From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Re: [PATCH V4 3/6] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device Date: Wed, 12 Jul 2017 23:48:43 -0700 Message-ID: <20170713064843.GX22780@codeaurora.org> References: <1499333825-7658-1-git-send-email-vivek.gautam@codeaurora.org> <1499333825-7658-4-git-send-email-vivek.gautam@codeaurora.org> <20170712225459.GZ22780@codeaurora.org> <5ee0bacd-e557-a6c4-a897-844fb12ea6ae@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <5ee0bacd-e557-a6c4-a897-844fb12ea6ae-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> 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 Cc: mark.rutland-5wv7dgnIgG8@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, stanimir.varbanov-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, linux-clk-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-arm-msm@vger.kernel.org On 07/13, Vivek Gautam wrote: > Hi Stephen, > > > On 07/13/2017 04:24 AM, Stephen Boyd wrote: > >On 07/06, Vivek Gautam wrote: > >>@@ -1231,12 +1237,18 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova, > >> static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova, > >> size_t size) > >> { > >>- struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops; > >>+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); > >>+ struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops; > >>+ size_t ret; > >> if (!ops) > >> return 0; > >>- return ops->unmap(ops, iova, size); > >>+ pm_runtime_get_sync(smmu_domain->smmu->dev); > >Can these map/unmap ops be called from an atomic context? I seem > >to recall that being a problem before. > > That's something which was dropped in the following patch merged in master: > 523d7423e21b iommu/arm-smmu: Remove io-pgtable spinlock > > Looks like we don't need locks here anymore? > While removing the spinlock around the map/unmap path may be one thing, I'm not sure that's all of them. Is there a path from an atomic DMA allocation (GFP_ATOMIC sort of thing) mapped into an IOMMU for a device that can eventually get down to here and attempt to turn a clk on? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751220AbdGMGss (ORCPT ); Thu, 13 Jul 2017 02:48:48 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:37362 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751161AbdGMGsp (ORCPT ); Thu, 13 Jul 2017 02:48:45 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 329C3602A8 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=sboyd@codeaurora.org Date: Wed, 12 Jul 2017 23:48:43 -0700 From: Stephen Boyd To: Vivek Gautam Cc: joro@8bytes.org, robin.murphy@arm.com, robh+dt@kernel.org, mark.rutland@arm.com, will.deacon@arm.com, m.szyprowski@samsung.com, robdclark@gmail.com, iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-msm@vger.kernel.org, sricharan@codeaurora.org, stanimir.varbanov@linaro.org, architt@codeaurora.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH V4 3/6] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device Message-ID: <20170713064843.GX22780@codeaurora.org> References: <1499333825-7658-1-git-send-email-vivek.gautam@codeaurora.org> <1499333825-7658-4-git-send-email-vivek.gautam@codeaurora.org> <20170712225459.GZ22780@codeaurora.org> <5ee0bacd-e557-a6c4-a897-844fb12ea6ae@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5ee0bacd-e557-a6c4-a897-844fb12ea6ae@codeaurora.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/13, Vivek Gautam wrote: > Hi Stephen, > > > On 07/13/2017 04:24 AM, Stephen Boyd wrote: > >On 07/06, Vivek Gautam wrote: > >>@@ -1231,12 +1237,18 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova, > >> static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova, > >> size_t size) > >> { > >>- struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops; > >>+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); > >>+ struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops; > >>+ size_t ret; > >> if (!ops) > >> return 0; > >>- return ops->unmap(ops, iova, size); > >>+ pm_runtime_get_sync(smmu_domain->smmu->dev); > >Can these map/unmap ops be called from an atomic context? I seem > >to recall that being a problem before. > > That's something which was dropped in the following patch merged in master: > 523d7423e21b iommu/arm-smmu: Remove io-pgtable spinlock > > Looks like we don't need locks here anymore? > While removing the spinlock around the map/unmap path may be one thing, I'm not sure that's all of them. Is there a path from an atomic DMA allocation (GFP_ATOMIC sort of thing) mapped into an IOMMU for a device that can eventually get down to here and attempt to turn a clk on? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project From mboxrd@z Thu Jan 1 00:00:00 1970 From: sboyd@codeaurora.org (Stephen Boyd) Date: Wed, 12 Jul 2017 23:48:43 -0700 Subject: [PATCH V4 3/6] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device In-Reply-To: <5ee0bacd-e557-a6c4-a897-844fb12ea6ae@codeaurora.org> References: <1499333825-7658-1-git-send-email-vivek.gautam@codeaurora.org> <1499333825-7658-4-git-send-email-vivek.gautam@codeaurora.org> <20170712225459.GZ22780@codeaurora.org> <5ee0bacd-e557-a6c4-a897-844fb12ea6ae@codeaurora.org> Message-ID: <20170713064843.GX22780@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/13, Vivek Gautam wrote: > Hi Stephen, > > > On 07/13/2017 04:24 AM, Stephen Boyd wrote: > >On 07/06, Vivek Gautam wrote: > >>@@ -1231,12 +1237,18 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova, > >> static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova, > >> size_t size) > >> { > >>- struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops; > >>+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); > >>+ struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops; > >>+ size_t ret; > >> if (!ops) > >> return 0; > >>- return ops->unmap(ops, iova, size); > >>+ pm_runtime_get_sync(smmu_domain->smmu->dev); > >Can these map/unmap ops be called from an atomic context? I seem > >to recall that being a problem before. > > That's something which was dropped in the following patch merged in master: > 523d7423e21b iommu/arm-smmu: Remove io-pgtable spinlock > > Looks like we don't need locks here anymore? > While removing the spinlock around the map/unmap path may be one thing, I'm not sure that's all of them. Is there a path from an atomic DMA allocation (GFP_ATOMIC sort of thing) mapped into an IOMMU for a device that can eventually get down to here and attempt to turn a clk on? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project