Re: [PATCH v6 03/07] iommu/ipmmu-vmsa: Break out utlb parsing code

Laurent Pinchart
2016-11-11T01:00:34Z

Hi Magnus,

Thank you for the patch.

On Thursday 20 Oct 2016 08:36:03 Magnus Damm wrote:
> From: Magnus Damm <damm+renesas@opensource.se>
>
> Break out the utlb parsing code and dev_data allocation into a
> separate function. This is preparation for future code sharing.
>
> Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
> Reviewed-by: Joerg Roedel <jroedel@suse.de>
> ---
>
> Changes since V5:
> - None
>
> Changes since V4:
> - Dropped hunk with fix to apply on top of:
> b1e2afc iommu/ipmmu-vmsa: Fix wrong error handle of ipmmu_add_device
>
> Changes since V3:
> - Initialize "mmu" to NULL, check before accessing
> - Removed group parameter from ipmmu_init_platform_device()
>
> Changes since V2:
> - Included this new patch from the following series:
> [PATCH 00/04] iommu/ipmmu-vmsa: IPMMU CONFIG_IOMMU_DMA update
> - Reworked code to fit on top on previous two patches in current series.
>
> drivers/iommu/ipmmu-vmsa.c | 58 ++++++++++++++++++++++++++---------------
> 1 file changed, 37 insertions(+), 21 deletions(-)
>
> --- 0006/drivers/iommu/ipmmu-vmsa.c
> +++ work/drivers/iommu/ipmmu-vmsa.c 2016-09-20 21:49:34.580607110 +0900
> @@ -647,22 +647,15 @@ static int ipmmu_find_utlbs(struct ipmmu
> return 0;
> }
>
> -static int ipmmu_add_device(struct device *dev)
> +static int ipmmu_init_platform_device(struct device *dev)

The device doesn't have to be a platform device, how about calling this
ipmmu_init_device_archdata() ?

> {
> struct ipmmu_vmsa_archdata *archdata;
> struct ipmmu_vmsa_device *mmu;
> - struct iommu_group *group = NULL;
> unsigned int *utlbs;
> unsigned int i;
> int num_utlbs;
> int ret = -ENODEV;
>
> - if (dev->archdata.iommu) {
> - dev_warn(dev, "IOMMU driver already assigned to device %s\n",
> - dev_name(dev));
> - return -EINVAL;
> - }
> -
> /* Find the master corresponding to the device. */
>
> num_utlbs = of_count_phandle_with_args(dev->of_node, "iommus",
> @@ -699,6 +692,36 @@ static int ipmmu_add_device(struct devic
> }
> }
>
> + archdata = kzalloc(sizeof(*archdata), GFP_KERNEL);
> + if (!archdata) {
> + ret = -ENOMEM;
> + goto error;
> + }
> +
> + archdata->mmu = mmu;
> + archdata->utlbs = utlbs;
> + archdata->num_utlbs = num_utlbs;
> + dev->archdata.iommu = archdata;
> + return 0;
> +
> +error:
> + kfree(utlbs);
> + return ret;
> +}
> +
> +static int ipmmu_add_device(struct device *dev)
> +{
> + struct ipmmu_vmsa_archdata *archdata;
> + struct ipmmu_vmsa_device *mmu = NULL;
> + struct iommu_group *group;
> + int ret;
> +
> + if (dev->archdata.iommu) {
> + dev_warn(dev, "IOMMU driver already assigned to device %s\n",
> + dev_name(dev));
> + return -EINVAL;
> + }
> +
> /* Create a device group and add the device to it. */
> group = iommu_group_alloc();
> if (IS_ERR(group)) {
> @@ -716,16 +739,9 @@ static int ipmmu_add_device(struct devic
> goto error;
> }
>
> - archdata = kzalloc(sizeof(*archdata), GFP_KERNEL);
> - if (!archdata) {
> - ret = -ENOMEM;
> + ret = ipmmu_init_platform_device(dev);
> + if (ret < 0)
> goto error;
> - }
> -
> - archdata->mmu = mmu;
> - archdata->utlbs = utlbs;
> - archdata->num_utlbs = num_utlbs;
> - dev->archdata.iommu = archdata;
>
> /*
> * Create the ARM mapping, used by the ARM DMA mapping core to
allocate
> @@ -736,6 +752,8 @@ static int ipmmu_add_device(struct devic
> * - Make the mapping size configurable ? We currently use a 2GB
mapping
> * at a 1GB offset to ensure that NULL VAs will fault.
> */
> + archdata = dev->archdata.iommu;
> + mmu = archdata->mmu;
> if (!mmu->mapping) {
> struct dma_iommu_mapping *mapping;
>
> @@ -760,10 +778,8 @@ static int ipmmu_add_device(struct devic
> return 0;
>
> error:
> - arm_iommu_release_mapping(mmu->mapping);
> -
> - kfree(dev->archdata.iommu);
> - kfree(utlbs);
> + if (mmu)
> + arm_iommu_release_mapping(mmu->mapping);

Looking at the surrounding code, shouldn't the mapping only be destroyed here
if it has been created by the same call to the function ? If there's an
existing mapping for the IPMMU instance and the arm_iommu_attach_device() call
fails, releasing the mapping seems to be a bug. As the bug isn't introduced by
this patch, we can fix it separately, but if you end up resubmitting due to
the first comment you could also add a fix.

>
> dev->archdata.iommu = NULL;

--
Regards,

Laurent Pinchart