From patchwork Fri Oct 28 02:33:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 13022984 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 96BAAFA3748 for ; Fri, 28 Oct 2022 02:34:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235011AbiJ1CeV (ORCPT ); Thu, 27 Oct 2022 22:34:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46422 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235884AbiJ1CeP (ORCPT ); Thu, 27 Oct 2022 22:34:15 -0400 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [IPv6:2a03:a000:7:0:5054:ff:fe1c:15ff]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CEE2BCBAE; Thu, 27 Oct 2022 19:34:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=2hrSO3obB1hPkB2I0g2avezDzM2fxuFWF0A6F6V6oiI=; b=Njb6lBV8/KytFxKCtx4nRVXc9F kg32OMF1Dar/iY6MkQvzhWxWZtBBEFetkJQxWiAiI/owJl+iRKMz5cOL5TqFy2mRFA1DzuzA2r/S6 LP5e5IEPI+ERoRpojDceUxwo8DfhigLXuHI4eio7JFbAM5SUuG23YpV/Ss0TTIM5MpAvJM7n6ARpg 6JtR8E6iGH4bZNs1mZpch6H3+d4gSj7PMw8UH3NDV/1vbHj6CN2uwV9yB21pC4o8JtEPVCqQLg5Vf Qg0u3NufIClP+vM5uoUQsaK8LEJYGdcCnv0j04wGYT/QOpm1vEAMIbO8DE1HH+FEsJvhjaV3nNwJb 1244xkZQ==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1ooFBw-00EorB-1H; Fri, 28 Oct 2022 02:33:52 +0000 From: Al Viro To: Christoph Hellwig Cc: David Howells , willy@infradead.org, dchinner@redhat.com, Steve French , Shyam Prasad N , Rohith Surabattula , Jeff Layton , Ira Weiny , torvalds@linux-foundation.org, linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 02/12] csum_and_copy_to_iter(): handle ITER_DISCARD Date: Fri, 28 Oct 2022 03:33:42 +0100 Message-Id: <20221028023352.3532080-2-viro@zeniv.linux.org.uk> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221028023352.3532080-1-viro@zeniv.linux.org.uk> References: <20221028023352.3532080-1-viro@zeniv.linux.org.uk> MIME-Version: 1.0 Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Not hard to implement - we are not copying anything here, so csum_and_memcpy() is not usable, but calculating a checksum of source directly is trivial... Signed-off-by: Al Viro --- lib/iov_iter.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index e9a8fc9ee8ee..020e009d71c5 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1549,8 +1549,12 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, __wsum sum, next; if (unlikely(iov_iter_is_discard(i))) { - WARN_ON(1); /* for now */ - return 0; + // can't use csum_memcpy() for that one - data is not copied + csstate->csum = csum_block_add(csstate->csum, + csum_partial(addr, bytes, 0), + csstate->off); + csstate->off += bytes; + return bytes; } sum = csum_shift(csstate->csum, csstate->off);