Re: [PATCH v9 07/10] iommu/arm-smmu-v3: Maintain a SID->device structure

Jonathan Cameron
2021-01-20T00:08:32Z

On Fri, 8 Jan 2021 15:52:15 +0100
Jean-Philippe Brucker <jean-philippe@linaro.org> wrote:

> When handling faults from the event or PRI queue, we need to find the
> struct device associated with a SID. Add a rb_tree to keep track of
> SIDs.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
One totally trivial point if you happen to be spinning again.

Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
with or without that.

> ---
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 13 +-
> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 161 ++++++++++++++++----
> 2 files changed, 144 insertions(+), 30 deletions(-)
>

...

>
> +static int arm_smmu_insert_master(struct arm_smmu_device *smmu,
> + struct arm_smmu_master *master)
> +{
> + int i;
> + int ret = 0;
> + struct arm_smmu_stream *new_stream, *cur_stream;
> + struct rb_node **new_node, *parent_node = NULL;
> + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);
> +
> + master->streams = kcalloc(fwspec->num_ids,
> + sizeof(struct arm_smmu_stream), GFP_KERNEL);
sizeof(*master->streams)

nitpick :) Saves reviewer going to check that master->streams is of the type they expect.

> + if (!master->streams)
> + return -ENOMEM;
> + master->num_streams = fwspec->num_ids;
> +
> + mutex_lock(&smmu->streams_mutex);
> + for (i = 0; i < fwspec->num_ids && !ret; i++) {
> + u32 sid = fwspec->ids[i];
> +
> + new_stream = &master->streams[i];
> + new_stream->id = sid;
> + new_stream->master = master;
> +
> + /*
> + * Check the SIDs are in range of the SMMU and our stream table
> + */
> + if (!arm_smmu_sid_in_range(smmu, sid)) {
> + ret = -ERANGE;
> + break;
> + }
> +
> + /* Ensure l2 strtab is initialised */
> + if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
> + ret = arm_smmu_init_l2_strtab(smmu, sid);
> + if (ret)
> + break;
> + }
> +
> + /* Insert into SID tree */
> + new_node = &(smmu->streams.rb_node);
> + while (*new_node) {
> + cur_stream = rb_entry(*new_node, struct arm_smmu_stream,
> + node);
> + parent_node = *new_node;
> + if (cur_stream->id > new_stream->id) {
> + new_node = &((*new_node)->rb_left);
> + } else if (cur_stream->id < new_stream->id) {
> + new_node = &((*new_node)->rb_right);
> + } else {
> + dev_warn(master->dev,
> + "stream %u already in tree\n",
> + cur_stream->id);
> + ret = -EINVAL;
> + break;
> + }
> + }
> +
> + if (!ret) {
> + rb_link_node(&new_stream->node, parent_node, new_node);
> + rb_insert_color(&new_stream->node, &smmu->streams);
> + }
> + }
> +
> + if (ret) {
> + for (; i > 0; i--)
> + rb_erase(&master->streams[i].node, &smmu->streams);
> + kfree(master->streams);
> + }
> + mutex_unlock(&smmu->streams_mutex);
> +
> + return ret;
> +}
...