On Wed, 17 Nov 2021 at 13:48, Jesper Dangaard Brouer <jbrouer@xxxxxxxxxx> wrote: > > Added CC: linux-mm@xxxxxxxxx > > On 17/11/2021 08.56, Yunsheng Lin wrote: > > This reverts commit d00e60ee54b12de945b8493cf18c1ada9e422514. > > > > 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: d00e60ee54b1 ("page_pool: disable dma mapping support for 32-bit arch with 64-bit DMA") > > Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx> > > --- > > include/linux/mm_types.h | 13 ++++++++++++- > > include/net/page_pool.h | 12 +++++++++++- > > net/core/page_pool.c | 10 ++++------ > > 3 files changed, 27 insertions(+), 8 deletions(-) > > Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> > > Too bad that we have to keep this code-uglyness in struct page, and > handling in page_pool. Indeed :( Acked-by: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx> > > > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > > index bb8c6f5f19bc..c3a6e6209600 100644 > > --- a/include/linux/mm_types.h > > +++ b/include/linux/mm_types.h > > @@ -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 { > > diff --git a/include/net/page_pool.h b/include/net/page_pool.h > > index 3855f069627f..a4082406a003 100644 > > --- a/include/net/page_pool.h > > +++ b/include/net/page_pool.h > > @@ -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) > > diff --git a/net/core/page_pool.c b/net/core/page_pool.c > > index 9b60e4301a44..1a6978427d6c 100644 > > --- a/net/core/page_pool.c > > +++ b/net/core/page_pool.c > > @@ -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; > > > > >
