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 84CF4276057; Tue, 27 May 2025 17:07:06 +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=1748365626; cv=none; b=U/RyxEpioH56BQg3DSJPBAvXAjVg82tur7z1oIX/dpwp8dHth9oeeW6x9CqmVdaWlnC0ySkzyzBksWjO17AuByK+mcohikd97hW5tF/wP0N/bapmAecE24yzBzaOKVESnd68SypsdG++ux/v5PVKZV3nj6jQcqthmEVzVxNpPEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748365626; c=relaxed/simple; bh=WwfkvbwBUmAxpgiaU9Z9McdPkVOENtUBoqWcPxvsfFI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OtxO4EXKYvFKcaxjIJ85ybkDSGsIJ4e+EKLz8CFxGkB9+xdm5GbwVJCQV2JJyaHvX98DpHZN9m1QTwZicrveRnNTqvTZmqEOOx47gPWaCeDvIg8m4JnK26BQ9a13aYNugT1XUqw10kRLEn5o/ARkmeuYBDEC+peS99z28Vw7XGA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=K/AfTg87; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="K/AfTg87" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CDD21C4CEE9; Tue, 27 May 2025 17:07:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748365626; bh=WwfkvbwBUmAxpgiaU9Z9McdPkVOENtUBoqWcPxvsfFI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K/AfTg87VJgqYb72RDsMO1dQmz+NWSa7mWR+ineHnEn08NgXpQLo8oN4xzkGoqQUo JgJgnomf62oBmA/+M7O8AdV1tI3zveHX7MMbECBtzDsH2X82BumzYFGBSNTSVhjSea vU6fv+icg42FEy/elzoN/mdqgdrDN3U8PTnKnXoc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mina Almasry , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 437/626] net: page_pool: avoid false positive warning if NAPI was never added Date: Tue, 27 May 2025 18:25:30 +0200 Message-ID: <20250527162502.761212565@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250527162445.028718347@linuxfoundation.org> References: <20250527162445.028718347@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ 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 2e3bb7669984a..764e0097ccf22 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -148,6 +148,18 @@ 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 7b20f6fcb82c0..c8ce069605c42 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" @@ -1108,11 +1109,7 @@ 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); WRITE_ONCE(pool->p.napi, NULL); } -- 2.39.5