From patchwork Tue Nov 12 20:22:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jason Gunthorpe X-Patchwork-Id: 11240027 X-Patchwork-Delegate: jgg@ziepe.ca Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 566131850 for ; Tue, 12 Nov 2019 20:22:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 36DDC21783 for ; Tue, 12 Nov 2019 20:22:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="mSX+wJ+8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726645AbfKLUWv (ORCPT ); Tue, 12 Nov 2019 15:22:51 -0500 Received: from mail-qk1-f195.google.com ([209.85.222.195]:35959 "EHLO mail-qk1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726376AbfKLUWv (ORCPT ); Tue, 12 Nov 2019 15:22:51 -0500 Received: by mail-qk1-f195.google.com with SMTP id d13so15696239qko.3 for ; Tue, 12 Nov 2019 12:22:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=RW58zr8YTNVHuTBfIVxZyU6EJd/oHLVvWKcypECtMjs=; b=mSX+wJ+8VUX1382IHhLVx6fBdAWs6gXvU0I32j+wK2yrM6ZkKGtovH1/NPjehZ8ovE 1T0Z0w4CHSgxOjOWg78rUMLlihvA2VQuqm44HX3C/1ZLAMQjsARlaHNBCW9gz6N48wKJ y9PM2onSIWQgFDrhE8sOQPU0nJxnAlm4dGvf735qGtY5kABa7ifc2bFJa2gjCHgJHDWB H9uN853ltamgQii1TxpifGWrSt8UcwbEHZ/zxACuyEsslH7wGCXdsqUB6pj/D0T30D1q 5KfZ1V6veRSoxZqHsr/Z2Op+C435uIf2bvVnVSct0GKZjzoJD+J9DajjzRnO10FRijpY fRpQ== 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=RW58zr8YTNVHuTBfIVxZyU6EJd/oHLVvWKcypECtMjs=; b=NZLD/1ZnfqTE22GfAnKROoM2tinYz1582upX4r79rMC3Jq2gGdX9IK//6J/YV+d0Th jPlwCsXYhE0oG70zE7L7sYEFG0ZHKOcQ2Qc5XxaeafdtCY2bsrxLpYsZ68Wl5uDpnyr+ MbZaZEoZ7SRgOIP4FD8SCtbMaLCtnkqcUwZAvwJJ5/d7urO1P+hvf/z4qqQyzk+hj5vN g63ZWQwmp11EG+oAEho4jvmGMgrK8DJ619BCRLO2Qy5EmfdHGmhBTuO4P/vVfO2zZcU+ aMG8lzEMvP7JeUl/6Vj23f1n7Jau5JlJ6wJZcDt6gU8c8eEfN8ASC71qkKtLKbP8LTbm 1SUA== X-Gm-Message-State: APjAAAWTAysi/Oowam6IKZR+5ZT4RalQSQgtgcMnIfFNSNrP9sbhCoKN jPXZ2H7ccYtyXOx4yeR3rYH8jsNny5c= X-Google-Smtp-Source: APXvYqwQcC+LL9E9LKfiZNHrcVJ95fvA4RxWhxexVl340jx3LOfHzjk66AKsaYtFFr6K39s9sLHHzA== X-Received: by 2002:a05:620a:110f:: with SMTP id o15mr14029771qkk.127.1573590169690; Tue, 12 Nov 2019 12:22:49 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-113-180.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.113.180]) by smtp.gmail.com with ESMTPSA id p33sm13643736qtf.80.2019.11.12.12.22.47 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 12 Nov 2019 12:22:48 -0800 (PST) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1iUcgZ-0003jm-8M; Tue, 12 Nov 2019 16:22:47 -0400 From: Jason Gunthorpe To: linux-mm@kvack.org, Jerome Glisse , Ralph Campbell , John Hubbard , Felix.Kuehling@amd.com Cc: linux-rdma@vger.kernel.org, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, Alex Deucher , Ben Skeggs , Boris Ostrovsky , =?utf-8?q?Christian_K=C3=B6ni?= =?utf-8?q?g?= , David Zhou , Dennis Dalessandro , Juergen Gross , Mike Marciniszyn , Oleksandr Andrushchenko , Petr Cvek , Stefano Stabellini , nouveau@lists.freedesktop.org, xen-devel@lists.xenproject.org, Christoph Hellwig , Jason Gunthorpe , Philip Yang Subject: [PATCH v3 03/14] mm/hmm: allow hmm_range to be used with a mmu_interval_notifier or hmm_mirror Date: Tue, 12 Nov 2019 16:22:20 -0400 Message-Id: <20191112202231.3856-4-jgg@ziepe.ca> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191112202231.3856-1-jgg@ziepe.ca> References: <20191112202231.3856-1-jgg@ziepe.ca> MIME-Version: 1.0 Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: Jason Gunthorpe hmm_mirror's handling of ranges does not use a sequence count which results in this bug: CPU0 CPU1 hmm_range_wait_until_valid(range) valid == true hmm_range_fault(range) hmm_invalidate_range_start() range->valid = false hmm_invalidate_range_end() range->valid = true hmm_range_valid(range) valid == true Where the hmm_range_valid() should not have succeeded. Adding the required sequence count would make it nearly identical to the new mmu_interval_notifier. Instead replace the hmm_mirror stuff with mmu_interval_notifier. Co-existence of the two APIs is the first step. Reviewed-by: Jérôme Glisse Tested-by: Philip Yang Tested-by: Ralph Campbell Signed-off-by: Jason Gunthorpe Reviewed-by: Christoph Hellwig --- include/linux/hmm.h | 5 +++++ mm/hmm.c | 25 +++++++++++++++++++------ 2 files changed, 24 insertions(+), 6 deletions(-) diff --git a/include/linux/hmm.h b/include/linux/hmm.h index 3fec513b9c00f1..fbb35c78637e57 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -145,6 +145,9 @@ enum hmm_pfn_value_e { /* * struct hmm_range - track invalidation lock on virtual address range * + * @notifier: an optional mmu_interval_notifier + * @notifier_seq: when notifier is used this is the result of + * mmu_interval_read_begin() * @hmm: the core HMM structure this range is active against * @vma: the vm area struct for the range * @list: all range lock are on a list @@ -159,6 +162,8 @@ enum hmm_pfn_value_e { * @valid: pfns array did not change since it has been fill by an HMM function */ struct hmm_range { + struct mmu_interval_notifier *notifier; + unsigned long notifier_seq; struct hmm *hmm; struct list_head list; unsigned long start; diff --git a/mm/hmm.c b/mm/hmm.c index 6b0136665407a3..8d060c5dabe37b 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -858,6 +858,14 @@ void hmm_range_unregister(struct hmm_range *range) } EXPORT_SYMBOL(hmm_range_unregister); +static bool needs_retry(struct hmm_range *range) +{ + if (range->notifier) + return mmu_interval_check_retry(range->notifier, + range->notifier_seq); + return !range->valid; +} + static const struct mm_walk_ops hmm_walk_ops = { .pud_entry = hmm_vma_walk_pud, .pmd_entry = hmm_vma_walk_pmd, @@ -898,18 +906,23 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags) const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP; unsigned long start = range->start, end; struct hmm_vma_walk hmm_vma_walk; - struct hmm *hmm = range->hmm; + struct mm_struct *mm; struct vm_area_struct *vma; int ret; - lockdep_assert_held(&hmm->mmu_notifier.mm->mmap_sem); + if (range->notifier) + mm = range->notifier->mm; + else + mm = range->hmm->mmu_notifier.mm; + + lockdep_assert_held(&mm->mmap_sem); do { /* If range is no longer valid force retry. */ - if (!range->valid) + if (needs_retry(range)) return -EBUSY; - vma = find_vma(hmm->mmu_notifier.mm, start); + vma = find_vma(mm, start); if (vma == NULL || (vma->vm_flags & device_vma)) return -EFAULT; @@ -939,7 +952,7 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags) start = hmm_vma_walk.last; /* Keep trying while the range is valid. */ - } while (ret == -EBUSY && range->valid); + } while (ret == -EBUSY && !needs_retry(range)); if (ret) { unsigned long i; @@ -997,7 +1010,7 @@ long hmm_range_dma_map(struct hmm_range *range, struct device *device, continue; /* Check if range is being invalidated */ - if (!range->valid) { + if (needs_retry(range)) { ret = -EBUSY; goto unmap; }