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=-8.2 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_2 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 A4F78C3A589 for ; Thu, 15 Aug 2019 22:47:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D074206C2 for ; Thu, 15 Aug 2019 22:47:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733235AbfHOWrK (ORCPT ); Thu, 15 Aug 2019 18:47:10 -0400 Received: from mga04.intel.com ([192.55.52.120]:58997 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729325AbfHOWrI (ORCPT ); Thu, 15 Aug 2019 18:47:08 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Aug 2019 15:47:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,389,1559545200"; d="scan'208";a="352372678" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga005.jf.intel.com with ESMTP; 15 Aug 2019 15:47:08 -0700 Date: Thu, 15 Aug 2019 15:50:51 -0700 From: Jacob Pan To: Andy Shevchenko Cc: iommu@lists.linux-foundation.org, LKML , Joerg Roedel , David Woodhouse , Alex Williamson , Eric Auger , Yi Liu , "Tian, Kevin" , Raj Ashok , Christoph Hellwig , Jean-Philippe Brucker , Lu Baolu , Jonathan Cameron , jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v5 16/19] iommu/vt-d: Misc macro clean up for SVM Message-ID: <20190815155051.0212b5e6@jacob-builder> In-Reply-To: References: <1565900005-62508-1-git-send-email-jacob.jun.pan@linux.intel.com> <1565900005-62508-17-git-send-email-jacob.jun.pan@linux.intel.com> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 16 Aug 2019 00:17:44 +0300 Andy Shevchenko wrote: > On Thu, Aug 15, 2019 at 11:52 PM Jacob Pan > wrote: > > > > Use combined macros for_each_svm_dev() to simplify SVM device > > iteration and error checking. > > > > Suggested-by: Andy Shevchenko > > Signed-off-by: Jacob Pan > > Reviewed-by: Eric Auger > > --- > > drivers/iommu/intel-svm.c | 85 > > +++++++++++++++++++++++------------------------ 1 file changed, 41 > > insertions(+), 44 deletions(-) > > > > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c > > index 5a688a5..ea6f2e2 100644 > > --- a/drivers/iommu/intel-svm.c > > +++ b/drivers/iommu/intel-svm.c > > @@ -218,6 +218,10 @@ static const struct mmu_notifier_ops > > intel_mmuops = { static DEFINE_MUTEX(pasid_mutex); > > static LIST_HEAD(global_svm_list); > > > > +#define for_each_svm_dev(svm, dev) \ > > + list_for_each_entry(sdev, &svm->devs, list) \ > > > + if (dev == sdev->dev) \ > > This should be > if (dev != sdev->dev) {} else > and no trailing \ is neeeded. > > The rationale of above form to avoid > for_each_foo() { > } else { > ...WTF?!.. > } > I understand, but until we have the else {} case we don't have anything to avoid. The current code only has a simple positive logic. > > + > > int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, > > struct svm_dev_ops *ops) { > > struct intel_iommu *iommu = intel_svm_device_to_iommu(dev); > > @@ -263,15 +267,13 @@ int intel_svm_bind_mm(struct device *dev, int > > *pasid, int flags, struct svm_dev_ goto out; > > } > > > > - list_for_each_entry(sdev, &svm->devs, list) > > { > > - if (dev == sdev->dev) { > > - if (sdev->ops != ops) { > > - ret = -EBUSY; > > - goto out; > > - } > > - sdev->users++; > > - goto success; > > + for_each_svm_dev(svm, dev) { > > + if (sdev->ops != ops) { > > + ret = -EBUSY; > > + goto out; > > } > > + sdev->users++; > > + goto success; > > } > > > > break; > > @@ -408,48 +410,43 @@ int intel_svm_unbind_mm(struct device *dev, > > int pasid) goto out; > > > > svm = ioasid_find(NULL, pasid, NULL); > > - if (IS_ERR(svm)) { > > + if (IS_ERR_OR_NULL(svm)) { > > ret = PTR_ERR(svm); > > goto out; > > } > > > > - if (!svm) > > - goto out; > > + for_each_svm_dev(svm, dev) { > > + ret = 0; > > + sdev->users--; > > + if (!sdev->users) { > > + list_del_rcu(&sdev->list); > > + /* Flush the PASID cache and IOTLB for this > > device. > > + * Note that we do depend on the hardware > > *not* using > > + * the PASID any more. Just as we depend on > > other > > + * devices never using PASIDs that they > > have no right > > + * to use. We have a *shared* PASID table, > > because it's > > + * large and has to be physically > > contiguous. So it's > > + * hard to be as defensive as we might > > like. */ > > + intel_pasid_tear_down_entry(iommu, dev, > > svm->pasid); > > + intel_flush_svm_range_dev(svm, sdev, 0, -1, > > 0, !svm->mm); > > + kfree_rcu(sdev, rcu); > > + > > + if (list_empty(&svm->devs)) { > > + ioasid_free(svm->pasid); > > + if (svm->mm) > > + > > mmu_notifier_unregister(&svm->notifier, svm->mm); > > > > - list_for_each_entry(sdev, &svm->devs, list) { > > - if (dev == sdev->dev) { > > - ret = 0; > > - sdev->users--; > > - if (!sdev->users) { > > - list_del_rcu(&sdev->list); > > - /* Flush the PASID cache and IOTLB > > for this device. > > - * Note that we do depend on the > > hardware *not* using > > - * the PASID any more. Just as we > > depend on other > > - * devices never using PASIDs that > > they have no right > > - * to use. We have a *shared* PASID > > table, because it's > > - * large and has to be physically > > contiguous. So it's > > - * hard to be as defensive as we > > might like. */ > > - intel_pasid_tear_down_entry(iommu, > > dev, svm->pasid); > > - intel_flush_svm_range_dev(svm, > > sdev, 0, -1, 0, !svm->mm); > > - kfree_rcu(sdev, rcu); > > - > > - if (list_empty(&svm->devs)) { > > - ioasid_free(svm->pasid); > > - if (svm->mm) > > - > > mmu_notifier_unregister(&svm->notifier, svm->mm); - > > - list_del(&svm->list); > > - > > - /* We mandate that no page > > faults may be outstanding > > - * for the PASID when > > intel_svm_unbind_mm() is called. > > - * If that is not obeyed, > > subtle errors will happen. > > - * Let's make them less > > subtle... */ > > - memset(svm, 0x6b, > > sizeof(*svm)); > > - kfree(svm); > > - } > > + list_del(&svm->list); > > + > > + /* We mandate that no page faults > > may be outstanding > > + * for the PASID when > > intel_svm_unbind_mm() is called. > > + * If that is not obeyed, subtle > > errors will happen. > > + * Let's make them less subtle... */ > > + memset(svm, 0x6b, sizeof(*svm)); > > + kfree(svm); > > } > > - break; > > } > > + break; > > } > > out: > > mutex_unlock(&pasid_mutex); > > @@ -585,7 +582,7 @@ static irqreturn_t prq_event_thread(int irq, > > void *d) > > * to unbind the mm while any page faults > > are outstanding. > > * So we only need RCU to protect the > > internal idr code. */ rcu_read_unlock(); > > - if (IS_ERR(svm) || !svm) { > > + if (IS_ERR_OR_NULL(svm)) { > > pr_err("%s: Page request for > > invalid PASID %d: %08llx %08llx\n", iommu->name, req->pasid, > > ((unsigned long long *)req)[0], ((unsigned long long *)req)[1]); > > -- > > 2.7.4 > > > > [Jacob Pan]