From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1A5E13327FE; Mon, 5 May 2025 22:35:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746484556; cv=none; b=akVoQAqyLIEUH0VapjKjpAyCLUpSizXthm3/G9AuJayxEfRbxy4wK4KxSu282L42xGhGWL6hd8dM9zrFSXuKCInBEtGmM4ib/PCe5ksE+ZFFOgL3nIPfHBXp4vc4BvMV2J7NwTyYjAUtybIFp4LsGf6330Gl8tfu82YQcfpSuMM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746484556; c=relaxed/simple; bh=N50elTsvLV/m+xQAOHeAKX14EuZ7+WW4CerdYMMbhFI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=WtnW5AM/KN35LZv17xEZfWiNLn1QifTyfH4XKHxBoNFd6JOIWp9ZY4YrkkuYd/T8TQxixCdtR55bwoaNBc6PN2ndl6CeGsmd3C0HSBwDTn6xOjUI6a6qV9GWrMPXTZr0PsGgGLJkhIuAfSPO5197hGhRdAC6goKCGGx8HBZ5NAc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XHtq7YJr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XHtq7YJr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3CD3AC4CEE4; Mon, 5 May 2025 22:35:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746484556; bh=N50elTsvLV/m+xQAOHeAKX14EuZ7+WW4CerdYMMbhFI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XHtq7YJrgQU4euZaYr9NUkUnBusOgvwbCM8uIqKNQduS4Bg274nMq1kwcxpFqAH3U +PnpN/vjDm1/XbelL2pvhtF/THUl4fVKj9f9WOWscdlY89IstWH5wP6fVeHhA7qNXw o5R+4U/sSn/mMx9cNnuX+Do7hFigNSo+6WXM1Bcns/Mo6sNuSRylvQbgFFnfzDxelJ SKR0jGazhOimXTJPBmHSxa82MYwWykNl5KOLGs5siSo2BSJ87ylvmHXVkb3ZTYJkfw ijivj+ASHdE8kpMpvqrxvBn8+IT5ZENV0TQ4Uwx/RWos2pAL3y9brl8KGlU4M/xV1X zyFxUNS4uIrJw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jakub Kicinski , Mina Almasry , Sasha Levin , davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, hawk@kernel.org, ilias.apalodimas@linaro.org, jdamato@fastly.com, sdf@fomichev.me, kuniyu@amazon.com, kory.maincent@bootlin.com, mkarsten@uwaterloo.ca, bigeasy@linutronix.de, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.14 534/642] net: page_pool: avoid false positive warning if NAPI was never added Date: Mon, 5 May 2025 18:12:30 -0400 Message-Id: <20250505221419.2672473-534-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505221419.2672473-1-sashal@kernel.org> References: <20250505221419.2672473-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.14.5 Content-Transfer-Encoding: 8bit From: Jakub Kicinski [ Upstream commit c1e00bc4be06cacee6307cedb9b55bbaddb5044d ] We expect NAPI to be in disabled state when page pool is torn down. But it is also legal if the NAPI is completely uninitialized. Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20250206225638.1387810-4-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/dev.h | 12 ++++++++++++ net/core/page_pool.c | 7 ++----- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/net/core/dev.h b/net/core/dev.h index a5b166bbd169a..caa13e431a6bc 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -299,6 +299,18 @@ void xdp_do_check_flushed(struct napi_struct *napi); static inline void xdp_do_check_flushed(struct napi_struct *napi) { } #endif +/* Best effort check that NAPI is not idle (can't be scheduled to run) */ +static inline void napi_assert_will_not_race(const struct napi_struct *napi) +{ + /* uninitialized instance, can't race */ + if (!napi->poll_list.next) + return; + + /* SCHED bit is set on disabled instances */ + WARN_ON(!test_bit(NAPI_STATE_SCHED, &napi->state)); + WARN_ON(READ_ONCE(napi->list_owner) != -1); +} + void kick_defer_list_purge(struct softnet_data *sd, unsigned int cpu); #define XMIT_RECURSION_LIMIT 8 diff --git a/net/core/page_pool.c b/net/core/page_pool.c index ede82c610936e..cca51aa2e876f 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -25,6 +25,7 @@ #include +#include "dev.h" #include "mp_dmabuf_devmem.h" #include "netmem_priv.h" #include "page_pool_priv.h" @@ -1146,11 +1147,7 @@ void page_pool_disable_direct_recycling(struct page_pool *pool) if (!pool->p.napi) return; - /* To avoid races with recycling and additional barriers make sure - * pool and NAPI are unlinked when NAPI is disabled. - */ - WARN_ON(!test_bit(NAPI_STATE_SCHED, &pool->p.napi->state)); - WARN_ON(READ_ONCE(pool->p.napi->list_owner) != -1); + napi_assert_will_not_race(pool->p.napi); mutex_lock(&page_pools_lock); WRITE_ONCE(pool->p.napi, NULL); -- 2.39.5