From patchwork Fri Nov 8 01:02:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jakub Kicinski X-Patchwork-Id: 13867381 X-Patchwork-Delegate: kuba@kernel.org 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 4EB21EC0 for ; Fri, 8 Nov 2024 01:02:56 +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=1731027777; cv=none; b=WEbmOztxffcT8WbtbeJEk5UTQqq0bxlakLmDbI/hRRxdFq8GgEwI6kICr7Kqx8AO4UKlLcgbVEgYJQ+1QAbX+MEhMwI0Dhe2+E64CO3nLwAvLcrbb71m7AdGyc59yfrvxueVdsQN4ibFloTsUaESYzMm7BGbt0h6ff/U4BCNyOM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731027777; c=relaxed/simple; bh=2OZRCx61sQHAFAXdvLON086QS03dsE6saKCPhFO1i78=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=uHpNx9QQWv64keysmAEnJddznRrprPp6QnBJIeKuikY1VGAgrn8/1LahBy2JMhjAMv7iqUnxoNy5CdZ+nqk7ai6MeaBueg7R4Y3RABcJ4s4aWhv8jBedhx2LgFUCGonxrSqwQCuvwNFXRogolOIlNbqC/b8v0t3Yot1M4PadYYw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R57QeacQ; 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="R57QeacQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DFE3C4CECC; Fri, 8 Nov 2024 01:02:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731027776; bh=2OZRCx61sQHAFAXdvLON086QS03dsE6saKCPhFO1i78=; h=From:To:Cc:Subject:Date:From; b=R57QeacQUb7lBZBONORty9I7jvrr5S9W4CGNgJyMRzNbvpC443hCObBZ1OILdO0pY mUv/XzVFY3xrQvSv5YPsNYDPCcq3ee+bRgXe5WM8P09TSCCxuFr48Z1hvdS0eJWaem PKECgsCMfzHWLnWF6veo/V8aPGA5EFiMWEzyH/pB6NRuZq8hhZKicZyLEMip0L0ecP LnEEsVoCXOijqzUp4Lq4JEfoWgrSuLNYgDkzTece6nVt+Cl66oLIVmrS7D/G/6ODK7 hvokaWgElK1c1vHK9ZwupcE/bIMnr4z3SBxAYwUs/+cbJxb7D9mO5nDz50CMatzGRy MSc/PhYObKFww== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, Jakub Kicinski , Simon Horman , jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us Subject: [PATCH net-next v2] net: sched: cls_api: improve the error message for ID allocation failure Date: Thu, 7 Nov 2024 17:02:54 -0800 Message-ID: <20241108010254.2995438-1-kuba@kernel.org> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org We run into an exhaustion problem with the kernel-allocated filter IDs. Our allocation problem can be fixed on the user space side, but the error message in this case was quite misleading: "Filter with specified priority/protocol not found" (EINVAL) Specifically when we can't allocate a _new_ ID because filter with lowest ID already _exists_, saying "filter not found", is confusing. Kernel allocates IDs in range of 0xc0000 -> 0x8000, giving out ID one lower than lowest existing in that range. The error message makes sense when tcf_chain_tp_find() gets called for GET and DEL but for NEW we need to provide more specific error messages for all three cases: - user wants the ID to be auto-allocated but filter with ID 0x8000 already exists - filter already exists and can be replaced, but user asked for a protocol change - filter doesn't exist Caller of tcf_chain_tp_insert_unique() doesn't set extack today, so don't bother plumbing it in. Reviewed-by: Simon Horman Signed-off-by: Jakub Kicinski --- v1 was sent a while back, I realized this is sitting in my tree I think I just forgot to send v2. v2: - don't add the extack if we don't find the filter during NEW v1: https://lore.kernel.org/20240912215306.2060709-1-kuba@kernel.org CC: jhs@mojatatu.com CC: xiyou.wangcong@gmail.com CC: jiri@resnulli.us --- net/sched/cls_api.c | 39 +++++++++++++++++++++++++-------------- 1 file changed, 25 insertions(+), 14 deletions(-) diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 2a7d856cc334..5c8d39b6b107 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -1933,7 +1933,8 @@ static void tcf_chain_tp_remove(struct tcf_chain *chain, static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain, struct tcf_chain_info *chain_info, u32 protocol, u32 prio, - bool prio_allocate); + bool prio_allocate, + struct netlink_ext_ack *extack); /* Try to insert new proto. * If proto with specified priority already exists, free new proto @@ -1957,8 +1958,7 @@ static struct tcf_proto *tcf_chain_tp_insert_unique(struct tcf_chain *chain, return ERR_PTR(-EAGAIN); } - tp = tcf_chain_tp_find(chain, &chain_info, - protocol, prio, false); + tp = tcf_chain_tp_find(chain, &chain_info, protocol, prio, false, NULL); if (!tp) err = tcf_chain_tp_insert(chain, &chain_info, tp_new); mutex_unlock(&chain->filter_chain_lock); @@ -2018,7 +2018,8 @@ static void tcf_chain_tp_delete_empty(struct tcf_chain *chain, static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain, struct tcf_chain_info *chain_info, u32 protocol, u32 prio, - bool prio_allocate) + bool prio_allocate, + struct netlink_ext_ack *extack) { struct tcf_proto **pprev; struct tcf_proto *tp; @@ -2029,9 +2030,14 @@ static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain, pprev = &tp->next) { if (tp->prio >= prio) { if (tp->prio == prio) { - if (prio_allocate || - (tp->protocol != protocol && protocol)) + if (prio_allocate) { + NL_SET_ERR_MSG(extack, "Lowest ID from auto-alloc range already in use"); + return ERR_PTR(-ENOSPC); + } + if (tp->protocol != protocol && protocol) { + NL_SET_ERR_MSG(extack, "Protocol mismatch for filter with specified priority"); return ERR_PTR(-EINVAL); + } } else { tp = NULL; } @@ -2312,9 +2318,8 @@ static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n, mutex_lock(&chain->filter_chain_lock); tp = tcf_chain_tp_find(chain, &chain_info, protocol, - prio, prio_allocate); + prio, prio_allocate, extack); if (IS_ERR(tp)) { - NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found"); err = PTR_ERR(tp); goto errout_locked; } @@ -2539,10 +2544,13 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n, mutex_lock(&chain->filter_chain_lock); tp = tcf_chain_tp_find(chain, &chain_info, protocol, - prio, false); - if (!tp || IS_ERR(tp)) { + prio, false, extack); + if (!tp) { + err = -ENOENT; NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found"); - err = tp ? PTR_ERR(tp) : -ENOENT; + goto errout_locked; + } else if (IS_ERR(tp)) { + err = PTR_ERR(tp); goto errout_locked; } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) { NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one"); @@ -2679,11 +2687,14 @@ static int tc_get_tfilter(struct sk_buff *skb, struct nlmsghdr *n, mutex_lock(&chain->filter_chain_lock); tp = tcf_chain_tp_find(chain, &chain_info, protocol, - prio, false); + prio, false, extack); mutex_unlock(&chain->filter_chain_lock); - if (!tp || IS_ERR(tp)) { + if (!tp) { + err = -ENOENT; NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found"); - err = tp ? PTR_ERR(tp) : -ENOENT; + goto errout; + } else if (IS_ERR(tp)) { + err = PTR_ERR(tp); goto errout; } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) { NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");