From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH v8 4/5] iommu/arm-smmu: Add the device_link between masters and smmu Date: Wed, 7 Mar 2018 12:47:28 +0000 Message-ID: References: <20180302101050.6191-1-vivek.gautam@codeaurora.org> <20180302101050.6191-5-vivek.gautam@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180302101050.6191-5-vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> Content-Language: en-GB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Vivek Gautam , joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, robdclark-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sboyd-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org List-Id: linux-arm-msm@vger.kernel.org On 02/03/18 10:10, Vivek Gautam wrote: > From: Sricharan R > > Finally add the device link between the master device and > smmu, so that the smmu gets runtime enabled/disabled only when the > master needs it. This is done from add_device callback which gets > called once when the master is added to the smmu. > > Signed-off-by: Sricharan R > Signed-off-by: Vivek Gautam > --- > drivers/iommu/arm-smmu.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 3d6a1875431f..bb1ea82c1003 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -217,6 +217,9 @@ struct arm_smmu_device { > > /* IOMMU core code handle */ > struct iommu_device iommu; > + > + /* runtime PM link to master */ > + struct device_link *link; Just the one? > }; > > enum arm_smmu_context_fmt { > @@ -1470,10 +1473,26 @@ static int arm_smmu_add_device(struct device *dev) > > iommu_device_link(&smmu->iommu, dev); > > + /* > + * Establish the link between smmu and master, so that the > + * smmu gets runtime enabled/disabled as per the master's > + * needs. > + */ > + smmu->link = device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME); Maybe I've misunderstood how the API works, but AFAICS the second and subsequent devices are all just going to overwrite (and leak) the link of the previous one... > + if (!smmu->link) { > + dev_warn(smmu->dev, "Unable to create device link between %s and %s\n", > + dev_name(smmu->dev), dev_name(dev)); > + ret = -ENODEV; > + goto out_unlink; > + } > + > arm_smmu_rpm_put(smmu); > > return 0; > > +out_unlink: > + iommu_device_unlink(&smmu->iommu, dev); > + arm_smmu_master_free_smes(fwspec); > out_rpm_put: > arm_smmu_rpm_put(smmu); > out_cfg_free: > @@ -1496,6 +1515,8 @@ static void arm_smmu_remove_device(struct device *dev) > cfg = fwspec->iommu_priv; > smmu = cfg->smmu; > > + device_link_del(smmu->link); ...and equivalently you end up with a double-free (or more) here of a link which may not have belonged to dev anyway. Robin. > + > ret = arm_smmu_rpm_get(smmu); > if (ret < 0) > return; > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754492AbeCGMsP (ORCPT ); Wed, 7 Mar 2018 07:48:15 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:50130 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754251AbeCGMrd (ORCPT ); Wed, 7 Mar 2018 07:47:33 -0500 Subject: Re: [PATCH v8 4/5] iommu/arm-smmu: Add the device_link between masters and smmu To: Vivek Gautam , joro@8bytes.org, robh+dt@kernel.org, mark.rutland@arm.com, rjw@rjwysocki.net, will.deacon@arm.com, robdclark@gmail.com, iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: tfiga@chromium.org, jcrouse@codeaurora.org, sboyd@codeaurora.org, sricharan@codeaurora.org, m.szyprowski@samsung.com, architt@codeaurora.org, linux-arm-msm@vger.kernel.org References: <20180302101050.6191-1-vivek.gautam@codeaurora.org> <20180302101050.6191-5-vivek.gautam@codeaurora.org> From: Robin Murphy Message-ID: Date: Wed, 7 Mar 2018 12:47:28 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180302101050.6191-5-vivek.gautam@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/03/18 10:10, Vivek Gautam wrote: > From: Sricharan R > > Finally add the device link between the master device and > smmu, so that the smmu gets runtime enabled/disabled only when the > master needs it. This is done from add_device callback which gets > called once when the master is added to the smmu. > > Signed-off-by: Sricharan R > Signed-off-by: Vivek Gautam > --- > drivers/iommu/arm-smmu.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 3d6a1875431f..bb1ea82c1003 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -217,6 +217,9 @@ struct arm_smmu_device { > > /* IOMMU core code handle */ > struct iommu_device iommu; > + > + /* runtime PM link to master */ > + struct device_link *link; Just the one? > }; > > enum arm_smmu_context_fmt { > @@ -1470,10 +1473,26 @@ static int arm_smmu_add_device(struct device *dev) > > iommu_device_link(&smmu->iommu, dev); > > + /* > + * Establish the link between smmu and master, so that the > + * smmu gets runtime enabled/disabled as per the master's > + * needs. > + */ > + smmu->link = device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME); Maybe I've misunderstood how the API works, but AFAICS the second and subsequent devices are all just going to overwrite (and leak) the link of the previous one... > + if (!smmu->link) { > + dev_warn(smmu->dev, "Unable to create device link between %s and %s\n", > + dev_name(smmu->dev), dev_name(dev)); > + ret = -ENODEV; > + goto out_unlink; > + } > + > arm_smmu_rpm_put(smmu); > > return 0; > > +out_unlink: > + iommu_device_unlink(&smmu->iommu, dev); > + arm_smmu_master_free_smes(fwspec); > out_rpm_put: > arm_smmu_rpm_put(smmu); > out_cfg_free: > @@ -1496,6 +1515,8 @@ static void arm_smmu_remove_device(struct device *dev) > cfg = fwspec->iommu_priv; > smmu = cfg->smmu; > > + device_link_del(smmu->link); ...and equivalently you end up with a double-free (or more) here of a link which may not have belonged to dev anyway. Robin. > + > ret = arm_smmu_rpm_get(smmu); > if (ret < 0) > return; >