2021-11-17 07:59:17

by Yunsheng Lin

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

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 <[email protected]>
---
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



2021-11-17 10:28:12

by Guillaume Tucker

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

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 <[email protected]>

Reported-by: "kernelci.org bot" <[email protected]>

Tested-by: "kernelci.org bot" <[email protected]>

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;
>
>


2021-11-17 11:48:49

by Jesper Dangaard Brouer

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

Added CC: [email protected]

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 <[email protected]>
> ---
> 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 <[email protected]>

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;
>
>


2021-11-17 11:52:07

by Ilias Apalodimas

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

On Wed, 17 Nov 2021 at 13:48, Jesper Dangaard Brouer <[email protected]> wrote:
>
> Added CC: [email protected]
>
> 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 <[email protected]>
> > ---
> > 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 <[email protected]>
>
> Too bad that we have to keep this code-uglyness in struct page, and
> handling in page_pool.

Indeed :(

Acked-by: Ilias Apalodimas <[email protected]>
>
>
> > 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;
> >
> >
>

2021-11-18 11:41:35

by patchwork-bot+netdevbpf

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

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:

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.
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