From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f42.google.com (mail-qg0-f42.google.com [209.85.192.42]) by kanga.kvack.org (Postfix) with ESMTP id C3C2D6B025F for ; Thu, 13 Aug 2015 15:16:18 -0400 (EDT) Received: by qged69 with SMTP id d69so37725381qge.0 for ; Thu, 13 Aug 2015 12:16:18 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id 81si5331275qhg.108.2015.08.13.12.16.16 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Aug 2015 12:16:18 -0700 (PDT) From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= Subject: [PATCH 11/15] HMM: add discard range helper (to clear and free resources for a range). Date: Thu, 13 Aug 2015 15:15:24 -0400 Message-Id: <1439493328-1028-12-git-send-email-jglisse@redhat.com> In-Reply-To: <1439493328-1028-1-git-send-email-jglisse@redhat.com> References: <1439493328-1028-1-git-send-email-jglisse@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Linus Torvalds , joro@8bytes.org, Mel Gorman , "H. Peter Anvin" , Peter Zijlstra , Andrea Arcangeli , Johannes Weiner , Larry Woodman , Rik van Riel , Dave Airlie , Brendan Conoboy , Joe Donohue , Christophe Harle , 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 , Leonid Shamis , Laurent Morichetti , Alexander Deucher , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= 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: JA(C)rA'me 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 d819ec9..10e1558 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -265,6 +265,9 @@ void hmm_mirror_unregister(struct hmm_mirror *mirror); struct hmm_mirror *hmm_mirror_ref(struct hmm_mirror *mirror); void hmm_mirror_unref(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 d652233..f271441 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -896,6 +896,30 @@ 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org