mm: rename migrate_pgmap_owner

MMU notifier ranges have a migrate_pgmap_owner field which is used by
drivers to store a pointer.  This is subsequently used by the driver
callback to filter MMU_NOTIFY_MIGRATE events.  Other notifier event types
can also benefit from this filtering, so rename the 'migrate_pgmap_owner'
field to 'owner' and create a new notifier initialisation function to
initialise this field.

Link: https://lkml.kernel.org/r/20210616105937.23201-6-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Suggested-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/vm/hmm.rst

@@ -332,7 +332,7 @@ between device driver specific code and shared common code:
    walks to fill in the ``args->src`` array with PFNs to be migrated.
    The ``invalidate_range_start()`` callback is passed a
    ``struct mmu_notifier_range`` with the ``event`` field set to
-   ``MMU_NOTIFY_MIGRATE`` and the ``migrate_pgmap_owner`` field set to
+   ``MMU_NOTIFY_MIGRATE`` and the ``owner`` field set to
    the ``args->pgmap_owner`` field passed to migrate_vma_setup(). This is
    allows the device driver to skip the invalidation callback and only
    invalidate device private MMU mappings that are actually migrating.

drivers/gpu/drm/nouveau/nouveau_svm.c

@@ -265,7 +265,7 @@ nouveau_svmm_invalidate_range_start(struct mmu_notifier *mn,
 	 * the invalidation is handled as part of the migration process.
 	 */
 	if (update->event == MMU_NOTIFY_MIGRATE &&
-	    update->migrate_pgmap_owner == svmm->vmm->cli->drm->dev)
+	    update->owner == svmm->vmm->cli->drm->dev)
 		goto out;
 
 	if (limit > svmm->unmanaged.start && start < svmm->unmanaged.limit) {

include/linux/mmu_notifier.h

@@ -41,7 +41,7 @@ struct mmu_interval_notifier;
  *
  * @MMU_NOTIFY_MIGRATE: used during migrate_vma_collect() invalidate to signal
  * a device driver to possibly ignore the invalidation if the
- * migrate_pgmap_owner field matches the driver's device private pgmap owner.
+ * owner field matches the driver's device private pgmap owner.
  */
 enum mmu_notifier_event {
 	MMU_NOTIFY_UNMAP = 0,
@@ -269,7 +269,7 @@ struct mmu_notifier_range {
 	unsigned long end;
 	unsigned flags;
 	enum mmu_notifier_event event;
-	void *migrate_pgmap_owner;
+	void *owner;
 };
 
 static inline int mm_has_notifiers(struct mm_struct *mm)
@@ -521,14 +521,14 @@ static inline void mmu_notifier_range_init(struct mmu_notifier_range *range,
 	range->flags = flags;
 }
 
-static inline void mmu_notifier_range_init_migrate(
+static inline void mmu_notifier_range_init_owner(
-			struct mmu_notifier_range *range, unsigned int flags,
+			struct mmu_notifier_range *range,
+			enum mmu_notifier_event event, unsigned int flags,
 			struct vm_area_struct *vma, struct mm_struct *mm,
-			unsigned long start, unsigned long end, void *pgmap)
+			unsigned long start, unsigned long end, void *owner)
 {
-	mmu_notifier_range_init(range, MMU_NOTIFY_MIGRATE, flags, vma, mm,
+	mmu_notifier_range_init(range, event, flags, vma, mm, start, end);
-				start, end);
+	range->owner = owner;
-	range->migrate_pgmap_owner = pgmap;
 }
 
 #define ptep_clear_flush_young_notify(__vma, __address, __ptep)		\
@@ -655,8 +655,8 @@ static inline void _mmu_notifier_range_init(struct mmu_notifier_range *range,
 
 #define mmu_notifier_range_init(range,event,flags,vma,mm,start,end)  \
 	_mmu_notifier_range_init(range, start, end)
-#define mmu_notifier_range_init_migrate(range, flags, vma, mm, start, end, \
+#define mmu_notifier_range_init_owner(range, event, flags, vma, mm, start, \
-					pgmap) \
+					end, owner) \
 	_mmu_notifier_range_init(range, start, end)
 
 static inline bool

lib/test_hmm.c

@@ -218,7 +218,7 @@ static bool dmirror_interval_invalidate(struct mmu_interval_notifier *mni,
 	 * the invalidation is handled as part of the migration process.
 	 */
 	if (range->event == MMU_NOTIFY_MIGRATE &&
-	    range->migrate_pgmap_owner == dmirror->mdevice)
+	    range->owner == dmirror->mdevice)
 		return true;
 
 	if (mmu_notifier_range_blockable(range))

mm/migrate.c

@@ -2416,8 +2416,8 @@ static void migrate_vma_collect(struct migrate_vma *migrate)
 	 * that the registered device driver can skip invalidating device
 	 * private page mappings that won't be migrated.
 	 */
-	mmu_notifier_range_init_migrate(&range, 0, migrate->vma,
+	mmu_notifier_range_init_owner(&range, MMU_NOTIFY_MIGRATE, 0,
-		migrate->vma->vm_mm, migrate->start, migrate->end,
+		migrate->vma, migrate->vma->vm_mm, migrate->start, migrate->end,
 		migrate->pgmap_owner);
 	mmu_notifier_invalidate_range_start(&range);
 
@@ -2927,9 +2927,9 @@ void migrate_vma_pages(struct migrate_vma *migrate)
 			if (!notified) {
 				notified = true;
 
-				mmu_notifier_range_init_migrate(&range, 0,
+				mmu_notifier_range_init_owner(&range,
-					migrate->vma, migrate->vma->vm_mm,
+					MMU_NOTIFY_MIGRATE, 0, migrate->vma,
-					addr, migrate->end,
+					migrate->vma->vm_mm, addr, migrate->end,
 					migrate->pgmap_owner);
 				mmu_notifier_invalidate_range_start(&range);
 			}