Commit f915b75b authored by Yunsheng Lin's avatar Yunsheng Lin Committed by David S. Miller
Browse files

page_pool: Revert "page_pool: disable dma mapping support..." 

This reverts commit d00e60ee.

As reported by Guillaume in [1]:
Enabling LPAE always enables CONFIG_ARCH_DMA_ADDR_T_64BIT
in 32-bit systems, which breaks the bootup proceess when a
ethernet driver is using page pool with PP_FLAG_DMA_MAP flag.
As we were hoping we had no active consumers for such system
when we removed the dma mapping support, and LPAE seems like
a common feature for 32 bits system, so revert it.

1. https://www.spinics.net/lists/netdev/msg779890.html



Fixes: d00e60ee ("page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA")
Signed-off-by: default avatarYunsheng Lin <linyunsheng@huawei.com>
Reported-by: default avatar"kernelci.org bot" <bot@kernelci.org>
Tested-by: default avatar"kernelci.org bot" <bot@kernelci.org>
Acked-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: default avatarIlias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a66998e0

include/linux/mm_types.h

+12 −1
Original line number Diff line number Diff line
@@ -105,8 +105,19 @@ struct page { 
			struct page_pool *pp;

			unsigned long _pp_mapping_pad;

			unsigned long dma_addr;

			union {

				/**

				 * dma_addr_upper: might require a 64-bit

				 * value on 32-bit architectures.

				 */

				unsigned long dma_addr_upper;

				/**

				 * For frag page support, not supported in

				 * 32-bit architectures with 64-bit DMA.

				 */

				atomic_long_t pp_frag_count;

			};

		};

		struct {	/* slab, slob and slub */

			union {

				struct list_head slab_list;

include/net/page_pool.h

+11 −1
Original line number Diff line number Diff line
@@ -216,14 +216,24 @@ static inline void page_pool_recycle_direct(struct page_pool *pool, 
	page_pool_put_full_page(pool, page, true);

}



#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT	\

		(sizeof(dma_addr_t) > sizeof(unsigned long))



static inline dma_addr_t page_pool_get_dma_addr(struct page *page)

{

	return page->dma_addr;

	dma_addr_t ret = page->dma_addr;



	if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)

		ret |= (dma_addr_t)page->dma_addr_upper << 16 << 16;



	return ret;

}



static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr)

{

	page->dma_addr = addr;

	if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)

		page->dma_addr_upper = upper_32_bits(addr);

}



static inline void page_pool_set_frag_count(struct page *page, long nr)

net/core/page_pool.c

+4 −6
Original line number Diff line number Diff line
@@ -49,12 +49,6 @@ static int page_pool_init(struct page_pool *pool, 
	 * which is the XDP_TX use-case.

	 */

	if (pool->p.flags & PP_FLAG_DMA_MAP) {

		/* DMA-mapping is not supported on 32-bit systems with

		 * 64-bit DMA mapping.

		 */

		if (sizeof(dma_addr_t) > sizeof(unsigned long))

			return -EOPNOTSUPP;



		if ((pool->p.dma_dir != DMA_FROM_DEVICE) &&

		    (pool->p.dma_dir != DMA_BIDIRECTIONAL))

			return -EINVAL;
@@ -75,6 +69,10 @@ static int page_pool_init(struct page_pool *pool, 
		 */

	}



	if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&

	    pool->p.flags & PP_FLAG_PAGE_FRAG)

		return -EINVAL;



	if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0)

		return -ENOMEM;