From patchwork Fri Apr 29 10:42:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 568523 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 367D7C4332F for ; Fri, 29 Apr 2022 10:45:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345729AbiD2KsW (ORCPT ); Fri, 29 Apr 2022 06:48:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358004AbiD2KsF (ORCPT ); Fri, 29 Apr 2022 06:48:05 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E9B7CA0CE; Fri, 29 Apr 2022 03:43:23 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 77EE6CE31B0; Fri, 29 Apr 2022 10:43:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66A53C385AD; Fri, 29 Apr 2022 10:43:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651228999; bh=EtH3uLb0oVcU5ZA8jXax1Kcu+FfvZi13RlPITGQ6mQA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VX0F8I2C95c21cXJkanT+xOGGwAeOluP8RWBlzh1AxWl8WRQ9x8Z1zRObZHdXvlKN R6a/UV9BpPDxI9OqPWCZfB7+TQHNn20NZfqjoa4T1bE4n4IEtBrynZCUVBUkI6/NIm sqA8WWwOTeDXQBYukOAalFH2R4XH4ABKNN1pS33A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Andreas Gruenbacher , "Darrick J. Wong" , Anand Jain Subject: [PATCH 5.15 25/33] iomap: Support partial direct I/O on user copy failures Date: Fri, 29 Apr 2022 12:42:12 +0200 Message-Id: <20220429104053.068440240@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220429104052.345760505@linuxfoundation.org> References: <20220429104052.345760505@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Andreas Gruenbacher commit 97308f8b0d867e9ef59528cd97f0db55ffdf5651 upstream In iomap_dio_rw, when iomap_apply returns an -EFAULT error and the IOMAP_DIO_PARTIAL flag is set, complete the request synchronously and return a partial result. This allows the caller to deal with the page fault and retry the remainder of the request. Signed-off-by: Andreas Gruenbacher Reviewed-by: Darrick J. Wong Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman --- fs/iomap/direct-io.c | 6 ++++++ include/linux/iomap.h | 7 +++++++ 2 files changed, 13 insertions(+) --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -581,6 +581,12 @@ __iomap_dio_rw(struct kiocb *iocb, struc if (iov_iter_rw(iter) == READ && iomi.pos >= dio->i_size) iov_iter_revert(iter, iomi.pos - dio->i_size); + if (ret == -EFAULT && dio->size && (dio_flags & IOMAP_DIO_PARTIAL)) { + if (!(iocb->ki_flags & IOCB_NOWAIT)) + wait_for_completion = true; + ret = 0; + } + /* magic error code to fall back to buffered I/O */ if (ret == -ENOTBLK) { wait_for_completion = true; --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -330,6 +330,13 @@ struct iomap_dio_ops { */ #define IOMAP_DIO_OVERWRITE_ONLY (1 << 1) +/* + * When a page fault occurs, return a partial synchronous result and allow + * the caller to retry the rest of the operation after dealing with the page + * fault. + */ +#define IOMAP_DIO_PARTIAL (1 << 2) + ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, const struct iomap_dio_ops *dops, unsigned int dio_flags);