HMM defines its own struct hmm_update which is passed to the
sync_cpu_device_pagetables() callback function. This is
sufficient when the only action is to invalidate. However,
a device may want to know the reason for the invalidation and
be able to see the new permissions on a range, update device access
rights or range statistics. Since sync_cpu_device_pagetables()
can be called from try_to_unmap(), the mmap_sem may not be held
and find_vma() is not safe to be called.
Pass the struct mmu_notifier_range to sync_cpu_device_pagetables()
to allow the full invalidation information to be used.
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
---
I'm sending this out now since we are updating many of the HMM APIs
and I think it will be useful.
drivers/gpu/drm/nouveau/nouveau_svm.c | 4 ++--
include/linux/hmm.h | 27 ++-------------------------
mm/hmm.c | 13 ++++---------
3 files changed, 8 insertions(+), 36 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
index 8c92374afcf2..c34b98fafe2f 100644
--- a/drivers/gpu/drm/nouveau/nouveau_svm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
@@ -252,13 +252,13 @@ nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit)
static int
nouveau_svmm_sync_cpu_device_pagetables(struct hmm_mirror *mirror,
- const struct hmm_update *update)
+ const struct mmu_notifier_range *update)
{
struct nouveau_svmm *svmm = container_of(mirror, typeof(*svmm), mirror);
unsigned long start = update->start;
unsigned long limit = update->end;
- if (!update->blockable)
+ if (!mmu_notifier_range_blockable(update))
return -EAGAIN;
SVMM_DBG(svmm, "invalidate %016lx-%016lx", start, limit);
diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 0fa8ea34ccef..07a2d38fde34 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -377,29 +377,6 @@ static inline uint64_t hmm_pfn_from_pfn(const struct hmm_range *range,
struct hmm_mirror;
-/*
- * enum hmm_update_event - type of update
- * @HMM_UPDATE_INVALIDATE: invalidate range (no indication as to why)
- */
-enum hmm_update_event {
- HMM_UPDATE_INVALIDATE,
-};
-
-/*
- * struct hmm_update - HMM update information for callback
- *
- * @start: virtual start address of the range to update
- * @end: virtual end address of the range to update
- * @event: event triggering the update (what is happening)
- * @blockable: can the callback block/sleep ?
- */
-struct hmm_update {
- unsigned long start;
- unsigned long end;
- enum hmm_update_event event;
- bool blockable;
-};
-
/*
* struct hmm_mirror_ops - HMM mirror device operations callback
*
@@ -420,7 +397,7 @@ struct hmm_mirror_ops {
/* sync_cpu_device_pagetables() - synchronize page tables
*
* @mirror: pointer to struct hmm_mirror
- * @update: update information (see struct hmm_update)
+ * @update: update information (see struct mmu_notifier_range)
* Return: -EAGAIN if update.blockable false and callback need to
* block, 0 otherwise.
*
@@ -434,7 +411,7 @@ struct hmm_mirror_ops {
* synchronous call.
*/
int (*sync_cpu_device_pagetables)(struct hmm_mirror *mirror,
- const struct hmm_update *update);
+ const struct mmu_notifier_range *update);
};
/*
diff --git a/mm/hmm.c b/mm/hmm.c
index 9aad3550f2bb..b49a43712554 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -164,7 +164,6 @@ static int hmm_invalidate_range_start(struct mmu_notifier *mn,
{
struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier);
struct hmm_mirror *mirror;
- struct hmm_update update;
struct hmm_range *range;
unsigned long flags;
int ret = 0;
@@ -173,15 +172,10 @@ static int hmm_invalidate_range_start(struct mmu_notifier *mn,
if (!kref_get_unless_zero(&hmm->kref))
return 0;
- update.start = nrange->start;
- update.end = nrange->end;
- update.event = HMM_UPDATE_INVALIDATE;
- update.blockable = mmu_notifier_range_blockable(nrange);
-
spin_lock_irqsave(&hmm->ranges_lock, flags);
hmm->notifiers++;
list_for_each_entry(range, &hmm->ranges, list) {
- if (update.end < range->start || update.start >= range->end)
+ if (nrange->end < range->start || nrange->start >= range->end)
continue;
range->valid = false;
@@ -198,9 +192,10 @@ static int hmm_invalidate_range_start(struct mmu_notifier *mn,
list_for_each_entry(mirror, &hmm->mirrors, list) {
int rc;
- rc = mirror->ops->sync_cpu_device_pagetables(mirror, &update);
+ rc = mirror->ops->sync_cpu_device_pagetables(mirror, nrange);
if (rc) {
- if (WARN_ON(update.blockable || rc != -EAGAIN))
+ if (WARN_ON(mmu_notifier_range_blockable(nrange) ||
+ rc != -EAGAIN))
continue;
ret = -EAGAIN;
break;
--
2.20.1
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