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Subject[PATCH v5 10/10] mmap locking API: rename mmap_sem to mmap_lock
From
Rename the mmap_sem field to mmap_lock. Any new uses of this lock
should now go through the new mmap locking api. The mmap_lock is
still implemented as a rwsem, though this could change in the future.

Signed-off-by: Michel Lespinasse <walken@google.com>
---
arch/ia64/mm/fault.c | 4 ++--
arch/x86/events/core.c | 4 ++--
arch/x86/mm/fault.c | 2 +-
drivers/gpu/drm/etnaviv/etnaviv_gem.c | 2 +-
include/linux/mm_types.h | 2 +-
include/linux/mmap_lock.h | 34 +++++++++++++--------------
mm/hmm.c | 2 +-
mm/memory.c | 2 +-
mm/mmap.c | 4 ++--
mm/mmu_notifier.c | 18 +++++++-------
mm/pagewalk.c | 15 ++++++------
mm/util.c | 4 ++--
12 files changed, 47 insertions(+), 46 deletions(-)

diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index 693f00b117e1..9b95050c2048 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -70,8 +70,8 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
| (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));

- /* mmap_sem is performance critical.... */
- prefetchw(&mm->mmap_sem);
+ /* mmap_lock is performance critical.... */
+ prefetchw(&mm->mmap_lock);

/*
* If we're in an interrupt or have no user context, we must not take the fault..
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index a619763e96e1..eda117ca1c43 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2179,10 +2179,10 @@ static void x86_pmu_event_mapped(struct perf_event *event, struct mm_struct *mm)
* userspace with CR4.PCE clear while another task is still
* doing on_each_cpu_mask() to propagate CR4.PCE.
*
- * For now, this can't happen because all callers hold mmap_sem
+ * For now, this can't happen because all callers hold mmap_lock
* for write. If this changes, we'll need a different solution.
*/
- lockdep_assert_held_write(&mm->mmap_sem);
+ lockdep_assert_held_write(&mm->mmap_lock);

if (atomic_inc_return(&mm->context.perf_rdpmc_allowed) == 1)
on_each_cpu_mask(mm_cpumask(mm), refresh_pce, NULL, 1);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 181f66b9049f..35f530f9dfc0 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1522,7 +1522,7 @@ dotraplinkage void
do_page_fault(struct pt_regs *regs, unsigned long hw_error_code,
unsigned long address)
{
- prefetchw(&current->mm->mmap_sem);
+ prefetchw(&current->mm->mmap_lock);
trace_page_fault_entries(regs, hw_error_code, address);

if (unlikely(kmmio_fault(regs, address)))
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
index dc9ef302f517..701f3995f621 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -661,7 +661,7 @@ static int etnaviv_gem_userptr_get_pages(struct etnaviv_gem_object *etnaviv_obj)
struct etnaviv_gem_userptr *userptr = &etnaviv_obj->userptr;
int ret, pinned = 0, npages = etnaviv_obj->base.size >> PAGE_SHIFT;

- might_lock_read(&current->mm->mmap_sem);
+ might_lock_read(&current->mm->mmap_lock);

if (userptr->mm != current->mm)
return -EPERM;
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 4aba6c0c2ba8..d13b90399c16 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -436,7 +436,7 @@ struct mm_struct {
spinlock_t page_table_lock; /* Protects page tables and some
* counters
*/
- struct rw_semaphore mmap_sem;
+ struct rw_semaphore mmap_lock;

struct list_head mmlist; /* List of maybe swapped mm's. These
* are globally strung together off
diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
index f7a3a9550cc5..f8db53f10c1c 100644
--- a/include/linux/mmap_lock.h
+++ b/include/linux/mmap_lock.h
@@ -4,67 +4,67 @@
#include <linux/mmdebug.h>

#define MMAP_LOCK_INITIALIZER(name) \
- .mmap_sem = __RWSEM_INITIALIZER(name.mmap_sem),
+ .mmap_lock = __RWSEM_INITIALIZER(name.mmap_lock),

static inline void mmap_init_lock(struct mm_struct *mm)
{
- init_rwsem(&mm->mmap_sem);
+ init_rwsem(&mm->mmap_lock);
}

static inline void mmap_write_lock(struct mm_struct *mm)
{
- down_write(&mm->mmap_sem);
+ down_write(&mm->mmap_lock);
}

static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)
{
- down_write_nested(&mm->mmap_sem, subclass);
+ down_write_nested(&mm->mmap_lock, subclass);
}

static inline int mmap_write_lock_killable(struct mm_struct *mm)
{
- return down_write_killable(&mm->mmap_sem);
+ return down_write_killable(&mm->mmap_lock);
}

static inline bool mmap_write_trylock(struct mm_struct *mm)
{
- return down_write_trylock(&mm->mmap_sem) != 0;
+ return down_write_trylock(&mm->mmap_lock) != 0;
}

static inline void mmap_write_unlock(struct mm_struct *mm)
{
- up_write(&mm->mmap_sem);
+ up_write(&mm->mmap_lock);
}

static inline void mmap_write_downgrade(struct mm_struct *mm)
{
- downgrade_write(&mm->mmap_sem);
+ downgrade_write(&mm->mmap_lock);
}

static inline void mmap_read_lock(struct mm_struct *mm)
{
- down_read(&mm->mmap_sem);
+ down_read(&mm->mmap_lock);
}

static inline int mmap_read_lock_killable(struct mm_struct *mm)
{
- return down_read_killable(&mm->mmap_sem);
+ return down_read_killable(&mm->mmap_lock);
}

static inline bool mmap_read_trylock(struct mm_struct *mm)
{
- return down_read_trylock(&mm->mmap_sem) != 0;
+ return down_read_trylock(&mm->mmap_lock) != 0;
}

static inline void mmap_read_unlock(struct mm_struct *mm)
{
- up_read(&mm->mmap_sem);
+ up_read(&mm->mmap_lock);
}

static inline bool mmap_read_trylock_non_owner(struct mm_struct *mm)
{
- if (down_read_trylock(&mm->mmap_sem)) {
- rwsem_release(&mm->mmap_sem.dep_map, _RET_IP_);
+ if (down_read_trylock(&mm->mmap_lock)) {
+ rwsem_release(&mm->mmap_lock.dep_map, _RET_IP_);
return true;
}
return false;
@@ -72,15 +72,15 @@ static inline bool mmap_read_trylock_non_owner(struct mm_struct *mm)

static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)
{
- up_read_non_owner(&mm->mmap_sem);
+ up_read_non_owner(&mm->mmap_lock);
}

static inline void mmap_assert_locked(struct mm_struct *mm)
{
if (IS_ENABLED(CONFIG_LOCKDEP) && debug_locks)
- VM_BUG_ON_MM(!lockdep_is_held(&mm->mmap_sem), mm);
+ VM_BUG_ON_MM(!lockdep_is_held(&mm->mmap_lock), mm);
else
- VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
+ VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
}

#endif /* _LINUX_MMAP_LOCK_H */
diff --git a/mm/hmm.c b/mm/hmm.c
index 280585833adf..8660aec6aafa 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -581,7 +581,7 @@ long hmm_range_fault(struct hmm_range *range)
struct mm_struct *mm = range->notifier->mm;
int ret;

- lockdep_assert_held(&mm->mmap_sem);
+ lockdep_assert_held(&mm->mmap_lock);

do {
/* If range is no longer valid force retry. */
diff --git a/mm/memory.c b/mm/memory.c
index 20f98ea8968e..c2963e7affa9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4811,7 +4811,7 @@ void __might_fault(const char *file, int line)
__might_sleep(file, line, 0);
#if defined(CONFIG_DEBUG_ATOMIC_SLEEP)
if (current->mm)
- might_lock_read(&current->mm->mmap_sem);
+ might_lock_read(&current->mm->mmap_lock);
#endif
}
EXPORT_SYMBOL(__might_fault);
diff --git a/mm/mmap.c b/mm/mmap.c
index 2f4ffccc5972..80a47031d5db 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3474,7 +3474,7 @@ static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
* The LSB of head.next can't change from under us
* because we hold the mm_all_locks_mutex.
*/
- down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem);
+ down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock);
/*
* We can safely modify head.next after taking the
* anon_vma->root->rwsem. If some other vma in this mm shares
@@ -3504,7 +3504,7 @@ static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping)
*/
if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags))
BUG();
- down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_sem);
+ down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock);
}
}

diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index cfd0a03bf5cc..6717278d6d49 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -599,7 +599,7 @@ void __mmu_notifier_invalidate_range(struct mm_struct *mm,
}

/*
- * Same as mmu_notifier_register but here the caller must hold the mmap_sem in
+ * Same as mmu_notifier_register but here the caller must hold the mmap_lock in
* write mode. A NULL mn signals the notifier is being registered for itree
* mode.
*/
@@ -609,7 +609,7 @@ int __mmu_notifier_register(struct mmu_notifier *subscription,
struct mmu_notifier_subscriptions *subscriptions = NULL;
int ret;

- lockdep_assert_held_write(&mm->mmap_sem);
+ lockdep_assert_held_write(&mm->mmap_lock);
BUG_ON(atomic_read(&mm->mm_users) <= 0);

if (IS_ENABLED(CONFIG_LOCKDEP)) {
@@ -623,7 +623,7 @@ int __mmu_notifier_register(struct mmu_notifier *subscription,
/*
* kmalloc cannot be called under mm_take_all_locks(), but we
* know that mm->notifier_subscriptions can't change while we
- * hold the write side of the mmap_sem.
+ * hold the write side of the mmap_lock.
*/
subscriptions = kzalloc(
sizeof(struct mmu_notifier_subscriptions), GFP_KERNEL);
@@ -655,7 +655,7 @@ int __mmu_notifier_register(struct mmu_notifier *subscription,
* readers. acquire can only be used while holding the mmgrab or
* mmget, and is safe because once created the
* mmu_notifier_subscriptions is not freed until the mm is destroyed.
- * As above, users holding the mmap_sem or one of the
+ * As above, users holding the mmap_lock or one of the
* mm_take_all_locks() do not need to use acquire semantics.
*/
if (subscriptions)
@@ -689,7 +689,7 @@ EXPORT_SYMBOL_GPL(__mmu_notifier_register);
* @mn: The notifier to attach
* @mm: The mm to attach the notifier to
*
- * Must not hold mmap_sem nor any other VM related lock when calling
+ * Must not hold mmap_lock nor any other VM related lock when calling
* this registration function. Must also ensure mm_users can't go down
* to zero while this runs to avoid races with mmu_notifier_release,
* so mm has to be current->mm or the mm should be pinned safely such
@@ -750,7 +750,7 @@ find_get_mmu_notifier(struct mm_struct *mm, const struct mmu_notifier_ops *ops)
* are the same.
*
* Each call to mmu_notifier_get() must be paired with a call to
- * mmu_notifier_put(). The caller must hold the write side of mm->mmap_sem.
+ * mmu_notifier_put(). The caller must hold the write side of mm->mmap_lock.
*
* While the caller has a mmu_notifier get the mm pointer will remain valid,
* and can be converted to an active mm pointer via mmget_not_zero().
@@ -761,7 +761,7 @@ struct mmu_notifier *mmu_notifier_get_locked(const struct mmu_notifier_ops *ops,
struct mmu_notifier *subscription;
int ret;

- lockdep_assert_held_write(&mm->mmap_sem);
+ lockdep_assert_held_write(&mm->mmap_lock);

if (mm->notifier_subscriptions) {
subscription = find_get_mmu_notifier(mm, ops);
@@ -983,7 +983,7 @@ int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub,
struct mmu_notifier_subscriptions *subscriptions;
int ret;

- might_lock(&mm->mmap_sem);
+ might_lock(&mm->mmap_lock);

subscriptions = smp_load_acquire(&mm->notifier_subscriptions);
if (!subscriptions || !subscriptions->has_itree) {
@@ -1006,7 +1006,7 @@ int mmu_interval_notifier_insert_locked(
mm->notifier_subscriptions;
int ret;

- lockdep_assert_held_write(&mm->mmap_sem);
+ lockdep_assert_held_write(&mm->mmap_lock);

if (!subscriptions || !subscriptions->has_itree) {
ret = __mmu_notifier_register(NULL, mm);
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 928df1638c30..d669a3146c0f 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -373,8 +373,9 @@ static int __walk_page_range(unsigned long start, unsigned long end,
* caller-specific data to callbacks, @private should be helpful.
*
* Locking:
- * Callers of walk_page_range() and walk_page_vma() should hold @mm->mmap_sem,
- * because these function traverse vma list and/or access to vma's data.
+ * Callers of walk_page_range() and walk_page_vma() should hold
+ * @mm->mmap_lock, because these function traverse the vma list
+ * and/or access the vma's data.
*/
int walk_page_range(struct mm_struct *mm, unsigned long start,
unsigned long end, const struct mm_walk_ops *ops,
@@ -395,7 +396,7 @@ int walk_page_range(struct mm_struct *mm, unsigned long start,
if (!walk.mm)
return -EINVAL;

- lockdep_assert_held(&walk.mm->mmap_sem);
+ lockdep_assert_held(&walk.mm->mmap_lock);

vma = find_vma(walk.mm, start);
do {
@@ -453,7 +454,7 @@ int walk_page_range_novma(struct mm_struct *mm, unsigned long start,
if (start >= end || !walk.mm)
return -EINVAL;

- lockdep_assert_held(&walk.mm->mmap_sem);
+ lockdep_assert_held(&walk.mm->mmap_lock);

return __walk_page_range(start, end, &walk);
}
@@ -472,7 +473,7 @@ int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
if (!walk.mm)
return -EINVAL;

- lockdep_assert_held(&walk.mm->mmap_sem);
+ lockdep_assert_held(&walk.mm->mmap_lock);

err = walk_page_test(vma->vm_start, vma->vm_end, &walk);
if (err > 0)
@@ -498,11 +499,11 @@ int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
* Also see walk_page_range() for additional information.
*
* Locking:
- * This function can't require that the struct mm_struct::mmap_sem is held,
+ * This function can't require that the struct mm_struct::mmap_lock is held,
* since @mapping may be mapped by multiple processes. Instead
* @mapping->i_mmap_rwsem must be held. This might have implications in the
* callbacks, and it's up tho the caller to ensure that the
- * struct mm_struct::mmap_sem is not needed.
+ * struct mm_struct::mmap_lock is not needed.
*
* Also this means that a caller can't rely on the struct
* vm_area_struct::vm_flags to be constant across a call,
diff --git a/mm/util.c b/mm/util.c
index ea2e15b21446..56c562f7ad19 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -425,7 +425,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
* @bypass_rlim: %true if checking RLIMIT_MEMLOCK should be skipped
*
* Assumes @task and @mm are valid (i.e. at least one reference on each), and
- * that mmap_sem is held as writer.
+ * that mmap_lock is held as writer.
*
* Return:
* * 0 on success
@@ -437,7 +437,7 @@ int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc,
unsigned long locked_vm, limit;
int ret = 0;

- lockdep_assert_held_write(&mm->mmap_sem);
+ lockdep_assert_held_write(&mm->mmap_lock);

locked_vm = mm->locked_vm;
if (inc) {
--
2.26.1.301.g55bc3eb7cb9-goog
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