diff options
| author | Matteo Croce <mcroce@microsoft.com> | 2021-06-07 22:02:36 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-06-08 00:11:47 +0300 |
| commit | c07aea3ef4d4076f18f567b98ed01e082e02ed51 (patch) | |
| tree | f52beca6a7fefeb1f14f7fb92efa914a3682b86f /net | |
| parent | 35cba15a504bf4f585bb9d78f47b22b28a1a06b2 (diff) | |
| download | linux-c07aea3ef4d4076f18f567b98ed01e082e02ed51.tar.xz | |
mm: add a signature in struct page
This is needed by the page_pool to avoid recycling a page not allocated
via page_pool.
The page->signature field is aliased to page->lru.next and
page->compound_head, but it can't be set by mistake because the
signature value is a bad pointer, and can't trigger a false positive
in PageTail() because the last bit is 0.
Co-developed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Matteo Croce <mcroce@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/page_pool.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 3c4c4c7a0402..e1321bc9d316 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -17,6 +17,7 @@ #include <linux/dma-mapping.h> #include <linux/page-flags.h> #include <linux/mm.h> /* for __put_page() */ +#include <linux/poison.h> #include <trace/events/page_pool.h> @@ -221,6 +222,8 @@ static struct page *__page_pool_alloc_page_order(struct page_pool *pool, return NULL; } + page->pp_magic |= PP_SIGNATURE; + /* Track how many pages are held 'in-flight' */ pool->pages_state_hold_cnt++; trace_page_pool_state_hold(pool, page, pool->pages_state_hold_cnt); @@ -263,6 +266,7 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool, put_page(page); continue; } + page->pp_magic |= PP_SIGNATURE; pool->alloc.cache[pool->alloc.count++] = page; /* Track how many pages are held 'in-flight' */ pool->pages_state_hold_cnt++; @@ -341,6 +345,8 @@ void page_pool_release_page(struct page_pool *pool, struct page *page) DMA_ATTR_SKIP_CPU_SYNC); page_pool_set_dma_addr(page, 0); skip_dma_unmap: + page->pp_magic = 0; + /* This may be the last page returned, releasing the pool, so * it is not safe to reference pool afterwards. */ |