[PATCH v6 10/12] mmap locking API: rename mmap_sem to mmap_lock

From: Michel Lespinasse
Date: Wed May 20 2020 - 01:30:01 EST

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@xxxxxxxxxx>
Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
---
arch/ia64/mm/fault.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 | 38 +++++++++++++--------------
mm/memory.c | 2 +-
mm/mmap.c | 4 +--
mm/mmu_notifier.c | 2 +-
8 files changed, 28 insertions(+), 28 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/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 43ef914e6468..b5bd86778cca 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;
@@ -72,19 +72,19 @@ 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)
{
- lockdep_assert_held(&mm->mmap_sem);
- VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
+ lockdep_assert_held(&mm->mmap_lock);
+ VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), 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);
+ lockdep_assert_held_write(&mm->mmap_lock);
+ VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
}

#endif /* _LINUX_MMAP_LOCK_H */
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 24eb9d1ed0a7..2f348b6c9c9a 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -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) {
--
2.26.2.761.g0e0b3e54be-goog