[173/178] net: page_pool: refactor dma_map into own function page_pool_dma_map

Commit Message

Andrew Morton April 30, 2021, 6:02 a.m. UTC

From: Jesper Dangaard Brouer <[e-mail]>
Subject: net: page_pool: refactor dma_map into own function page_pool_dma_map

In preparation for next patch, move the dma mapping into its own function,
as this will make it easier to follow the changes.

[ilias.apalodimas: make page_pool_dma_map return boolean]
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Jesper Dangaard Brouer <[e-mail]>
Signed-off-by: Mel Gorman <[e-mail]>
Reviewed-by: Ilias Apalodimas <[e-mail]>
Reviewed-by: Alexander Lobakin <[e-mail]>
Cc: Alexander Duyck <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: Chuck Lever <[e-mail]>
Cc: David Miller <[e-mail]>
Cc: Matthew Wilcox (Oracle) <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 net/core/page_pool.c |   45 +++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 19 deletions(-)

Patch

--- a/net/core/page_pool.c~net-page_pool-refactor-dma_map-into-own-function-page_pool_dma_map
+++ a/net/core/page_pool.c
@@ -180,14 +180,37 @@  static void page_pool_dma_sync_for_devic
 					 pool->p.dma_dir);
 }
 
+static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
+{
+	dma_addr_t dma;
+
+	/* Setup DMA mapping: use 'struct page' area for storing DMA-addr
+	 * since dma_addr_t can be either 32 or 64 bits and does not always fit
+	 * into page private data (i.e 32bit cpu with 64bit DMA caps)
+	 * This mapping is kept for lifetime of page, until leaving pool.
+	 */
+	dma = dma_map_page_attrs(pool->p.dev, page, 0,
+				 (PAGE_SIZE << pool->p.order),
+				 pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+	if (dma_mapping_error(pool->p.dev, dma))
+		return false;
+
+	page->dma_addr = dma;
+
+	if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+		page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
+
+	return true;
+}
+
 /* slow path */
 noinline
 static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
 						 gfp_t _gfp)
 {
+	unsigned int pp_flags = pool->p.flags;
 	struct page *page;
 	gfp_t gfp = _gfp;
-	dma_addr_t dma;
 
 	/* We could always set __GFP_COMP, and avoid this branch, as
 	 * prep_new_page() can handle order-0 with __GFP_COMP.
@@ -211,30 +234,14 @@  static struct page *__page_pool_alloc_pa
 	if (!page)
 		return NULL;
 
-	if (!(pool->p.flags & PP_FLAG_DMA_MAP))
-		goto skip_dma_map;
-
-	/* Setup DMA mapping: use 'struct page' area for storing DMA-addr
-	 * since dma_addr_t can be either 32 or 64 bits and does not always fit
-	 * into page private data (i.e 32bit cpu with 64bit DMA caps)
-	 * This mapping is kept for lifetime of page, until leaving pool.
-	 */
-	dma = dma_map_page_attrs(pool->p.dev, page, 0,
-				 (PAGE_SIZE << pool->p.order),
-				 pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
-	if (dma_mapping_error(pool->p.dev, dma)) {
+	if ((pp_flags & PP_FLAG_DMA_MAP) &&
+	    unlikely(!page_pool_dma_map(pool, page))) {
 		put_page(page);
 		return NULL;
 	}
-	page->dma_addr = dma;
 
-	if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
-		page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
-
-skip_dma_map:
 	/* Track how many pages are held 'in-flight' */
 	pool->pages_state_hold_cnt++;
-
 	trace_page_pool_state_hold(pool, page, pool->pages_state_hold_cnt);
 
 	/* When page just alloc'ed is should/must have refcnt 1. */