From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from invmail4.hynix.com (exvmail4.hynix.com [166.125.252.92]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B829A2DE6F8; Thu, 16 Oct 2025 06:37:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=166.125.252.92 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760596636; cv=none; b=KQd0dhFjfFtgiMhtT11SZN/0GjhSYiDRCugV+qej7v0lhgnNSw3tFhZuQfA3ncPdfabzw3Z38ucr9EH5a7/xXn05rZYTw4x0nDCvoWaAbmncjsKBsBUjGAPqljcHGA7GRI8k1ub7Ek9/xXp3Zw+r/xnAf70twzdjQeSZG/CNrTk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760596636; c=relaxed/simple; bh=K34ehr8RNb8WkyEDgQ2XhDAjvJhbuEBHYZnegCjBiwo=; h=From:To:Cc:Subject:Date:Message-Id; b=ecJGTYEMhVy3qZ2tSbLE8fo3ghe37XMNNviKtoYIjj0oEmjHvwhx55swCk18egBXgk6VFuWpZY6V9WNIF2ct+WoLaieF+vkT1LRvqr6aq0YCu8dsMW6EfLCSilKgUxbpuG6OaDhz5PrChD1vaZNGZDppru6L5FNVcyQkB09rMrE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-c45ff70000001609-31-68f092937ca6 From: Byungchul Park To: axboe@kernel.dk, kuba@kernel.org, pabeni@redhat.com, almasrymina@google.com, asml.silence@gmail.com Cc: davem@davemloft.net, edumazet@google.com, horms@kernel.org, hawk@kernel.org, ilias.apalodimas@linaro.org, sdf@fomichev.me, dw@davidwei.uk, ap420073@gmail.com, dtatulea@nvidia.com, byungchul@sk.com, toke@redhat.com, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, kernel_team@skhynix.com, max.byungchul.park@gmail.com Subject: [PATCH net-next] page_pool: check if nmdesc->pp is !NULL to confirm its usage as pp for net_iov Date: Thu, 16 Oct 2025 15:36:57 +0900 Message-Id: <20251016063657.81064-1-byungchul@sk.com> X-Mailer: git-send-email 2.17.1 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrPLMWRmVeSWpSXmKPExsXC9ZZnoe7kSR8yDDqfWlis/lFh8XPNcyaL Oau2MVqsvtvPZjHnfAuLxc5dzxktXs1Yy2bx9Ngjdos97duZLR71n2Cz6G35zWzxrvUci8WF bX2sFpd3zWGzuDCxl9Xi2AIxi2+n3zBaXJ25i8ni0uFHLA7CHltW3mTyuDZjIovHjX2nmDx2 zrrL7rFgU6nH5bOlHptWdbJ53Lm2h82jt/kdm8f7fVfZPD5vkgvgjuKySUnNySxLLdK3S+DK 6Hi/gaXglGzFjPdXGBsYl0l0MXJySAiYSMw81MQOY0/8eoEZxGYTUJe4ceMnmC0ikC9xaMdW pi5GLg5mgX9MEnMX9LGCJIQFMiR2vmwDa2YRUJU4d+YRI4jNK2AqMf/tX2aIofISqzccYAZp lhB4zybxZcZ/FoiEpMTBFTdYJjByL2BkWMUolJlXlpuYmWOil1GZl1mhl5yfu4kRGMzLav9E 72D8dCH4EKMAB6MSD++DFe8zhFgTy4orcw8xSnAwK4nwMhR8yBDiTUmsrEotyo8vKs1JLT7E KM3BoiTOa/StPEVIID2xJDU7NbUgtQgmy8TBKdXAaJ+2PEhQ8WX/5lC597Ki8w+lszDfUi/2 ydioxmfwuPrukjT1dVME2A+zbWk++677d/5Dpn4fl9u3E17KlXz6c+wq86xtUnMPL86/3Cyz VEymsmtTfHyO8hGGx2HJVXlrQxzi/Ngiq9tnSElcDDx9mGn2opLLa/Rvv5ji4j9lmvcOnyaN LPZmJZbijERDLeai4kQAlyq2smICAAA= X-Brightmail-Tracker: H4sIAAAAAAAAAwFSAq39CAMSvwMaCGludGVybmFsIgYKBApOO4Mtk5LwaDCpyys4q/h4OPms 5wI4nKq2ATir3Y8GOM6UmwY4nM+EBDi5uucBOOqYrQY45cbiBzi8h7cDOOKPyAY4jYT7Azju hc4EOMOdyQU40LaOBTjTupwGONCRjQU4xqAWOPbL7AE41Zm6AjjSw+IEQBVItKnZAkjWmJEE SNi+ygJIuZrdB0igsnVI0811SLKqiQZI3Na8BkiNg+4GSO++1QZI9ttISKPo8AJI87IeUA1a CjxkZWxpdmVyLz5gCmiI77AEcModeJjv1AGAAaYYigEJCBgQNBiR9dADigEJCAYQJxjY2PkD igEJCBQQbxjCuLUCigEKCAMQ/gIYnaCOBYoBCQgTEGgYuemGB4oBCQgEECUYzsziAYoBCQgN EDUYn+39A4oBCQgYEB8Yq7DAA5ABCKABAKoBFGludm1haWw1LnNraHluaXguY29tsgEGCgSm ffyRuAH000fCARAIASIMDeCo72gSBWF2c3ltwgEYCAMiFA0AcPBoEg1kYXl6ZXJvX3J1bGVz wgEbCAQiFw1KV2VgEhBnYXRla2VlcGVyX3J1bGVzwgECCAkagAEcoB1FfvYRkChl5zqcwYZN zHZD4qtyrTXlnd0IhKxlQwlmxl0dTsgDEJMgBUZoFoegYmLTfcizDeoELaPIelMI35Fe9c5/ CcUgcc+Hw9CgKzgoM8SGz8W7cZHptyuoSM1r+r9npqGbJzPLum90AhvFyLLNIDfyr8kdppRN d4in5yIEc2hhMSoDcnNheM0lv1ICAAA= X-CFilter-Loop: Reflected Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: ->pp_magic field in struct page is current used to identify if a page belongs to a page pool. However, ->pp_magic will be removed and page type bit in struct page e.g. PGTY_netpp should be used for that purpose. As a preparation, the check for net_iov, that is not page-backed, should avoid using ->pp_magic since net_iov doens't have to do with page type. Instead, nmdesc->pp can be used if a net_iov or its nmdesc belongs to a page pool, by making sure nmdesc->pp is NULL otherwise. For page-backed netmem, just leave unchanged as is, while for net_iov, make sure nmdesc->pp is initialized to NULL and use nmdesc->pp for the check. Signed-off-by: Byungchul Park --- io_uring/zcrx.c | 4 ++++ net/core/devmem.c | 1 + net/core/netmem_priv.h | 6 ++++++ net/core/page_pool.c | 16 ++++++++++++++-- 4 files changed, 25 insertions(+), 2 deletions(-) diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c index 723e4266b91f..cf78227c0ca6 100644 --- a/io_uring/zcrx.c +++ b/io_uring/zcrx.c @@ -450,6 +450,10 @@ static int io_zcrx_create_area(struct io_zcrx_ifq *ifq, area->freelist[i] = i; atomic_set(&area->user_refs[i], 0); niov->type = NET_IOV_IOURING; + + /* niov->desc.pp is already initialized to NULL by + * kvmalloc_array(__GFP_ZERO). + */ } area->free_count = nr_iovs; diff --git a/net/core/devmem.c b/net/core/devmem.c index d9de31a6cc7f..f81b700f1fd1 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -291,6 +291,7 @@ net_devmem_bind_dmabuf(struct net_device *dev, niov = &owner->area.niovs[i]; niov->type = NET_IOV_DMABUF; niov->owner = &owner->area; + niov->desc.pp = NULL; page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov), net_devmem_get_dma_addr(niov)); if (direction == DMA_TO_DEVICE) diff --git a/net/core/netmem_priv.h b/net/core/netmem_priv.h index 23175cb2bd86..fb21cc19176b 100644 --- a/net/core/netmem_priv.h +++ b/net/core/netmem_priv.h @@ -22,6 +22,12 @@ static inline void netmem_clear_pp_magic(netmem_ref netmem) static inline bool netmem_is_pp(netmem_ref netmem) { + /* Use ->pp for net_iov to identify if it's pp, which requires + * that non-pp net_iov should have ->pp NULL'd. + */ + if (netmem_is_net_iov(netmem)) + return !!netmem_to_nmdesc(netmem)->pp; + return (netmem_get_pp_magic(netmem) & PP_MAGIC_MASK) == PP_SIGNATURE; } diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 1a5edec485f1..2756b78754b0 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -699,7 +699,13 @@ s32 page_pool_inflight(const struct page_pool *pool, bool strict) void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem) { netmem_set_pp(netmem, pool); - netmem_or_pp_magic(netmem, PP_SIGNATURE); + + /* For page-backed, pp_magic is used to identify if it's pp. + * For net_iov, it's ensured nmdesc->pp is non-NULL if it's pp + * and nmdesc->pp is NULL if it's not. + */ + if (!netmem_is_net_iov(netmem)) + netmem_or_pp_magic(netmem, PP_SIGNATURE); /* Ensuring all pages have been split into one fragment initially: * page_pool_set_pp_info() is only called once for every page when it @@ -714,7 +720,13 @@ void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem) void page_pool_clear_pp_info(netmem_ref netmem) { - netmem_clear_pp_magic(netmem); + /* For page-backed, pp_magic is used to identify if it's pp. + * For net_iov, it's ensured nmdesc->pp is non-NULL if it's pp + * and nmdesc->pp is NULL if it's not. + */ + if (!netmem_is_net_iov(netmem)) + netmem_clear_pp_magic(netmem); + netmem_set_pp(netmem, NULL); } base-commit: e1f5bb196f0b0eee197e06d361f8ac5f091c2963 -- 2.17.1