Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756824AbbEUTg4 (ORCPT ); Thu, 21 May 2015 15:36:56 -0400 Received: from mail-qk0-f171.google.com ([209.85.220.171]:36801 "EHLO mail-qk0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756395AbbEUTdy (ORCPT ); Thu, 21 May 2015 15:33:54 -0400 From: j.glisse@gmail.com To: akpm@linux-foundation.org Cc: , linux-mm@kvack.org, Linus Torvalds , , Mel Gorman , "H. Peter Anvin" , Peter Zijlstra , Andrea Arcangeli , Johannes Weiner , Larry Woodman , Rik van Riel , Dave Airlie , Brendan Conoboy , Joe Donohue , Duncan Poole , Sherry Cheung , Subhash Gutti , John Hubbard , Mark Hairgrove , Lucien Dunning , Cameron Buschardt , Arvind Gopalakrishnan , Haggai Eran , Shachar Raindel , Liran Liss , Roland Dreier , Ben Sander , Greg Stoner , John Bridgman , Michael Mantor , Paul Blinzer , Laurent Morichetti , Alexander Deucher , Oded Gabbay , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Subject: [PATCH 11/36] HMM: add discard range helper (to clear and free resources for a range). Date: Thu, 21 May 2015 15:31:20 -0400 Message-Id: <1432236705-4209-12-git-send-email-j.glisse@gmail.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1432236705-4209-1-git-send-email-j.glisse@gmail.com> References: <1432236705-4209-1-git-send-email-j.glisse@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2524 Lines: 73 From: Jérôme Glisse A common use case is for device driver to stop caring for a range of address long before said range is munmapped by userspace program. To avoid keeping track of such range provide an helper function that will free HMM resources for a range of address. NOTE THAT DEVICE DRIVER MUST MAKE SURE THE HARDWARE WILL NO LONGER ACCESS THE RANGE BECAUSE CALLING THIS HELPER ! Signed-off-by: Jérôme Glisse --- include/linux/hmm.h | 3 +++ mm/hmm.c | 24 ++++++++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/include/linux/hmm.h b/include/linux/hmm.h index fdb1975..ec05df8 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -250,6 +250,9 @@ struct hmm_mirror { int hmm_mirror_register(struct hmm_mirror *mirror); void hmm_mirror_unregister(struct hmm_mirror *mirror); int hmm_mirror_fault(struct hmm_mirror *mirror, struct hmm_event *event); +void hmm_mirror_range_discard(struct hmm_mirror *mirror, + unsigned long start, + unsigned long end); #endif /* CONFIG_HMM */ diff --git a/mm/hmm.c b/mm/hmm.c index 8ec9ffa..4cab3f2 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -916,6 +916,30 @@ out: } EXPORT_SYMBOL(hmm_mirror_fault); +/* hmm_mirror_range_discard() - discard a range of address. + * + * @mirror: The mirror struct. + * @start: Start address of the range to discard (inclusive). + * @end: End address of the range to discard (exclusive). + * + * Call when device driver want to stop mirroring a range of address and free + * any HMM resources associated with that range (including dma mapping if any). + * + * THIS FUNCTION ASSUME THAT DRIVER ALREADY STOPPED USING THE RANGE OF ADDRESS + * AND THUS DO NOT PERFORM ANY SYNCHRONIZATION OR UPDATE WITH THE DRIVER TO + * INVALIDATE SAID RANGE. + */ +void hmm_mirror_range_discard(struct hmm_mirror *mirror, + unsigned long start, + unsigned long end) +{ + struct hmm_event event; + + hmm_event_init(&event, mirror->hmm, start, end, HMM_MUNMAP); + hmm_mirror_update_pt(mirror, &event, NULL); +} +EXPORT_SYMBOL(hmm_mirror_range_discard); + /* hmm_mirror_register() - register mirror against current process for a device. * * @mirror: The mirror struct being registered. -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/