From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olav Haugan Subject: Re: [PATCH v5 1/1] iommu-api: Add map_sg/unmap_sg functions Date: Thu, 16 Oct 2014 10:23:07 -0700 Message-ID: <543FFEFB.2010604@codeaurora.org> References: <1407797150-515-1-git-send-email-ohaugan@codeaurora.org> <1407797150-515-2-git-send-email-ohaugan@codeaurora.org> <20140925170108.GE8306@8bytes.org> <5432E757.10201@codeaurora.org> <20141015091652.GB13162@ulmo> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.codeaurora.org ([198.145.11.231]:59593 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751298AbaJPRXK (ORCPT ); Thu, 16 Oct 2014 13:23:10 -0400 In-Reply-To: <20141015091652.GB13162@ulmo> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Thierry Reding Cc: Joerg Roedel , laurent.pinchart+renesas@ideasonboard.com, konrad.wilk@oracle.com, mitchelh@codeaurora.org, linux-arm-msm@vger.kernel.org, will.deacon@arm.com, iommu@lists.linux-foundation.org, robdclark@gmail.com, Varun.Sethi@freescale.com, kgene.kim@samsung.com, dwmw2@infradead.org, linux-arm-kernel@lists.infradead.org, hdoyu@nvidia.com On 10/15/2014 2:16 AM, Thierry Reding wrote: > On Mon, Oct 06, 2014 at 12:02:47PM -0700, Olav Haugan wrote: >> On 9/25/2014 10:01 AM, Joerg Roedel wrote: >>> On Mon, Aug 11, 2014 at 03:45:50PM -0700, Olav Haugan wrote: >>>> +static inline int iommu_map_sg(struct iommu_domain *domain, unsigned long iova, >>>> + struct scatterlist *sg, unsigned int nents, >>>> + int prot, unsigned long flags) >>>> +{ >>>> + return domain->ops->map_sg(domain, iova, sg, nents, prot, flags); >>>> +} >>>> + >>>> +static inline int iommu_unmap_sg(struct iommu_domain *domain, >>>> + unsigned long iova, size_t size, >>>> + unsigned long flags) >>>> +{ >>>> + return domain->ops->unmap_sg(domain, iova, size, flags); >>>> +} >>> >>> I have thought a little bit more about this interface and think that it >>> would be better to just return a size_t from iommu_map_sg(). The >>> function returns the amount of address space mapped by it, 0 in the >>> worst case. >>> >>> This makes it easy to unmap the region just with >>> iommu_unmap(domain, iova, size) in the end and removing the need for a >>> new iommu_unmap_sg() function. Also the error-path of the map_sg >>> call-backs becomes easier as the function then just returns the amount >>> of address-space already mapped before the error happened. >>> >>> So the prototype would be: >>> >>> size_t iommu_map_sg(struct iommu_domain *domain, >>> unsigned long iova, >>> struct scatterlist *sg, >>> unsigned int nents, >>> int prot); >>> >>> (as I said before, the flags parameter should not be added by this >>> patch-set). >>> >> >> Ok, sounds good. I'll post v6 soon. > > Perhaps make the return value ssize_t so that we can propagate errors? > I am fine with that. Joerg? Thanks, .Olav -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project From mboxrd@z Thu Jan 1 00:00:00 1970 From: ohaugan@codeaurora.org (Olav Haugan) Date: Thu, 16 Oct 2014 10:23:07 -0700 Subject: [PATCH v5 1/1] iommu-api: Add map_sg/unmap_sg functions In-Reply-To: <20141015091652.GB13162@ulmo> References: <1407797150-515-1-git-send-email-ohaugan@codeaurora.org> <1407797150-515-2-git-send-email-ohaugan@codeaurora.org> <20140925170108.GE8306@8bytes.org> <5432E757.10201@codeaurora.org> <20141015091652.GB13162@ulmo> Message-ID: <543FFEFB.2010604@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10/15/2014 2:16 AM, Thierry Reding wrote: > On Mon, Oct 06, 2014 at 12:02:47PM -0700, Olav Haugan wrote: >> On 9/25/2014 10:01 AM, Joerg Roedel wrote: >>> On Mon, Aug 11, 2014 at 03:45:50PM -0700, Olav Haugan wrote: >>>> +static inline int iommu_map_sg(struct iommu_domain *domain, unsigned long iova, >>>> + struct scatterlist *sg, unsigned int nents, >>>> + int prot, unsigned long flags) >>>> +{ >>>> + return domain->ops->map_sg(domain, iova, sg, nents, prot, flags); >>>> +} >>>> + >>>> +static inline int iommu_unmap_sg(struct iommu_domain *domain, >>>> + unsigned long iova, size_t size, >>>> + unsigned long flags) >>>> +{ >>>> + return domain->ops->unmap_sg(domain, iova, size, flags); >>>> +} >>> >>> I have thought a little bit more about this interface and think that it >>> would be better to just return a size_t from iommu_map_sg(). The >>> function returns the amount of address space mapped by it, 0 in the >>> worst case. >>> >>> This makes it easy to unmap the region just with >>> iommu_unmap(domain, iova, size) in the end and removing the need for a >>> new iommu_unmap_sg() function. Also the error-path of the map_sg >>> call-backs becomes easier as the function then just returns the amount >>> of address-space already mapped before the error happened. >>> >>> So the prototype would be: >>> >>> size_t iommu_map_sg(struct iommu_domain *domain, >>> unsigned long iova, >>> struct scatterlist *sg, >>> unsigned int nents, >>> int prot); >>> >>> (as I said before, the flags parameter should not be added by this >>> patch-set). >>> >> >> Ok, sounds good. I'll post v6 soon. > > Perhaps make the return value ssize_t so that we can propagate errors? > I am fine with that. Joerg? Thanks, .Olav -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project