The patch titled
Subject: mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked()
has been added to the -mm tree. Its filename is
mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Michel Lespinasse <walken@xxxxxxxxxx>
Subject: mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked()
Add new APIs to assert that mmap_sem is held.
Using this instead of rwsem_is_locked and lockdep_assert_held[_write]
makes the assertions more tolerant of future changes to the lock type.
Link: http://lkml.kernel.org/r/20200520052908.204642-10-walken@xxxxxxxxxx
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Cc: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Laurent Dufour <ldufour@xxxxxxxxxxxxx>
Cc: Liam Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Ying Han <yinghan@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/events/core.c | 2 +-
fs/userfaultfd.c | 6 +++---
include/linux/mmap_lock.h | 14 ++++++++++++++
mm/gup.c | 2 +-
mm/hmm.c | 2 +-
mm/memory.c | 2 +-
mm/mmu_notifier.c | 6 +++---
mm/pagewalk.c | 6 +++---
mm/util.c | 2 +-
9 files changed, 28 insertions(+), 14 deletions(-)
--- a/arch/x86/events/core.c~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/arch/x86/events/core.c
@@ -2181,7 +2181,7 @@ static void x86_pmu_event_mapped(struct
* For now, this can't happen because all callers hold mmap_sem
* for write. If this changes, we'll need a different solution.
*/
- lockdep_assert_held_write(&mm->mmap_sem);
+ mmap_assert_write_locked(mm);
if (atomic_inc_return(&mm->context.perf_rdpmc_allowed) == 1)
on_each_cpu_mask(mm_cpumask(mm), cr4_update_pce, NULL, 1);
--- a/fs/userfaultfd.c~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/fs/userfaultfd.c
@@ -234,7 +234,7 @@ static inline bool userfaultfd_huge_must
pte_t *ptep, pte;
bool ret = true;
- VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+ mmap_assert_locked(mm);
ptep = huge_pte_offset(mm, address, vma_mmu_pagesize(vma));
@@ -286,7 +286,7 @@ static inline bool userfaultfd_must_wait
pte_t *pte;
bool ret = true;
- VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+ mmap_assert_locked(mm);
pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
@@ -405,7 +405,7 @@ vm_fault_t handle_userfault(struct vm_fa
* Coredumping runs without mmap_sem so we can only check that
* the mmap_sem is held, if PF_DUMPCORE was not set.
*/
- WARN_ON_ONCE(!rwsem_is_locked(&mm->mmap_sem));
+ mmap_assert_locked(mm);
ctx = vmf->vma->vm_userfaultfd_ctx.ctx;
if (!ctx)
--- a/include/linux/mmap_lock.h~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/include/linux/mmap_lock.h
@@ -1,6 +1,8 @@
#ifndef _LINUX_MMAP_LOCK_H
#define _LINUX_MMAP_LOCK_H
+#include <linux/mmdebug.h>
+
#define MMAP_LOCK_INITIALIZER(name) \
.mmap_sem = __RWSEM_INITIALIZER((name).mmap_sem),
@@ -73,4 +75,16 @@ static inline void mmap_read_unlock_non_
up_read_non_owner(&mm->mmap_sem);
}
+static inline void mmap_assert_locked(struct mm_struct *mm)
+{
+ lockdep_assert_held(&mm->mmap_sem);
+ VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
+}
+
+static inline void mmap_assert_write_locked(struct mm_struct *mm)
+{
+ lockdep_assert_held_write(&mm->mmap_sem);
+ VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
+}
+
#endif /* _LINUX_MMAP_LOCK_H */
--- a/mm/gup.c~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/mm/gup.c
@@ -1410,7 +1410,7 @@ long populate_vma_page_range(struct vm_a
VM_BUG_ON(end & ~PAGE_MASK);
VM_BUG_ON_VMA(start < vma->vm_start, vma);
VM_BUG_ON_VMA(end > vma->vm_end, vma);
- VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
+ mmap_assert_locked(mm);
gup_flags = FOLL_TOUCH | FOLL_POPULATE | FOLL_MLOCK;
if (vma->vm_flags & VM_LOCKONFAULT)
--- a/mm/hmm.c~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/mm/hmm.c
@@ -563,7 +563,7 @@ int hmm_range_fault(struct hmm_range *ra
struct mm_struct *mm = range->notifier->mm;
int ret;
- lockdep_assert_held(&mm->mmap_sem);
+ mmap_assert_locked(mm);
do {
/* If range is no longer valid force retry. */
--- a/mm/memory.c~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/mm/memory.c
@@ -1211,7 +1211,7 @@ static inline unsigned long zap_pud_rang
next = pud_addr_end(addr, end);
if (pud_trans_huge(*pud) || pud_devmap(*pud)) {
if (next - addr != HPAGE_PUD_SIZE) {
- VM_BUG_ON_VMA(!rwsem_is_locked(&tlb->mm->mmap_sem), vma);
+ mmap_assert_locked(tlb->mm);
split_huge_pud(vma, pud, addr);
} else if (zap_huge_pud(tlb, vma, pud, addr))
goto next;
--- a/mm/mmu_notifier.c~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/mm/mmu_notifier.c
@@ -609,7 +609,7 @@ int __mmu_notifier_register(struct mmu_n
struct mmu_notifier_subscriptions *subscriptions = NULL;
int ret;
- lockdep_assert_held_write(&mm->mmap_sem);
+ mmap_assert_write_locked(mm);
BUG_ON(atomic_read(&mm->mm_users) <= 0);
if (IS_ENABLED(CONFIG_LOCKDEP)) {
@@ -761,7 +761,7 @@ struct mmu_notifier *mmu_notifier_get_lo
struct mmu_notifier *subscription;
int ret;
- lockdep_assert_held_write(&mm->mmap_sem);
+ mmap_assert_write_locked(mm);
if (mm->notifier_subscriptions) {
subscription = find_get_mmu_notifier(mm, ops);
@@ -1006,7 +1006,7 @@ int mmu_interval_notifier_insert_locked(
mm->notifier_subscriptions;
int ret;
- lockdep_assert_held_write(&mm->mmap_sem);
+ mmap_assert_write_locked(mm);
if (!subscriptions || !subscriptions->has_itree) {
ret = __mmu_notifier_register(NULL, mm);
--- a/mm/pagewalk.c~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/mm/pagewalk.c
@@ -395,7 +395,7 @@ int walk_page_range(struct mm_struct *mm
if (!walk.mm)
return -EINVAL;
- lockdep_assert_held(&walk.mm->mmap_sem);
+ mmap_assert_locked(walk.mm);
vma = find_vma(walk.mm, start);
do {
@@ -453,7 +453,7 @@ int walk_page_range_novma(struct mm_stru
if (start >= end || !walk.mm)
return -EINVAL;
- lockdep_assert_held(&walk.mm->mmap_sem);
+ mmap_assert_locked(walk.mm);
return __walk_page_range(start, end, &walk);
}
@@ -472,7 +472,7 @@ int walk_page_vma(struct vm_area_struct
if (!walk.mm)
return -EINVAL;
- lockdep_assert_held(&walk.mm->mmap_sem);
+ mmap_assert_locked(walk.mm);
err = walk_page_test(vma->vm_start, vma->vm_end, &walk);
if (err > 0)
--- a/mm/util.c~mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked
+++ a/mm/util.c
@@ -437,7 +437,7 @@ int __account_locked_vm(struct mm_struct
unsigned long locked_vm, limit;
int ret = 0;
- lockdep_assert_held_write(&mm->mmap_sem);
+ mmap_assert_write_locked(mm);
locked_vm = mm->locked_vm;
if (inc) {
_
Patches currently in -mm which might be from walken@xxxxxxxxxx are
mmap-locking-api-initial-implementation-as-rwsem-wrappers.patch
mmu-notifier-use-the-new-mmap-locking-api.patch
dma-reservations-use-the-new-mmap-locking-api.patch
mmap-locking-api-use-coccinelle-to-convert-mmap_sem-rwsem-call-sites.patch
mmap-locking-api-convert-mmap_sem-call-sites-missed-by-coccinelle.patch
mmap-locking-api-convert-nested-write-lock-sites.patch
mmap-locking-api-add-mmap_read_trylock_non_owner.patch
mmap-locking-api-add-mmap_lock_initializer.patch
mmap-locking-api-add-mmap_assert_locked-and-mmap_assert_write_locked.patch
mmap-locking-api-rename-mmap_sem-to-mmap_lock.patch
mmap-locking-api-convert-mmap_sem-api-comments.patch
mmap-locking-api-convert-mmap_sem-comments.patch
