Merge tag 'dma-mapping-6.10-2024-05-20' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - optimize DMA sync calls when they are no-ops (Alexander Lobakin)

 - fix swiotlb padding for untrusted devices (Michael Kelley)

 - add documentation for swiotb (Michael Kelley)

* tag 'dma-mapping-6.10-2024-05-20' of git://git.infradead.org/users/hch/dma-mapping:
  dma: fix DMA sync for drivers not calling dma_set_mask*()
  xsk: use generic DMA sync shortcut instead of a custom one
  page_pool: check for DMA sync shortcut earlier
  page_pool: don't use driver-set flags field directly
  page_pool: make sure frag API fields don't span between cachelines
  iommu/dma: avoid expensive indirect calls for sync operations
  dma: avoid redundant calls for sync operations
  dma: compile-out DMA sync op calls when not used
  iommu/dma: fix zeroing of bounce buffer padding used by untrusted devices
  swiotlb: remove alloc_size argument to swiotlb_tbl_map_single()
  Documentation/core-api: add swiotlb documentation

Documentation/core-api/index.rst

@@ -102,6 +102,7 @@ more memory-management documentation in Documentation/mm/index.rst.
    dma-api-howto
    dma-attributes
    dma-isa-lpc
+   swiotlb
    mm-api
    genalloc
    pin_user_pages

drivers/iommu/dma-iommu.c

@@ -1152,9 +1152,6 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 	 */
 	if (dev_use_swiotlb(dev, size, dir) &&
 	    iova_offset(iovad, phys | size)) {
-		void *padding_start;
-		size_t padding_size, aligned_size;
-
 		if (!is_swiotlb_active(dev)) {
 			dev_warn_once(dev, "DMA bounce buffers are inactive, unable to map unaligned transaction.\n");
 			return DMA_MAPPING_ERROR;
@@ -1162,24 +1159,30 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 
 		trace_swiotlb_bounced(dev, phys, size);
 
-		aligned_size = iova_align(iovad, size);
-		phys = swiotlb_tbl_map_single(dev, phys, size, aligned_size,
+		phys = swiotlb_tbl_map_single(dev, phys, size,
 					      iova_mask(iovad), dir, attrs);
 
 		if (phys == DMA_MAPPING_ERROR)
 			return DMA_MAPPING_ERROR;
 
-		/* Cleanup the padding area. */
-		padding_start = phys_to_virt(phys);
-		padding_size = aligned_size;
+		/*
+		 * Untrusted devices should not see padding areas with random
+		 * leftover kernel data, so zero the pre- and post-padding.
+		 * swiotlb_tbl_map_single() has initialized the bounce buffer
+		 * proper to the contents of the original memory buffer.
+		 */
+		if (dev_is_untrusted(dev)) {
+			size_t start, virt = (size_t)phys_to_virt(phys);
 
-		if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
-		    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) {
-			padding_start += size;
-			padding_size -= size;
-		}
+			/* Pre-padding */
+			start = iova_align_down(iovad, virt);
+			memset((void *)start, 0, virt - start);
 
-		memset(padding_start, 0, padding_size);
+			/* Post-padding */
+			start = virt + size;
+			memset((void *)start, 0,
+			       iova_align(iovad, start) - start);
+		}
 	}
 
 	if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
@@ -1718,7 +1721,8 @@ static size_t iommu_dma_max_mapping_size(struct device *dev)
 }
 
 static const struct dma_map_ops iommu_dma_ops = {
-	.flags			= DMA_F_PCI_P2PDMA_SUPPORTED,
+	.flags			= DMA_F_PCI_P2PDMA_SUPPORTED |
+				  DMA_F_CAN_SKIP_SYNC,
 	.alloc			= iommu_dma_alloc,
 	.free			= iommu_dma_free,
 	.alloc_pages_op		= dma_common_alloc_pages,

drivers/net/ethernet/engleder/tsnep_main.c

@@ -1587,7 +1587,7 @@ static int tsnep_rx_poll_zc(struct tsnep_rx *rx, struct napi_struct *napi,
 		length = __le32_to_cpu(entry->desc_wb->properties) &
 			 TSNEP_DESC_LENGTH_MASK;
 		xsk_buff_set_size(entry->xdp, length - ETH_FCS_LEN);
-		xsk_buff_dma_sync_for_cpu(entry->xdp, rx->xsk_pool);
+		xsk_buff_dma_sync_for_cpu(entry->xdp);
 
 		/* RX metadata with timestamps is in front of actual data,
 		 * subtract metadata size to get length of actual data and

drivers/net/ethernet/freescale/dpaa2/dpaa2-xsk.c

@@ -55,7 +55,7 @@ static u32 dpaa2_xsk_run_xdp(struct dpaa2_eth_priv *priv,
 	xdp_set_data_meta_invalid(xdp_buff);
 	xdp_buff->rxq = &ch->xdp_rxq;
 
-	xsk_buff_dma_sync_for_cpu(xdp_buff, ch->xsk_pool);
+	xsk_buff_dma_sync_for_cpu(xdp_buff);
 	xdp_act = bpf_prog_run_xdp(xdp_prog, xdp_buff);
 
 	/* xdp.data pointer may have changed */

drivers/net/ethernet/intel/i40e/i40e_xsk.c

@@ -482,7 +482,7 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget)
 
 		bi = *i40e_rx_bi(rx_ring, next_to_process);
 		xsk_buff_set_size(bi, size);
-		xsk_buff_dma_sync_for_cpu(bi, rx_ring->xsk_pool);
+		xsk_buff_dma_sync_for_cpu(bi);
 
 		if (!first)
 			first = bi;

drivers/net/ethernet/intel/ice/ice_xsk.c

@@ -878,7 +878,7 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
 				   ICE_RX_FLX_DESC_PKT_LEN_M;
 
 		xsk_buff_set_size(xdp, size);
-		xsk_buff_dma_sync_for_cpu(xdp, xsk_pool);
+		xsk_buff_dma_sync_for_cpu(xdp);
 
 		if (!first) {
 			first = xdp;

drivers/net/ethernet/intel/igc/igc_main.c

@@ -2812,7 +2812,7 @@ static int igc_clean_rx_irq_zc(struct igc_q_vector *q_vector, const int budget)
 		}
 
 		bi->xdp->data_end = bi->xdp->data + size;
-		xsk_buff_dma_sync_for_cpu(bi->xdp, ring->xsk_pool);
+		xsk_buff_dma_sync_for_cpu(bi->xdp);
 
 		res = __igc_xdp_run_prog(adapter, prog, bi->xdp);
 		switch (res) {

drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c

@@ -303,7 +303,7 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector,
 		}
 
 		bi->xdp->data_end = bi->xdp->data + size;
-		xsk_buff_dma_sync_for_cpu(bi->xdp, rx_ring->xsk_pool);
+		xsk_buff_dma_sync_for_cpu(bi->xdp);
 		xdp_res = ixgbe_run_xdp_zc(adapter, rx_ring, bi->xdp);
 
 		if (likely(xdp_res & (IXGBE_XDP_TX | IXGBE_XDP_REDIR))) {

drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c

@@ -270,7 +270,7 @@ struct sk_buff *mlx5e_xsk_skb_from_cqe_mpwrq_linear(struct mlx5e_rq *rq,
 	/* mxbuf->rq is set on allocation, but cqe is per-packet so set it here */
 	mxbuf->cqe = cqe;
 	xsk_buff_set_size(&mxbuf->xdp, cqe_bcnt);
-	xsk_buff_dma_sync_for_cpu(&mxbuf->xdp, rq->xsk_pool);
+	xsk_buff_dma_sync_for_cpu(&mxbuf->xdp);
 	net_prefetch(mxbuf->xdp.data);
 
 	/* Possible flows:
@@ -319,7 +319,7 @@ struct sk_buff *mlx5e_xsk_skb_from_cqe_linear(struct mlx5e_rq *rq,
 	/* mxbuf->rq is set on allocation, but cqe is per-packet so set it here */
 	mxbuf->cqe = cqe;
 	xsk_buff_set_size(&mxbuf->xdp, cqe_bcnt);
-	xsk_buff_dma_sync_for_cpu(&mxbuf->xdp, rq->xsk_pool);
+	xsk_buff_dma_sync_for_cpu(&mxbuf->xdp);
 	net_prefetch(mxbuf->xdp.data);
 
 	prog = rcu_dereference(rq->xdp_prog);

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

@@ -917,7 +917,7 @@ INDIRECT_CALLABLE_SCOPE bool mlx5e_post_rx_wqes(struct mlx5e_rq *rq)
 
 	if (!rq->xsk_pool) {
 		count = mlx5e_refill_rx_wqes(rq, head, wqe_bulk);
-	} else if (likely(!rq->xsk_pool->dma_need_sync)) {
+	} else if (likely(!dma_dev_need_sync(rq->pdev))) {
 		mlx5e_xsk_free_rx_wqes(rq, head, wqe_bulk);
 		count = mlx5e_xsk_alloc_rx_wqes_batched(rq, head, wqe_bulk);
 	} else {

drivers/net/ethernet/netronome/nfp/nfd3/xsk.c

@@ -184,7 +184,7 @@ nfp_nfd3_xsk_rx(struct nfp_net_rx_ring *rx_ring, int budget,
 		xrxbuf->xdp->data += meta_len;
 		xrxbuf->xdp->data_end = xrxbuf->xdp->data + pkt_len;
 		xdp_set_data_meta_invalid(xrxbuf->xdp);
-		xsk_buff_dma_sync_for_cpu(xrxbuf->xdp, r_vec->xsk_pool);
+		xsk_buff_dma_sync_for_cpu(xrxbuf->xdp);
 		net_prefetch(xrxbuf->xdp->data);
 
 		if (meta_len) {

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -5361,7 +5361,7 @@ static int stmmac_rx_zc(struct stmmac_priv *priv, int limit, u32 queue)
 
 		/* RX buffer is good and fit into a XSK pool buffer */
 		buf->xdp->data_end = buf->xdp->data + buf1_len;
-		xsk_buff_dma_sync_for_cpu(buf->xdp, rx_q->xsk_pool);
+		xsk_buff_dma_sync_for_cpu(buf->xdp);
 
 		prog = READ_ONCE(priv->xdp_prog);
 		res = __stmmac_xdp_run_prog(priv, prog, buf->xdp);

drivers/xen/swiotlb-xen.c

@@ -216,7 +216,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 	 */
 	trace_swiotlb_bounced(dev, dev_addr, size);
 
-	map = swiotlb_tbl_map_single(dev, phys, size, size, 0, dir, attrs);
+	map = swiotlb_tbl_map_single(dev, phys, size, 0, dir, attrs);
 	if (map == (phys_addr_t)DMA_MAPPING_ERROR)
 		return DMA_MAPPING_ERROR;
 

include/linux/device.h

@@ -691,6 +691,7 @@ struct device_physical_location {
  *		and optionall (if the coherent mask is large enough) also
  *		for dma allocations.  This flag is managed by the dma ops
  *		instance from ->dma_supported.
+ * @dma_skip_sync: DMA sync operations can be skipped for coherent buffers.
  *
  * At the lowest level, every device in a Linux system is represented by an
  * instance of struct device. The device structure contains the information
@@ -803,6 +804,9 @@ struct device {
 #ifdef CONFIG_DMA_OPS_BYPASS
 	bool			dma_ops_bypass : 1;
 #endif
+#ifdef CONFIG_DMA_NEED_SYNC
+	bool			dma_skip_sync:1;
+#endif
 };
 
 /**

include/linux/dma-map-ops.h

@@ -18,8 +18,11 @@ struct iommu_ops;
  *
  * DMA_F_PCI_P2PDMA_SUPPORTED: Indicates the dma_map_ops implementation can
  * handle PCI P2PDMA pages in the map_sg/unmap_sg operation.
+ * DMA_F_CAN_SKIP_SYNC: DMA sync operations can be skipped if the device is
+ * coherent and it's not an SWIOTLB buffer.
  */
 #define DMA_F_PCI_P2PDMA_SUPPORTED     (1 << 0)
+#define DMA_F_CAN_SKIP_SYNC            (1 << 1)
 
 struct dma_map_ops {
 	unsigned int flags;
@@ -273,6 +276,15 @@ static inline bool dev_is_dma_coherent(struct device *dev)
 }
 #endif /* CONFIG_ARCH_HAS_DMA_COHERENCE_H */
 
+static inline void dma_reset_need_sync(struct device *dev)
+{
+#ifdef CONFIG_DMA_NEED_SYNC
+	/* Reset it only once so that the function can be called on hotpath */
+	if (unlikely(dev->dma_skip_sync))
+		dev->dma_skip_sync = false;
+#endif
+}
+
 /*
  * Check whether potential kmalloc() buffers are safe for non-coherent DMA.
  */

include/linux/dma-mapping.h

@@ -117,14 +117,6 @@ dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr,
 		size_t size, enum dma_data_direction dir, unsigned long attrs);
 void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
 		enum dma_data_direction dir, unsigned long attrs);
-void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
-		enum dma_data_direction dir);
-void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
-		size_t size, enum dma_data_direction dir);
-void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
-		    int nelems, enum dma_data_direction dir);
-void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
-		       int nelems, enum dma_data_direction dir);
 void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t flag, unsigned long attrs);
 void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
@@ -147,7 +139,6 @@ u64 dma_get_required_mask(struct device *dev);
 bool dma_addressing_limited(struct device *dev);
 size_t dma_max_mapping_size(struct device *dev);
 size_t dma_opt_mapping_size(struct device *dev);
-bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
 unsigned long dma_get_merge_boundary(struct device *dev);
 struct sg_table *dma_alloc_noncontiguous(struct device *dev, size_t size,
 		enum dma_data_direction dir, gfp_t gfp, unsigned long attrs);
@@ -195,22 +186,6 @@ static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
 }
-static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
-		size_t size, enum dma_data_direction dir)
-{
-}
-static inline void dma_sync_single_for_device(struct device *dev,
-		dma_addr_t addr, size_t size, enum dma_data_direction dir)
-{
-}
-static inline void dma_sync_sg_for_cpu(struct device *dev,
-		struct scatterlist *sg, int nelems, enum dma_data_direction dir)
-{
-}
-static inline void dma_sync_sg_for_device(struct device *dev,
-		struct scatterlist *sg, int nelems, enum dma_data_direction dir)
-{
-}
 static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
 {
 	return -ENOMEM;
@@ -277,10 +252,6 @@ static inline size_t dma_opt_mapping_size(struct device *dev)
 {
 	return 0;
 }
-static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
-{
-	return false;
-}
 static inline unsigned long dma_get_merge_boundary(struct device *dev)
 {
 	return 0;
@@ -310,6 +281,82 @@ static inline int dma_mmap_noncontiguous(struct device *dev,
 }
 #endif /* CONFIG_HAS_DMA */
 
+#if defined(CONFIG_HAS_DMA) && defined(CONFIG_DMA_NEED_SYNC)
+void __dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
+		enum dma_data_direction dir);
+void __dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
+		size_t size, enum dma_data_direction dir);
+void __dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+		int nelems, enum dma_data_direction dir);
+void __dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+		int nelems, enum dma_data_direction dir);
+bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr);
+
+static inline bool dma_dev_need_sync(const struct device *dev)
+{
+	/* Always call DMA sync operations when debugging is enabled */
+	return !dev->dma_skip_sync || IS_ENABLED(CONFIG_DMA_API_DEBUG);
+}
+
+static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
+		size_t size, enum dma_data_direction dir)
+{
+	if (dma_dev_need_sync(dev))
+		__dma_sync_single_for_cpu(dev, addr, size, dir);
+}
+
+static inline void dma_sync_single_for_device(struct device *dev,
+		dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+	if (dma_dev_need_sync(dev))
+		__dma_sync_single_for_device(dev, addr, size, dir);
+}
+
+static inline void dma_sync_sg_for_cpu(struct device *dev,
+		struct scatterlist *sg, int nelems, enum dma_data_direction dir)
+{
+	if (dma_dev_need_sync(dev))
+		__dma_sync_sg_for_cpu(dev, sg, nelems, dir);
+}
+
+static inline void dma_sync_sg_for_device(struct device *dev,
+		struct scatterlist *sg, int nelems, enum dma_data_direction dir)
+{
+	if (dma_dev_need_sync(dev))
+		__dma_sync_sg_for_device(dev, sg, nelems, dir);
+}
+
+static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
+{
+	return dma_dev_need_sync(dev) ? __dma_need_sync(dev, dma_addr) : false;
+}
+#else /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */
+static inline bool dma_dev_need_sync(const struct device *dev)
+{
+	return false;
+}
+static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
+		size_t size, enum dma_data_direction dir)
+{
+}
+static inline void dma_sync_single_for_device(struct device *dev,
+		dma_addr_t addr, size_t size, enum dma_data_direction dir)
+{
+}
+static inline void dma_sync_sg_for_cpu(struct device *dev,
+		struct scatterlist *sg, int nelems, enum dma_data_direction dir)
+{
+}
+static inline void dma_sync_sg_for_device(struct device *dev,
+		struct scatterlist *sg, int nelems, enum dma_data_direction dir)
+{
+}
+static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
+{
+	return false;
+}
+#endif /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */
+
 struct page *dma_alloc_pages(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
 void dma_free_pages(struct device *dev, size_t size, struct page *page,

include/linux/iova.h

@@ -65,6 +65,11 @@ static inline size_t iova_align(struct iova_domain *iovad, size_t size)
 	return ALIGN(size, iovad->granule);
 }
 
+static inline size_t iova_align_down(struct iova_domain *iovad, size_t size)
+{
+	return ALIGN_DOWN(size, iovad->granule);
+}
+
 static inline dma_addr_t iova_dma_addr(struct iova_domain *iovad, struct iova *iova)
 {
 	return (dma_addr_t)iova->pfn_lo << iova_shift(iovad);

include/linux/swiotlb.h

@@ -43,7 +43,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask,
 extern void __init swiotlb_update_mem_attributes(void);
 
 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,
-		size_t mapping_size, size_t alloc_size,
+		size_t mapping_size,
 		unsigned int alloc_aligned_mask, enum dma_data_direction dir,
 		unsigned long attrs);
 

include/net/page_pool/types.h

@@ -45,7 +45,6 @@ struct pp_alloc_cache {
 
 /**
  * struct page_pool_params - page pool parameters
- * @flags:	PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV
  * @order:	2^order pages on allocation
  * @pool_size:	size of the ptr_ring
  * @nid:	NUMA node id to allocate from pages from
@@ -55,10 +54,11 @@ struct pp_alloc_cache {
  * @dma_dir:	DMA mapping direction
  * @max_len:	max DMA sync memory size for PP_FLAG_DMA_SYNC_DEV
  * @offset:	DMA sync address offset for PP_FLAG_DMA_SYNC_DEV
+ * @netdev:	corresponding &net_device for Netlink introspection
+ * @flags:	PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV, PP_FLAG_SYSTEM_POOL
  */
 struct page_pool_params {
 	struct_group_tagged(page_pool_params_fast, fast,
-		unsigned int	flags;
 		unsigned int	order;
 		unsigned int	pool_size;
 		int		nid;
@@ -70,6 +70,7 @@ struct page_pool_params {
 	);
 	struct_group_tagged(page_pool_params_slow, slow,
 		struct net_device *netdev;
+		unsigned int	flags;
 /* private: used by test code only */
 		void (*init_callback)(struct page *page, void *arg);
 		void *init_arg;
@@ -130,12 +131,28 @@ struct page_pool {
 	struct page_pool_params_fast p;
 
 	int cpuid;
-	bool has_init_callback;
+	u32 pages_state_hold_cnt;
+
+	bool has_init_callback:1;	/* slow::init_callback is set */
+	bool dma_map:1;			/* Perform DMA mapping */
+	bool dma_sync:1;		/* Perform DMA sync */
+#ifdef CONFIG_PAGE_POOL_STATS
+	bool system:1;			/* This is a global percpu pool */
+#endif
 
+	/* The following block must stay within one cacheline. On 32-bit
+	 * systems, sizeof(long) == sizeof(int), so that the block size is
+	 * ``3 * sizeof(long)``. On 64-bit systems, the actual size is
+	 * ``2 * sizeof(long) + sizeof(int)``. The closest pow-2 to both of
+	 * them is ``4 * sizeof(long)``, so just use that one for simplicity.
+	 * Having it aligned to a cacheline boundary may be excessive and
+	 * doesn't bring any good.
+	 */
+	__cacheline_group_begin(frag) __aligned(4 * sizeof(long));
 	long frag_users;
 	struct page *frag_page;
 	unsigned int frag_offset;
-	u32 pages_state_hold_cnt;
+	__cacheline_group_end(frag);
 
 	struct delayed_work release_dw;
 	void (*disconnect)(void *pool);

include/net/xdp_sock_drv.h

@@ -219,13 +219,10 @@ static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool
 	return meta;
 }
 
-static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool)
+static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp)
 {
 	struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
 
-	if (!pool->dma_need_sync)
-		return;
-
 	xp_dma_sync_for_cpu(xskb);
 }
 
@@ -402,7 +399,7 @@ static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool
 	return NULL;
 }
 
-static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool)
+static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp)
 {
 }
 

include/net/xsk_buff_pool.h

@@ -43,7 +43,6 @@ struct xsk_dma_map {
 	refcount_t users;
 	struct list_head list; /* Protected by the RTNL_LOCK */
 	u32 dma_pages_cnt;
-	bool dma_need_sync;
 };
 
 struct xsk_buff_pool {
@@ -82,7 +81,6 @@ struct xsk_buff_pool {
 	u8 tx_metadata_len; /* inherited from umem */
 	u8 cached_need_wakeup;
 	bool uses_need_wakeup;
-	bool dma_need_sync;
 	bool unaligned;
 	bool tx_sw_csum;
 	void *addrs;
@@ -155,21 +153,17 @@ static inline dma_addr_t xp_get_frame_dma(struct xdp_buff_xsk *xskb)
 	return xskb->frame_dma;
 }
 
-void xp_dma_sync_for_cpu_slow(struct xdp_buff_xsk *xskb);
 static inline void xp_dma_sync_for_cpu(struct xdp_buff_xsk *xskb)
 {
-	xp_dma_sync_for_cpu_slow(xskb);
+	dma_sync_single_for_cpu(xskb->pool->dev, xskb->dma,
+				xskb->pool->frame_len,
+				DMA_BIDIRECTIONAL);
 }
 
-void xp_dma_sync_for_device_slow(struct xsk_buff_pool *pool, dma_addr_t dma,
-				 size_t size);
 static inline void xp_dma_sync_for_device(struct xsk_buff_pool *pool,
 					  dma_addr_t dma, size_t size)
 {
-	if (!pool->dma_need_sync)
-		return;
-
-	xp_dma_sync_for_device_slow(pool, dma, size);
+	dma_sync_single_for_device(pool->dev, dma, size, DMA_BIDIRECTIONAL);
 }
 
 /* Masks for xdp_umem_page flags.

kernel/dma/Kconfig

@@ -107,6 +107,11 @@ config DMA_BOUNCE_UNALIGNED_KMALLOC
 	bool
 	depends on SWIOTLB
 
+config DMA_NEED_SYNC
+	def_bool ARCH_HAS_SYNC_DMA_FOR_DEVICE || ARCH_HAS_SYNC_DMA_FOR_CPU || \
+		 ARCH_HAS_SYNC_DMA_FOR_CPU_ALL || DMA_API_DEBUG || DMA_OPS || \
+		 SWIOTLB
+
 config DMA_RESTRICTED_POOL
 	bool "DMA Restricted Pool"
 	depends on OF && OF_RESERVED_MEM && SWIOTLB

kernel/dma/mapping.c

@@ -329,7 +329,8 @@ void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
 }
 EXPORT_SYMBOL(dma_unmap_resource);
 
-void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
+#ifdef CONFIG_DMA_NEED_SYNC
+void __dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
 		enum dma_data_direction dir)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -341,9 +342,9 @@ void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
 		ops->sync_single_for_cpu(dev, addr, size, dir);
 	debug_dma_sync_single_for_cpu(dev, addr, size, dir);
 }
-EXPORT_SYMBOL(dma_sync_single_for_cpu);
+EXPORT_SYMBOL(__dma_sync_single_for_cpu);
 
-void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
+void __dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
 		size_t size, enum dma_data_direction dir)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -355,9 +356,9 @@ void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
 		ops->sync_single_for_device(dev, addr, size, dir);
 	debug_dma_sync_single_for_device(dev, addr, size, dir);
 }
-EXPORT_SYMBOL(dma_sync_single_for_device);
+EXPORT_SYMBOL(__dma_sync_single_for_device);
 
-void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+void __dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 		    int nelems, enum dma_data_direction dir)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -369,9 +370,9 @@ void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
 		ops->sync_sg_for_cpu(dev, sg, nelems, dir);
 	debug_dma_sync_sg_for_cpu(dev, sg, nelems, dir);
 }
-EXPORT_SYMBOL(dma_sync_sg_for_cpu);
+EXPORT_SYMBOL(__dma_sync_sg_for_cpu);
 
-void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+void __dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 		       int nelems, enum dma_data_direction dir)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -383,7 +384,47 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 		ops->sync_sg_for_device(dev, sg, nelems, dir);
 	debug_dma_sync_sg_for_device(dev, sg, nelems, dir);
 }
-EXPORT_SYMBOL(dma_sync_sg_for_device);
+EXPORT_SYMBOL(__dma_sync_sg_for_device);
+
+bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (dma_map_direct(dev, ops))
+		/*
+		 * dma_skip_sync could've been reset on first SWIOTLB buffer
+		 * mapping, but @dma_addr is not necessary an SWIOTLB buffer.
+		 * In this case, fall back to more granular check.
+		 */
+		return dma_direct_need_sync(dev, dma_addr);
+	return true;
+}
+EXPORT_SYMBOL_GPL(__dma_need_sync);
+
+static void dma_setup_need_sync(struct device *dev)
+{
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (dma_map_direct(dev, ops) || (ops->flags & DMA_F_CAN_SKIP_SYNC))
+		/*
+		 * dma_skip_sync will be reset to %false on first SWIOTLB buffer
+		 * mapping, if any. During the device initialization, it's
+		 * enough to check only for the DMA coherence.
+		 */
+		dev->dma_skip_sync = dev_is_dma_coherent(dev);
+	else if (!ops->sync_single_for_device && !ops->sync_single_for_cpu &&
+		 !ops->sync_sg_for_device && !ops->sync_sg_for_cpu)
+		/*
+		 * Synchronization is not possible when none of DMA sync ops
+		 * is set.
+		 */
+		dev->dma_skip_sync = true;
+	else
+		dev->dma_skip_sync = false;
+}
+#else /* !CONFIG_DMA_NEED_SYNC */
+static inline void dma_setup_need_sync(struct device *dev) { }
+#endif /* !CONFIG_DMA_NEED_SYNC */
 
 /*
  * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems
@@ -773,6 +814,8 @@ int dma_set_mask(struct device *dev, u64 mask)
 
 	arch_dma_set_mask(dev, mask);
 	*dev->dma_mask = mask;
+	dma_setup_need_sync(dev);
+
 	return 0;
 }
 EXPORT_SYMBOL(dma_set_mask);
@@ -841,16 +884,6 @@ size_t dma_opt_mapping_size(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dma_opt_mapping_size);
 
-bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
-{
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-
-	if (dma_map_direct(dev, ops))
-		return dma_direct_need_sync(dev, dma_addr);
-	return ops->sync_single_for_cpu || ops->sync_single_for_device;
-}
-EXPORT_SYMBOL_GPL(dma_need_sync);
-
 unsigned long dma_get_merge_boundary(struct device *dev)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);

kernel/dma/swiotlb.c

@@ -1340,15 +1340,40 @@ static unsigned long mem_used(struct io_tlb_mem *mem)
 
 #endif /* CONFIG_DEBUG_FS */
 
+/**
+ * swiotlb_tbl_map_single() - bounce buffer map a single contiguous physical area
+ * @dev:		Device which maps the buffer.
+ * @orig_addr:		Original (non-bounced) physical IO buffer address
+ * @mapping_size:	Requested size of the actual bounce buffer, excluding
+ *			any pre- or post-padding for alignment
+ * @alloc_align_mask:	Required start and end alignment of the allocated buffer
+ * @dir:		DMA direction
+ * @attrs:		Optional DMA attributes for the map operation
+ *
+ * Find and allocate a suitable sequence of IO TLB slots for the request.
+ * The allocated space starts at an alignment specified by alloc_align_mask,
+ * and the size of the allocated space is rounded up so that the total amount
+ * of allocated space is a multiple of (alloc_align_mask + 1). If
+ * alloc_align_mask is zero, the allocated space may be at any alignment and
+ * the size is not rounded up.
+ *
+ * The returned address is within the allocated space and matches the bits
+ * of orig_addr that are specified in the DMA min_align_mask for the device. As
+ * such, this returned address may be offset from the beginning of the allocated
+ * space. The bounce buffer space starting at the returned address for
+ * mapping_size bytes is initialized to the contents of the original IO buffer
+ * area. Any pre-padding (due to an offset) and any post-padding (due to
+ * rounding-up the size) is not initialized.
+ */
 phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
-		size_t mapping_size, size_t alloc_size,
-		unsigned int alloc_align_mask, enum dma_data_direction dir,
-		unsigned long attrs)
+		size_t mapping_size, unsigned int alloc_align_mask,
+		enum dma_data_direction dir, unsigned long attrs)
 {
 	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
 	unsigned int offset;
 	struct io_tlb_pool *pool;
 	unsigned int i;
+	size_t size;
 	int index;
 	phys_addr_t tlb_addr;
 	unsigned short pad_slots;
@@ -1362,23 +1387,33 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
 	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
 		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
 
-	if (mapping_size > alloc_size) {
-		dev_warn_once(dev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
-			      mapping_size, alloc_size);
-		return (phys_addr_t)DMA_MAPPING_ERROR;
-	}
+	/*
+	 * The default swiotlb memory pool is allocated with PAGE_SIZE
+	 * alignment. If a mapping is requested with larger alignment,
+	 * the mapping may be unable to use the initial slot(s) in all
+	 * sets of IO_TLB_SEGSIZE slots. In such case, a mapping request
+	 * of or near the maximum mapping size would always fail.
+	 */
+	dev_WARN_ONCE(dev, alloc_align_mask > ~PAGE_MASK,
+		"Alloc alignment may prevent fulfilling requests with max mapping_size\n");
 
 	offset = swiotlb_align_offset(dev, alloc_align_mask, orig_addr);
-	index = swiotlb_find_slots(dev, orig_addr,
-				   alloc_size + offset, alloc_align_mask, &pool);
+	size = ALIGN(mapping_size + offset, alloc_align_mask + 1);
+	index = swiotlb_find_slots(dev, orig_addr, size, alloc_align_mask, &pool);
 	if (index == -1) {
 		if (!(attrs & DMA_ATTR_NO_WARN))
 			dev_warn_ratelimited(dev,
 	"swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
-				 alloc_size, mem->nslabs, mem_used(mem));
+				 size, mem->nslabs, mem_used(mem));
 		return (phys_addr_t)DMA_MAPPING_ERROR;
 	}
 
+	/*
+	 * If dma_skip_sync was set, reset it on first SWIOTLB buffer
+	 * mapping to always sync SWIOTLB buffers.
+	 */
+	dma_reset_need_sync(dev);
+
 	/*
 	 * Save away the mapping from the original address to the DMA address.
 	 * This is needed when we sync the memory.  Then we sync the buffer if
@@ -1388,7 +1423,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
 	offset &= (IO_TLB_SIZE - 1);
 	index += pad_slots;
 	pool->slots[index].pad_slots = pad_slots;
-	for (i = 0; i < nr_slots(alloc_size + offset); i++)
+	for (i = 0; i < (nr_slots(size) - pad_slots); i++)
 		pool->slots[index + i].orig_addr = slot_addr(orig_addr, i);
 	tlb_addr = slot_addr(pool->start, index) + offset;
 	/*
@@ -1543,8 +1578,7 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size,
 
 	trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size);
 
-	swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, 0, dir,
-			attrs);
+	swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, 0, dir, attrs);
 	if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR)
 		return DMA_MAPPING_ERROR;
 

net/core/page_pool.c

@@ -173,19 +173,29 @@ static void page_pool_producer_unlock(struct page_pool *pool,
 		spin_unlock_bh(&pool->ring.producer_lock);
 }
 
+static void page_pool_struct_check(void)
+{
+	CACHELINE_ASSERT_GROUP_MEMBER(struct page_pool, frag, frag_users);
+	CACHELINE_ASSERT_GROUP_MEMBER(struct page_pool, frag, frag_page);
+	CACHELINE_ASSERT_GROUP_MEMBER(struct page_pool, frag, frag_offset);
+	CACHELINE_ASSERT_GROUP_SIZE(struct page_pool, frag, 4 * sizeof(long));
+}
+
 static int page_pool_init(struct page_pool *pool,
 			  const struct page_pool_params *params,
 			  int cpuid)
 {
 	unsigned int ring_qsize = 1024; /* Default */
 
+	page_pool_struct_check();
+
 	memcpy(&pool->p, &params->fast, sizeof(pool->p));
 	memcpy(&pool->slow, &params->slow, sizeof(pool->slow));
 
 	pool->cpuid = cpuid;
 
 	/* Validate only known flags were used */
-	if (pool->p.flags & ~(PP_FLAG_ALL))
+	if (pool->slow.flags & ~PP_FLAG_ALL)
 		return -EINVAL;
 
 	if (pool->p.pool_size)
@@ -199,22 +209,26 @@ 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.flags & PP_FLAG_DMA_MAP) {
+	if (pool->slow.flags & PP_FLAG_DMA_MAP) {
 		if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&
 		    (pool->p.dma_dir != DMA_BIDIRECTIONAL))
 			return -EINVAL;
+
+		pool->dma_map = true;
 	}
 
-	if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) {
+	if (pool->slow.flags & PP_FLAG_DMA_SYNC_DEV) {
 		/* In order to request DMA-sync-for-device the page
 		 * needs to be mapped
 		 */
-		if (!(pool->p.flags & PP_FLAG_DMA_MAP))
+		if (!(pool->slow.flags & PP_FLAG_DMA_MAP))
 			return -EINVAL;
 
 		if (!pool->p.max_len)
 			return -EINVAL;
 
+		pool->dma_sync = true;
+
 		/* pool->p.offset has to be set according to the address
 		 * offset used by the DMA engine to start copying rx data
 		 */
@@ -223,7 +237,7 @@ static int page_pool_init(struct page_pool *pool,
 	pool->has_init_callback = !!pool->slow.init_callback;
 
 #ifdef CONFIG_PAGE_POOL_STATS
-	if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL)) {
+	if (!(pool->slow.flags & PP_FLAG_SYSTEM_POOL)) {
 		pool->recycle_stats = alloc_percpu(struct page_pool_recycle_stats);
 		if (!pool->recycle_stats)
 			return -ENOMEM;
@@ -233,12 +247,13 @@ static int page_pool_init(struct page_pool *pool,
 		 * (also percpu) page pool instance.
 		 */
 		pool->recycle_stats = &pp_system_recycle_stats;
+		pool->system = true;
 	}
 #endif
 
 	if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0) {
 #ifdef CONFIG_PAGE_POOL_STATS
-		if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL))
+		if (!pool->system)
 			free_percpu(pool->recycle_stats);
 #endif
 		return -ENOMEM;
@@ -249,7 +264,7 @@ static int page_pool_init(struct page_pool *pool,
 	/* Driver calling page_pool_create() also call page_pool_destroy() */
 	refcount_set(&pool->user_cnt, 1);
 
-	if (pool->p.flags & PP_FLAG_DMA_MAP)
+	if (pool->dma_map)
 		get_device(pool->p.dev);
 
 	return 0;
@@ -259,11 +274,11 @@ static void page_pool_uninit(struct page_pool *pool)
 {
 	ptr_ring_cleanup(&pool->ring, NULL);
 
-	if (pool->p.flags & PP_FLAG_DMA_MAP)
+	if (pool->dma_map)
 		put_device(pool->p.dev);
 
 #ifdef CONFIG_PAGE_POOL_STATS
-	if (!(pool->p.flags & PP_FLAG_SYSTEM_POOL))
+	if (!pool->system)
 		free_percpu(pool->recycle_stats);
 #endif
 }
@@ -384,16 +399,26 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
 	return page;
 }
 
-static void page_pool_dma_sync_for_device(const struct page_pool *pool,
+static void __page_pool_dma_sync_for_device(const struct page_pool *pool,
 					    const struct page *page,
-					  unsigned int dma_sync_size)
+					    u32 dma_sync_size)
 {
+#if defined(CONFIG_HAS_DMA) && defined(CONFIG_DMA_NEED_SYNC)
 	dma_addr_t dma_addr = page_pool_get_dma_addr(page);
 
 	dma_sync_size = min(dma_sync_size, pool->p.max_len);
-	dma_sync_single_range_for_device(pool->p.dev, dma_addr,
-					 pool->p.offset, dma_sync_size,
-					 pool->p.dma_dir);
+	__dma_sync_single_for_device(pool->p.dev, dma_addr + pool->p.offset,
+				     dma_sync_size, pool->p.dma_dir);
+#endif
+}
+
+static __always_inline void
+page_pool_dma_sync_for_device(const struct page_pool *pool,
+			      const struct page *page,
+			      u32 dma_sync_size)
+{
+	if (pool->dma_sync && dma_dev_need_sync(pool->p.dev))
+		__page_pool_dma_sync_for_device(pool, page, dma_sync_size);
 }
 
 static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
@@ -415,7 +440,6 @@ static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
 	if (page_pool_set_dma_addr(page, dma))
 		goto unmap_failed;
 
-	if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
 	page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
 
 	return true;
@@ -461,8 +485,7 @@ static struct page *__page_pool_alloc_page_order(struct page_pool *pool,
 	if (unlikely(!page))
 		return NULL;
 
-	if ((pool->p.flags & PP_FLAG_DMA_MAP) &&
-	    unlikely(!page_pool_dma_map(pool, page))) {
+	if (pool->dma_map && unlikely(!page_pool_dma_map(pool, page))) {
 		put_page(page);
 		return NULL;
 	}
@@ -482,8 +505,8 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
 						 gfp_t gfp)
 {
 	const int bulk = PP_ALLOC_CACHE_REFILL;
-	unsigned int pp_flags = pool->p.flags;
 	unsigned int pp_order = pool->p.order;
+	bool dma_map = pool->dma_map;
 	struct page *page;
 	int i, nr_pages;
 
@@ -508,8 +531,7 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
 	 */
 	for (i = 0; i < nr_pages; i++) {
 		page = pool->alloc.cache[i];
-		if ((pp_flags & PP_FLAG_DMA_MAP) &&
-		    unlikely(!page_pool_dma_map(pool, page))) {
+		if (dma_map && unlikely(!page_pool_dma_map(pool, page))) {
 			put_page(page);
 			continue;
 		}
@@ -582,7 +604,7 @@ void __page_pool_release_page_dma(struct page_pool *pool, struct page *page)
 {
 	dma_addr_t dma;
 
-	if (!(pool->p.flags & PP_FLAG_DMA_MAP))
+	if (!pool->dma_map)
 		/* Always account for inflight pages, even if we didn't
 		 * map them
 		 */
@@ -665,7 +687,7 @@ static bool __page_pool_page_can_be_recycled(const struct page *page)
 }
 
 /* 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
+ * If pool->dma_sync 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.
@@ -688,9 +710,7 @@ __page_pool_put_page(struct page_pool *pool, struct page *page,
 	if (likely(__page_pool_page_can_be_recycled(page))) {
 		/* Read barrier done in page_ref_count / READ_ONCE */
 
-		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
-			page_pool_dma_sync_for_device(pool, page,
-						      dma_sync_size);
+		page_pool_dma_sync_for_device(pool, page, dma_sync_size);
 
 		if (allow_direct && page_pool_recycle_in_cache(page, pool))
 			return NULL;
@@ -829,9 +849,7 @@ static struct page *page_pool_drain_frag(struct page_pool *pool,
 		return NULL;
 
 	if (__page_pool_page_can_be_recycled(page)) {
-		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
 		page_pool_dma_sync_for_device(pool, page, -1);
-
 		return page;
 	}
 

net/xdp/xsk_buff_pool.c

@@ -338,7 +338,6 @@ static struct xsk_dma_map *xp_create_dma_map(struct device *dev, struct net_devi
 
 	dma_map->netdev = netdev;
 	dma_map->dev = dev;
-	dma_map->dma_need_sync = false;
 	dma_map->dma_pages_cnt = nr_pages;
 	refcount_set(&dma_map->users, 1);
 	list_add(&dma_map->list, &umem->xsk_dma_list);
@@ -424,7 +423,6 @@ static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_
 
 	pool->dev = dma_map->dev;
 	pool->dma_pages_cnt = dma_map->dma_pages_cnt;
-	pool->dma_need_sync = dma_map->dma_need_sync;
 	memcpy(pool->dma_pages, dma_map->dma_pages,
 	       pool->dma_pages_cnt * sizeof(*pool->dma_pages));
 
@@ -460,8 +458,6 @@ int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
 			__xp_dma_unmap(dma_map, attrs);
 			return -ENOMEM;
 		}
-		if (dma_need_sync(dev, dma))
-			dma_map->dma_need_sync = true;
 		dma_map->dma_pages[i] = dma;
 	}
 
@@ -557,11 +553,9 @@ struct xdp_buff *xp_alloc(struct xsk_buff_pool *pool)
 	xskb->xdp.data_meta = xskb->xdp.data;
 	xskb->xdp.flags = 0;
 
-	if (pool->dma_need_sync) {
-		dma_sync_single_range_for_device(pool->dev, xskb->dma, 0,
-						 pool->frame_len,
-						 DMA_BIDIRECTIONAL);
-	}
+	if (pool->dev)
+		xp_dma_sync_for_device(pool, xskb->dma, pool->frame_len);
+
 	return &xskb->xdp;
 }
 EXPORT_SYMBOL(xp_alloc);
@@ -633,7 +627,7 @@ u32 xp_alloc_batch(struct xsk_buff_pool *pool, struct xdp_buff **xdp, u32 max)
 {
 	u32 nb_entries1 = 0, nb_entries2;
 
-	if (unlikely(pool->dma_need_sync)) {
+	if (unlikely(pool->dev && dma_dev_need_sync(pool->dev))) {
 		struct xdp_buff *buff;
 
 		/* Slow path */
@@ -693,18 +687,3 @@ dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
 		(addr & ~PAGE_MASK);
 }
 EXPORT_SYMBOL(xp_raw_get_dma);
-
-void xp_dma_sync_for_cpu_slow(struct xdp_buff_xsk *xskb)
-{
-	dma_sync_single_range_for_cpu(xskb->pool->dev, xskb->dma, 0,
-				      xskb->pool->frame_len, DMA_BIDIRECTIONAL);
-}
-EXPORT_SYMBOL(xp_dma_sync_for_cpu_slow);
-
-void xp_dma_sync_for_device_slow(struct xsk_buff_pool *pool, dma_addr_t dma,
-				 size_t size)
-{
-	dma_sync_single_range_for_device(pool->dev, dma, 0,
-					 size, DMA_BIDIRECTIONAL);
-}
-EXPORT_SYMBOL(xp_dma_sync_for_device_slow);