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=-15.8 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 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 7DA84C433B4 for ; Thu, 22 Apr 2021 04:36:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5C6B06144A for ; Thu, 22 Apr 2021 04:36:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230119AbhDVEgh (ORCPT ); Thu, 22 Apr 2021 00:36:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:54678 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbhDVEgg (ORCPT ); Thu, 22 Apr 2021 00:36:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6CE9861437; Thu, 22 Apr 2021 04:36:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619066162; bh=fAk3LIn9zIR7iTi06FFtNDheQtLtLc8pj6HsJlVU1Ak=; h=Date:From:To:Subject:From; b=z9P4+DDG2NYLCNK/e01QrvTHYhBd16EK++rxCWoBM63vs/X8NZAav3ANHTf6tyNlG 2m4oWn4ygtdkOob312P30YiYF4Hrk0t/raSdvzITNVi3f4d3utpLFFFSYOT3oZCv7V +Vk8RBJUBruct7nxXYyuvnxu4jaH0NPQ7VMXHmNw= Date: Wed, 21 Apr 2021 21:36:01 -0700 From: akpm@linux-foundation.org To: dchinner@redhat.com, hannes@cmpxchg.org, hch@lst.de, hughd@google.com, jack@suse.cz, kirill.shutemov@linux.intel.com, mm-commits@vger.kernel.org, william.kucharski@oracle.com, willy@infradead.org, yang.shi@linux.alibaba.com Subject: + mm-filemap-fix-mapping_seek_hole_data-on-thp-32-bit.patch added to -mm tree Message-ID: <20210422043601._ozQ0-vjO%akpm@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 The patch titled Subject: mm/filemap: fix mapping_seek_hole_data on THP & 32-bit has been added to the -mm tree. Its filename is mm-filemap-fix-mapping_seek_hole_data-on-thp-32-bit.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-filemap-fix-mapping_seek_hole_data-on-thp-32-bit.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-filemap-fix-mapping_seek_hole_data-on-thp-32-bit.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins Subject: mm/filemap: fix mapping_seek_hole_data on THP & 32-bit No problem on 64-bit without huge pages, but xfstests generic/285 and other SEEK_HOLE/SEEK_DATA tests have regressed on huge tmpfs, and on 32-bit architectures, with the new mapping_seek_hole_data(). Several different bugs turned out to need fixing. u64 casts added to stop unfortunate sign-extension when shifting (and let's use shifts throughout, rather than mixed with * and /). Use round_up() when advancing pos, to stop assuming that pos was already THP-aligned when advancing it by THP-size. (But I believe this use of round_up() assumes that any THP must be THP-aligned: true while tmpfs enforces that alignment, and is the only fs with FS_THP_SUPPORT; but might need to be generalized in the future? If I try to generalize it right now, I'm sure to get it wrong!) Use xas_set() when iterating away from a THP, so that xa_index stays in synch with start, instead of drifting away to return bogus offset. Check start against end to avoid wrapping 32-bit xa_index to 0 (and to handle these additional cases, seek_data or not, it's easier to break the loop than goto: so rearrange exit from the function). Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104211737410.3299@eggly.anvils Fixes: 41139aa4c3a3 ("mm/filemap: add mapping_seek_hole_data") Signed-off-by: Hugh Dickins Cc: Christoph Hellwig Cc: Dave Chinner Cc: Jan Kara Cc: Johannes Weiner Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: William Kucharski Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/filemap.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) --- a/mm/filemap.c~mm-filemap-fix-mapping_seek_hole_data-on-thp-32-bit +++ a/mm/filemap.c @@ -2677,8 +2677,8 @@ unsigned int seek_page_size(struct xa_st loff_t mapping_seek_hole_data(struct address_space *mapping, loff_t start, loff_t end, int whence) { - XA_STATE(xas, &mapping->i_pages, start >> PAGE_SHIFT); - pgoff_t max = (end - 1) / PAGE_SIZE; + XA_STATE(xas, &mapping->i_pages, (u64)start >> PAGE_SHIFT); + pgoff_t max = (u64)(end - 1) >> PAGE_SHIFT; bool seek_data = (whence == SEEK_DATA); struct page *page; @@ -2687,7 +2687,8 @@ loff_t mapping_seek_hole_data(struct add rcu_read_lock(); while ((page = find_get_entry(&xas, max, XA_PRESENT))) { - loff_t pos = xas.xa_index * PAGE_SIZE; + loff_t pos = (u64)xas.xa_index << PAGE_SHIFT; + unsigned int seek_size; if (start < pos) { if (!seek_data) @@ -2695,25 +2696,25 @@ loff_t mapping_seek_hole_data(struct add start = pos; } - pos += seek_page_size(&xas, page); + seek_size = seek_page_size(&xas, page); + pos = round_up((u64)pos + 1, seek_size); start = page_seek_hole_data(&xas, mapping, page, start, pos, seek_data); if (start < pos) goto unlock; + if (start >= end) + break; + if (seek_size > PAGE_SIZE) + xas_set(&xas, (u64)pos >> PAGE_SHIFT); if (!xa_is_value(page)) put_page(page); } - rcu_read_unlock(); - if (seek_data) - return -ENXIO; - goto out; - + start = -ENXIO; unlock: rcu_read_unlock(); - if (!xa_is_value(page)) + if (page && !xa_is_value(page)) put_page(page); -out: if (start > end) return end; return start; _ Patches currently in -mm which might be from hughd@google.com are mm-filemap-fix-find_lock_entries-hang-on-32-bit-thp.patch mm-filemap-fix-mapping_seek_hole_data-on-thp-32-bit.patch mm-restore-node-stat-checking-in-proc-sys-vm-stat_refresh.patch mm-no-more-einval-from-proc-sys-vm-stat_refresh.patch mm-proc-sys-vm-stat_refresh-skip-checking-known-negative-stats.patch mm-proc-sys-vm-stat_refresh-stop-checking-monotonic-numa-stats.patch