From patchwork Tue May 26 19:51:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 11571179 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D79C3159A for ; Tue, 26 May 2020 19:52:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE4A4207D8 for ; Tue, 26 May 2020 19:52:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="bmGfUVJW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389257AbgEZTvi (ORCPT ); Tue, 26 May 2020 15:51:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389290AbgEZTvf (ORCPT ); Tue, 26 May 2020 15:51:35 -0400 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AFCBC03E979 for ; Tue, 26 May 2020 12:51:34 -0700 (PDT) Received: by mail-pj1-x1043.google.com with SMTP id z15so279298pjb.0 for ; Tue, 26 May 2020 12:51:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ooHBrOZD/3Y3JOqiI+j5WGnGx9rNLKp4UPlTrA3k0fA=; b=bmGfUVJWYu6f/+lClc0yvwBvsEefc8SiuJxE38gUHmvCG67ZCMQ1ZoFC93WjnhwWQ4 yZg7fQlvm/Sucx7ncKy3qvV98rMGm86zWQnvA8hq14lOsPQmzOry1k+ft5gveL4FUJQL gaUBcnu8T8B55uU9BUZgRqOrmN0p82G3CTFOtVxJUrhxYK5Gn/8JEk4HKkHRhEAIvpxF 8iJj/6xBx4Ipgxa4B/+4ClHWKS0rVZdsYpFYzgcgIZxh9GvRIk8QENgpCADWhtcWb7U6 btJvYpMYxIv2afcSGCvbCXlq8oQ8SvKxQmlD9hcdrFZzniK3vSqmkl4k4ZoCvIJr0Avu Vabw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ooHBrOZD/3Y3JOqiI+j5WGnGx9rNLKp4UPlTrA3k0fA=; b=fz6lrTVMVndy8uidKhFa94BqCsX+8V1ic7DzgOKjNswMn0MDIIzlL2YBBvG3AqmgMc ZuZRqLPehqye3kOv68UnabhaayD+g/XV0M5vfBXfhv7H0+wE9RvC7OqQIQodJX9ZiF5a iukIvNjp6w42i1fgxXmTtM01XMEUoA28bSYgtcHNN254a35MuiczZ3SHpjs2Zwco+K2e rlpA3TlID2XkbFMmKlM+93ZLob1r2coPYGjNM90f1GEdzAcFvd5Bny/vBm2n3TPJkoMz DPYgYRyUm3ly8E00DmsCGQ1/Sx93JOfgDoTYh5rVnA4pvodr7WcXn9WkoadJz5UNLIKI mNZg== X-Gm-Message-State: AOAM532LiklAT1KrU/amX0QdTJgx3MNfyWKW/ht199NJassiNLGII6p4 t3vGqQWJkG3iVZ9+jfZBsDBERw== X-Google-Smtp-Source: ABdhPJwGQ4LouRwKTJPsAC18WrHUCMfjZtLRZJD5qeryOylS8TBNaNMGloP6eX183Bgo+/GUML+3Rg== X-Received: by 2002:a17:902:b110:: with SMTP id q16mr1318137plr.221.1590522693552; Tue, 26 May 2020 12:51:33 -0700 (PDT) Received: from x1.lan ([2605:e000:100e:8c61:94bb:59d2:caf6:70e1]) by smtp.gmail.com with ESMTPSA id c184sm313943pfc.57.2020.05.26.12.51.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 May 2020 12:51:33 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, Jens Axboe Subject: [PATCH 05/12] mm: support async buffered reads in generic_file_buffered_read() Date: Tue, 26 May 2020 13:51:16 -0600 Message-Id: <20200526195123.29053-6-axboe@kernel.dk> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200526195123.29053-1-axboe@kernel.dk> References: <20200526195123.29053-1-axboe@kernel.dk> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Use the async page locking infrastructure, if IOCB_WAITQ is set in the passed in iocb. The caller must expect an -EIOCBQUEUED return value, which means that IO is started but not done yet. This is similar to how O_DIRECT signals the same operation. Once the callback is received by the caller for IO completion, the caller must retry the operation. Signed-off-by: Jens Axboe Acked-by: Johannes Weiner --- mm/filemap.c | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index c746541b1d49..18022de7dc33 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1219,6 +1219,14 @@ static int __wait_on_page_locked_async(struct page *page, return ret; } +static int wait_on_page_locked_async(struct page *page, + struct wait_page_queue *wait) +{ + if (!PageLocked(page)) + return 0; + return __wait_on_page_locked_async(compound_head(page), wait, false); +} + /** * put_and_wait_on_page_locked - Drop a reference and wait for it to be unlocked * @page: The page to wait for. @@ -2058,17 +2066,25 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb, index, last_index - index); } if (!PageUptodate(page)) { - if (iocb->ki_flags & IOCB_NOWAIT) { - put_page(page); - goto would_block; - } - /* * See comment in do_read_cache_page on why * wait_on_page_locked is used to avoid unnecessarily * serialisations and why it's safe. */ - error = wait_on_page_locked_killable(page); + if (iocb->ki_flags & IOCB_WAITQ) { + if (written) { + put_page(page); + goto out; + } + error = wait_on_page_locked_async(page, + iocb->ki_waitq); + } else { + if (iocb->ki_flags & IOCB_NOWAIT) { + put_page(page); + goto would_block; + } + error = wait_on_page_locked_killable(page); + } if (unlikely(error)) goto readpage_error; if (PageUptodate(page)) @@ -2156,7 +2172,10 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb, page_not_up_to_date: /* Get exclusive access to the page ... */ - error = lock_page_killable(page); + if (iocb->ki_flags & IOCB_WAITQ) + error = lock_page_async(page, iocb->ki_waitq); + else + error = lock_page_killable(page); if (unlikely(error)) goto readpage_error;