From patchwork Thu Dec 12 19:01:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 11289231 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 DA85814E3 for ; Thu, 12 Dec 2019 19:01:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8CD324654 for ; Thu, 12 Dec 2019 19:01:43 +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="haFgiW36" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730625AbfLLTBm (ORCPT ); Thu, 12 Dec 2019 14:01:42 -0500 Received: from mail-il1-f193.google.com ([209.85.166.193]:40510 "EHLO mail-il1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730261AbfLLTBm (ORCPT ); Thu, 12 Dec 2019 14:01:42 -0500 Received: by mail-il1-f193.google.com with SMTP id b15so2941111ila.7 for ; Thu, 12 Dec 2019 11:01:42 -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=o3zF2IoLkG99aJLG3KAoCKldE2uwFDYuWKBNVHHKeAg=; b=haFgiW36qK83MkfbXn59ksnSEeEsdMHyWL9vgaQPI/2M7BzIcgSEL5tmvJUk3CVyL9 gaIUjsxIuvc2Scx+pXvX18Vol2DgeB6lck/Md1S9G8ORheTieuSd5A3FA09ZBu9H7LwU y8V5EwFbsXEx36zibedzoA5a9jooRrvi1Vufw6Bd6hsBuKZPJZHp7Qw3uMUUMmhZ5WTD jijcETsNbJTE6e2rQ/pBA1N0y4a+Prc5V7u02l8GVhZMpObLBF+CWkI4cN+2hZd+ZVU7 v0wh3XrdAMhdaZNFvhnzz8UZY6e+m1OGDnOo39MZvia9Cgm5RurFCcDKsOl4s4SvRxAt X6Qg== 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=o3zF2IoLkG99aJLG3KAoCKldE2uwFDYuWKBNVHHKeAg=; b=UqGVyJdTNjY1skLsBycuioFW1qAwppYqQ6k1ezVltOl5QvvgRRTs2l05KiuhSiYRNL mW9dItLlDeheBqMkRWxi8TQo06ecR2cdocQ4TkMn61j/vaa7M08A0wjT44ifbCcMBBm4 nb6W8/Wa9Zp2Imvi3364VIeVRcw/KCSuHFNtAc0UI978A26+9hT+pcGdi7QBJuokH4Pb stpJ7xiVvtPJa5eCCwNxIGJ7Yo4BYH7z/+5BH43cm/SkUQ9NUH4GgADszRzbhAXCEgdw Wtz8RvTQPCtCy9eUJRxGDhOkN3iJKQ/xdZ6OTmHKH6HpFU0PNrt6/HwMCnHalR01k/1N gRVg== X-Gm-Message-State: APjAAAVFHZbKioeXaEN4+X2wZ3XW4yIGA5m1NO8GrGSEJtJcgU5F8fu1 HBWAmhcWGY6ga7o82Nc9GwO2HA== X-Google-Smtp-Source: APXvYqy4Ha1ZPT0wkuEbZwzKrQRha4JXZvcnVJOgvUSyZMjxrG63y4ujfU5A0qzhnHglt6gsLEgwZw== X-Received: by 2002:a92:4781:: with SMTP id e1mr9348975ilk.147.1576177301694; Thu, 12 Dec 2019 11:01:41 -0800 (PST) Received: from x1.thefacebook.com ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id i22sm1957745ill.40.2019.12.12.11.01.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Dec 2019 11:01:41 -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 3/5] mm: make buffered writes work with RWF_UNCACHED Date: Thu, 12 Dec 2019 12:01:31 -0700 Message-Id: <20191212190133.18473-4-axboe@kernel.dk> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191212190133.18473-1-axboe@kernel.dk> References: <20191212190133.18473-1-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 00b8e87fb9cf..fbcd4537979d 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);