[PATCH 6/7] mm: Use p4dp_get() for accessing P4D entries

From: Anshuman Khandual
Date: Fri Sep 13 2024 - 04:47:39 EST

Convert P4D accesses via p4dp_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: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Uladzislau Rezki <urezki@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Cc: linux-perf-users@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
drivers/misc/sgi-gru/grufault.c | 2 +-
fs/userfaultfd.c | 4 ++--
include/linux/pgtable.h | 6 +++---
kernel/events/core.c | 2 +-
mm/gup.c | 6 +++---
mm/hugetlb.c | 2 +-
mm/kasan/init.c | 10 +++++-----
mm/kasan/shadow.c | 2 +-
mm/memory-failure.c | 2 +-
mm/memory.c | 14 +++++++-------
mm/page_vma_mapped.c | 2 +-
mm/pagewalk.c | 6 +++---
mm/percpu.c | 4 ++--
mm/pgalloc-track.h | 2 +-
mm/pgtable-generic.c | 4 ++--
mm/ptdump.c | 2 +-
mm/rmap.c | 4 ++--
mm/sparse-vmemmap.c | 4 ++--
mm/vmalloc.c | 24 ++++++++++++------------
mm/vmscan.c | 6 +++---
20 files changed, 54 insertions(+), 54 deletions(-)

diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 0a06ec92f090..cdca93398b44 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -216,7 +216,7 @@ static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
goto err;

p4dp = p4d_offset(pgdp, vaddr);
- if (unlikely(p4d_none(*p4dp)))
+ if (unlikely(p4d_none(p4dp_get(p4dp))))
goto err;

pudp = pud_offset(p4dp, vaddr);
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 27a3e9285fbf..4044e15cdfd9 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -307,10 +307,10 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
if (!pgd_present(*pgd))
goto out;
p4d = p4d_offset(pgd, address);
- if (!p4d_present(*p4d))
+ if (!p4d_present(p4dp_get(p4d)))
goto out;
pud = pud_offset(p4d, address);
- if (!pud_present(*pud))
+ if (!pud_present(pudp_get(pud)))
goto out;
pmd = pmd_offset(pud, address);
again:
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index b25a0a505ce6..b3e40f06c8c4 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1078,7 +1078,7 @@ static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b)

#define set_p4d_safe(p4dp, p4d) \
({ \
- WARN_ON_ONCE(p4d_present(*p4dp) && !p4d_same(*p4dp, p4d)); \
+ WARN_ON_ONCE(p4d_present(p4dp_get(p4dp)) && !p4d_same(p4dp_get(p4dp), p4d)); \
set_p4d(p4dp, p4d); \
})

@@ -1248,9 +1248,9 @@ static inline int pgd_none_or_clear_bad(pgd_t *pgd)

static inline int p4d_none_or_clear_bad(p4d_t *p4d)
{
- if (p4d_none(*p4d))
+ if (p4d_none(p4dp_get(p4d)))
return 1;
- if (unlikely(p4d_bad(*p4d))) {
+ if (unlikely(p4d_bad(p4dp_get(p4d)))) {
p4d_clear_bad(p4d);
return 1;
}
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 35e2f2789246..4e56a276ed25 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7611,7 +7611,7 @@ static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
return pgd_leaf_size(pgd);

p4dp = p4d_offset_lockless(pgdp, pgd, addr);
- p4d = READ_ONCE(*p4dp);
+ p4d = p4dp_get(p4dp);
if (!p4d_present(p4d))
return 0;

diff --git a/mm/gup.c b/mm/gup.c
index 300fc7eb306c..3a97d0263052 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1014,7 +1014,7 @@ static struct page *follow_p4d_mask(struct vm_area_struct *vma,
p4d_t *p4dp, p4d;

p4dp = p4d_offset(pgdp, address);
- p4d = READ_ONCE(*p4dp);
+ p4d = p4dp_get(p4dp);
BUILD_BUG_ON(p4d_leaf(p4d));

if (!p4d_present(p4d) || p4d_bad(p4d))
@@ -1114,7 +1114,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
if (pgd_none(*pgd))
return -EFAULT;
p4d = p4d_offset(pgd, address);
- if (p4d_none(*p4d))
+ if (p4d_none(p4dp_get(p4d)))
return -EFAULT;
pud = pud_offset(p4d, address);
if (pud_none(pudp_get(pud)))
@@ -3245,7 +3245,7 @@ static int gup_fast_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr,

p4dp = p4d_offset_lockless(pgdp, pgd, addr);
do {
- p4d_t p4d = READ_ONCE(*p4dp);
+ p4d_t p4d = p4dp_get(p4dp);

next = p4d_addr_end(addr, end);
if (!p4d_present(p4d))
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a3820242b01e..4fdb91c8cc2b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7454,7 +7454,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
if (!pgd_present(*pgd))
return NULL;
p4d = p4d_offset(pgd, addr);
- if (!p4d_present(*p4d))
+ if (!p4d_present(p4dp_get(p4d)))
return NULL;

pud = pud_offset(p4d, addr);
diff --git a/mm/kasan/init.c b/mm/kasan/init.c
index f4cf519443e1..02af738fee5e 100644
--- a/mm/kasan/init.c
+++ b/mm/kasan/init.c
@@ -208,7 +208,7 @@ static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
continue;
}

- if (p4d_none(*p4d)) {
+ if (p4d_none(p4dp_get(p4d))) {
pud_t *p;

if (slab_is_available()) {
@@ -330,7 +330,7 @@ static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d)
return;
}

- pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d)));
+ pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(p4dp_get(p4d))));
p4d_clear(p4d);
}

@@ -341,7 +341,7 @@ static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd)

for (i = 0; i < PTRS_PER_P4D; i++) {
p4d = p4d_start + i;
- if (!p4d_none(*p4d))
+ if (!p4d_none(p4dp_get(p4d)))
return;
}

@@ -434,10 +434,10 @@ static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,

next = p4d_addr_end(addr, end);

- if (!p4d_present(*p4d))
+ if (!p4d_present(p4dp_get(p4d)))
continue;

- if (kasan_pud_table(*p4d)) {
+ if (kasan_pud_table(p4dp_get(p4d))) {
if (IS_ALIGNED(addr, P4D_SIZE) &&
IS_ALIGNED(next, P4D_SIZE)) {
p4d_clear(p4d);
diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index dbd8164c75f1..52150cc5ae5f 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -194,7 +194,7 @@ static bool shadow_mapped(unsigned long addr)
if (pgd_none(*pgd))
return false;
p4d = p4d_offset(pgd, addr);
- if (p4d_none(*p4d))
+ if (p4d_none(p4dp_get(p4d)))
return false;
pud = pud_offset(p4d, addr);
if (pud_none(pudp_get(pud)))
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index fbb63401fb51..3d900cc039b3 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -414,7 +414,7 @@ static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma,
if (!pgd_present(*pgd))
return 0;
p4d = p4d_offset(pgd, address);
- if (!p4d_present(*p4d))
+ if (!p4d_present(p4dp_get(p4d)))
return 0;
pud = pud_offset(p4d, address);
if (!pud_present(pudp_get(pud)))
diff --git a/mm/memory.c b/mm/memory.c
index af6c9346493c..7e6bb051d187 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2902,11 +2902,11 @@ static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd,
}
do {
next = p4d_addr_end(addr, end);
- if (p4d_none(*p4d) && !create)
+ if (p4d_none(p4dp_get(p4d)) && !create)
continue;
- if (WARN_ON_ONCE(p4d_leaf(*p4d)))
+ if (WARN_ON_ONCE(p4d_leaf(p4dp_get(p4d))))
return -EINVAL;
- if (!p4d_none(*p4d) && WARN_ON_ONCE(p4d_bad(*p4d))) {
+ if (!p4d_none(p4dp_get(p4d)) && WARN_ON_ONCE(p4d_bad(p4dp_get(p4d)))) {
if (!create)
continue;
p4d_clear_bad(p4d);
@@ -6058,7 +6058,7 @@ int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address)
return -ENOMEM;

spin_lock(&mm->page_table_lock);
- if (!p4d_present(*p4d)) {
+ if (!p4d_present(p4dp_get(p4d))) {
mm_inc_nr_puds(mm);
smp_wmb(); /* See comment in pmd_install() */
p4d_populate(mm, p4d, new);
@@ -6082,7 +6082,7 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
return -ENOMEM;

ptl = pud_lock(mm, pud);
- if (!pud_present(*pud)) {
+ if (!pud_present(pudp_get(pud))) {
mm_inc_nr_pmds(mm);
smp_wmb(); /* See comment in pmd_install() */
pud_populate(mm, pud, new);
@@ -6143,11 +6143,11 @@ int follow_pte(struct vm_area_struct *vma, unsigned long address,
goto out;

p4d = p4d_offset(pgd, address);
- if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d)))
+ if (p4d_none(p4dp_get(p4d)) || unlikely(p4d_bad(p4dp_get(p4d))))
goto out;

pud = pud_offset(p4d, address);
- if (pud_none(*pud) || unlikely(pud_bad(*pud)))
+ if (pud_none(pudp_get(pud)) || unlikely(pud_bad(pudp_get(pud))))
goto out;

pmd = pmd_offset(pud, address);
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 511266307771..a33f92db2666 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -217,7 +217,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
continue;
}
p4d = p4d_offset(pgd, pvmw->address);
- if (!p4d_present(*p4d)) {
+ if (!p4d_present(p4dp_get(p4d))) {
step_forward(pvmw, P4D_SIZE);
continue;
}
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index c3019a160e77..1d32c6da1a0d 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -145,7 +145,7 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
do {
again:
next = pud_addr_end(addr, end);
- if (pud_none(*pud)) {
+ if (pud_none(pudp_get(pud))) {
if (ops->pte_hole)
err = ops->pte_hole(addr, next, depth, walk);
if (err)
@@ -163,14 +163,14 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
if (walk->action == ACTION_AGAIN)
goto again;

- if ((!walk->vma && (pud_leaf(*pud) || !pud_present(*pud))) ||
+ if ((!walk->vma && (pud_leaf(pudp_get(pud)) || !pud_present(pudp_get(pud)))) ||
walk->action == ACTION_CONTINUE ||
!(ops->pmd_entry || ops->pte_entry))
continue;

if (walk->vma)
split_huge_pud(walk->vma, pud, addr);
- if (pud_none(*pud))
+ if (pud_none(pudp_get(pud)))
goto again;

err = walk_pmd_range(pud, addr, next, walk);
diff --git a/mm/percpu.c b/mm/percpu.c
index 7ee77c0fd5e3..58660e8eb892 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -3192,7 +3192,7 @@ void __init __weak pcpu_populate_pte(unsigned long addr)
}

p4d = p4d_offset(pgd, addr);
- if (p4d_none(*p4d)) {
+ if (p4d_none(p4dp_get(p4d))) {
pud = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
if (!pud)
goto err_alloc;
@@ -3200,7 +3200,7 @@ void __init __weak pcpu_populate_pte(unsigned long addr)
}

pud = pud_offset(p4d, addr);
- if (pud_none(*pud)) {
+ if (pud_none(pudp_get(pud))) {
pmd = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
if (!pmd)
goto err_alloc;
diff --git a/mm/pgalloc-track.h b/mm/pgalloc-track.h
index 0f6b809431a3..3db8ccbcb141 100644
--- a/mm/pgalloc-track.h
+++ b/mm/pgalloc-track.h
@@ -20,7 +20,7 @@ static inline pud_t *pud_alloc_track(struct mm_struct *mm, p4d_t *p4d,
unsigned long address,
pgtbl_mod_mask *mod_mask)
{
- if (unlikely(p4d_none(*p4d))) {
+ if (unlikely(p4d_none(p4dp_get(p4d)))) {
if (__pud_alloc(mm, p4d, address))
return NULL;
*mod_mask |= PGTBL_P4D_MODIFIED;
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 5bd02c6208e7..7e0a4974b0fc 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -31,7 +31,7 @@ void pgd_clear_bad(pgd_t *pgd)
#ifndef __PAGETABLE_P4D_FOLDED
void p4d_clear_bad(p4d_t *p4d)
{
- p4d_ERROR(*p4d);
+ p4d_ERROR(p4dp_get(p4d));
p4d_clear(p4d);
}
#endif
@@ -39,7 +39,7 @@ void p4d_clear_bad(p4d_t *p4d)
#ifndef __PAGETABLE_PUD_FOLDED
void pud_clear_bad(pud_t *pud)
{
- pud_ERROR(*pud);
+ pud_ERROR(pudp_get(pud));
pud_clear(pud);
}
#endif
diff --git a/mm/ptdump.c b/mm/ptdump.c
index 32ae8e829329..2c40224b8ad0 100644
--- a/mm/ptdump.c
+++ b/mm/ptdump.c
@@ -53,7 +53,7 @@ static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct ptdump_state *st = walk->private;
- p4d_t val = READ_ONCE(*p4d);
+ p4d_t val = p4dp_get(p4d);

#if CONFIG_PGTABLE_LEVELS > 3 && \
(defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
diff --git a/mm/rmap.c b/mm/rmap.c
index ec668c48bccc..829d0cf5e384 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -813,11 +813,11 @@ pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address)
goto out;

p4d = p4d_offset(pgd, address);
- if (!p4d_present(*p4d))
+ if (!p4d_present(p4dp_get(p4d)))
goto out;

pud = pud_offset(p4d, address);
- if (!pud_present(*pud))
+ if (!pud_present(pudp_get(pud)))
goto out;

pmd = pmd_offset(pud, address);
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index c89706e107ce..2bd1c95f107a 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -203,7 +203,7 @@ void __weak __meminit pmd_init(void *addr)
pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
{
pud_t *pud = pud_offset(p4d, addr);
- if (pud_none(*pud)) {
+ if (pud_none(pudp_get(pud))) {
void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
if (!p)
return NULL;
@@ -220,7 +220,7 @@ void __weak __meminit pud_init(void *addr)
p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
{
p4d_t *p4d = p4d_offset(pgd, addr);
- if (p4d_none(*p4d)) {
+ if (p4d_none(p4dp_get(p4d))) {
void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
if (!p)
return NULL;
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d27aa1ebaad6..c67b067f4686 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -200,7 +200,7 @@ static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
if (!IS_ALIGNED(phys_addr, PUD_SIZE))
return 0;

- if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
+ if (pud_present(pudp_get(pud)) && !pud_free_pmd_page(pud, addr))
return 0;

return pud_set_huge(pud, phys_addr, prot);
@@ -251,7 +251,7 @@ static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
if (!IS_ALIGNED(phys_addr, P4D_SIZE))
return 0;

- if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
+ if (p4d_present(p4dp_get(p4d)) && !p4d_free_pud_page(p4d, addr))
return 0;

return p4d_set_huge(p4d, phys_addr, prot);
@@ -396,7 +396,7 @@ static void vunmap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end,
next = pud_addr_end(addr, end);

cleared = pud_clear_huge(pud);
- if (cleared || pud_bad(*pud))
+ if (cleared || pud_bad(pudp_get(pud)))
*mask |= PGTBL_PUD_MODIFIED;

if (cleared)
@@ -418,7 +418,7 @@ static void vunmap_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end,
next = p4d_addr_end(addr, end);

p4d_clear_huge(p4d);
- if (p4d_bad(*p4d))
+ if (p4d_bad(p4dp_get(p4d)))
*mask |= PGTBL_P4D_MODIFIED;

if (p4d_none_or_clear_bad(p4d))
@@ -760,19 +760,19 @@ struct page *vmalloc_to_page(const void *vmalloc_addr)
return NULL;

p4d = p4d_offset(pgd, addr);
- if (p4d_none(*p4d))
+ if (p4d_none(p4dp_get(p4d)))
return NULL;
- if (p4d_leaf(*p4d))
- return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT);
- if (WARN_ON_ONCE(p4d_bad(*p4d)))
+ if (p4d_leaf(p4dp_get(p4d)))
+ return p4d_page(p4dp_get(p4d)) + ((addr & ~P4D_MASK) >> PAGE_SHIFT);
+ if (WARN_ON_ONCE(p4d_bad(p4dp_get(p4d))))
return NULL;

pud = pud_offset(p4d, addr);
- if (pud_none(*pud))
+ if (pud_none(pudp_get(pud)))
return NULL;
- if (pud_leaf(*pud))
- return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
- if (WARN_ON_ONCE(pud_bad(*pud)))
+ if (pud_leaf(pudp_get(pud)))
+ return pud_page(pudp_get(pud)) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
+ if (WARN_ON_ONCE(pud_bad(pudp_get(pud))))
return NULL;

pmd = pmd_offset(pud, addr);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index bd489c1af228..b16925b5f072 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3421,7 +3421,7 @@ static void walk_pmd_range_locked(pud_t *pud, unsigned long addr, struct vm_area
DEFINE_MAX_SEQ(walk->lruvec);
int old_gen, new_gen = lru_gen_from_seq(max_seq);

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

/* try to batch at most 1+MIN_LRU_BATCH+1 entries */
if (*first == -1) {
@@ -3501,7 +3501,7 @@ static void walk_pmd_range(pud_t *pud, unsigned long start, unsigned long end,
struct lru_gen_mm_walk *walk = args->private;
struct lru_gen_mm_state *mm_state = get_mm_state(walk->lruvec);

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

/*
* Finish an entire PMD in two passes: the first only reaches to PTE
@@ -3579,7 +3579,7 @@ static int walk_pud_range(p4d_t *p4d, unsigned long start, unsigned long end,
unsigned long next;
struct lru_gen_mm_walk *walk = args->private;

- VM_WARN_ON_ONCE(p4d_leaf(*p4d));
+ VM_WARN_ON_ONCE(p4d_leaf(p4dp_get(p4d)));

pud = pud_offset(p4d, start & P4D_MASK);
restart:
--
2.25.1