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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 11FB1C433E1 for ; Wed, 20 May 2020 02:35:00 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AC4892075F for ; Wed, 20 May 2020 02:34:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC4892075F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 544FB8409C; Wed, 20 May 2020 02:34:59 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 6cbcAQuExnqR; Wed, 20 May 2020 02:34:58 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id 0C2AF876DD; Wed, 20 May 2020 02:34:58 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id D04B0C07FF; Wed, 20 May 2020 02:34:57 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id AC2A1C0176 for ; Wed, 20 May 2020 02:34:56 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 93FAB86F72 for ; Wed, 20 May 2020 02:34:56 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tvXNkkY21wSH for ; Wed, 20 May 2020 02:34:55 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by fraxinus.osuosl.org (Postfix) with ESMTPS id EE3CE86F57 for ; Wed, 20 May 2020 02:34:54 +0000 (UTC) IronPort-SDR: wrZjDd3YsiIVheF4mM8aorxZGLoA6aAtgaSVthtdPb92w3Bn4NPCmc5OTmCUmVHvyFs5zyLF22 L7z1HjKbDdnw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 May 2020 19:34:54 -0700 IronPort-SDR: y2u51+kwTFswQRFD6YmX6PzgJ0no4jnfWp3CT42vA9s1EqU6bKcHcmk2wdtTnrchSOQF0tPwEo FBXqOrvwrjLg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,412,1583222400"; d="scan'208";a="282526388" Received: from allen-box.sh.intel.com (HELO [10.239.159.139]) ([10.239.159.139]) by orsmga002.jf.intel.com with ESMTP; 19 May 2020 19:34:49 -0700 Subject: Re: [PATCH v7 02/24] iommu/ioasid: Add ioasid references To: Jean-Philippe Brucker , iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-mm@kvack.org References: <20200519175502.2504091-1-jean-philippe@linaro.org> <20200519175502.2504091-3-jean-philippe@linaro.org> From: Lu Baolu Message-ID: Date: Wed, 20 May 2020 10:31:15 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200519175502.2504091-3-jean-philippe@linaro.org> Content-Language: en-US Cc: fenghua.yu@intel.com, kevin.tian@intel.com, jgg@ziepe.ca, catalin.marinas@arm.com, robin.murphy@arm.com, hch@infradead.org, zhangfei.gao@linaro.org, felix.kuehling@amd.com, will@kernel.org, christian.koenig@amd.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 5/20/20 1:54 AM, Jean-Philippe Brucker wrote: > Let IOASID users take references to existing ioasids with ioasid_get(). > ioasid_put() drops a reference and only frees the ioasid when its > reference number is zero. It returns true if the ioasid was freed. > For drivers that don't call ioasid_get(), ioasid_put() is the same as > ioasid_free(). > > Signed-off-by: Jean-Philippe Brucker > --- > v6->v7: rename ioasid_free() to ioasid_put(), add WARN in ioasid_get() > --- > include/linux/ioasid.h | 10 ++++++++-- > drivers/iommu/intel-iommu.c | 4 ++-- > drivers/iommu/intel-svm.c | 6 +++--- > drivers/iommu/ioasid.c | 38 +++++++++++++++++++++++++++++++++---- > 4 files changed, 47 insertions(+), 11 deletions(-) > > diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h > index 6f000d7a0ddc..e9dacd4b9f6b 100644 > --- a/include/linux/ioasid.h > +++ b/include/linux/ioasid.h > @@ -34,7 +34,8 @@ struct ioasid_allocator_ops { > #if IS_ENABLED(CONFIG_IOASID) > ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max, > void *private); > -void ioasid_free(ioasid_t ioasid); > +void ioasid_get(ioasid_t ioasid); > +bool ioasid_put(ioasid_t ioasid); > void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, > bool (*getter)(void *)); > int ioasid_register_allocator(struct ioasid_allocator_ops *allocator); > @@ -48,10 +49,15 @@ static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, > return INVALID_IOASID; > } > > -static inline void ioasid_free(ioasid_t ioasid) > +static inline void ioasid_get(ioasid_t ioasid) > { > } > > +static inline bool ioasid_put(ioasid_t ioasid) > +{ > + return false; > +} > + > static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid, > bool (*getter)(void *)) > { > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index ed21ce6d1238..0230f35480ee 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -5432,7 +5432,7 @@ static void auxiliary_unlink_device(struct dmar_domain *domain, > domain->auxd_refcnt--; > > if (!domain->auxd_refcnt && domain->default_pasid > 0) > - ioasid_free(domain->default_pasid); > + ioasid_put(domain->default_pasid); > } > > static int aux_domain_add_dev(struct dmar_domain *domain, > @@ -5494,7 +5494,7 @@ static int aux_domain_add_dev(struct dmar_domain *domain, > spin_unlock(&iommu->lock); > spin_unlock_irqrestore(&device_domain_lock, flags); > if (!domain->auxd_refcnt && domain->default_pasid > 0) > - ioasid_free(domain->default_pasid); > + ioasid_put(domain->default_pasid); > > return ret; > } > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c > index 2998418f0a38..86f1264bd07c 100644 > --- a/drivers/iommu/intel-svm.c > +++ b/drivers/iommu/intel-svm.c > @@ -353,7 +353,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ > if (mm) { > ret = mmu_notifier_register(&svm->notifier, mm); > if (ret) { > - ioasid_free(svm->pasid); > + ioasid_put(svm->pasid); > kfree(svm); > kfree(sdev); > goto out; > @@ -371,7 +371,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ > if (ret) { > if (mm) > mmu_notifier_unregister(&svm->notifier, mm); > - ioasid_free(svm->pasid); > + ioasid_put(svm->pasid); > kfree(svm); > kfree(sdev); > goto out; > @@ -447,7 +447,7 @@ int intel_svm_unbind_mm(struct device *dev, int pasid) > kfree_rcu(sdev, rcu); > > if (list_empty(&svm->devs)) { > - ioasid_free(svm->pasid); > + ioasid_put(svm->pasid); > if (svm->mm) > mmu_notifier_unregister(&svm->notifier, svm->mm); > list_del(&svm->list); > diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c > index 0f8dd377aada..50ee27bbd04e 100644 > --- a/drivers/iommu/ioasid.c > +++ b/drivers/iommu/ioasid.c > @@ -2,7 +2,7 @@ > /* > * I/O Address Space ID allocator. There is one global IOASID space, split into > * subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and > - * free IOASIDs with ioasid_alloc and ioasid_free. > + * free IOASIDs with ioasid_alloc and ioasid_put. > */ > #include > #include > @@ -15,6 +15,7 @@ struct ioasid_data { > struct ioasid_set *set; > void *private; > struct rcu_head rcu; > + refcount_t refs; > }; > > /* > @@ -314,6 +315,7 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max, > > data->set = set; > data->private = private; > + refcount_set(&data->refs, 1); > > /* > * Custom allocator needs allocator data to perform platform specific > @@ -346,11 +348,34 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max, > EXPORT_SYMBOL_GPL(ioasid_alloc); > > /** > - * ioasid_free - Free an IOASID > + * ioasid_get - obtain a reference to the IOASID > + */ > +void ioasid_get(ioasid_t ioasid) > +{ > + struct ioasid_data *ioasid_data; > + > + spin_lock(&ioasid_allocator_lock); > + ioasid_data = xa_load(&active_allocator->xa, ioasid); > + if (ioasid_data) > + refcount_inc(&ioasid_data->refs); > + else > + WARN_ON(1); > + spin_unlock(&ioasid_allocator_lock); > +} > +EXPORT_SYMBOL_GPL(ioasid_get); > + > +/** > + * ioasid_put - Release a reference to an ioasid > * @ioasid: the ID to remove > + * > + * Put a reference to the IOASID, free it when the number of references drops to > + * zero. > + * > + * Return: %true if the IOASID was freed, %false otherwise. > */ > -void ioasid_free(ioasid_t ioasid) > +bool ioasid_put(ioasid_t ioasid) > { > + bool free = false; > struct ioasid_data *ioasid_data; > > spin_lock(&ioasid_allocator_lock); > @@ -360,6 +385,10 @@ void ioasid_free(ioasid_t ioasid) > goto exit_unlock; > } > > + free = refcount_dec_and_test(&ioasid_data->refs); > + if (!free) > + goto exit_unlock; > + > active_allocator->ops->free(ioasid, active_allocator->ops->pdata); > /* Custom allocator needs additional steps to free the xa element */ > if (active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) { > @@ -369,8 +398,9 @@ void ioasid_free(ioasid_t ioasid) > > exit_unlock: > spin_unlock(&ioasid_allocator_lock); > + return free; > } > -EXPORT_SYMBOL_GPL(ioasid_free); > +EXPORT_SYMBOL_GPL(ioasid_put); > > /** > * ioasid_find - Find IOASID data > Reviewed-by: Lu Baolu Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu