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=-6.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 376C7C82632 for ; Tue, 3 Nov 2020 10:35:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B109921D40 for ; Tue, 3 Nov 2020 10:34:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="uf64q9LX"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="9UUmg4St" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B109921D40 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9C5786B00C0; Tue, 3 Nov 2020 05:34:05 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 94EDC6B00C2; Tue, 3 Nov 2020 05:34:05 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 74F4E6B00C0; Tue, 3 Nov 2020 05:34:05 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0143.hostedemail.com [216.40.44.143]) by kanga.kvack.org (Postfix) with ESMTP id 3AA3E6B00C2 for ; Tue, 3 Nov 2020 05:34:05 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id C827C181AEF00 for ; Tue, 3 Nov 2020 10:34:04 +0000 (UTC) X-FDA: 77442746808.20.comb93_520be89272b7 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id 7C73B180C07A3; Tue, 3 Nov 2020 10:34:04 +0000 (UTC) X-HE-Tag: comb93_520be89272b7 X-Filterd-Recvd-Size: 6612 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by imf32.hostedemail.com (Postfix) with ESMTP; Tue, 3 Nov 2020 10:34:03 +0000 (UTC) Message-Id: <20201103095859.429620021@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1604399638; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=K8tv6h9J8+1UjPWtbytb7n5SLceTF9zssV9oZox9W+U=; b=uf64q9LXpQapNhFORU08nfOObcnFcEm4O++QW3WS6I7k3PJKYg+0B5NUxZRCRpxpJWSJho 6xCfQbqF5SWvLd2UYygGAALn2A2cjEifSfE4kf1+lKthwGt5ShPb/JyjRiq2V4kL9NKneV tvQ85atLaLObNYw1Jsdictp7672OClv95UAV+BsfoahjIYRt6P7B73zNvPr/RXHjqQjiYX vqMn0VJZZuCLL83EiOOEEIiubdkjOyq0xQINIUxnhAvI+2Q8C2Ufm8JbRZw6Epe6CCDO+G IFnnudgMnXS/B/7Pn2ZHYkeEolyKh/60lfi2O9rR4T7flfqnXTUrlacqqg4vtA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1604399638; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=K8tv6h9J8+1UjPWtbytb7n5SLceTF9zssV9oZox9W+U=; b=9UUmg4StD1+gf6xD44eY0tbCb4Wv9S+7TAD5110OmAjL1mF4moT3f8RAipzm2mr9CGQRvT 96qYqMQSY/G9MBCw== Date: Tue, 03 Nov 2020 10:27:40 +0100 From: Thomas Gleixner To: LKML Cc: Linus Torvalds , Peter Zijlstra , Paul McKenney , Christoph Hellwig , Sebastian Andrzej Siewior , Thomas Bogendoerfer , linux-mips@vger.kernel.org, Andrew Morton , linux-mm@kvack.org, Alexander Viro , Benjamin LaHaise , linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, Chris Mason , Josef Bacik , David Sterba , linux-btrfs@vger.kernel.org, x86@kernel.org, Vineet Gupta , linux-snps-arc@lists.infradead.org, Russell King , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, Michal Simek , Nick Hu , Greentime Hu , Vincent Chen , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, "David S. Miller" , sparclinux@vger.kernel.org, Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Christian Koenig , Huang Rui , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, VMware Graphics , Roland Scheidegger , Dave Airlie , Gerd Hoffmann , virtualization@lists.linux-foundation.org, spice-devel@lists.freedesktop.org, Ben Skeggs , nouveau@lists.freedesktop.org, Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , intel-gfx@lists.freedesktop.org Subject: [patch V3 28/37] mips/crashdump: Simplify copy_oldmem_page() References: <20201103092712.714480842@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-transfer-encoding: 8-bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Replace kmap_atomic_pfn() with kmap_local_pfn() which is preemptible and can take page faults. Remove the indirection of the dump page and the related cruft which is not longer required. Signed-off-by: Thomas Gleixner Cc: Thomas Bogendoerfer Cc: linux-mips@vger.kernel.org --- V3: New patch --- arch/mips/kernel/crash_dump.c | 42 +++++++----------------------------------- 1 file changed, 7 insertions(+), 35 deletions(-) --- a/arch/mips/kernel/crash_dump.c +++ b/arch/mips/kernel/crash_dump.c @@ -5,8 +5,6 @@ #include #include -static void *kdump_buf_page; - /** * copy_oldmem_page - copy one page from "oldmem" * @pfn: page frame number to be copied @@ -17,51 +15,25 @@ static void *kdump_buf_page; * @userbuf: if set, @buf is in user address space, use copy_to_user(), * otherwise @buf is in kernel address space, use memcpy(). * - * Copy a page from "oldmem". For this page, there is no pte mapped + * Copy a page from "oldmem". For this page, there might be no pte mapped * in the current kernel. - * - * Calling copy_to_user() in atomic context is not desirable. Hence first - * copying the data to a pre-allocated kernel page and then copying to user - * space in non-atomic context. */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, + unsigned long offset, int userbuf) { void *vaddr; if (!csize) return 0; - vaddr = kmap_atomic_pfn(pfn); + vaddr = kmap_local_pfn(pfn); if (!userbuf) { - memcpy(buf, (vaddr + offset), csize); - kunmap_atomic(vaddr); + memcpy(buf, vaddr + offset, csize); } else { - if (!kdump_buf_page) { - pr_warn("Kdump: Kdump buffer page not allocated\n"); - - return -EFAULT; - } - copy_page(kdump_buf_page, vaddr); - kunmap_atomic(vaddr); - if (copy_to_user(buf, (kdump_buf_page + offset), csize)) - return -EFAULT; + if (copy_to_user(buf, vaddr + offset, csize)) + csize = -EFAULT; } return csize; } - -static int __init kdump_buf_page_init(void) -{ - int ret = 0; - - kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!kdump_buf_page) { - pr_warn("Kdump: Failed to allocate kdump buffer page\n"); - ret = -ENOMEM; - } - - return ret; -} -arch_initcall(kdump_buf_page_init);