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 1F6D8296D37; Mon, 12 May 2025 17:31:03 +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=1747071064; cv=none; b=k3OAtubmY5tpI5QyWz+I2zdgbXfn9soUOe/+T5gTM+V4eoUYqAf2XwN7MjgmdPl3dlSexA6HOxa+qkbe8oUZT81caHIBBfFwDRzXGB3yi8nCGSoWd2HaB5dUwLOKSR830HCmO/pDnm6kcz9L/b+5OiNinlVdYhQmlS/f/viZo2s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747071064; c=relaxed/simple; bh=+HetUBcEfTRv1+LxZtu6Z9tO9oKCG9LWMz9/wfxtLjQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OMgg9ccaagOzUZ97rR5H+JKdbgDd3dk/dDiEped97Sbajfj+TZAB9jIW455/IR9nqHUiL1Y4+2371hViLZ3DxM3QE1QsIgiD6u8KZeQfMzLiM+e+Vzqn9ygeB/dIPJsRB/X6TDxtxTtb6zIN2HnaP7ldfz5oMHVjoFKx3MXYMck= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=E+jJoX11; 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="E+jJoX11" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 39F88C4CEE9; Mon, 12 May 2025 17:31:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1747071063; bh=+HetUBcEfTRv1+LxZtu6Z9tO9oKCG9LWMz9/wfxtLjQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E+jJoX11mmxuLdmBB99rxsYz1pXisaIGOBqsz83OvQJd6/I+E0suwi513oVxhjNa9 w+388NWXDQASXqx78F/XZFvfhrDJ8RMq0ICd3quaRYq/meXi15SCNI4q3O7Ip3j3JH bCF8Z1BNlNl+0+5SpJD7pecDu7VArOAgDePbFSJU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Oliver Hartkopp , Marc Kleine-Budde , Sasha Levin Subject: [PATCH 5.15 05/54] can: gw: use call_rcu() instead of costly synchronize_rcu() Date: Mon, 12 May 2025 19:29:17 +0200 Message-ID: <20250512172015.862204116@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250512172015.643809034@linuxfoundation.org> References: <20250512172015.643809034@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 181d4447905d551cc664f1e7e796b482c1eec992 ] Commit fb8696ab14ad ("can: gw: synchronize rcu operations before removing gw job entry") added three synchronize_rcu() calls to make sure one rcu grace period was observed before freeing a "struct cgw_job" (which are tiny objects). This should be converted to call_rcu() to avoid adding delays in device / network dismantles. Use the rcu_head that was already in struct cgw_job, not yet used. Link: https://lore.kernel.org/all/20220207190706.1499190-1-eric.dumazet@gmail.com Signed-off-by: Eric Dumazet Cc: Oliver Hartkopp Tested-by: Oliver Hartkopp Signed-off-by: Marc Kleine-Budde Stable-dep-of: 511e64e13d8c ("can: gw: fix RCU/BH usage in cgw_create_job()") Signed-off-by: Sasha Levin --- net/can/gw.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/net/can/gw.c b/net/can/gw.c index d8861e862f157..20e74fe7d0906 100644 --- a/net/can/gw.c +++ b/net/can/gw.c @@ -577,6 +577,13 @@ static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj) gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj); } +static void cgw_job_free_rcu(struct rcu_head *rcu_head) +{ + struct cgw_job *gwj = container_of(rcu_head, struct cgw_job, rcu); + + kmem_cache_free(cgw_cache, gwj); +} + static int cgw_notifier(struct notifier_block *nb, unsigned long msg, void *ptr) { @@ -596,8 +603,7 @@ static int cgw_notifier(struct notifier_block *nb, if (gwj->src.dev == dev || gwj->dst.dev == dev) { hlist_del(&gwj->list); cgw_unregister_filter(net, gwj); - synchronize_rcu(); - kmem_cache_free(cgw_cache, gwj); + call_rcu(&gwj->rcu, cgw_job_free_rcu); } } } @@ -1155,8 +1161,7 @@ static void cgw_remove_all_jobs(struct net *net) hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) { hlist_del(&gwj->list); cgw_unregister_filter(net, gwj); - synchronize_rcu(); - kmem_cache_free(cgw_cache, gwj); + call_rcu(&gwj->rcu, cgw_job_free_rcu); } } @@ -1224,8 +1229,7 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh, hlist_del(&gwj->list); cgw_unregister_filter(net, gwj); - synchronize_rcu(); - kmem_cache_free(cgw_cache, gwj); + call_rcu(&gwj->rcu, cgw_job_free_rcu); err = 0; break; } -- 2.39.5