[PATCH net-next v2 2/5] mm: add a signature in struct page
From: Matteo Croce <hidden>
Date: 2021-04-02 18:18:15
Also in:
lkml
Subsystem:
memory management - core, networking [general], page pool, the rest · Maintainers:
Andrew Morton, David Hildenbrand, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jesper Dangaard Brouer, Ilias Apalodimas, Linus Torvalds
From: Matteo Croce <redacted> This is needed by the page_pool to avoid recycling a page not allocated via page_pool. Signed-off-by: Matteo Croce <redacted> --- include/linux/mm_types.h | 1 + include/net/page_pool.h | 2 ++ net/core/page_pool.c | 4 ++++ 3 files changed, 7 insertions(+)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 6613b26a8894..ef2d0d5f62e4 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h@@ -101,6 +101,7 @@ struct page { * 32-bit architectures. */ dma_addr_t dma_addr; + unsigned long signature; }; struct { /* slab, slob and slub */ union {
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index b5b195305346..b30405e84b5e 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h@@ -63,6 +63,8 @@ */ #define PP_ALLOC_CACHE_SIZE 128 #define PP_ALLOC_CACHE_REFILL 64 +#define PP_SIGNATURE 0x20210303 + struct pp_alloc_cache { u32 count; void *cache[PP_ALLOC_CACHE_SIZE];
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index ad8b0707af04..2ae9b554ef98 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c@@ -232,6 +232,8 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool, page_pool_dma_sync_for_device(pool, page, pool->p.max_len); skip_dma_map: + page->signature = PP_SIGNATURE; + /* Track how many pages are held 'in-flight' */ pool->pages_state_hold_cnt++;
@@ -302,6 +304,8 @@ void page_pool_release_page(struct page_pool *pool, struct page *page) DMA_ATTR_SKIP_CPU_SYNC); page->dma_addr = 0; skip_dma_unmap: + page->signature = 0; + /* This may be the last page returned, releasing the pool, so * it is not safe to reference pool afterwards. */
--
2.30.2