From patchwork Tue Mar 28 21:58:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13191591 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 C2924C6FD18 for ; Tue, 28 Mar 2023 21:58:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229958AbjC1V6X (ORCPT ); Tue, 28 Mar 2023 17:58:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55406 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229975AbjC1V6S (ORCPT ); Tue, 28 Mar 2023 17:58:18 -0400 Received: from mail-pl1-x62a.google.com (mail-pl1-x62a.google.com [IPv6:2607:f8b0:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 56CDADE for ; Tue, 28 Mar 2023 14:58:17 -0700 (PDT) Received: by mail-pl1-x62a.google.com with SMTP id d9443c01a7336-1a25eabf3f1so892365ad.0 for ; Tue, 28 Mar 2023 14:58:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1680040697; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=BLSXksapHQJHwuesIk/XJE3QbuW+vdF3HCe0ZJppDrI=; b=oVPmmwlI2dvn8+WmkC37EqP4r+18J/8/XG5fJd5DqPym0TTne/xJSDXPmaYIADKlHQ o/XezQjHqI5SuTTNF/dwFVkoCwvOHDYnqnsTX5OTq7ap7m4eRXN6GgYpNjaidhlJeBOk iTvWnPlzFAKYZKtKtKo+Q0tQDCvmYyPu0YSlxjKnQfRqCxecXpQe0IbKC5abGAs79ziR 0HULkSUdZedgR7pGiM3obIGSVnjAvvOKqKSGab6vTZi07MUyNcQsJ6Pj3YGQmWUMZppC t46JgsEdoQqc2whuLXhAjE4VFM1PEOZTQz6scloYkX+fYy8MebZJUitiASH594TswI1o U2jA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680040697; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=BLSXksapHQJHwuesIk/XJE3QbuW+vdF3HCe0ZJppDrI=; b=e1KaQX6GihXkTC5OMYj0HaYjAghS+fh4Pdh2TbYHL21hZcA/7DTXqgYSl3NdvwGKJd 1OYHDp7MHl2nXaLjZY/bJHMGTFJ5gg1f6huU8g+G0i89+lCl6YYg6SPTe5bSMYHmMCfR Ldx09hEpgYeCEJ6v7rTMSKwA5n/9qNTj5OPiPsjhedx10RDAAciEFAPuJSs8KTpoUZ+b 1HnASi5kTkSwWGwS6cfS7X2P3MgPT7+UCHPCcb34WOsAJrcHU6e/00xJs0IMvU2JWOPO q91D0/9xaKQlmQX0/NMBVBRVCorrky3KDMMDUUu4ibbhUHyIf7aHcUTuQDcTz1bs35UF b7RQ== X-Gm-Message-State: AAQBX9d1qhb+2rZZzxQ7LuqL3DZ4nMdT4CDczy2V4S3Y7+9IbESDgc1I 0GR/7VeNd2ZEAwNAdoTBFJsesbF9jVP1ij4jWH71+Q== X-Google-Smtp-Source: AKy350YpPlylR1kkDcOiYdyCp8k1z5f6to2vT+vKUXz/rFvQwCn6momKviBLdxto084ZL81BpBEOaw== X-Received: by 2002:a17:902:864b:b0:1a1:d395:e85c with SMTP id y11-20020a170902864b00b001a1d395e85cmr14142422plt.0.1680040696742; Tue, 28 Mar 2023 14:58:16 -0700 (PDT) Received: from localhost.localdomain ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id t20-20020a1709028c9400b001a04b92ddffsm21560171plo.140.2023.03.28.14.58.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Mar 2023 14:58:16 -0700 (PDT) From: Jens Axboe To: linux-fsdevel@vger.kernel.org Cc: torvalds@linux-foundation.org, brauner@kernel.org, viro@zeniv.linux.org.uk, Jens Axboe Subject: [PATCH 2/9] iov_iter: teach iov_iter_iovec() to deal with ITER_UBUF Date: Tue, 28 Mar 2023 15:58:04 -0600 Message-Id: <20230328215811.903557-3-axboe@kernel.dk> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230328215811.903557-1-axboe@kernel.dk> References: <20230328215811.903557-1-axboe@kernel.dk> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Even if we're returning an iovec, we can trivially fill it in with the details from an ITER_UBUF as well. This enables loops that assume ITER_IOVEC to deal with ITER_UBUF transparently. Suggested-by: Al Viro Signed-off-by: Jens Axboe --- include/linux/uio.h | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/include/linux/uio.h b/include/linux/uio.h index 27e3fd942960..3b4403efcce1 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -143,13 +143,29 @@ static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs) return ret; } +/* + * Don't assume we're called with ITER_IOVEC, enable usage of ITER_UBUF + * as well by simply filling in the iovec. + */ static inline struct iovec iov_iter_iovec(const struct iov_iter *iter) { - return (struct iovec) { - .iov_base = iter->iov->iov_base + iter->iov_offset, - .iov_len = min(iter->count, - iter->iov->iov_len - iter->iov_offset), - }; + if (WARN_ON_ONCE(!iter->user_backed)) { + return (struct iovec) { + .iov_base = NULL, + .iov_len = 0 + }; + } else if (iter_is_ubuf(iter)) { + return (struct iovec) { + .iov_base = iter->ubuf + iter->iov_offset, + .iov_len = iter->count + }; + } else { + return (struct iovec) { + .iov_base = iter->iov->iov_base + iter->iov_offset, + .iov_len = min(iter->count, + iter->iov->iov_len - iter->iov_offset), + }; + } } size_t copy_page_from_iter_atomic(struct page *page, unsigned offset,