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 55F6D18B14 for ; Sat, 7 Oct 2023 15:57:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nBd1o104" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48388C433C7; Sat, 7 Oct 2023 15:57:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696694254; bh=FdT0hRiVUetymc4htP5coHs/oBEZ3Uyq+kymb8Y2DpQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nBd1o104P6neQxI5O+GltjAU3rrUklfWY8d2142pc/H7mAqrbdQu02oK2QjMNS/M7 YiGP5Ro+vzKL8/E3g2d1Ctkd6QpA6WdK+uQOGn9/1JANxW8aAJZ3XULf0TmSoPAaXG r6SMq0pwVsOW/R2cr/mKSVu5UIh/ff5OzwDtbq8TbXgiwKvpUmB4zkwCkvziWzy6sp HalIoKSTqTDanMYRlnx465Cb9/xomChLFzTnAO5n2TE0CS3ukSsDcrr2FcEtoW2bRu BdNAnqdw6H7/YBba6/p4azRz70rNmkWITuxORN795qPnDm0OybnccFMMD+tu5NRePF cC6dZnQa5Fnbw== Date: Sat, 7 Oct 2023 17:57:30 +0200 From: Simon Horman To: =?utf-8?B?S8O2cnk=?= Maincent Cc: "David S. Miller" , Michal Kubecek , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Maxime Chevallier , thomas.petazzoni@bootlin.com, Eric Dumazet , Jakub Kicinski , Paolo Abeni Subject: Re: [PATCH net v2 1/1] ethtool: Fix mod state of verbose no_mask bitset Message-ID: <20231007155730.GF831234@kernel.org> References: <20231006141246.3747944-1-kory.maincent@bootlin.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20231006141246.3747944-1-kory.maincent@bootlin.com> On Fri, Oct 06, 2023 at 04:12:46PM +0200, Köry Maincent wrote: > From: Kory Maincent > > A bitset without mask in a _SET request means we want exactly the bits in > the bitset to be set. This works correctly for compact format but when > verbose format is parsed, ethnl_update_bitset32_verbose() only sets the > bits present in the request bitset but does not clear the rest. The commit > 6699170376ab fixes this issue by clearing the whole target bitmap before we > start iterating. The solution proposed brought an issue with the behavior > of the mod variable. As the bitset is always cleared the old val will > always differ to the new val. > > Fix it by adding a new temporary variable which save the state of the old > bitmap. > > Fixes: 6699170376ab ("ethtool: fix application of verbose no_mask bitset") > Signed-off-by: Kory Maincent > --- > > Changes in v2: > - Fix the allocated size. > --- > net/ethtool/bitset.c | 31 +++++++++++++++++++++++++------ > 1 file changed, 25 insertions(+), 6 deletions(-) > > diff --git a/net/ethtool/bitset.c b/net/ethtool/bitset.c > index 0515d6604b3b..8a6b35c920cd 100644 > --- a/net/ethtool/bitset.c > +++ b/net/ethtool/bitset.c > @@ -432,7 +432,9 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits, > struct netlink_ext_ack *extack, bool *mod) > { > struct nlattr *bit_attr; > + u32 *tmp = NULL; > bool no_mask; > + bool dummy; > int rem; > int ret; > > @@ -448,8 +450,16 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits, > } > > no_mask = tb[ETHTOOL_A_BITSET_NOMASK]; > - if (no_mask) > - ethnl_bitmap32_clear(bitmap, 0, nbits, mod); > + if (no_mask) { > + unsigned int nwords = DIV_ROUND_UP(nbits, 32); > + unsigned int nbytes = nwords * sizeof(u32); Hi Köry, Thanks for addressing my concerns regarding the size calculations in v1. I think that a comment is warranted describing the fact that only the map, and not the mask part, is taken into account in the size calculations above. > + > + tmp = kcalloc(nwords, sizeof(u32), GFP_KERNEL); > + if (!tmp) > + return -ENOMEM; > + memcpy(tmp, bitmap, nbytes); > + ethnl_bitmap32_clear(bitmap, 0, nbits, &dummy); > + } Perhaps we could consider something line the following. Which would avoid the need for the n_mask condition in the nla_for_each_nested() loop further below. ... saved_bitmap = kcalloc(nwords, sizeof(u32), GFP_KERNEL); if (!saved_bitmap) return -ENOMEM; memcpy(saved_bitmap, bitmap, nbytes); ethnl_bitmap32_clear(bitmap, 0, nbits, &dummy); orig_bitmap = saved_bitmap; } else { orig_bitmap = bitmap; } (Choosing names for variables seems hard today.) > > nla_for_each_nested(bit_attr, tb[ETHTOOL_A_BITSET_BITS], rem) { > bool old_val, new_val; > @@ -458,13 +468,19 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits, > if (nla_type(bit_attr) != ETHTOOL_A_BITSET_BITS_BIT) { > NL_SET_ERR_MSG_ATTR(extack, bit_attr, > "only ETHTOOL_A_BITSET_BITS_BIT allowed in ETHTOOL_A_BITSET_BITS"); > - return -EINVAL; > + ret = -EINVAL; > + goto out; > } > ret = ethnl_parse_bit(&idx, &new_val, nbits, bit_attr, no_mask, > names, extack); > if (ret < 0) > - return ret; > - old_val = bitmap[idx / 32] & ((u32)1 << (idx % 32)); > + goto out; > + > + if (no_mask) > + old_val = tmp[idx / 32] & ((u32)1 << (idx % 32)); > + else > + old_val = bitmap[idx / 32] & ((u32)1 << (idx % 32)); > + > if (new_val != old_val) { > if (new_val) > bitmap[idx / 32] |= ((u32)1 << (idx % 32)); > @@ -474,7 +490,10 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits, > } > } > > - return 0; > + ret = 0; > +out: > + kfree(tmp); > + return ret; > } > > static int ethnl_compact_sanity_checks(unsigned int nbits, > -- > 2.25.1 >