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mm/mmu_notifiers: Use 'subscription' as the variable name for mmu_notifier

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The 'subscription' is placed on the 'notifier_subscriptions' list.

This eliminates the poor name 'mn' for this variable.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Jason Gunthorpe 2020-01-14 11:11:17 -04:00
parent 984cfe4e25
commit 1991722a70
2 changed files with 117 additions and 96 deletions
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30
include/linux/mmu_notifier.h
View File

@ -73,7 +73,7 @@ struct mmu_notifier_ops {
* through the gart alias address, so leading to memory
* corruption.
*/
void (*release)(struct mmu_notifier *mn,
void (*release)(struct mmu_notifier *subscription,
struct mm_struct *mm);
/*
@ -85,7 +85,7 @@ struct mmu_notifier_ops {
* Start-end is necessary in case the secondary MMU is mapping the page
* at a smaller granularity than the primary MMU.
*/
int (*clear_flush_young)(struct mmu_notifier *mn,
int (*clear_flush_young)(struct mmu_notifier *subscription,
struct mm_struct *mm,
unsigned long start,
unsigned long end);
@ -95,7 +95,7 @@ struct mmu_notifier_ops {
* latter, it is supposed to test-and-clear the young/accessed bitflag
* in the secondary pte, but it may omit flushing the secondary tlb.
*/
int (*clear_young)(struct mmu_notifier *mn,
int (*clear_young)(struct mmu_notifier *subscription,
struct mm_struct *mm,
unsigned long start,
unsigned long end);
@ -106,7 +106,7 @@ struct mmu_notifier_ops {
* frequently used without actually clearing the flag or tearing
* down the secondary mapping on the page.
*/
int (*test_young)(struct mmu_notifier *mn,
int (*test_young)(struct mmu_notifier *subscription,
struct mm_struct *mm,
unsigned long address);
@ -114,7 +114,7 @@ struct mmu_notifier_ops {
* change_pte is called in cases that pte mapping to page is changed:
* for example, when ksm remaps pte to point to a new shared page.
*/
void (*change_pte)(struct mmu_notifier *mn,
void (*change_pte)(struct mmu_notifier *subscription,
struct mm_struct *mm,
unsigned long address,
pte_t pte);
@ -169,9 +169,9 @@ struct mmu_notifier_ops {
* invalidate_range_end.
*
*/
int (*invalidate_range_start)(struct mmu_notifier *mn,
int (*invalidate_range_start)(struct mmu_notifier *subscription,
const struct mmu_notifier_range *range);
void (*invalidate_range_end)(struct mmu_notifier *mn,
void (*invalidate_range_end)(struct mmu_notifier *subscription,
const struct mmu_notifier_range *range);
/*
@ -192,8 +192,10 @@ struct mmu_notifier_ops {
* of what was passed to invalidate_range_start()/end(), if
* called between those functions.
*/
void (*invalidate_range)(struct mmu_notifier *mn, struct mm_struct *mm,
unsigned long start, unsigned long end);
void (*invalidate_range)(struct mmu_notifier *subscription,
struct mm_struct *mm,
unsigned long start,
unsigned long end);
/*
* These callbacks are used with the get/put interface to manage the
@ -206,7 +208,7 @@ struct mmu_notifier_ops {
* and cannot sleep.
*/
struct mmu_notifier *(*alloc_notifier)(struct mm_struct *mm);
void (*free_notifier)(struct mmu_notifier *mn);
void (*free_notifier)(struct mmu_notifier *subscription);
};
/*
@ -280,14 +282,14 @@ mmu_notifier_get(const struct mmu_notifier_ops *ops, struct mm_struct *mm)
up_write(&mm->mmap_sem);
return ret;
}
void mmu_notifier_put(struct mmu_notifier *mn);
void mmu_notifier_put(struct mmu_notifier *subscription);
void mmu_notifier_synchronize(void);
extern int mmu_notifier_register(struct mmu_notifier *mn,
extern int mmu_notifier_register(struct mmu_notifier *subscription,
struct mm_struct *mm);
extern int __mmu_notifier_register(struct mmu_notifier *mn,
extern int __mmu_notifier_register(struct mmu_notifier *subscription,
struct mm_struct *mm);
extern void mmu_notifier_unregister(struct mmu_notifier *mn,
extern void mmu_notifier_unregister(struct mmu_notifier *subscription,
struct mm_struct *mm);
unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni);

183
mm/mmu_notifier.c
View File

@ -294,7 +294,7 @@ static void mn_itree_release(struct mmu_notifier_subscriptions *subscriptions,
static void mn_hlist_release(struct mmu_notifier_subscriptions *subscriptions,
struct mm_struct *mm)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int id;
/*
@ -302,27 +302,27 @@ static void mn_hlist_release(struct mmu_notifier_subscriptions *subscriptions,
* ->release returns.
*/
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &subscriptions->list, hlist)
hlist_for_each_entry_rcu(subscription, &subscriptions->list, hlist)
/*
* If ->release runs before mmu_notifier_unregister it must be
* handled, as it's the only way for the driver to flush all
* existing sptes and stop the driver from establishing any more
* sptes before all the pages in the mm are freed.
*/
if (mn->ops->release)
mn->ops->release(mn, mm);
if (subscription->ops->release)
subscription->ops->release(subscription, mm);
spin_lock(&subscriptions->lock);
while (unlikely(!hlist_empty(&subscriptions->list))) {
mn = hlist_entry(subscriptions->list.first, struct mmu_notifier,
hlist);
subscription = hlist_entry(subscriptions->list.first,
struct mmu_notifier, hlist);
/*
* We arrived before mmu_notifier_unregister so
* mmu_notifier_unregister will do nothing other than to wait
* for ->release to finish and for mmu_notifier_unregister to
* return.
*/
hlist_del_init_rcu(&mn->hlist);
hlist_del_init_rcu(&subscription->hlist);
}
spin_unlock(&subscriptions->lock);
srcu_read_unlock(&srcu, id);
@ -360,13 +360,15 @@ int __mmu_notifier_clear_flush_young(struct mm_struct *mm,
unsigned long start,
unsigned long end)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int young = 0, id;
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->notifier_subscriptions->list, hlist) {
if (mn->ops->clear_flush_young)
young |= mn->ops->clear_flush_young(mn, mm, start, end);
hlist_for_each_entry_rcu(subscription,
&mm->notifier_subscriptions->list, hlist) {
if (subscription->ops->clear_flush_young)
young |= subscription->ops->clear_flush_young(
subscription, mm, start, end);
}
srcu_read_unlock(&srcu, id);
@ -377,13 +379,15 @@ int __mmu_notifier_clear_young(struct mm_struct *mm,
unsigned long start,
unsigned long end)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int young = 0, id;
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->notifier_subscriptions->list, hlist) {
if (mn->ops->clear_young)
young |= mn->ops->clear_young(mn, mm, start, end);
hlist_for_each_entry_rcu(subscription,
&mm->notifier_subscriptions->list, hlist) {
if (subscription->ops->clear_young)
young |= subscription->ops->clear_young(subscription,
mm, start, end);
}
srcu_read_unlock(&srcu, id);
@ -393,13 +397,15 @@ int __mmu_notifier_clear_young(struct mm_struct *mm,
int __mmu_notifier_test_young(struct mm_struct *mm,
unsigned long address)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int young = 0, id;
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->notifier_subscriptions->list, hlist) {
if (mn->ops->test_young) {
young = mn->ops->test_young(mn, mm, address);
hlist_for_each_entry_rcu(subscription,
&mm->notifier_subscriptions->list, hlist) {
if (subscription->ops->test_young) {
young = subscription->ops->test_young(subscription, mm,
address);
if (young)
break;
}
@ -412,14 +418,15 @@ int __mmu_notifier_test_young(struct mm_struct *mm,
void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address,
pte_t pte)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int id;
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->notifier_subscriptions->list,
hlist) {
if (mn->ops->change_pte)
mn->ops->change_pte(mn, mm, address, pte);
hlist_for_each_entry_rcu(subscription,
&mm->notifier_subscriptions->list, hlist) {
if (subscription->ops->change_pte)
subscription->ops->change_pte(subscription, mm, address,
pte);
}
srcu_read_unlock(&srcu, id);
}
@ -456,24 +463,28 @@ static int mn_hlist_invalidate_range_start(
struct mmu_notifier_subscriptions *subscriptions,
struct mmu_notifier_range *range)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int ret = 0;
int id;
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &subscriptions->list, hlist) {
if (mn->ops->invalidate_range_start) {
hlist_for_each_entry_rcu(subscription, &subscriptions->list, hlist) {
const struct mmu_notifier_ops *ops = subscription->ops;
if (ops->invalidate_range_start) {
int _ret;
if (!mmu_notifier_range_blockable(range))
non_block_start();
_ret = mn->ops->invalidate_range_start(mn, range);
_ret = ops->invalidate_range_start(subscription, range);
if (!mmu_notifier_range_blockable(range))
non_block_end();
if (_ret) {
pr_info("%pS callback failed with %d in %sblockable context.\n",
mn->ops->invalidate_range_start, _ret,
!mmu_notifier_range_blockable(range) ? "non-" : "");
ops->invalidate_range_start, _ret,
!mmu_notifier_range_blockable(range) ?
"non-" :
"");
WARN_ON(mmu_notifier_range_blockable(range) ||
_ret != -EAGAIN);
ret = _ret;
@ -505,11 +516,11 @@ static void
mn_hlist_invalidate_end(struct mmu_notifier_subscriptions *subscriptions,
struct mmu_notifier_range *range, bool only_end)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int id;
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &subscriptions->list, hlist) {
hlist_for_each_entry_rcu(subscription, &subscriptions->list, hlist) {
/*
* Call invalidate_range here too to avoid the need for the
* subsystem of having to register an invalidate_range_end
@ -523,14 +534,16 @@ mn_hlist_invalidate_end(struct mmu_notifier_subscriptions *subscriptions,
* is safe to do when we know that a call to invalidate_range()
* already happen under page table lock.
*/
if (!only_end && mn->ops->invalidate_range)
mn->ops->invalidate_range(mn, range->mm,
range->start,
range->end);
if (mn->ops->invalidate_range_end) {
if (!only_end && subscription->ops->invalidate_range)
subscription->ops->invalidate_range(subscription,
range->mm,
range->start,
range->end);
if (subscription->ops->invalidate_range_end) {
if (!mmu_notifier_range_blockable(range))
non_block_start();
mn->ops->invalidate_range_end(mn, range);
subscription->ops->invalidate_range_end(subscription,
range);
if (!mmu_notifier_range_blockable(range))
non_block_end();
}
@ -556,13 +569,15 @@ void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range,
void __mmu_notifier_invalidate_range(struct mm_struct *mm,
unsigned long start, unsigned long end)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int id;
id = srcu_read_lock(&srcu);
hlist_for_each_entry_rcu(mn, &mm->notifier_subscriptions->list, hlist) {
if (mn->ops->invalidate_range)
mn->ops->invalidate_range(mn, mm, start, end);
hlist_for_each_entry_rcu(subscription,
&mm->notifier_subscriptions->list, hlist) {
if (subscription->ops->invalidate_range)
subscription->ops->invalidate_range(subscription, mm,
start, end);
}
srcu_read_unlock(&srcu, id);
}
@ -572,7 +587,8 @@ void __mmu_notifier_invalidate_range(struct mm_struct *mm,
* write mode. A NULL mn signals the notifier is being registered for itree
* mode.
*/
int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
int __mmu_notifier_register(struct mmu_notifier *subscription,
struct mm_struct *mm)
{
struct mmu_notifier_subscriptions *subscriptions = NULL;
int ret;
@ -629,14 +645,14 @@ int __mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
if (subscriptions)
smp_store_release(&mm->notifier_subscriptions, subscriptions);
if (mn) {
if (subscription) {
/* Pairs with the mmdrop in mmu_notifier_unregister_* */
mmgrab(mm);
mn->mm = mm;
mn->users = 1;
subscription->mm = mm;
subscription->users = 1;
spin_lock(&mm->notifier_subscriptions->lock);
hlist_add_head_rcu(&mn->hlist,
hlist_add_head_rcu(&subscription->hlist,
&mm->notifier_subscriptions->list);
spin_unlock(&mm->notifier_subscriptions->lock);
} else
@ -668,15 +684,16 @@ EXPORT_SYMBOL_GPL(__mmu_notifier_register);
* mmu_notifier_unregister() or mmu_notifier_put() must be always called to
* unregister the notifier.
*
* While the caller has a mmu_notifier get the mn->mm pointer will remain
* While the caller has a mmu_notifier get the subscription->mm pointer will remain
* valid, and can be converted to an active mm pointer via mmget_not_zero().
*/
int mmu_notifier_register(struct mmu_notifier *mn, struct mm_struct *mm)
int mmu_notifier_register(struct mmu_notifier *subscription,
struct mm_struct *mm)
{
int ret;
down_write(&mm->mmap_sem);
ret = __mmu_notifier_register(mn, mm);
ret = __mmu_notifier_register(subscription, mm);
up_write(&mm->mmap_sem);
return ret;
}
@ -685,20 +702,20 @@ EXPORT_SYMBOL_GPL(mmu_notifier_register);
static struct mmu_notifier *
find_get_mmu_notifier(struct mm_struct *mm, const struct mmu_notifier_ops *ops)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
spin_lock(&mm->notifier_subscriptions->lock);
hlist_for_each_entry_rcu(mn, &mm->notifier_subscriptions->list,
hlist) {
if (mn->ops != ops)
hlist_for_each_entry_rcu(subscription,
&mm->notifier_subscriptions->list, hlist) {
if (subscription->ops != ops)
continue;
if (likely(mn->users != UINT_MAX))
mn->users++;
if (likely(subscription->users != UINT_MAX))
subscription->users++;
else
mn = ERR_PTR(-EOVERFLOW);
subscription = ERR_PTR(-EOVERFLOW);
spin_unlock(&mm->notifier_subscriptions->lock);
return mn;
return subscription;
}
spin_unlock(&mm->notifier_subscriptions->lock);
return NULL;
@ -724,27 +741,27 @@ find_get_mmu_notifier(struct mm_struct *mm, const struct mmu_notifier_ops *ops)
struct mmu_notifier *mmu_notifier_get_locked(const struct mmu_notifier_ops *ops,
struct mm_struct *mm)
{
struct mmu_notifier *mn;
struct mmu_notifier *subscription;
int ret;
lockdep_assert_held_write(&mm->mmap_sem);
if (mm->notifier_subscriptions) {
mn = find_get_mmu_notifier(mm, ops);
if (mn)
return mn;
subscription = find_get_mmu_notifier(mm, ops);
if (subscription)
return subscription;
}
mn = ops->alloc_notifier(mm);
if (IS_ERR(mn))
return mn;
mn->ops = ops;
ret = __mmu_notifier_register(mn, mm);
subscription = ops->alloc_notifier(mm);
if (IS_ERR(subscription))
return subscription;
subscription->ops = ops;
ret = __mmu_notifier_register(subscription, mm);
if (ret)
goto out_free;
return mn;
return subscription;
out_free:
mn->ops->free_notifier(mn);
subscription->ops->free_notifier(subscription);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(mmu_notifier_get_locked);
@ -767,11 +784,12 @@ void __mmu_notifier_subscriptions_destroy(struct mm_struct *mm)
* and only after mmu_notifier_unregister returned we're guaranteed
* that ->release or any other method can't run anymore.
*/
void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm)
void mmu_notifier_unregister(struct mmu_notifier *subscription,
struct mm_struct *mm)
{
BUG_ON(atomic_read(&mm->mm_count) <= 0);
if (!hlist_unhashed(&mn->hlist)) {
if (!hlist_unhashed(&subscription->hlist)) {
/*
* SRCU here will force exit_mmap to wait for ->release to
* finish before freeing the pages.
@ -783,8 +801,8 @@ void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm)
* exit_mmap will block in mmu_notifier_release to guarantee
* that ->release is called before freeing the pages.
*/
if (mn->ops->release)
mn->ops->release(mn, mm);
if (subscription->ops->release)
subscription->ops->release(subscription, mm);
srcu_read_unlock(&srcu, id);
spin_lock(&mm->notifier_subscriptions->lock);
@ -792,7 +810,7 @@ void mmu_notifier_unregister(struct mmu_notifier *mn, struct mm_struct *mm)
* Can not use list_del_rcu() since __mmu_notifier_release
* can delete it before we hold the lock.
*/
hlist_del_init_rcu(&mn->hlist);
hlist_del_init_rcu(&subscription->hlist);
spin_unlock(&mm->notifier_subscriptions->lock);
}
@ -810,10 +828,11 @@ EXPORT_SYMBOL_GPL(mmu_notifier_unregister);
static void mmu_notifier_free_rcu(struct rcu_head *rcu)
{
struct mmu_notifier *mn = container_of(rcu, struct mmu_notifier, rcu);
struct mm_struct *mm = mn->mm;
struct mmu_notifier *subscription =
container_of(rcu, struct mmu_notifier, rcu);
struct mm_struct *mm = subscription->mm;
mn->ops->free_notifier(mn);
subscription->ops->free_notifier(subscription);
/* Pairs with the get in __mmu_notifier_register() */
mmdrop(mm);
}
@ -840,17 +859,17 @@ static void mmu_notifier_free_rcu(struct rcu_head *rcu)
* Modules calling this function must call mmu_notifier_synchronize() in
* their __exit functions to ensure the async work is completed.
*/
void mmu_notifier_put(struct mmu_notifier *mn)
void mmu_notifier_put(struct mmu_notifier *subscription)
{
struct mm_struct *mm = mn->mm;
struct mm_struct *mm = subscription->mm;
spin_lock(&mm->notifier_subscriptions->lock);
if (WARN_ON(!mn->users) || --mn->users)
if (WARN_ON(!subscription->users) || --subscription->users)
goto out_unlock;
hlist_del_init_rcu(&mn->hlist);
hlist_del_init_rcu(&subscription->hlist);
spin_unlock(&mm->notifier_subscriptions->lock);
call_srcu(&srcu, &mn->rcu, mmu_notifier_free_rcu);
call_srcu(&srcu, &subscription->rcu, mmu_notifier_free_rcu);
return;
out_unlock: