From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F886C433E0 for ; Wed, 24 Feb 2021 20:03:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D3E264F27 for ; Wed, 24 Feb 2021 20:03:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235186AbhBXUDR (ORCPT ); Wed, 24 Feb 2021 15:03:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:55472 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235242AbhBXUC1 (ORCPT ); Wed, 24 Feb 2021 15:02:27 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4132D64E7A; Wed, 24 Feb 2021 20:01:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614196906; bh=G/hO3Rnc1ew2BsKhMRd+zRTTHSdeEe5zj0NmD4Ixw64=; h=Date:From:To:Subject:In-Reply-To:From; b=EQYjTzH+iKQGk53pf7Zsh36awevfIq5t1FcXGf6MmQMD0ybpgBHfLFwtRl2LU4Tv0 cad4VzJnxt+ALywiAqXycpdT92itcCh7z0nBpuTS4kcXYsPNKCTfoCyPcwM/8NJ1+Z sa2p3yiTIIaoOF9G16lRd3JYtCwvfiesDWdGSdUU= Date: Wed, 24 Feb 2021 12:01:45 -0800 From: Andrew Morton To: akpm@linux-foundation.org, asml.silence@gmail.com, axboe@kernel.dk, hch@lst.de, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk Subject: [patch 029/173] mm/filemap: don't revert iter on -EIOCBQUEUED Message-ID: <20210224200145.tzDYWtTYF%akpm@linux-foundation.org> In-Reply-To: <20210224115824.1e289a6895087f10c41dd8d6@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Pavel Begunkov Subject: mm/filemap: don't revert iter on -EIOCBQUEUED Currently, if I/O is enqueued for async execution direct paths of generic_file_{read,write}_iter() will always revert the iter. There are no users expecting that, and that is also costly. Leave iterators as is on -EIOCBQUEUED. Link: https://lkml.kernel.org/r/f5247b60e7abbd2ff850cd108491f53a2e0c501a.1610207781.git.asml.silence@gmail.com Signed-off-by: Pavel Begunkov Reviewed-by: Christoph Hellwig Cc: Al Viro Cc: Jens Axboe Signed-off-by: Andrew Morton --- mm/filemap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/filemap.c~mm-filemap-dont-revert-iter-on-eiocbqueued +++ a/mm/filemap.c @@ -2615,7 +2615,8 @@ generic_file_read_iter(struct kiocb *ioc iocb->ki_pos += retval; count -= retval; } - iov_iter_revert(iter, count - iov_iter_count(iter)); + if (retval != -EIOCBQUEUED) + iov_iter_revert(iter, count - iov_iter_count(iter)); /* * Btrfs can have a short DIO read if we encounter @@ -3426,7 +3427,8 @@ generic_file_direct_write(struct kiocb * } iocb->ki_pos = pos; } - iov_iter_revert(from, write_len - iov_iter_count(from)); + if (written != -EIOCBQUEUED) + iov_iter_revert(from, write_len - iov_iter_count(from)); out: return written; } _