[PATCH net] page_pool: Revert "page_pool: disable dma mapping support..."

[PATCH net] page_pool: Revert "page_pool: disable dma mapping support..."

[Yunsheng Lin]

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@huawei.com>
---
 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(-)

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;
 
-- 
2.33.0

Re: [PATCH net] page_pool: Revert "page_pool: disable dma mapping support..."

[Guillaume Tucker]

On 17/11/2021 07:56, 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@huawei.com>

Reported-by: "kernelci.org bot" <bot@kernelci.org>

Tested-by: "kernelci.org bot" <bot@kernelci.org>

Here's some test results with the revert patch applied on top of
mainline, to confirm the platform boots again:

  https://staging.kernelci.org/test/plan/id/6194d88fbe0f345a9b1760aa/

Thanks,
Guillaume

> ---
>  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(-)
> 
> 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;
>  
> 

Re: [PATCH net] page_pool: Revert "page_pool: disable dma mapping support..."

[Jesper Dangaard Brouer]

Added CC: linux-mm@kvack.org

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@huawei.com>
> ---
>   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@redhat.com>

Too bad that we have to keep this code-uglyness in struct page, and 
handling in page_pool.


> 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;
>   
> 

Re: [PATCH net] page_pool: Revert "page_pool: disable dma mapping support..."

[Ilias Apalodimas]

On Wed, 17 Nov 2021 at 13:48, Jesper Dangaard Brouer <jbrouer@redhat.com> wrote:
>
> Added CC: linux-mm@kvack.org
>
> 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@huawei.com>
> > ---
> >   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@redhat.com>
>
> 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@linaro.org>
>
>
> > 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;
> >
> >
>

Re: [PATCH net] page_pool: Revert "page_pool: disable dma mapping support..."

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Wed, 17 Nov 2021 15:56:52 +0800 you 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.
> 
> [...]

Here is the summary with links:
  - [net] page_pool: Revert "page_pool: disable dma mapping support..."
    https://git.kernel.org/netdev/net/c/f915b75bffb7

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html