From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73976EB64DA for ; Tue, 4 Jul 2023 17:19:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231889AbjGDRTQ (ORCPT ); Tue, 4 Jul 2023 13:19:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231894AbjGDRTQ (ORCPT ); Tue, 4 Jul 2023 13:19:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0762510CA; Tue, 4 Jul 2023 10:19:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 996696132A; Tue, 4 Jul 2023 17:19:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D770C433C8; Tue, 4 Jul 2023 17:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1688491154; bh=n/1SKK4xF03Yp2pUYhLstwmUNmos1rf2SDsw/6rtFCc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HA9azoRSkkUvt+UmiQiMSjGkaxLNSigeqU6fnbYOgXCsmcCsHmKocuZnx678mFTzv qZPNtEZe431SOIGQj+V1uVsBruwCkya1uSg4+phGuhpI8+eZoMpfiZ9jfKPB11u1Qi +Tjaukf1+7IJsJZbhkB0vvpDqipccP30uh7X3dM1VcvjMOZP0R2nLJbYdrRkZfsun8 Pp4+JYyf4v14vl5zqK6Is8duap+xazjN4BqtRwmMRutsw0SmVgnl15V++RtOQ4bpDh GvLIUlFlCszChveNd5NCySjJAd/6HcvIQswqGFfcMb/yn9aoDNUZknA76fO7EtBqaT Xtz6nXhWEr8sQ== Date: Tue, 4 Jul 2023 20:19:09 +0300 From: Leon Romanovsky To: Dan Carpenter Cc: Guy Levi , Yishai Hadas , Jason Gunthorpe , linux-rdma@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] RDMA/mlx4: Make check for invalid flags stricter Message-ID: <20230704171909.GE6455@unreal> References: <233ed975-982d-422a-b498-410f71d8a101@moroto.mountain> <20230704133841.GD6455@unreal> <359dc6de-2b08-4baa-99cc-d5e5f6e6ce43@kadam.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <359dc6de-2b08-4baa-99cc-d5e5f6e6ce43@kadam.mountain> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Tue, Jul 04, 2023 at 05:07:17PM +0300, Dan Carpenter wrote: > On Tue, Jul 04, 2023 at 04:38:41PM +0300, Leon Romanovsky wrote: > > On Thu, Jun 29, 2023 at 09:07:37AM +0300, Dan Carpenter wrote: > > > This code is trying to ensure that only the flags specified in the list > > > are allowed. The problem is that ucmd->rx_hash_fields_mask is a u64 and > > > the flags are an enum which is treated as a u32 in this context. That > > > means the test doesn't check whether the highest 32 bits are zero. > > > > > > Fixes: 4d02ebd9bbbd ("IB/mlx4: Fix RSS hash fields restrictions") > > > Signed-off-by: Dan Carpenter > > > --- > > > The MLX4_IB_RX_HASH_INNER value is declared as > > > "MLX4_IB_RX_HASH_INNER = 1ULL << 31," which suggests that it > > > should be type ULL but that doesn't work. It will still be basically a > > > u32. (Enum types are weird). > > > > Can you please elaborate more why enum left to be int? It is surprise to me. > > Enum types are not defined very strictly in C so it's up to the > compiler. > > Clang, GCC and Sparse implement them in the same way. They default > to u32 unless the values can't fit, then they become whatever type fits. > So if you have a negative, it becomes an int or a big value changes the > type to unsigned long. > > Since 1ULL < 31 fits in u32 the type is just u32. Thanks for an explanation, I found the relevant sentence in the C standard as well. "The choice of type is implementation-deļ¬ned, 128) but shall be capable of representing the values of all the members of the enumeration." Thanks > > regards, > dan carpenter > > #include > > enum example_one { > VAL = 1ULL << 31, > }; > > enum example_two { > NEGATIVE = -2, > }; > > enum example_three { > BIG = 1ULL << 32, > }; > > int main(void) > { > enum example_one one = -1; > enum example_two two = -1; > enum example_three three = -1; > > printf("%lu\n", sizeof(enum example_one)); > > if (one > 0) > printf("one unsigned\n"); > if (two < 0) > printf("two signed\n"); > > printf("%lu\n", sizeof(enum example_three)); > if (three > 0) > printf("three unsigned\n"); > > return 0; > } > >