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 AF64A1DEFF3 for ; Tue, 11 Mar 2025 04:36:53 +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=1741667814; cv=none; b=XNbxIE0C7i8w+eZW2O8KGVAo6P6+vIuDD31lkhKvr6/HM7yOga9FkhcY05i/Wux0SAffc8gCYA7Bc28r5vi6OeSCu7ZK3MxdHqEIq9SUUB1OQoioaT8pBQtmdrg8ohNLfVMfRQM9scuLmJQs3w182nLd2qr3u2Wa88iHQSao5T4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741667814; c=relaxed/simple; bh=c4W81ZvmYn9grfmgsES+E1br7CFkxMQFDhCQVqvxjcE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KJb/eaZumQdqqVkepin+8twJy0av3FPeG647Ts9be0m0xgm96rl1cnszzCFsKQ8HaSmEqS0SWaahMQOxDR+omj5AfBMPFVKAbMgGIKH219hzdtR7NVBSj1mIjYaZeCYu3ztmYHVQsDHrYfMXHR7UGwezn9M8Qb9SULN34metxCw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=st91uS89; 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="st91uS89" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FD81C4CEE9; Tue, 11 Mar 2025 04:36:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741667813; bh=c4W81ZvmYn9grfmgsES+E1br7CFkxMQFDhCQVqvxjcE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=st91uS89oHB0qqmfaHxdvwEiYwBP9M3t5qjMKVG8Dv6MkLW3fpE4ZuvKrG6X2TNOs KLruV+J4SmveSau9gW+oHGKiRYbQX7sqxWJ4DAHkTxAVNRY6ajllnsxa3o7QGevAyC OJksXNoeLsMiBGzwLrXkUYGmvG4sDkbIOzSQeswSQz1lzwC//aqPwUXEyl3xjkivwf tXB4qqQbhRiJjwxXLUXLBSyCgJ8f4xESAoVkmC8jZkcXrbwu7XfRJ5q6mI2VEr4hi0 0g7pR85ydjIQ1fL1j3BqdL7zQsCDoW+ToIjIUrIHN7Em6br55fLWtLOMSgPJKErOA4 cHoDl/mf2hvYw== Date: Mon, 10 Mar 2025 21:36:51 -0700 From: Eric Biggers To: Herbert Xu Cc: Linux Crypto Mailing List Subject: Re: [v2 PATCH 2/3] crypto: scatterwalk - Add memcpy_sglist Message-ID: <20250311043651.GA1263@sol.localdomain> References: <18a6df64615a10be64c3c902f8b1f36e472548d7.1741318360.git.herbert@gondor.apana.org.au> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <18a6df64615a10be64c3c902f8b1f36e472548d7.1741318360.git.herbert@gondor.apana.org.au> On Fri, Mar 07, 2025 at 11:36:19AM +0800, Herbert Xu wrote: > Add memcpy_sglist which copies one SG list to another. > > Signed-off-by: Herbert Xu > --- > crypto/scatterwalk.c | 27 +++++++++++++++++++++++++++ > include/crypto/scatterwalk.h | 3 +++ > 2 files changed, 30 insertions(+) > > diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c > index 20a28c6d94da..8225801488d5 100644 > --- a/crypto/scatterwalk.c > +++ b/crypto/scatterwalk.c > @@ -86,6 +86,33 @@ void memcpy_to_sglist(struct scatterlist *sg, unsigned int start, > } > EXPORT_SYMBOL_GPL(memcpy_to_sglist); > > +void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src, > + unsigned int nbytes) > +{ > + struct scatter_walk swalk; > + struct scatter_walk dwalk; > + > + if (unlikely(nbytes == 0)) /* in case sg == NULL */ > + return; > + > + scatterwalk_start(&swalk, src); > + scatterwalk_start(&dwalk, dst); > + > + do { > + unsigned int slen, dlen; > + unsigned int len; > + > + slen = scatterwalk_next(&swalk, nbytes); > + dlen = scatterwalk_next(&dwalk, nbytes); > + len = min(slen, dlen); > + memcpy(dwalk.addr, swalk.addr, len); > + scatterwalk_done_dst(&dwalk, len); > + scatterwalk_done_src(&swalk, len); > + nbytes -= len; > + } while (nbytes); > +} > +EXPORT_SYMBOL_GPL(memcpy_sglist); Actually this new function is useless as-is, since it invokes undefined behavior when the source and destination coincide (which can happen even when src == dst), and all the potential callers need to handle that case. I'm working on a fixed version. - Eric