+++ /dev/null
-From: Yunsheng Lin <linyunsheng@huawei.com>
-Date: Fri, 13 Oct 2023 14:48:21 +0800
-Subject: [PATCH] page_pool: fragment API support for 32-bit arch with 64-bit
- DMA
-
-Currently page_pool_alloc_frag() is not supported in 32-bit
-arch with 64-bit DMA because of the overlap issue between
-pp_frag_count and dma_addr_upper in 'struct page' for those
-arches, which seems to be quite common, see [1], which means
-driver may need to handle it when using fragment API.
-
-It is assumed that the combination of the above arch with an
-address space >16TB does not exist, as all those arches have
-64b equivalent, it seems logical to use the 64b version for a
-system with a large address space. It is also assumed that dma
-address is page aligned when we are dma mapping a page aligned
-buffer, see [2].
-
-That means we're storing 12 bits of 0 at the lower end for a
-dma address, we can reuse those bits for the above arches to
-support 32b+12b, which is 16TB of memory.
-
-If we make a wrong assumption, a warning is emitted so that
-user can report to us.
-
-1. https://lore.kernel.org/all/20211117075652.58299-1-linyunsheng@huawei.com/
-2. https://lore.kernel.org/all/20230818145145.4b357c89@kernel.org/
-
-Tested-by: Alexander Lobakin <aleksander.lobakin@intel.com>
-Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
-CC: Lorenzo Bianconi <lorenzo@kernel.org>
-CC: Alexander Duyck <alexander.duyck@gmail.com>
-CC: Liang Chen <liangchen.linux@gmail.com>
-CC: Guillaume Tucker <guillaume.tucker@collabora.com>
-CC: Matthew Wilcox <willy@infradead.org>
-CC: Linux-MM <linux-mm@kvack.org>
-Link: https://lore.kernel.org/r/20231013064827.61135-2-linyunsheng@huawei.com
-Signed-off-by: Jakub Kicinski <kuba@kernel.org>
----
-
---- a/include/linux/mm_types.h
-+++ b/include/linux/mm_types.h
-@@ -125,18 +125,7 @@ struct page {
- struct page_pool *pp;
- unsigned long _pp_mapping_pad;
- unsigned long dma_addr;
-- 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;
-- };
-+ atomic_long_t pp_frag_count;
- };
- struct { /* Tail pages of compound page */
- unsigned long compound_head; /* Bit zero is set */
---- a/include/net/page_pool/helpers.h
-+++ b/include/net/page_pool/helpers.h
-@@ -197,7 +197,7 @@ static inline void page_pool_recycle_dir
- page_pool_put_full_page(pool, page, true);
- }
-
--#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \
-+#define PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA \
- (sizeof(dma_addr_t) > sizeof(unsigned long))
-
- /**
-@@ -211,17 +211,25 @@ static inline dma_addr_t page_pool_get_d
- {
- 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;
-+ if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA)
-+ ret <<= PAGE_SHIFT;
-
- return ret;
- }
-
--static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr)
-+static inline bool page_pool_set_dma_addr(struct page *page, dma_addr_t addr)
- {
-+ if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) {
-+ page->dma_addr = addr >> PAGE_SHIFT;
-+
-+ /* We assume page alignment to shave off bottom bits,
-+ * if this "compression" doesn't work we need to drop.
-+ */
-+ return addr != (dma_addr_t)page->dma_addr << PAGE_SHIFT;
-+ }
-+
- page->dma_addr = addr;
-- if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
-- page->dma_addr_upper = upper_32_bits(addr);
-+ return false;
- }
-
- static inline bool page_pool_put(struct page_pool *pool)
---- a/net/core/page_pool.c
-+++ b/net/core/page_pool.c
-@@ -211,10 +211,6 @@ static int page_pool_init(struct page_po
- */
- }
-
-- if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&
-- pool->p.flags & PP_FLAG_PAGE_FRAG)
-- return -EINVAL;
--
- #ifdef CONFIG_PAGE_POOL_STATS
- pool->recycle_stats = alloc_percpu(struct page_pool_recycle_stats);
- if (!pool->recycle_stats)
-@@ -363,12 +359,20 @@ static bool page_pool_dma_map(struct pag
- if (dma_mapping_error(pool->p.dev, dma))
- return false;
-
-- page_pool_set_dma_addr(page, dma);
-+ if (page_pool_set_dma_addr(page, dma))
-+ goto unmap_failed;
-
- if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
- page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
-
- return true;
-+
-+unmap_failed:
-+ WARN_ON_ONCE("unexpected DMA address, please report to netdev@");
-+ dma_unmap_page_attrs(pool->p.dev, dma,
-+ PAGE_SIZE << pool->p.order, pool->p.dma_dir,
-+ DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING);
-+ return false;
- }
-
- static void page_pool_set_pp_info(struct page_pool *pool,
--- /dev/null
+From: Yunsheng Lin <linyunsheng@huawei.com>
+Date: Fri, 13 Oct 2023 14:48:21 +0800
+Subject: [PATCH] page_pool: fragment API support for 32-bit arch with 64-bit
+ DMA
+
+Currently page_pool_alloc_frag() is not supported in 32-bit
+arch with 64-bit DMA because of the overlap issue between
+pp_frag_count and dma_addr_upper in 'struct page' for those
+arches, which seems to be quite common, see [1], which means
+driver may need to handle it when using fragment API.
+
+It is assumed that the combination of the above arch with an
+address space >16TB does not exist, as all those arches have
+64b equivalent, it seems logical to use the 64b version for a
+system with a large address space. It is also assumed that dma
+address is page aligned when we are dma mapping a page aligned
+buffer, see [2].
+
+That means we're storing 12 bits of 0 at the lower end for a
+dma address, we can reuse those bits for the above arches to
+support 32b+12b, which is 16TB of memory.
+
+If we make a wrong assumption, a warning is emitted so that
+user can report to us.
+
+1. https://lore.kernel.org/all/20211117075652.58299-1-linyunsheng@huawei.com/
+2. https://lore.kernel.org/all/20230818145145.4b357c89@kernel.org/
+
+Tested-by: Alexander Lobakin <aleksander.lobakin@intel.com>
+Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
+CC: Lorenzo Bianconi <lorenzo@kernel.org>
+CC: Alexander Duyck <alexander.duyck@gmail.com>
+CC: Liang Chen <liangchen.linux@gmail.com>
+CC: Guillaume Tucker <guillaume.tucker@collabora.com>
+CC: Matthew Wilcox <willy@infradead.org>
+CC: Linux-MM <linux-mm@kvack.org>
+Link: https://lore.kernel.org/r/20231013064827.61135-2-linyunsheng@huawei.com
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+---
+
+--- a/include/linux/mm_types.h
++++ b/include/linux/mm_types.h
+@@ -125,18 +125,7 @@ struct page {
+ struct page_pool *pp;
+ unsigned long _pp_mapping_pad;
+ unsigned long dma_addr;
+- 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;
+- };
++ atomic_long_t pp_frag_count;
+ };
+ struct { /* Tail pages of compound page */
+ unsigned long compound_head; /* Bit zero is set */
+--- a/include/net/page_pool/helpers.h
++++ b/include/net/page_pool/helpers.h
+@@ -197,7 +197,7 @@ static inline void page_pool_recycle_dir
+ page_pool_put_full_page(pool, page, true);
+ }
+
+-#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \
++#define PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA \
+ (sizeof(dma_addr_t) > sizeof(unsigned long))
+
+ /**
+@@ -211,17 +211,25 @@ static inline dma_addr_t page_pool_get_d
+ {
+ 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;
++ if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA)
++ ret <<= PAGE_SHIFT;
+
+ return ret;
+ }
+
+-static inline void page_pool_set_dma_addr(struct page *page, dma_addr_t addr)
++static inline bool page_pool_set_dma_addr(struct page *page, dma_addr_t addr)
+ {
++ if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) {
++ page->dma_addr = addr >> PAGE_SHIFT;
++
++ /* We assume page alignment to shave off bottom bits,
++ * if this "compression" doesn't work we need to drop.
++ */
++ return addr != (dma_addr_t)page->dma_addr << PAGE_SHIFT;
++ }
++
+ page->dma_addr = addr;
+- if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT)
+- page->dma_addr_upper = upper_32_bits(addr);
++ return false;
+ }
+
+ static inline bool page_pool_put(struct page_pool *pool)
+--- a/net/core/page_pool.c
++++ b/net/core/page_pool.c
+@@ -211,10 +211,6 @@ static int page_pool_init(struct page_po
+ */
+ }
+
+- if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&
+- pool->p.flags & PP_FLAG_PAGE_FRAG)
+- return -EINVAL;
+-
+ #ifdef CONFIG_PAGE_POOL_STATS
+ pool->recycle_stats = alloc_percpu(struct page_pool_recycle_stats);
+ if (!pool->recycle_stats)
+@@ -363,12 +359,20 @@ static bool page_pool_dma_map(struct pag
+ if (dma_mapping_error(pool->p.dev, dma))
+ return false;
+
+- page_pool_set_dma_addr(page, dma);
++ if (page_pool_set_dma_addr(page, dma))
++ goto unmap_failed;
+
+ if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
+ page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
+
+ return true;
++
++unmap_failed:
++ WARN_ON_ONCE("unexpected DMA address, please report to netdev@");
++ dma_unmap_page_attrs(pool->p.dev, dma,
++ PAGE_SIZE << pool->p.order, pool->p.dma_dir,
++ DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING);
++ return false;
+ }
+
+ static void page_pool_set_pp_info(struct page_pool *pool,
projects / openwrt / staging / nbd.git / commitdiff