From patchwork Fri Mar 25 01:32:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 554334 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 338A3C433FE for ; Fri, 25 Mar 2022 01:33:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357476AbiCYBex (ORCPT ); Thu, 24 Mar 2022 21:34:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357433AbiCYBeu (ORCPT ); Thu, 24 Mar 2022 21:34:50 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6AACFBF957; Thu, 24 Mar 2022 18:32:34 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 20D39B82725; Fri, 25 Mar 2022 01:32:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB7FEC340F5; Fri, 25 Mar 2022 01:32:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648171951; bh=w0bI3Ty/SlZwSBVN4SYYKCXms9Mthysi0KPWBON/EUA=; h=Date:To:From:Subject:From; b=TAbq7qcRjt62JTs5TkkTYLY1ijkF6QzVwpAZLWiy/fEi/vl1AWAYE6YO/N5oguS3t prdChDvF7VYwmakH627VtsYyZ+Cc655aZqsNqvOdE101tLY5py0Y1HYP8sN+ZTJWmO I4EI1Dn6pLr6BCyRXueW3iHB/bXePB3Y6WTt5mc0= Date: Thu, 24 Mar 2022 18:32:31 -0700 To: mm-commits@vger.kernel.org, vbabka@suse.cz, surenb@google.com, stable@vger.kernel.org, sfr@canb.auug.org.au, rientjes@google.com, nadav.amit@gmail.com, minchan@kernel.org, mhocko@suse.com, quic_charante@quicinc.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged] mm-madvise-return-correct-bytes-advised-with-process_madvise.patch removed from -mm tree Message-Id: <20220325013231.BB7FEC340F5@smtp.kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm: madvise: return correct bytes advised with process_madvise has been removed from the -mm tree. Its filename was mm-madvise-return-correct-bytes-advised-with-process_madvise.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Charan Teja Kalla Subject: mm: madvise: return correct bytes advised with process_madvise Patch series "mm: madvise: return correct bytes processed with process_madvise", v2. With the process_madvise(), always choose to return non zero processed bytes over an error. This can help the user to know on which VMA, passed in the 'struct iovec' vector list, is failed to advise thus can take the decission of retrying/skipping on that VMA. This patch (of 2): The process_madvise() system call returns error even after processing some VMA's passed in the 'struct iovec' vector list which leaves the user confused to know where to restart the advise next. It is also against this syscall man page[1] documentation where it mentions that "return value may be less than the total number of requested bytes, if an error occurred after some iovec elements were already processed.". Consider a user passed 10 VMA's in the 'struct iovec' vector list of which 9 are processed but one. Then it just returns the error caused on that failed VMA despite the first 9 VMA's processed, leaving the user confused about on which VMA it is failed. Returning the number of bytes processed here can help the user to know which VMA it is failed on and thus can retry/skip the advise on that VMA. [1]https://man7.org/linux/man-pages/man2/process_madvise.2.html. Link: https://lkml.kernel.org/r/cover.1647008754.git.quic_charante@quicinc.com Link: https://lkml.kernel.org/r/125b61a0edcee5c2db8658aed9d06a43a19ccafc.1647008754.git.quic_charante@quicinc.com Fixes: ecb8ac8b1f14("mm/madvise: introduce process_madvise() syscall: an external memory hinting API") Signed-off-by: Charan Teja Kalla Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: David Rientjes Cc: Stephen Rothwell Cc: Minchan Kim Cc: Nadav Amit Cc: Michal Hocko Cc: Signed-off-by: Andrew Morton --- mm/madvise.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/mm/madvise.c~mm-madvise-return-correct-bytes-advised-with-process_madvise +++ a/mm/madvise.c @@ -1435,8 +1435,7 @@ SYSCALL_DEFINE5(process_madvise, int, pi iov_iter_advance(&iter, iovec.iov_len); } - if (ret == 0) - ret = total_len - iov_iter_count(&iter); + ret = (total_len - iov_iter_count(&iter)) ? : ret; release_mm: mmput(mm);