(*pud)) {
+ if (!pud_none(pudp_get(pud))) {
if (write) {
- if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) {
- WARN_ON_ONCE(!is_huge_zero_pud(*pud));
+ if (pud_pfn(pudp_get(pud)) != pfn_t_to_pfn(pfn)) {
+ WARN_ON_ONCE(!is_huge_zero_pud(pudp_get(pud)));
goto out_unlock;
}
- entry = pud_mkyoung(*pud);
+ entry = pud_mkyoung(pudp_get(pud));
entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
if (pudp_set_access_flags(vma, addr, pud, entry, 1))
update_mmu_cache_pud(vma, addr, pud);
@@ -1475,7 +1475,7 @@ void touch_pud(struct vm_area_struct *vma, unsigned long addr,
{
pud_t _pud;

- _pud = pud_mkyoung(*pud);
+ _pud = pud_mkyoung(pudp_get(pud));
if (write)
_pud = pud_mkdirty(_pud);
if (pudp_set_access_flags(vma, addr & HPAGE_PUD_MASK,
@@ -2284,7 +2284,7 @@ spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma)
spinlock_t *ptl;

ptl = pud_lock(vma->vm_mm, pud);
- if (likely(pud_trans_huge(*pud) || pud_devmap(*pud)))
+ if (likely(pud_trans_huge(pudp_get(pud)) || pud_devmap(pudp_get(pud))))
return ptl;
spin_unlock(ptl);
return NULL;
@@ -2318,7 +2318,7 @@ static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud,
VM_BUG_ON(haddr & ~HPAGE_PUD_MASK);
VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma);
- VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud));
+ VM_BUG_ON(!pud_trans_huge(pudp_get(pud)) && !pud_devmap(pudp_get(pud)));

count_vm_event(THP_SPLIT_PUD);

@@ -2336,7 +2336,7 @@ void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
(address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE);
mmu_notifier_invalidate_range_start(&range);
ptl = pud_lock(vma->vm_mm, pud);
- if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud)))
+ if (unlikely(!pud_trans_huge(pudp_get(pud)) && !pud_devmap(pudp_get(pud))))
goto out;
__split_huge_pud_locked(vma, pud, range.start);

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index aaf508be0a2b..a3820242b01e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7328,7 +7328,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
goto out;

spin_lock(&mm->page_table_lock);
- if (pud_none(*pud)) {
+ if (pud_none(pudp_get(pud))) {
pud_populate(mm, pud,
(pmd_t *)((unsigned long)spte & PAGE_MASK));
mm_inc_nr_pmds(mm);
@@ -7417,7 +7417,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
pte = (pte_t *)pud;
} else {
BUG_ON(sz != PMD_SIZE);
- if (want_pmd_share(vma, addr) && pud_none(*pud))
+ if (want_pmd_share(vma, addr) && pud_none(pudp_get(pud)))
pte = huge_pmd_share(mm, vma, addr, pud);
else
pte = (pte_t *)pmd_alloc(mm, pud, addr);
@@ -7461,7 +7461,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
if (sz == PUD_SIZE)
/* must be pud huge, non-present or none */
return (pte_t *)pud;
- if (!pud_present(*pud))
+ if (!pud_present(pudp_get(pud)))
return NULL;
/* must have a valid entry and size to go further */

diff --git a/mm/kasan/init.c b/mm/kasan/init.c
index 4418bcdcb2aa..f4cf519443e1 100644
--- a/mm/kasan/init.c
+++ b/mm/kasan/init.c
@@ -162,7 +162,7 @@ static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
continue;
}

- if (pud_none(*pud)) {
+ if (pud_none(pudp_get(pud))) {
pmd_t *p;

if (slab_is_available()) {
@@ -315,7 +315,7 @@ static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud)
return;
}

- pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud)));
+ pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(pudp_get(pud))));
pud_clear(pud);
}

@@ -326,7 +326,7 @@ static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d)

for (i = 0; i < PTRS_PER_PUD; i++) {
pud = pud_start + i;
- if (!pud_none(*pud))
+ if (!pud_none(pudp_get(pud)))
return;
}

@@ -407,10 +407,10 @@ static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,

next = pud_addr_end(addr, end);

- if (!pud_present(*pud))
+ if (!pud_present(pudp_get(pud)))
continue;

- if (kasan_pmd_table(*pud)) {
+ if (kasan_pmd_table(pudp_get(pud))) {
if (IS_ALIGNED(addr, PUD_SIZE) &&
IS_ALIGNED(next, PUD_SIZE)) {
pud_clear(pud);
diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index aec16a7236f7..dbd8164c75f1 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -197,9 +197,9 @@ static bool shadow_mapped(unsigned long addr)
if (p4d_none(*p4d))
return false;
pud = pud_offset(p4d, addr);
- if (pud_none(*pud))
+ if (pud_none(pudp_get(pud)))
return false;
- if (pud_leaf(*pud))
+ if (pud_leaf(pudp_get(pud)))
return true;
pmd = pmd_offset(pud, addr);
if (pmd_none(pmdp_get(pmd)))
diff --git a/mm/mapping_dirty_helpers.c b/mm/mapping_dirty_helpers.c
index 2f8829b3541a..c556cc4e3480 100644
--- a/mm/mapping_dirty_helpers.c
+++ b/mm/mapping_dirty_helpers.c
@@ -149,7 +149,7 @@ static int wp_clean_pud_entry(pud_t *pud, unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
- pud_t pudval = READ_ONCE(*pud);
+ pud_t pudval = pudp_get(pud);

/* Do not split a huge pud */
if (pud_trans_huge(pudval) || pud_devmap(pudval)) {
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 305dbef3cc4d..fbb63401fb51 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -417,9 +417,9 @@ static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma,
if (!p4d_present(*p4d))
return 0;
pud = pud_offset(p4d, address);
- if (!pud_present(*pud))
+ if (!pud_present(pudp_get(pud)))
return 0;
- if (pud_devmap(*pud))
+ if (pud_devmap(pudp_get(pud)))
return PUD_SHIFT;
pmd = pmd_offset(pud, address);
if (!pmd_present(pmdp_get(pmd)))
diff --git a/mm/memory.c b/mm/memory.c
index 43953a6d350f..af6c9346493c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1753,7 +1753,7 @@ static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
pud = pud_offset(p4d, addr);
do {
next = pud_addr_end(addr, end);
- if (pud_trans_huge(*pud) || pud_devmap(*pud)) {
+ if (pud_trans_huge(pudp_get(pud)) || pud_devmap(pudp_get(pud))) {
if (next - addr != HPAGE_PUD_SIZE) {
mmap_assert_locked(tlb->mm);
split_huge_pud(vma, pud, addr);
@@ -2819,7 +2819,7 @@ static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
unsigned long next;
int err = 0;

- BUG_ON(pud_leaf(*pud));
+ BUG_ON(pud_leaf(pudp_get(pud)));

if (create) {
pmd = pmd_alloc_track(mm, pud, addr, mask);
@@ -2866,11 +2866,11 @@ static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,
}
do {
next = pud_addr_end(addr, end);
- if (pud_none(*pud) && !create)
+ if (pud_none(pudp_get(pud)) && !create)
continue;
- if (WARN_ON_ONCE(pud_leaf(*pud)))
+ if (WARN_ON_ONCE(pud_leaf(pudp_get(pud))))
return -EINVAL;
- if (!pud_none(*pud) && WARN_ON_ONCE(pud_bad(*pud))) {
+ if (!pud_none(pudp_get(pud)) && WARN_ON_ONCE(pud_bad(pudp_get(pud)))) {
if (!create)
continue;
pud_clear_bad(pud);
diff --git a/mm/page_table_check.c b/mm/page_table_check.c
index 48a2cf56c80e..2a22d098b0b1 100644
--- a/mm/page_table_check.c
+++ b/mm/page_table_check.c
@@ -254,7 +254,7 @@ void __page_table_check_pud_set(struct mm_struct *mm, pud_t *pudp, pud_t pud)
if (&init_mm == mm)
return;

- __page_table_check_pud_clear(mm, *pudp);
+ __page_table_check_pud_clear(mm, pudp_get(pudp));
if (pud_user_accessible_page(pud)) {
page_table_check_set(pud_pfn(pud), PUD_SIZE >> PAGE_SHIFT,
pud_write(pud));
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index ae5cc42aa208..511266307771 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -222,7 +222,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
continue;
}
pud = pud_offset(p4d, pvmw->address);
- if (!pud_present(*pud)) {
+ if (!pud_present(pudp_get(pud))) {
step_forward(pvmw, PUD_SIZE);
continue;
}
diff --git a/mm/pgalloc-track.h b/mm/pgalloc-track.h
index e9e879de8649..0f6b809431a3 100644
--- a/mm/pgalloc-track.h
+++ b/mm/pgalloc-track.h
@@ -33,7 +33,7 @@ static inline pmd_t *pmd_alloc_track(struct mm_struct *mm, pud_t *pud,
unsigned long address,
pgtbl_mod_mask *mod_mask)
{
- if (unlikely(pud_none(*pud))) {
+ if (unlikely(pud_none(pudp_get(pud)))) {
if (__pmd_alloc(mm, pud, address))
return NULL;
*mod_mask |= PGTBL_PUD_MODIFIED;
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index a5045d0fc73e..5bd02c6208e7 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -153,7 +153,7 @@ pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
pud_t pud;

VM_BUG_ON(address & ~HPAGE_PUD_MASK);
- VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
+ VM_BUG_ON(!pud_trans_huge(pudp_get(pudp)) && !pud_devmap(pudp_get(pudp)));
pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
return pud;
diff --git a/mm/ptdump.c b/mm/ptdump.c
index e17588a32012..32ae8e829329 100644
--- a/mm/ptdump.c
+++ b/mm/ptdump.c
@@ -30,7 +30,7 @@ static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
- pgd_t val = READ_ONCE(*pgd);
+ pgd_t val = pgdp_get(pgd);

#if CONFIG_PGTABLE_LEVELS > 4 && \
(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
@@ -76,7 +76,7 @@ static int ptdump_pud_entry(pud_t *pud, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
- pud_t val = READ_ONCE(*pud);
+ pud_t val = pudp_get(pud);

#if CONFIG_PGTABLE_LEVELS > 2 && \
(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
--
2.25.1