From patchwork Mon Mar 27 23:27:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13190234 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 7D7B0C761A6 for ; Mon, 27 Mar 2023 23:27:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230514AbjC0X1j (ORCPT ); Mon, 27 Mar 2023 19:27:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230220AbjC0X1c (ORCPT ); Mon, 27 Mar 2023 19:27:32 -0400 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16E3B2723 for ; Mon, 27 Mar 2023 16:27:26 -0700 (PDT) Received: by mail-pj1-x1034.google.com with SMTP id lr16-20020a17090b4b9000b0023f187954acso10695850pjb.2 for ; Mon, 27 Mar 2023 16:27:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1679959645; x=1682551645; 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=kguXiZPFcvLxJWrtyUvMfJvLBJN9Ay1HNtZpd3doRKU=; b=oudBH5W1YN7luLtpSU6havksFDdCltkYkitZ66kKZEwqtJauy6VPvCVeuVpvEurLEv s29FljZyUQJ7lWExCkoDNsRFq3+yBwse8uHXRlxNGbk2IuKmtAiItlA5FFTkBvBYrXCY CtGv1lNIrGpgZ91fxxvFQ+Vbzd2cSjqiqmAOTdPWZVbPBV4lVNUVsC1DHGf7puqRUFoO BJFeChHwj1Bzgrbg4wXhMngsCRL7beXhjWd0utPtemMXTQGGYIVaPtGBsf9p7JVIve6q xLTOKEeZZISK7n21wTpVI4vM5BJYPJGTM09Pw5Uf2OH/NgxISY8uNwxmeFd8ixpzNH4i M8tg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679959645; x=1682551645; 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=kguXiZPFcvLxJWrtyUvMfJvLBJN9Ay1HNtZpd3doRKU=; b=k4GMfVdY2rmFKtxwFnEiONRgreLeOFGOrBIfi+r5vsDOQu5CA46WGBNjmR8f/gkGzR OugwmNGYEv1oGL2jmJ99cJz6s/fiIVO/Qa75nrNRwU4evtCQfWdietkl49GhQIX9+1gv R5dcqlWtMCfLOww107VtMVDr+Qz8IBJdMps/VDvD0LZEUGdEbBZhta6uy5cSjue9McO/ Jzoyv/pW8mpo11cxZmEWw0oFpMihYqlo1l11LYg9K+gCxg4Bd6DoeRcEbRsgyVTvB7dQ mgTojbGnySvfaPKhBRRDKB6NCvQwqPgYRu5ZX8RBnybR4/kkS8uYQ4yqLZT1K7qiyeZu AO2A== X-Gm-Message-State: AAQBX9fpLdBX8Ov3w7eYr9rovmnBHEPJSDNgbJmM1Y2+2icC0eDRF3LS g0E52gV8bfejmHAjQd7j/6qnWYMEXlu6PwmGjoFXCA== X-Google-Smtp-Source: AKy350ZZlUS/vQzXVfCu/6DG10e1c/E30kpBAbfbpaB5nPmBlRHTZQK7hLQUYFl+pUCRhkTaGyTc4g== X-Received: by 2002:a17:902:b607:b0:1a2:6092:2193 with SMTP id b7-20020a170902b60700b001a260922193mr562802pls.4.1679959645229; Mon, 27 Mar 2023 16:27:25 -0700 (PDT) Received: from localhost.localdomain ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id s14-20020a170902b18e00b001a1ccb37847sm15534222plr.146.2023.03.27.16.27.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Mar 2023 16:27:24 -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 1/3] iov_iter: teach iov_iter_iovec() to deal with ITER_UBUF Date: Mon, 27 Mar 2023 17:27:11 -0600 Message-Id: <20230327232713.313974-2-axboe@kernel.dk> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230327232713.313974-1-axboe@kernel.dk> References: <20230327232713.313974-1-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. This is done in preparation for automatically importing single segment iovecs as ITER_UBUF. 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,