From: Jason Gunthorpe <jgg@mellanox.com>
Date: Tue, 14 Jan 2020 11:29:52 -0400
Subject: mm/mmu_notifiers: Use 'interval_sub' as the variable for
mmu_interval_notifier
Git-commit: 5292e24a6acf5694e0a32c31e3321964176bc17e
Patch-mainline: v5.6-rc1
References: jsc#SLE-16387
The 'interval_sub' is placed on the 'notifier_subscriptions' interval
tree.
This eliminates the poor name 'mni' for this variable.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
Documentation/vm/hmm.rst | 22 +++---
include/linux/mmu_notifier.h | 38 ++++++------
mm/mmu_notifier.c | 136 +++++++++++++++++++++++--------------------
3 files changed, 105 insertions(+), 91 deletions(-)
--- a/Documentation/vm/hmm.rst
+++ b/Documentation/vm/hmm.rst
@@ -149,14 +149,14 @@ CPU page table into a device page table;
device driver that wants to mirror a process address space must start with the
registration of a mmu_interval_notifier::
- mni->ops = &driver_ops;
- int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni,
- unsigned long start, unsigned long length,
- struct mm_struct *mm);
-
-During the driver_ops->invalidate() callback the device driver must perform
-the update action to the range (mark range read only, or fully unmap,
-etc.). The device must complete the update before the driver callback returns.
+ int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub,
+ struct mm_struct *mm, unsigned long start,
+ unsigned long length,
+ const struct mmu_interval_notifier_ops *ops);
+
+During the ops->invalidate() callback the device driver must perform the
+update action to the range (mark range read only, or fully unmap, etc.). The
+device must complete the update before the driver callback returns.
When the device driver wants to populate a range of virtual addresses, it can
use::
@@ -183,7 +183,7 @@ The usage pattern is::
struct hmm_range range;
...
- range.notifier = &mni;
+ range.notifier = &interval_sub;
range.start = ...;
range.end = ...;
range.pfns = ...;
@@ -191,11 +191,11 @@ The usage pattern is::
range.values = ...;
range.pfn_shift = ...;
- if (!mmget_not_zero(mni->notifier.mm))
+ if (!mmget_not_zero(interval_sub->notifier.mm))
return -EFAULT;
again:
- range.notifier_seq = mmu_interval_read_begin(&mni);
+ range.notifier_seq = mmu_interval_read_begin(&interval_sub);
down_read(&mm->mmap_sem);
ret = hmm_range_fault(&range, HMM_RANGE_SNAPSHOT);
if (ret) {
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -237,7 +237,7 @@ struct mmu_notifier {
* was required but mmu_notifier_range_blockable(range) is false.
*/
struct mmu_interval_notifier_ops {
- bool (*invalidate)(struct mmu_interval_notifier *mni,
+ bool (*invalidate)(struct mmu_interval_notifier *interval_sub,
const struct mmu_notifier_range *range,
unsigned long cur_seq);
};
@@ -292,20 +292,21 @@ extern int __mmu_notifier_register(struc
extern void mmu_notifier_unregister(struct mmu_notifier *subscription,
struct mm_struct *mm);
-unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni);
-int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni,
+unsigned long
+mmu_interval_read_begin(struct mmu_interval_notifier *interval_sub);
+int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub,
struct mm_struct *mm, unsigned long start,
unsigned long length,
const struct mmu_interval_notifier_ops *ops);
int mmu_interval_notifier_insert_locked(
- struct mmu_interval_notifier *mni, struct mm_struct *mm,
+ struct mmu_interval_notifier *interval_sub, struct mm_struct *mm,
unsigned long start, unsigned long length,
const struct mmu_interval_notifier_ops *ops);
-void mmu_interval_notifier_remove(struct mmu_interval_notifier *mni);
+void mmu_interval_notifier_remove(struct mmu_interval_notifier *interval_sub);
/**
* mmu_interval_set_seq - Save the invalidation sequence
- * @mni - The mni passed to invalidate
+ * @interval_sub - The subscription passed to invalidate
* @cur_seq - The cur_seq passed to the invalidate() callback
*
* This must be called unconditionally from the invalidate callback of a
@@ -316,15 +317,16 @@ void mmu_interval_notifier_remove(struct
* If the caller does not call mmu_interval_read_begin() or
* mmu_interval_read_retry() then this call is not required.
*/
-static inline void mmu_interval_set_seq(struct mmu_interval_notifier *mni,
- unsigned long cur_seq)
+static inline void
+mmu_interval_set_seq(struct mmu_interval_notifier *interval_sub,
+ unsigned long cur_seq)
{
- WRITE_ONCE(mni->invalidate_seq, cur_seq);
+ WRITE_ONCE(interval_sub->invalidate_seq, cur_seq);
}
/**
* mmu_interval_read_retry - End a read side critical section against a VA range
- * mni: The range
+ * interval_sub: The subscription
* seq: The return of the paired mmu_interval_read_begin()
*
* This MUST be called under a user provided lock that is also held
@@ -336,15 +338,16 @@ static inline void mmu_interval_set_seq(
* Returns true if an invalidation collided with this critical section, and
* the caller should retry.
*/
-static inline bool mmu_interval_read_retry(struct mmu_interval_notifier *mni,
- unsigned long seq)
+static inline bool
+mmu_interval_read_retry(struct mmu_interval_notifier *interval_sub,
+ unsigned long seq)
{
- return mni->invalidate_seq != seq;
+ return interval_sub->invalidate_seq != seq;
}
/**
* mmu_interval_check_retry - Test if a collision has occurred
- * mni: The range
+ * interval_sub: The subscription
* seq: The return of the matching mmu_interval_read_begin()
*
* This can be used in the critical section between mmu_interval_read_begin()
@@ -359,11 +362,12 @@ static inline bool mmu_interval_read_ret
* This call can be used as part of loops and other expensive operations to
* expedite a retry.
*/
-static inline bool mmu_interval_check_retry(struct mmu_interval_notifier *mni,
- unsigned long seq)
+static inline bool
+mmu_interval_check_retry(struct mmu_interval_notifier *interval_sub,
+ unsigned long seq)
{
/* Pairs with the WRITE_ONCE in mmu_interval_set_seq() */
- return READ_ONCE(mni->invalidate_seq) != seq;
+ return READ_ONCE(interval_sub->invalidate_seq) != seq;
}
extern void __mmu_notifier_subscriptions_destroy(struct mm_struct *mm);
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -81,7 +81,7 @@ struct mmu_notifier_subscriptions {
* seq & 1 # True if a writer exists
*
* The later state avoids some expensive work on inv_end in the common case of
- * no mni monitoring the VA.
+ * no mmu_interval_notifier monitoring the VA.
*/
static bool
mn_itree_is_invalidating(struct mmu_notifier_subscriptions *subscriptions)
@@ -114,13 +114,13 @@ mn_itree_inv_start_range(struct mmu_noti
}
static struct mmu_interval_notifier *
-mn_itree_inv_next(struct mmu_interval_notifier *mni,
+mn_itree_inv_next(struct mmu_interval_notifier *interval_sub,
const struct mmu_notifier_range *range)
{
struct interval_tree_node *node;
- node = interval_tree_iter_next(&mni->interval_tree, range->start,
- range->end - 1);
+ node = interval_tree_iter_next(&interval_sub->interval_tree,
+ range->start, range->end - 1);
if (!node)
return NULL;
return container_of(node, struct mmu_interval_notifier, interval_tree);
@@ -128,7 +128,7 @@ mn_itree_inv_next(struct mmu_interval_no
static void mn_itree_inv_end(struct mmu_notifier_subscriptions *subscriptions)
{
- struct mmu_interval_notifier *mni;
+ struct mmu_interval_notifier *interval_sub;
struct hlist_node *next;
spin_lock(&subscriptions->lock);
@@ -147,15 +147,16 @@ static void mn_itree_inv_end(struct mmu_
* they are progressed. This arrangement for tree updates is used to
* avoid using a blocking lock during invalidate_range_start.
*/
- hlist_for_each_entry_safe(mni, next, &subscriptions->deferred_list,
+ hlist_for_each_entry_safe(interval_sub, next,
+ &subscriptions->deferred_list,
deferred_item) {
- if (RB_EMPTY_NODE(&mni->interval_tree.rb))
- interval_tree_insert(&mni->interval_tree,
+ if (RB_EMPTY_NODE(&interval_sub->interval_tree.rb))
+ interval_tree_insert(&interval_sub->interval_tree,
&subscriptions->itree);
else
- interval_tree_remove(&mni->interval_tree,
+ interval_tree_remove(&interval_sub->interval_tree,
&subscriptions->itree);
- hlist_del(&mni->deferred_item);
+ hlist_del(&interval_sub->deferred_item);
}
spin_unlock(&subscriptions->lock);
@@ -165,12 +166,12 @@ static void mn_itree_inv_end(struct mmu_
/**
* mmu_interval_read_begin - Begin a read side critical section against a VA
* range
- * mni: The range to use
+ * interval_sub: The interval subscription
*
* mmu_iterval_read_begin()/mmu_iterval_read_retry() implement a
- * collision-retry scheme similar to seqcount for the VA range under mni. If
- * the mm invokes invalidation during the critical section then
- * mmu_interval_read_retry() will return true.
+ * collision-retry scheme similar to seqcount for the VA range under
+ * subscription. If the mm invokes invalidation during the critical section
+ * then mmu_interval_read_retry() will return true.
*
* This is useful to obtain shadow PTEs where teardown or setup of the SPTEs
* require a blocking context. The critical region formed by this can sleep,
@@ -181,25 +182,26 @@ static void mn_itree_inv_end(struct mmu_
*
* The return value should be passed to mmu_interval_read_retry().
*/
-unsigned long mmu_interval_read_begin(struct mmu_interval_notifier *mni)
+unsigned long
+mmu_interval_read_begin(struct mmu_interval_notifier *interval_sub)
{
struct mmu_notifier_subscriptions *subscriptions =
- mni->mm->notifier_subscriptions;
+ interval_sub->mm->notifier_subscriptions;
unsigned long seq;
bool is_invalidating;
/*
- * If the mni has a different seq value under the user_lock than we
- * started with then it has collided.
+ * If the subscription has a different seq value under the user_lock
+ * than we started with then it has collided.
*
- * If the mni currently has the same seq value as the subscriptions
- * seq, then it is currently between invalidate_start/end and is
- * colliding.
+ * If the subscription currently has the same seq value as the
+ * subscriptions seq, then it is currently between
+ * invalidate_start/end and is colliding.
*
* The locking looks broadly like this:
* mn_tree_invalidate_start(): mmu_interval_read_begin():
* spin_lock
- * seq = READ_ONCE(mni->invalidate_seq);
+ * seq = READ_ONCE(interval_sub->invalidate_seq);
* seq == subs->invalidate_seq
* spin_unlock
* spin_lock
@@ -208,7 +210,7 @@ unsigned long mmu_interval_read_begin(st
* op->invalidate_range():
* user_lock
* mmu_interval_set_seq()
- * mni->invalidate_seq = seq
+ * interval_sub->invalidate_seq = seq
* user_unlock
*
* [Required: mmu_interval_read_retry() == true]
@@ -220,7 +222,7 @@ unsigned long mmu_interval_read_begin(st
*
* user_lock
* mmu_interval_read_retry():
- * mni->invalidate_seq != seq
+ * interval_sub->invalidate_seq != seq
* user_unlock
*
* Barriers are not needed here as any races here are closed by an
@@ -229,12 +231,12 @@ unsigned long mmu_interval_read_begin(st
*/
spin_lock(&subscriptions->lock);
/* Pairs with the WRITE_ONCE in mmu_interval_set_seq() */
- seq = READ_ONCE(mni->invalidate_seq);
+ seq = READ_ONCE(interval_sub->invalidate_seq);
is_invalidating = seq == subscriptions->invalidate_seq;
spin_unlock(&subscriptions->lock);
/*
- * mni->invalidate_seq must always be set to an odd value via
+ * interval_sub->invalidate_seq must always be set to an odd value via
* mmu_interval_set_seq() using the provided cur_seq from
* mn_itree_inv_start_range(). This ensures that if seq does wrap we
* will always clear the below sleep in some reasonable time as
@@ -266,13 +268,16 @@ static void mn_itree_release(struct mmu_
.start = 0,
.end = ULONG_MAX,
};
- struct mmu_interval_notifier *mni;
+ struct mmu_interval_notifier *interval_sub;
unsigned long cur_seq;
bool ret;
- for (mni = mn_itree_inv_start_range(subscriptions, &range, &cur_seq);
- mni; mni = mn_itree_inv_next(mni, &range)) {
- ret = mni->ops->invalidate(mni, &range, cur_seq);
+ for (interval_sub =
+ mn_itree_inv_start_range(subscriptions, &range, &cur_seq);
+ interval_sub;
+ interval_sub = mn_itree_inv_next(interval_sub, &range)) {
+ ret = interval_sub->ops->invalidate(interval_sub, &range,
+ cur_seq);
WARN_ON(!ret);
}
@@ -434,14 +439,17 @@ void __mmu_notifier_change_pte(struct mm
static int mn_itree_invalidate(struct mmu_notifier_subscriptions *subscriptions,
const struct mmu_notifier_range *range)
{
- struct mmu_interval_notifier *mni;
+ struct mmu_interval_notifier *interval_sub;
unsigned long cur_seq;
- for (mni = mn_itree_inv_start_range(subscriptions, range, &cur_seq);
- mni; mni = mn_itree_inv_next(mni, range)) {
+ for (interval_sub =
+ mn_itree_inv_start_range(subscriptions, range, &cur_seq);
+ interval_sub;
+ interval_sub = mn_itree_inv_next(interval_sub, range)) {
bool ret;
- ret = mni->ops->invalidate(mni, range, cur_seq);
+ ret = interval_sub->ops->invalidate(interval_sub, range,
+ cur_seq);
if (!ret) {
if (WARN_ON(mmu_notifier_range_blockable(range)))
continue;
@@ -878,20 +886,21 @@ out_unlock:
EXPORT_SYMBOL_GPL(mmu_notifier_put);
static int __mmu_interval_notifier_insert(
- struct mmu_interval_notifier *mni, struct mm_struct *mm,
+ struct mmu_interval_notifier *interval_sub, struct mm_struct *mm,
struct mmu_notifier_subscriptions *subscriptions, unsigned long start,
unsigned long length, const struct mmu_interval_notifier_ops *ops)
{
- mni->mm = mm;
- mni->ops = ops;
- RB_CLEAR_NODE(&mni->interval_tree.rb);
- mni->interval_tree.start = start;
+ interval_sub->mm = mm;
+ interval_sub->ops = ops;
+ RB_CLEAR_NODE(&interval_sub->interval_tree.rb);
+ interval_sub->interval_tree.start = start;
/*
* Note that the representation of the intervals in the interval tree
* considers the ending point as contained in the interval.
*/
if (length == 0 ||
- check_add_overflow(start, length - 1, &mni->interval_tree.last))
+ check_add_overflow(start, length - 1,
+ &interval_sub->interval_tree.last))
return -EOVERFLOW;
/* Must call with a mmget() held */
@@ -911,30 +920,31 @@ static int __mmu_interval_notifier_inser
* possibility for live lock, instead defer the add to
* mn_itree_inv_end() so this algorithm is deterministic.
*
- * In all cases the value for the mni->invalidate_seq should be
+ * In all cases the value for the interval_sub->invalidate_seq should be
* odd, see mmu_interval_read_begin()
*/
spin_lock(&subscriptions->lock);
if (subscriptions->active_invalidate_ranges) {
if (mn_itree_is_invalidating(subscriptions))
- hlist_add_head(&mni->deferred_item,
+ hlist_add_head(&interval_sub->deferred_item,
&subscriptions->deferred_list);
else {
subscriptions->invalidate_seq |= 1;
- interval_tree_insert(&mni->interval_tree,
+ interval_tree_insert(&interval_sub->interval_tree,
&subscriptions->itree);
}
- mni->invalidate_seq = subscriptions->invalidate_seq;
+ interval_sub->invalidate_seq = subscriptions->invalidate_seq;
} else {
WARN_ON(mn_itree_is_invalidating(subscriptions));
/*
- * The starting seq for a mni not under invalidation should be
- * odd, not equal to the current invalidate_seq and
+ * The starting seq for a subscription not under invalidation
+ * should be odd, not equal to the current invalidate_seq and
* invalidate_seq should not 'wrap' to the new seq any time
* soon.
*/
- mni->invalidate_seq = subscriptions->invalidate_seq - 1;
- interval_tree_insert(&mni->interval_tree,
+ interval_sub->invalidate_seq =
+ subscriptions->invalidate_seq - 1;
+ interval_tree_insert(&interval_sub->interval_tree,
&subscriptions->itree);
}
spin_unlock(&subscriptions->lock);
@@ -943,7 +953,7 @@ static int __mmu_interval_notifier_inser
/**
* mmu_interval_notifier_insert - Insert an interval notifier
- * @mni: Interval notifier to register
+ * @interval_sub: Interval subscription to register
* @start: Starting virtual address to monitor
* @length: Length of the range to monitor
* @mm : mm_struct to attach to
@@ -956,7 +966,7 @@ static int __mmu_interval_notifier_inser
* The caller must use the normal interval notifier read flow via
* mmu_interval_read_begin() to establish SPTEs for this range.
*/
-int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni,
+int mmu_interval_notifier_insert(struct mmu_interval_notifier *interval_sub,
struct mm_struct *mm, unsigned long start,
unsigned long length,
const struct mmu_interval_notifier_ops *ops)
@@ -973,13 +983,13 @@ int mmu_interval_notifier_insert(struct
return ret;
subscriptions = mm->notifier_subscriptions;
}
- return __mmu_interval_notifier_insert(mni, mm, subscriptions, start,
- length, ops);
+ return __mmu_interval_notifier_insert(interval_sub, mm, subscriptions,
+ start, length, ops);
}
EXPORT_SYMBOL_GPL(mmu_interval_notifier_insert);
int mmu_interval_notifier_insert_locked(
- struct mmu_interval_notifier *mni, struct mm_struct *mm,
+ struct mmu_interval_notifier *interval_sub, struct mm_struct *mm,
unsigned long start, unsigned long length,
const struct mmu_interval_notifier_ops *ops)
{
@@ -995,14 +1005,14 @@ int mmu_interval_notifier_insert_locked(
return ret;
subscriptions = mm->notifier_subscriptions;
}
- return __mmu_interval_notifier_insert(mni, mm, subscriptions, start,
- length, ops);
+ return __mmu_interval_notifier_insert(interval_sub, mm, subscriptions,
+ start, length, ops);
}
EXPORT_SYMBOL_GPL(mmu_interval_notifier_insert_locked);
/**
* mmu_interval_notifier_remove - Remove a interval notifier
- * @mni: Interval notifier to unregister
+ * @interval_sub: Interval subscription to unregister
*
* This function must be paired with mmu_interval_notifier_insert(). It cannot
* be called from any ops callback.
@@ -1010,9 +1020,9 @@ EXPORT_SYMBOL_GPL(mmu_interval_notifier_
* Once this returns ops callbacks are no longer running on other CPUs and
* will not be called in future.
*/
-void mmu_interval_notifier_remove(struct mmu_interval_notifier *mni)
+void mmu_interval_notifier_remove(struct mmu_interval_notifier *interval_sub)
{
- struct mm_struct *mm = mni->mm;
+ struct mm_struct *mm = interval_sub->mm;
struct mmu_notifier_subscriptions *subscriptions =
mm->notifier_subscriptions;
unsigned long seq = 0;
@@ -1025,16 +1035,16 @@ void mmu_interval_notifier_remove(struct
* remove is being called after insert put this on the
* deferred list, but before the deferred list was processed.
*/
- if (RB_EMPTY_NODE(&mni->interval_tree.rb)) {
- hlist_del(&mni->deferred_item);
+ if (RB_EMPTY_NODE(&interval_sub->interval_tree.rb)) {
+ hlist_del(&interval_sub->deferred_item);
} else {
- hlist_add_head(&mni->deferred_item,
+ hlist_add_head(&interval_sub->deferred_item,
&subscriptions->deferred_list);
seq = subscriptions->invalidate_seq;
}
} else {
- WARN_ON(RB_EMPTY_NODE(&mni->interval_tree.rb));
- interval_tree_remove(&mni->interval_tree,
+ WARN_ON(RB_EMPTY_NODE(&interval_sub->interval_tree.rb));
+ interval_tree_remove(&interval_sub->interval_tree,
&subscriptions->itree);
}
spin_unlock(&subscriptions->lock);