From: Yunsheng Lin <linyunsheng@huawei.com>
To: <davem@davemloft.net>, <kuba@kernel.org>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linuxarm@openeuler.org>, <hawk@kernel.org>,
<ilias.apalodimas@linaro.org>, <akpm@linux-foundation.org>,
<peterz@infradead.org>, <vbabka@suse.cz>, <willy@infradead.org>,
<will@kernel.org>, <feng.tang@intel.com>, <jgg@ziepe.ca>,
<ebiederm@xmission.com>, <aarcange@redhat.com>,
<guillaume.tucker@collabora.com>
Subject: [PATCH net] page_pool: Revert "page_pool: disable dma mapping support..."
Date: Wed, 17 Nov 2021 15:56:52 +0800 [thread overview]
Message-ID: <20211117075652.58299-1-linyunsheng@huawei.com> (raw)
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
next reply other threads:[~2021-11-17 7:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 7:56 Yunsheng Lin [this message]
2021-11-17 10:28 ` [PATCH net] page_pool: Revert "page_pool: disable dma mapping support..." Guillaume Tucker
2021-11-17 11:48 ` Jesper Dangaard Brouer
2021-11-17 11:51 ` Ilias Apalodimas
2021-11-18 11:40 ` patchwork-bot+netdevbpf
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