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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 47E1EC3A5A6 for ; Mon, 23 Sep 2019 04:26:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 25FE12087C for ; Mon, 23 Sep 2019 04:26:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406610AbfIWE0y (ORCPT ); Mon, 23 Sep 2019 00:26:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34770 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405826AbfIWE0x (ORCPT ); Mon, 23 Sep 2019 00:26:53 -0400 Received: from mail-pl1-f200.google.com (mail-pl1-f200.google.com [209.85.214.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6A9B63B71F for ; Mon, 23 Sep 2019 04:26:52 +0000 (UTC) Received: by mail-pl1-f200.google.com with SMTP id f8so175833plj.10 for ; Sun, 22 Sep 2019 21:26:52 -0700 (PDT) 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=N4oZOlVdiq1iUNu2ipKdKrBjjBpOUecRmSvPVqDDXZc=; b=Oq/7zhuZwAz0bwKWpXkx9GKeYzfIjCbrpGX6d3F2LwpOwahJjeSqoBcfIna//oxwWw GwlaoVdav9S7vcWBgIXOr1l8b2fvHYt+FwDc+IJX8FmeGjplFIAFLPzKCvk9UVR31PQH VtbBNKrHIJudAlobDVGzrGKWUfuNDdgkwoudxiQ9hIKDZ4FQWKBWJLytUB16673PbWZv GmPvi+l51EItSvkIjgwQjh7uurgudDKCYnh2rgYUKBFvgwCSeV++R5bXdY9WxHgX4wui aKBKJzfly1ooLSmB1jFWVANyn1c6ghl/0/6P3LqpjfdZ9rfZD6AScV8XJR2U/Nd+G2li YhrA== X-Gm-Message-State: APjAAAUBEWn4R8NWmH5hZCW47ofSYfKbgYsHeh2N0xF68sLB30k/V/2w PHWjqjznqnELkiqL0HvKMYb/MRYISodfmhoe9ykQifrtMClUs4ZFZPlVAY4X3JpTuN/oAIEzYwY 7T1kVrrLM1wXpkB7Kx8Huoo4z X-Received: by 2002:a17:902:166:: with SMTP id 93mr30567156plb.195.1569212811912; Sun, 22 Sep 2019 21:26:51 -0700 (PDT) X-Google-Smtp-Source: APXvYqye+DK7u0JotOoJqpvnTZrRb6/Qt3/D8C+ZXa1+qVSUReRHxlafT5dNKcY1JDA9hSKH4gDDqQ== X-Received: by 2002:a17:902:166:: with SMTP id 93mr30567137plb.195.1569212811739; Sun, 22 Sep 2019 21:26:51 -0700 (PDT) Received: from xz-x1.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id x20sm11781867pfp.120.2019.09.22.21.26.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 22 Sep 2019 21:26:51 -0700 (PDT) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , peterx@redhat.com, Martin Cracauer , Marty McFadden , Shaohua Li , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Linus Torvalds , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: [PATCH v4 10/10] mm/userfaultfd: Honor FAULT_FLAG_KILLABLE in fault path Date: Mon, 23 Sep 2019 12:25:23 +0800 Message-Id: <20190923042523.10027-11-peterx@redhat.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190923042523.10027-1-peterx@redhat.com> References: <20190923042523.10027-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Userfaultfd fault path was by default killable even if the caller does not have FAULT_FLAG_KILLABLE. That makes sense before in that when with gup we don't have FAULT_FLAG_KILLABLE properly set before. Now after previous patch we've got FAULT_FLAG_KILLABLE applied even for gup code so it should also make sense to let userfaultfd to honor the FAULT_FLAG_KILLABLE. Because we're unconditionally setting FAULT_FLAG_KILLABLE in gup code right now, this patch should have no functional change. It also cleaned the code a little bit by introducing some helpers. Signed-off-by: Peter Xu --- fs/userfaultfd.c | 36 ++++++++++++++++++++++++++++-------- 1 file changed, 28 insertions(+), 8 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 2b3b48e94ae4..8c5863ccbf0e 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -334,6 +334,30 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx, return ret; } +/* Should pair with userfaultfd_signal_pending() */ +static inline long userfaultfd_get_blocking_state(unsigned int flags) +{ + if (flags & FAULT_FLAG_INTERRUPTIBLE) + return TASK_INTERRUPTIBLE; + + if (flags & FAULT_FLAG_KILLABLE) + return TASK_KILLABLE; + + return TASK_UNINTERRUPTIBLE; +} + +/* Should pair with userfaultfd_get_blocking_state() */ +static inline bool userfaultfd_signal_pending(unsigned int flags) +{ + if (flags & FAULT_FLAG_INTERRUPTIBLE) + return signal_pending(current); + + if (flags & FAULT_FLAG_KILLABLE) + return fatal_signal_pending(current); + + return false; +} + /* * The locking rules involved in returning VM_FAULT_RETRY depending on * FAULT_FLAG_ALLOW_RETRY, FAULT_FLAG_RETRY_NOWAIT and @@ -355,7 +379,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) struct userfaultfd_ctx *ctx; struct userfaultfd_wait_queue uwq; vm_fault_t ret = VM_FAULT_SIGBUS; - bool must_wait, return_to_userland; + bool must_wait; long blocking_state; /* @@ -462,9 +486,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) uwq.ctx = ctx; uwq.waken = false; - return_to_userland = vmf->flags & FAULT_FLAG_INTERRUPTIBLE; - blocking_state = return_to_userland ? TASK_INTERRUPTIBLE : - TASK_KILLABLE; + blocking_state = userfaultfd_get_blocking_state(vmf->flags); spin_lock_irq(&ctx->fault_pending_wqh.lock); /* @@ -490,8 +512,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) up_read(&mm->mmap_sem); if (likely(must_wait && !READ_ONCE(ctx->released) && - (return_to_userland ? !signal_pending(current) : - !fatal_signal_pending(current)))) { + userfaultfd_signal_pending(vmf->flags))) { wake_up_poll(&ctx->fd_wqh, EPOLLIN); schedule(); ret |= VM_FAULT_MAJOR; @@ -513,8 +534,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) set_current_state(blocking_state); if (READ_ONCE(uwq.waken) || READ_ONCE(ctx->released) || - (return_to_userland ? signal_pending(current) : - fatal_signal_pending(current))) + userfaultfd_signal_pending(vmf->flags)) break; schedule(); } -- 2.21.0