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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 77C40C433E0 for ; Thu, 11 Jun 2020 01:42:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 570E7207ED for ; Thu, 11 Jun 2020 01:42:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591839752; bh=EljkInNLGMvn8sqEOhIvgvEadNNBohcUyaI6FD1kgZE=; h=Date:From:To:Subject:In-Reply-To:List-ID:From; b=WQDz7mi0d/CVcaA2C7hi7zT55zVjqxhGGajpT6g93ZDN+h3nkRfSB5JLAx54bP7Il tGoM0hPBMDu/ExiKYa/BBjsFS5QVziUMWjt1y8e21u51bkeCyF1W2KFywteNRf8M/p yLWAfsEnBmYvO2Zk+UKZa4YW2dYBUqk4Eqwxa2Qg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726462AbgFKBmc (ORCPT ); Wed, 10 Jun 2020 21:42:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:51340 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726268AbgFKBmc (ORCPT ); Wed, 10 Jun 2020 21:42:32 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 28CA02078D; Thu, 11 Jun 2020 01:42:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591839751; bh=EljkInNLGMvn8sqEOhIvgvEadNNBohcUyaI6FD1kgZE=; h=Date:From:To:Subject:In-Reply-To:From; b=LIq0fEA7SCIuFbScjnV89IgLtJRgIjp8jESzuS0m/3POTwT4f/tOqqWLzuJtaKKFA PM3Oin1p9Xcvnw4x13iivhZPMJaPtaTa0fovtM73CH0EEgY9D9PPJSWNACSXNrv3q5 ewx4Ttrqgv0ZPzzGyCl8hv1PSqo/gDa+rOfwYMVc= Date: Wed, 10 Jun 2020 18:42:29 -0700 From: Andrew Morton To: akpm@linux-foundation.org, alexander.h.duyck@linux.intel.com, axboe@kernel.dk, bgeffon@google.com, christian.brauner@ubuntu.com, christian@brauner.io, dancol@google.com, hannes@cmpxchg.org, jannh@google.com, joaodias@google.com, joel@joelfernandes.org, ktkhai@virtuozzo.com, linux-man@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, minchan@kernel.org, mm-commits@vger.kernel.org, oleksandr@redhat.com, shakeelb@google.com, sj38.park@gmail.com, sjpark@amazon.de, sonnyrao@google.com, sspatil@google.com, surenb@google.com, timmurray@google.com, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 21/25] mm/madvise: support both pid and pidfd for process_madvise Message-ID: <20200611014229.aHtg-8rXi%akpm@linux-foundation.org> In-Reply-To: <20200610184053.3fa7368ab80e23bfd44de71f@linux-foundation.org> User-Agent: s-nail v14.8.16 Sender: linux-man-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org From: Minchan Kim Subject: mm/madvise: support both pid and pidfd for process_madvise There is a demand[1] to support pid as well pidfd for process_madvise to reduce unnecessary syscall to get pidfd if the user has control of the target process (ie, they could guarantee the process is not gone or pid is not reused). This patch aims for supporting both options like waitid(2). So, the syscall is currently, int process_madvise(idtype_t idtype, id_t id, void *addr, size_t length, int advice, unsigned long flags); @which is actually idtype_t for userspace library and currently, it supports P_PID and P_PIDFD. [1] https://lore.kernel.org/linux-mm/9d849087-3359-c4ab-fbec-859e8186c509@virtuozzo.com/ Link: http://lkml.kernel.org/r/20200302193630.68771-6-minchan@kernel.org Signed-off-by: Minchan Kim Suggested-by: Kirill Tkhai Reviewed-by: Suren Baghdasaryan Reviewed-by: Vlastimil Babka Cc: Christian Brauner Cc: Alexander Duyck Cc: Brian Geffon Cc: Daniel Colascione Cc: Jann Horn Cc: Jens Axboe Cc: Joel Fernandes Cc: Johannes Weiner Cc: John Dias Cc: Michal Hocko Cc: Oleksandr Natalenko Cc: Sandeep Patil Cc: SeongJae Park Cc: SeongJae Park Cc: Shakeel Butt Cc: Sonny Rao Cc: Tim Murray Cc: Christian Brauner Cc: Signed-off-by: Andrew Morton --- include/linux/syscalls.h | 3 ++- mm/madvise.c | 36 +++++++++++++++++++++++------------- 2 files changed, 25 insertions(+), 14 deletions(-) --- a/include/linux/syscalls.h~mm-support-both-pid-and-pidfd-for-process_madvise +++ a/include/linux/syscalls.h @@ -878,7 +878,8 @@ asmlinkage long sys_munlockall(void); asmlinkage long sys_mincore(unsigned long start, size_t len, unsigned char __user * vec); asmlinkage long sys_madvise(unsigned long start, size_t len, int behavior); -asmlinkage long sys_process_madvise(int pidfd, unsigned long start, + +asmlinkage long sys_process_madvise(int which, pid_t pid, unsigned long start, size_t len, int behavior, unsigned long flags); asmlinkage long sys_remap_file_pages(unsigned long start, unsigned long size, unsigned long prot, unsigned long pgoff, --- a/mm/madvise.c~mm-support-both-pid-and-pidfd-for-process_madvise +++ a/mm/madvise.c @@ -1208,11 +1208,10 @@ SYSCALL_DEFINE3(madvise, unsigned long, return do_madvise(current, current->mm, start, len_in, behavior); } -SYSCALL_DEFINE5(process_madvise, int, pidfd, unsigned long, start, +SYSCALL_DEFINE6(process_madvise, int, which, pid_t, upid, unsigned long, start, size_t, len_in, int, behavior, unsigned long, flags) { int ret; - struct fd f; struct pid *pid; struct task_struct *task; struct mm_struct *mm; @@ -1223,20 +1222,31 @@ SYSCALL_DEFINE5(process_madvise, int, pi if (!process_madvise_behavior_valid(behavior)) return -EINVAL; - f = fdget(pidfd); - if (!f.file) - return -EBADF; - - pid = pidfd_pid(f.file); - if (IS_ERR(pid)) { - ret = PTR_ERR(pid); - goto fdput; + switch (which) { + case P_PID: + if (upid <= 0) + return -EINVAL; + + pid = find_get_pid(upid); + if (!pid) + return -ESRCH; + break; + case P_PIDFD: + if (upid < 0) + return -EINVAL; + + pid = pidfd_get_pid(upid); + if (IS_ERR(pid)) + return PTR_ERR(pid); + break; + default: + return -EINVAL; } task = get_pid_task(pid, PIDTYPE_PID); if (!task) { ret = -ESRCH; - goto fdput; + goto put_pid; } mm = mm_access(task, PTRACE_MODE_ATTACH_FSCREDS); @@ -1249,7 +1259,7 @@ SYSCALL_DEFINE5(process_madvise, int, pi mmput(mm); release_task: put_task_struct(task); -fdput: - fdput(f); +put_pid: + put_pid(pid); return ret; } _