1 files changed, 42 insertions, 36 deletions

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 10d2b255df5e..ef98372facf6 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -43,9 +43,11 @@ static int page_pool_init(struct page_pool *pool,
 	 * DMA_BIDIRECTIONAL is for allowing page used for DMA sending,
 	 * which is the XDP_TX use-case.
 	 */
-	if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
-	    (pool->p.dma_dir != DMA_BIDIRECTIONAL))
-		return -EINVAL;
+	if (pool->p.flags & PP_FLAG_DMA_MAP) {
+		if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
+		    (pool->p.dma_dir != DMA_BIDIRECTIONAL))
+			return -EINVAL;
+	}
 
 	if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) {
 		/* In order to request DMA-sync-for-device the page
@@ -96,7 +98,7 @@ struct page_pool *page_pool_create(const struct page_pool_params *params)
 }
 EXPORT_SYMBOL(page_pool_create);
 
-static void __page_pool_return_page(struct page_pool *pool, struct page *page);
+static void page_pool_return_page(struct page_pool *pool, struct page *page);
 
 noinline
 static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
@@ -136,7 +138,7 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
 			 * (2) break out to fallthrough to alloc_pages_node.
 			 * This limit stress on page buddy alloactor.
 			 */
-			__page_pool_return_page(pool, page);
+			page_pool_return_page(pool, page);
 			page = NULL;
 			break;
 		}
@@ -274,18 +276,25 @@ static s32 page_pool_inflight(struct page_pool *pool)
 	return inflight;
 }
 
-/* Cleanup page_pool state from page */
-static void __page_pool_clean_page(struct page_pool *pool,
-				   struct page *page)
+/* Disconnects a page (from a page_pool).  API users can have a need
+ * to disconnect a page (from a page_pool), to allow it to be used as
+ * a regular page (that will eventually be returned to the normal
+ * page-allocator via put_page).
+ */
+void page_pool_release_page(struct page_pool *pool, struct page *page)
 {
 	dma_addr_t dma;
 	int count;
 
 	if (!(pool->p.flags & PP_FLAG_DMA_MAP))
+		/* Always account for inflight pages, even if we didn't
+		 * map them
+		 */
 		goto skip_dma_unmap;
 
 	dma = page->dma_addr;
-	/* DMA unmap */
+
+	/* When page is unmapped, it cannot be returned our pool */
 	dma_unmap_page_attrs(pool->p.dev, dma,
 			     PAGE_SIZE << pool->p.order, pool->p.dma_dir,
 			     DMA_ATTR_SKIP_CPU_SYNC);
@@ -297,21 +306,12 @@ skip_dma_unmap:
 	count = atomic_inc_return(&pool->pages_state_release_cnt);
 	trace_page_pool_state_release(pool, page, count);
 }
-
-/* unmap the page and clean our state */
-void page_pool_unmap_page(struct page_pool *pool, struct page *page)
-{
-	/* When page is unmapped, this implies page will not be
-	 * returned to page_pool.
-	 */
-	__page_pool_clean_page(pool, page);
-}
-EXPORT_SYMBOL(page_pool_unmap_page);
+EXPORT_SYMBOL(page_pool_release_page);
 
 /* Return a page to the page allocator, cleaning up our state */
-static void __page_pool_return_page(struct page_pool *pool, struct page *page)
+static void page_pool_return_page(struct page_pool *pool, struct page *page)
 {
-	__page_pool_clean_page(pool, page);
+	page_pool_release_page(pool, page);
 
 	put_page(page);
 	/* An optimization would be to call __free_pages(page, pool->p.order)
@@ -320,8 +320,7 @@ static void __page_pool_return_page(struct page_pool *pool, struct page *page)
 	 */
 }
 
-static bool __page_pool_recycle_into_ring(struct page_pool *pool,
-				   struct page *page)
+static bool page_pool_recycle_in_ring(struct page_pool *pool, struct page *page)
 {
 	int ret;
 	/* BH protection not needed if current is serving softirq */
@@ -338,7 +337,7 @@ static bool __page_pool_recycle_into_ring(struct page_pool *pool,
  *
  * Caller must provide appropriate safe context.
  */
-static bool __page_pool_recycle_direct(struct page *page,
+static bool page_pool_recycle_in_cache(struct page *page,
 				       struct page_pool *pool)
 {
 	if (unlikely(pool->alloc.count == PP_ALLOC_CACHE_SIZE))
@@ -357,8 +356,14 @@ static bool pool_page_reusable(struct page_pool *pool, struct page *page)
 	return !page_is_pfmemalloc(page);
 }
 
-void __page_pool_put_page(struct page_pool *pool, struct page *page,
-			  unsigned int dma_sync_size, bool allow_direct)
+/* If the page refcnt == 1, this will try to recycle the page.
+ * if PP_FLAG_DMA_SYNC_DEV is set, we'll try to sync the DMA area for
+ * the configured size min(dma_sync_size, pool->max_len).
+ * If the page refcnt != 1, then the page will be returned to memory
+ * subsystem.
+ */
+void page_pool_put_page(struct page_pool *pool, struct page *page,
+			unsigned int dma_sync_size, bool allow_direct)
 {
 	/* This allocator is optimized for the XDP mode that uses
 	 * one-frame-per-page, but have fallbacks that act like the
@@ -375,12 +380,12 @@ void __page_pool_put_page(struct page_pool *pool, struct page *page,
 						      dma_sync_size);
 
 		if (allow_direct && in_serving_softirq())
-			if (__page_pool_recycle_direct(page, pool))
+			if (page_pool_recycle_in_cache(page, pool))
 				return;
 
-		if (!__page_pool_recycle_into_ring(pool, page)) {
+		if (!page_pool_recycle_in_ring(pool, page)) {
 			/* Cache full, fallback to free pages */
-			__page_pool_return_page(pool, page);
+			page_pool_return_page(pool, page);
 		}
 		return;
 	}
@@ -397,12 +402,13 @@ void __page_pool_put_page(struct page_pool *pool, struct page *page,
 	 * doing refcnt based recycle tricks, meaning another process
 	 * will be invoking put_page.
 	 */
-	__page_pool_clean_page(pool, page);
+	/* Do not replace this with page_pool_return_page() */
+	page_pool_release_page(pool, page);
 	put_page(page);
 }
-EXPORT_SYMBOL(__page_pool_put_page);
+EXPORT_SYMBOL(page_pool_put_page);
 
-static void __page_pool_empty_ring(struct page_pool *pool)
+static void page_pool_empty_ring(struct page_pool *pool)
 {
 	struct page *page;
 
@@ -413,7 +419,7 @@ static void __page_pool_empty_ring(struct page_pool *pool)
 			pr_crit("%s() page_pool refcnt %d violation\n",
 				__func__, page_ref_count(page));
 
-		__page_pool_return_page(pool, page);
+		page_pool_return_page(pool, page);
 	}
 }
 
@@ -443,7 +449,7 @@ static void page_pool_empty_alloc_cache_once(struct page_pool *pool)
 	 */
 	while (pool->alloc.count) {
 		page = pool->alloc.cache[--pool->alloc.count];
-		__page_pool_return_page(pool, page);
+		page_pool_return_page(pool, page);
 	}
 }
 
@@ -455,7 +461,7 @@ static void page_pool_scrub(struct page_pool *pool)
 	/* No more consumers should exist, but producers could still
 	 * be in-flight.
 	 */
-	__page_pool_empty_ring(pool);
+	page_pool_empty_ring(pool);
 }
 
 static int page_pool_release(struct page_pool *pool)
@@ -529,7 +535,7 @@ void page_pool_update_nid(struct page_pool *pool, int new_nid)
 	/* Flush pool alloc cache, as refill will check NUMA node */
 	while (pool->alloc.count) {
 		page = pool->alloc.cache[--pool->alloc.count];
-		__page_pool_return_page(pool, page);
+		page_pool_return_page(pool, page);
 	}
 }
 EXPORT_SYMBOL(page_pool_update_nid);