[PATCH 8/9] nouveau/dmem: Add support for multiple page types

[Alistair Popple <apopple@xxxxxxxxxx>]

Device private pages are used to track a per-page migrate_to_ram()
callback which is called when the CPU attempts to access a GPU page from
the CPU. Currently the same callback is used for all GPU pages tracked
by Nouveau. However a future patch requires support for calling a
different callback when accessing some GPU pages.

This patch extends the existing Nouveau device private page allocator to
make it easier to allocate device private pages with different callbacks
but should not introduce any functional changes.

Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
---
 drivers/gpu/drm/nouveau/nouveau_dmem.c | 27 ++++++++++++++------------
 drivers/gpu/drm/nouveau/nouveau_dmem.h |  5 +++++
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index 9579bd001f11..8fb4949f3778 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -67,6 +67,7 @@ struct nouveau_dmem_chunk {
 	struct nouveau_bo *bo;
 	struct nouveau_drm *drm;
 	unsigned long callocated;
+	enum nouveau_dmem_type type;
 	struct dev_pagemap pagemap;
 };
 
@@ -81,7 +82,7 @@ struct nouveau_dmem {
 	struct nouveau_dmem_migrate migrate;
 	struct list_head chunks;
 	struct mutex mutex;
-	struct page *free_pages;
+	struct page *free_pages[NOUVEAU_DMEM_NTYPES];
 	spinlock_t lock;
 };
 
@@ -112,8 +113,8 @@ static void nouveau_dmem_page_free(struct page *page)
 	struct nouveau_dmem *dmem = chunk->drm->dmem;
 
 	spin_lock(&dmem->lock);
-	page->zone_device_data = dmem->free_pages;
-	dmem->free_pages = page;
+	page->zone_device_data = dmem->free_pages[chunk->type];
+	dmem->free_pages[chunk->type] = page;
 
 	WARN_ON(!chunk->callocated);
 	chunk->callocated--;
@@ -224,7 +225,8 @@ static const struct dev_pagemap_ops nouveau_dmem_pagemap_ops = {
 };
 
 static int
-nouveau_dmem_chunk_alloc(struct nouveau_drm *drm, struct page **ppage)
+nouveau_dmem_chunk_alloc(struct nouveau_drm *drm, struct page **ppage,
+	enum nouveau_dmem_type type)
 {
 	struct nouveau_dmem_chunk *chunk;
 	struct resource *res;
@@ -248,6 +250,7 @@ nouveau_dmem_chunk_alloc(struct nouveau_drm *drm, struct page **ppage)
 	}
 
 	chunk->drm = drm;
+	chunk->type = type;
 	chunk->pagemap.type = MEMORY_DEVICE_PRIVATE;
 	chunk->pagemap.range.start = res->start;
 	chunk->pagemap.range.end = res->end;
@@ -279,8 +282,8 @@ nouveau_dmem_chunk_alloc(struct nouveau_drm *drm, struct page **ppage)
 	page = pfn_to_page(pfn_first);
 	spin_lock(&drm->dmem->lock);
 	for (i = 0; i < DMEM_CHUNK_NPAGES - 1; ++i, ++page) {
-		page->zone_device_data = drm->dmem->free_pages;
-		drm->dmem->free_pages = page;
+		page->zone_device_data = drm->dmem->free_pages[type];
+		drm->dmem->free_pages[type] = page;
 	}
 	*ppage = page;
 	chunk->callocated++;
@@ -304,22 +307,22 @@ nouveau_dmem_chunk_alloc(struct nouveau_drm *drm, struct page **ppage)
 }
 
 static struct page *
-nouveau_dmem_page_alloc_locked(struct nouveau_drm *drm)
+nouveau_dmem_page_alloc_locked(struct nouveau_drm *drm, enum nouveau_dmem_type type)
 {
 	struct nouveau_dmem_chunk *chunk;
 	struct page *page = NULL;
 	int ret;
 
 	spin_lock(&drm->dmem->lock);
-	if (drm->dmem->free_pages) {
-		page = drm->dmem->free_pages;
-		drm->dmem->free_pages = page->zone_device_data;
+	if (drm->dmem->free_pages[type]) {
+		page = drm->dmem->free_pages[type];
+		drm->dmem->free_pages[type] = page->zone_device_data;
 		chunk = nouveau_page_to_chunk(page);
 		chunk->callocated++;
 		spin_unlock(&drm->dmem->lock);
 	} else {
 		spin_unlock(&drm->dmem->lock);
-		ret = nouveau_dmem_chunk_alloc(drm, &page);
+		ret = nouveau_dmem_chunk_alloc(drm, &page, type);
 		if (ret)
 			return NULL;
 	}
@@ -577,7 +580,7 @@ static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm,
 	if (!(src & MIGRATE_PFN_MIGRATE))
 		goto out;
 
-	dpage = nouveau_dmem_page_alloc_locked(drm);
+	dpage = nouveau_dmem_page_alloc_locked(drm, NOUVEAU_DMEM);
 	if (!dpage)
 		goto out;
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.h b/drivers/gpu/drm/nouveau/nouveau_dmem.h
index 64da5d3635c8..02e261c4acf1 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.h
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.h
@@ -28,6 +28,11 @@ struct nouveau_drm;
 struct nouveau_svmm;
 struct hmm_range;
 
+enum nouveau_dmem_type {
+	NOUVEAU_DMEM,
+	NOUVEAU_DMEM_NTYPES, /* Number of types, must be last */
+};
+
 #if IS_ENABLED(CONFIG_DRM_NOUVEAU_SVM)
 void nouveau_dmem_init(struct nouveau_drm *);
 void nouveau_dmem_fini(struct nouveau_drm *);
-- 
2.20.1