From patchwork Tue Dec 17 14:39:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 11297765 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 A76D96C1 for ; Tue, 17 Dec 2019 14:39:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 775552467B for ; Tue, 17 Dec 2019 14:39:58 +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="tLwP2zT0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728667AbfLQOj5 (ORCPT ); Tue, 17 Dec 2019 09:39:57 -0500 Received: from mail-il1-f196.google.com ([209.85.166.196]:38835 "EHLO mail-il1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727926AbfLQOjy (ORCPT ); Tue, 17 Dec 2019 09:39:54 -0500 Received: by mail-il1-f196.google.com with SMTP id f5so8547061ilq.5 for ; Tue, 17 Dec 2019 06:39:54 -0800 (PST) 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=EOt7OEDxASzJpz4aW2OtR1NM6hhZ1aYaA0R6ITxPWMg=; b=tLwP2zT0MtI2kOTe48uSomwZIjJUT0pySzMCDXzO1sNdjdjOCFI1XHkUHEOozqFc8c nD8w1OUooAyprmV1auAjotvgf/lwQQgtJmjU0OOuifVAcFA6tNABcFtRb6VTMGQNvXW8 R+UIQQhagkuaIdQ7XtSKY2NXtNhP26jjoETMW/zxAtTmWwRpQW/LEGudNmZGscJC8QcP 5bfFqpV+WXfMvXGjvCr86gr0YU9WkuoxK8tJyuGnk+U8na/TmrO8XsxhHpezKrsvh+V8 wbxIlP/OlD3s6ghZTqeNhQeYNghwcPJnzfXH2JT64KUq2IgoyaXWFWMfddWHwG8HGDQK 3y0A== 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=EOt7OEDxASzJpz4aW2OtR1NM6hhZ1aYaA0R6ITxPWMg=; b=nbaNJTkRN7BW0xETGnOC83IwWCJyh3S1kXnEvtqwZ3wG+N9J/Eevz0I93Fd0NNuVqI 5tGfRgMU7cJ5ElJAE118qTQHT2IxPlXEvNoJc6A9TT8mlgJz4dxO3/g2HQbb0+A9ISkC lbElVNF1jemZqltC3sCP4lhGodo9m933WBQ6LCB2MIJKXBlIxtMDaso08JYvI68pjgLA TIJ1SIqX7J+/MhtuXB+Q24RrgmMQo9lZnMU1oTrMYIpP97oc7lnOgqEDQWwxBnDSNv07 zZEBRGjPiQK/pscSysLLQNnuKAvViKjSJw5Cjif73m9JS5+Eya3ciFFCaSkfvkRjpijE UpXQ== X-Gm-Message-State: APjAAAXDOw5iMthm/d9ppj96r7rDWnGgr0Jc7BdZTXQ1HbOkka5KpP0F Ai05WiNnHxV+O+MtZkwkqbLwZwwKYEa5FA== X-Google-Smtp-Source: APXvYqy373igjl5RaNDqw4GXVKR/B2FPaCQeTRyE7cK02n7sdyI5xVepqdHZGKv7py+DgJxlDb4Q6Q== X-Received: by 2002:a92:cb11:: with SMTP id s17mr10211920ilo.114.1576593593985; Tue, 17 Dec 2019 06:39:53 -0800 (PST) Received: from x1.thefacebook.com ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id w21sm5285255ioc.34.2019.12.17.06.39.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Dec 2019 06:39:53 -0800 (PST) From: Jens Axboe To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org Cc: willy@infradead.org, clm@fb.com, torvalds@linux-foundation.org, david@fromorbit.com, Jens Axboe Subject: [PATCH 3/6] mm: make buffered writes work with RWF_UNCACHED Date: Tue, 17 Dec 2019 07:39:45 -0700 Message-Id: <20191217143948.26380-4-axboe@kernel.dk> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191217143948.26380-1-axboe@kernel.dk> References: <20191217143948.26380-1-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 If RWF_UNCACHED is set for io_uring (or pwritev2(2)), we'll drop the cache instantiated for buffered writes. If new pages aren't instantiated, we leave them alone. This provides similar semantics to reads with RWF_UNCACHED set. Signed-off-by: Jens Axboe --- include/linux/fs.h | 1 + mm/filemap.c | 41 +++++++++++++++++++++++++++++++++++++++-- 2 files changed, 40 insertions(+), 2 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index bf58db1bc032..5ea5fc167524 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -285,6 +285,7 @@ enum positive_aop_returns { #define AOP_FLAG_NOFS 0x0002 /* used by filesystem to direct * helper code (eg buffer layer) * to clear GFP_FS from alloc */ +#define AOP_FLAG_UNCACHED 0x0004 /* * oh the beauties of C type declarations. diff --git a/mm/filemap.c b/mm/filemap.c index 522152ed86d8..0b5f29b30c34 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3277,10 +3277,12 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping, pgoff_t index, unsigned flags) { struct page *page; - int fgp_flags = FGP_LOCK|FGP_WRITE|FGP_CREAT; + int fgp_flags = FGP_LOCK|FGP_WRITE; if (flags & AOP_FLAG_NOFS) fgp_flags |= FGP_NOFS; + if (!(flags & AOP_FLAG_UNCACHED)) + fgp_flags |= FGP_CREAT; page = pagecache_get_page(mapping, index, fgp_flags, mapping_gfp_mask(mapping)); @@ -3301,6 +3303,9 @@ ssize_t generic_perform_write(struct file *file, ssize_t written = 0; unsigned int flags = 0; + if (iocb->ki_flags & IOCB_UNCACHED) + flags |= AOP_FLAG_UNCACHED; + do { struct page *page; unsigned long offset; /* Offset into pagecache page */ @@ -3333,10 +3338,16 @@ ssize_t generic_perform_write(struct file *file, break; } +retry: status = a_ops->write_begin(file, mapping, pos, bytes, flags, &page, &fsdata); - if (unlikely(status < 0)) + if (unlikely(status < 0)) { + if (status == -ENOMEM && (flags & AOP_FLAG_UNCACHED)) { + flags &= ~AOP_FLAG_UNCACHED; + goto retry; + } break; + } if (mapping_writably_mapped(mapping)) flush_dcache_page(page); @@ -3372,6 +3383,32 @@ ssize_t generic_perform_write(struct file *file, balance_dirty_pages_ratelimited(mapping); } while (iov_iter_count(i)); + if (written && (iocb->ki_flags & IOCB_UNCACHED)) { + loff_t end; + + pos = iocb->ki_pos; + end = pos + written; + + status = filemap_write_and_wait_range(mapping, pos, end); + if (status) + goto out; + + /* + * No pages were created for this range, we're done + */ + if (flags & AOP_FLAG_UNCACHED) + goto out; + + /* + * Try to invalidate cache pages for the range we just wrote. + * We don't care if invalidation fails as the write has still + * worked and leaving clean uptodate pages in the page cache + * isn't a corruption vector for uncached IO. + */ + invalidate_inode_pages2_range(mapping, + pos >> PAGE_SHIFT, end >> PAGE_SHIFT); + } +out: return written ? written : status; } EXPORT_SYMBOL(generic_perform_write);