drm/ttm: page allocation use page array instead of list

Use the ttm_tt pages array for pages allocations, move the list
unwinding into the page allocation functions.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>

drivers/gpu/drm/ttm/ttm_page_alloc.c

@@ -619,8 +619,10 @@ static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
  * @return count of pages still required to fulfill the request.
  */
 static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
-		struct list_head *pages, int ttm_flags,
-		enum ttm_caching_state cstate, unsigned count)
+					struct list_head *pages,
+					int ttm_flags,
+					enum ttm_caching_state cstate,
+					unsigned count)
 {
 	unsigned long irq_flags;
 	struct list_head *p;
@@ -664,13 +666,15 @@ static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
  * On success pages list will hold count number of correctly
  * cached pages.
  */
-int ttm_get_pages(struct list_head *pages, int flags,
-		  enum ttm_caching_state cstate, unsigned count,
+int ttm_get_pages(struct page **pages, int flags,
+		  enum ttm_caching_state cstate, unsigned npages,
 		  dma_addr_t *dma_address)
 {
 	struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
+	struct list_head plist;
 	struct page *p = NULL;
 	gfp_t gfp_flags = GFP_USER;
+	unsigned count;
 	int r;
 
 	/* set zero flag for page allocation if required */
@@ -684,7 +688,7 @@ int ttm_get_pages(struct list_head *pages, int flags,
 		else
 			gfp_flags |= GFP_HIGHUSER;
 
-		for (r = 0; r < count; ++r) {
+		for (r = 0; r < npages; ++r) {
 			p = alloc_page(gfp_flags);
 			if (!p) {
 
@@ -693,85 +697,100 @@ int ttm_get_pages(struct list_head *pages, int flags,
 				return -ENOMEM;
 			}
 
-			list_add(&p->lru, pages);
+			pages[r] = p;
 		}
 		return 0;
 	}
 
-
 	/* combine zero flag to pool flags */
 	gfp_flags |= pool->gfp_flags;
 
 	/* First we take pages from the pool */
-	count = ttm_page_pool_get_pages(pool, pages, flags, cstate, count);
+	INIT_LIST_HEAD(&plist);
+	npages = ttm_page_pool_get_pages(pool, &plist, flags, cstate, npages);
+	count = 0;
+	list_for_each_entry(p, &plist, lru) {
+		pages[count++] = p;
+	}
 
 	/* clear the pages coming from the pool if requested */
 	if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
-		list_for_each_entry(p, pages, lru) {
+		list_for_each_entry(p, &plist, lru) {
 			clear_page(page_address(p));
 		}
 	}
 
 	/* If pool didn't have enough pages allocate new one. */
-	if (count > 0) {
+	if (npages > 0) {
 		/* ttm_alloc_new_pages doesn't reference pool so we can run
 		 * multiple requests in parallel.
 		 **/
-		r = ttm_alloc_new_pages(pages, gfp_flags, flags, cstate, count);
+		INIT_LIST_HEAD(&plist);
+		r = ttm_alloc_new_pages(&plist, gfp_flags, flags, cstate, npages);
+		list_for_each_entry(p, &plist, lru) {
+			pages[count++] = p;
+		}
 		if (r) {
 			/* If there is any pages in the list put them back to
 			 * the pool. */
 			printk(KERN_ERR TTM_PFX
 			       "Failed to allocate extra pages "
 			       "for large request.");
-			ttm_put_pages(pages, 0, flags, cstate, NULL);
+			ttm_put_pages(pages, count, flags, cstate, NULL);
 			return r;
 		}
 	}
 
-
 	return 0;
 }
 
 /* Put all pages in pages list to correct pool to wait for reuse */
-void ttm_put_pages(struct list_head *pages, unsigned page_count, int flags,
+void ttm_put_pages(struct page **pages, unsigned npages, int flags,
 		   enum ttm_caching_state cstate, dma_addr_t *dma_address)
 {
 	unsigned long irq_flags;
 	struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
-	struct page *p, *tmp;
+	unsigned i;
 
 	if (pool == NULL) {
 		/* No pool for this memory type so free the pages */
-
-		list_for_each_entry_safe(p, tmp, pages, lru) {
-			__free_page(p);
+		for (i = 0; i < npages; i++) {
+			if (pages[i]) {
+				if (page_count(pages[i]) != 1)
+					printk(KERN_ERR TTM_PFX
+					       "Erroneous page count. "
+					       "Leaking pages.\n");
+				__free_page(pages[i]);
+				pages[i] = NULL;
+			}
 		}
-		/* Make the pages list empty */
-		INIT_LIST_HEAD(pages);
 		return;
 	}
-	if (page_count == 0) {
-		list_for_each_entry_safe(p, tmp, pages, lru) {
-			++page_count;
-		}
-	}
 
 	spin_lock_irqsave(&pool->lock, irq_flags);
-	list_splice_init(pages, &pool->list);
-	pool->npages += page_count;
+	for (i = 0; i < npages; i++) {
+		if (pages[i]) {
+			if (page_count(pages[i]) != 1)
+				printk(KERN_ERR TTM_PFX
+				       "Erroneous page count. "
+				       "Leaking pages.\n");
+			list_add_tail(&pages[i]->lru, &pool->list);
+			pages[i] = NULL;
+			pool->npages++;
+		}
+	}
 	/* Check that we don't go over the pool limit */
-	page_count = 0;
+	npages = 0;
 	if (pool->npages > _manager->options.max_size) {
-		page_count = pool->npages - _manager->options.max_size;
+		npages = pool->npages - _manager->options.max_size;
 		/* free at least NUM_PAGES_TO_ALLOC number of pages
 		 * to reduce calls to set_memory_wb */
-		if (page_count < NUM_PAGES_TO_ALLOC)
-			page_count = NUM_PAGES_TO_ALLOC;
+		if (npages < NUM_PAGES_TO_ALLOC)
+			npages = NUM_PAGES_TO_ALLOC;
 	}
 	spin_unlock_irqrestore(&pool->lock, irq_flags);
-	if (page_count)
-		ttm_page_pool_free(pool, page_count);
+	if (npages)
+		ttm_page_pool_free(pool, npages);
 }
 
 static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,

drivers/gpu/drm/ttm/ttm_tt.c

@@ -66,22 +66,16 @@ static void ttm_tt_free_page_directory(struct ttm_tt *ttm)
 static struct page *__ttm_tt_get_page(struct ttm_tt *ttm, int index)
 {
 	struct page *p;
-	struct list_head h;
 	struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
 	int ret;
 
 	if (NULL == (p = ttm->pages[index])) {
 
-		INIT_LIST_HEAD(&h);
-
-		ret = ttm_get_pages(&h, ttm->page_flags, ttm->caching_state, 1,
+		ret = ttm_get_pages(&p, ttm->page_flags, ttm->caching_state, 1,
 				    &ttm->dma_address[index]);
-
 		if (ret != 0)
 			return NULL;
 
-		p = list_first_entry(&h, struct page, lru);
-
 		ret = ttm_mem_global_alloc_page(mem_glob, p, false, false);
 		if (unlikely(ret != 0))
 			goto out_err;
@@ -90,9 +84,7 @@ static struct page *__ttm_tt_get_page(struct ttm_tt *ttm, int index)
 	}
 	return p;
 out_err:
-	INIT_LIST_HEAD(&h);
-	list_add(&p->lru, &h);
-	ttm_put_pages(&h, 1, ttm->page_flags,
+	ttm_put_pages(&p, 1, ttm->page_flags,
 		      ttm->caching_state, &ttm->dma_address[index]);
 	return NULL;
 }
@@ -243,33 +235,19 @@ EXPORT_SYMBOL(ttm_tt_set_placement_caching);
 
 static void ttm_tt_free_alloced_pages(struct ttm_tt *ttm)
 {
-	int i;
-	unsigned count = 0;
-	struct list_head h;
-	struct page *cur_page;
 	struct ttm_backend *be = ttm->be;
-
-	INIT_LIST_HEAD(&h);
+	unsigned i;
 
 	if (be)
 		be->func->clear(be);
 	for (i = 0; i < ttm->num_pages; ++i) {
-
-		cur_page = ttm->pages[i];
-		ttm->pages[i] = NULL;
-		if (cur_page) {
-			if (page_count(cur_page) != 1)
-				printk(KERN_ERR TTM_PFX
-				       "Erroneous page count. "
-				       "Leaking pages.\n");
+		if (ttm->pages[i]) {
 			ttm_mem_global_free_page(ttm->glob->mem_glob,
-						 cur_page);
-			list_add(&cur_page->lru, &h);
-			count++;
+						 ttm->pages[i]);
+			ttm_put_pages(&ttm->pages[i], 1, ttm->page_flags,
+				      ttm->caching_state, &ttm->dma_address[i]);
 		}
 	}
-	ttm_put_pages(&h, count, ttm->page_flags, ttm->caching_state,
-		      ttm->dma_address);
 	ttm->state = tt_unpopulated;
 }
 

include/drm/ttm/ttm_page_alloc.h

@@ -38,10 +38,10 @@
  * @count: number of pages to allocate.
  * @dma_address: The DMA (bus) address of pages (if TTM_PAGE_FLAG_DMA32 set).
  */
-int ttm_get_pages(struct list_head *pages,
+int ttm_get_pages(struct page **pages,
 		  int flags,
 		  enum ttm_caching_state cstate,
-		  unsigned count,
+		  unsigned npages,
 		  dma_addr_t *dma_address);
 /**
  * Put linked list of pages to pool.
@@ -53,8 +53,8 @@ int ttm_get_pages(struct list_head *pages,
  * @cstate: ttm caching state.
  * @dma_address: The DMA (bus) address of pages (if TTM_PAGE_FLAG_DMA32 set).
  */
-void ttm_put_pages(struct list_head *pages,
-		   unsigned page_count,
+void ttm_put_pages(struct page **pages,
+		   unsigned npages,
 		   int flags,
 		   enum ttm_caching_state cstate,
 		   dma_addr_t *dma_address);