From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f44.google.com (mail-lf0-f44.google.com [209.85.215.44]) by kanga.kvack.org (Postfix) with ESMTP id C521A6B0005 for ; Wed, 3 Feb 2016 01:27:05 -0500 (EST) Received: by mail-lf0-f44.google.com with SMTP id m1so7196088lfg.0 for ; Tue, 02 Feb 2016 22:27:05 -0800 (PST) Received: from mail-lb0-x244.google.com (mail-lb0-x244.google.com. [2a00:1450:4010:c04::244]) by mx.google.com with ESMTPS id r72si3057891lfr.149.2016.02.02.22.27.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Feb 2016 22:27:04 -0800 (PST) Received: by mail-lb0-x244.google.com with SMTP id bc4so287215lbc.0 for ; Tue, 02 Feb 2016 22:27:03 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <1453929472-25566-1-git-send-email-matthew.r.wilcox@intel.com> Date: Wed, 3 Feb 2016 09:27:03 +0300 Message-ID: Subject: Re: [PATCH 0/5] Fix races & improve the radix tree iterator patterns From: Konstantin Khlebnikov Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: Andrew Morton , Hugh Dickins , Ohad Ben-Cohen , Matthew Wilcox , Linux Kernel Mailing List , linux-fsdevel , "linux-mm@kvack.org" On Thu, Jan 28, 2016 at 10:17 AM, Konstantin Khlebnikov wrote: > On Thu, Jan 28, 2016 at 12:17 AM, Matthew Wilcox > wrote: >> From: Matthew Wilcox >> >> The first two patches here are bugfixes, and I would like to see them >> make their way into stable ASAP since they can lead to data corruption >> (very low probabilty). >> >> The last three patches do not qualify as bugfixes. They simply improve >> the standard pattern used to do radix tree iterations by removing the >> 'goto restart' part. Partially this is because this is an ugly & >> confusing goto, and partially because with multi-order entries in the >> tree, it'll be more likely that we'll see an indirect_ptr bit, and >> it's more efficient to kep going from the point of the iteration we're >> currently in than restart from the beginning each time. > > Ack whole set. > > I think we should go deeper in hide dereference/retry inside iterator. > Something like radix_tree_for_each_data(data, slot, root, iter, start). > I'll prepare patch for that. After second thought: there'ra not so many users for new sugar. This scheme with radix_tree_deref_retry - radix_tree_iter_retry complicated but fine. > >> >> Matthew Wilcox (5): >> radix-tree: Fix race in gang lookup >> hwspinlock: Fix race between radix tree insertion and lookup >> btrfs: Use radix_tree_iter_retry() >> mm: Use radix_tree_iter_retry() >> radix-tree,shmem: Introduce radix_tree_iter_next() >> >> drivers/hwspinlock/hwspinlock_core.c | 4 +++ >> fs/btrfs/tests/btrfs-tests.c | 3 +- >> include/linux/radix-tree.h | 31 +++++++++++++++++++++ >> lib/radix-tree.c | 12 ++++++-- >> mm/filemap.c | 53 ++++++++++++------------------------ >> mm/shmem.c | 30 ++++++++++---------- >> 6 files changed, 78 insertions(+), 55 deletions(-) >> >> -- >> 2.7.0.rc3 >> >> -- >> To unsubscribe, send a message with 'unsubscribe linux-mm' in >> the body to majordomo@kvack.org. For more info on Linux MM, >> see: http://www.linux-mm.org/ . >> Don't email: email@kvack.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org