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

This reverts commit d00e60ee54.

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: d00e60ee54 ("page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Tested-by: "kernelci.org bot" <bot@kernelci.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yunsheng Lin 2021-11-17 15:56:52 +08:00 committed by David S. Miller
parent a66998e0fb
commit f915b75bff
3 changed files with 27 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
include/linux/mm_types.h
View File

@ -105,7 +105,18 @@ struct page {
struct page_pool *pp;
unsigned long _pp_mapping_pad;
unsigned long dma_addr;
atomic_long_t pp_frag_count;
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 {

12
include/net/page_pool.h
View File

@ -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)

10
net/core/page_pool.c
View File

@ -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;