From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793214507; b=JbefnzMSyZRQytpzKiP7eKGKRkRw/mBuWK8mNKVzdgTT1pLFwe+Y6tXhOXiccMnNU46/ vq/C2bQ6jmjqF45NKVJyTlRBYgg6aK/umUkkGd4bZCPHDnHCaANlqI9EMri0j8czvwCAV BUxKQn3T0tvt3R978gLiHYI0Rc04b/GpUUJoTCkjC/cQ+I9v7+B1LABfdFwJXJPS02q2m FbkxeFmJBniCwmc2meqc2W9cT5yyunHawz1N6GxQLsA13/3EIJT/ykmFsVug0l0lOD+3b RHs9ydfDPJh94zPWCiixGYIIIx/+m5T2UXDF8AqovFCqoPfMDDfIAqrj7ntuuA0Tjbg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793214507; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=8lBVzV5D1BD4w+8qqLwrQ4xbwykawaJuQf4koQr/OVY=; b=NkGHJ9F0GJyJsG3MvibpQuOSinYM8auYSrLuY1p3HSL0ACzUEOvKXu6I/MyX82diWHbP 20W+iam1K2CTPd5IGwS/TRyX2zwbiHYoEzXxvV9PyRcMSuvrAivZyrv4P1zv3+dRltqIV GW6Z96WQ+LLxMKmtsS977+yLbKGnwHxHL1rKiuxqjJlFzfDy8WFY/niWKsaDJ2ZWRi2ZJ Zy5qptijdeKv1GFKKUXBuTcDU3SyOXesNVNv4bzrgguKyE+Rg8kcJfeZPNxowjFtCz0C4 8dZF4q4LjrlzzUgSD3ItshjzWkqZV7pjHIGi/URLKSPWYNsWTJP57Op9Ncv5Svo7jAg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=NdPdwhGK; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6968A606BFBD; Wed, 28 Oct 2026 19:08:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=NdPdwhGK Received: by smtp.kernel.org (Postfix) with ESMTPSA id 891121F031E1; Wed, 28 Oct 2026 19:08:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793214507; bh=8lBVzV5D1BD4w+8qqLwrQ4xbwykawaJuQf4koQr/OVY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=NdPdwhGKds9qK0eEeWutiFR++VX9+ecEO52X/IAE1OgaG0f4LX3lwtXky4xRFaF5v O59gkg46RZRJDMVyUda5x489zW97WUZlmKsriJ6m8J32XoSQvmX6KX+pY6mJbxNDjP rz0TJb4bJbXaMOa0wygCq0d4ZryygD5fS6UJWvaI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Daniel Starke , Sasha Levin Subject: [PATCH 6.1 0856/1887] tty: n_gsm: introduce macro for minimal unit size Date: Wed, 28 Oct 2026 17:49:12 +0100 Message-ID: <20261028170518.903123487@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170459.200466217@linuxfoundation.org> References: <20261028170459.200466217@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Starke [ Upstream commit 7a1212475f5e313c11300272f34ffa32462bbeef ] n_gsm has a minimal protocol overhead of 7 bytes. The current code already checks whether the configured MRU/MTU size is at least one byte more than this. Introduce the macro MIN_MTU to make this value more obvious. Signed-off-by: Daniel Starke Link: https://lore.kernel.org/r/20221103091743.2119-1-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 3cf0b3c243e5 ("tty: n_gsm: Don't block input queue by waiting MSC") Signed-off-by: Sasha Levin --- drivers/tty/n_gsm.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index fc52a7a38df32..165a70ab1f004 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -89,6 +89,7 @@ module_param(debug, int, 0600); */ #define MAX_MRU 1500 #define MAX_MTU 1500 +#define MIN_MTU (PROT_OVERHEAD + 1) /* SOF, ADDR, CTRL, LEN1, LEN2, ..., FCS, EOF */ #define PROT_OVERHEAD 7 #define GSM_NET_TX_TIMEOUT (HZ*10) @@ -2771,7 +2772,9 @@ static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) if ((c->adaption != 1 && c->adaption != 2) || c->k) return -EOPNOTSUPP; /* Check the MRU/MTU range looks sane */ - if (c->mru > MAX_MRU || c->mtu > MAX_MTU || c->mru < 8 || c->mtu < 8) + if (c->mru < MIN_MTU || c->mtu < MIN_MTU) + return -EINVAL; + if (c->mru > MAX_MRU || c->mtu > MAX_MTU) return -EINVAL; if (c->n2 > 255) return -EINVAL; @@ -3360,7 +3363,7 @@ static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) return -ENOMEM; } net->mtu = dlci->gsm->mtu; - net->min_mtu = 8; + net->min_mtu = MIN_MTU; net->max_mtu = dlci->gsm->mtu; mux_net = netdev_priv(net); mux_net->dlci = dlci; -- 2.53.0