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SubjectRe: [PATCH v5 1/8] interconnect: Add generic on-chip interconnect API
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Hi Matthias,

Thanks for reviewing!

On 06/27/2018 02:34 AM, Matthias Kaehlcke wrote:
> Hi Georgi,
>
> On Wed, Jun 20, 2018 at 03:11:34PM +0300, Georgi Djakov wrote:
>> This patch introduce a new API to get requirements and configure the
>
> nit: s/introduce/introduces/

Thanks!

[..]

>> + if (found) {
>> + struct icc_path *path = path_allocate(dst, depth);
>> +
>> + if (IS_ERR(path))
>> + return path;
>> +
>> + /* initialize the path */
>> + for (i = 0; i < path->num_nodes; i++) {
>> + node = path->reqs[i].node;
>> + path->reqs[i].dev = dev;
>> + node->provider->users++;
>
> nit: doing the assignment of path->reqs[i].dev before assiging 'node'
> or after incrementing the 'users' would slightly improve readability.

Ok, will re-factor this a bit.

>> +static int apply_constraints(struct icc_path *path)
>> +{
>> + struct icc_node *next, *prev = NULL;
>> + int ret = 0;
>> + int i;
>> +
>> + for (i = 0; i < path->num_nodes; i++, prev = next) {
>> + struct icc_provider *p;
>> +
>> + next = path->reqs[i].node;
>> + /*
>> + * Both endpoints should be valid master-slave pairs of the
>> + * same interconnect provider that will be configured.
>> + */
>> + if (!prev || next->provider != prev->provider)
>> + continue;
>> +
>> + p = next->provider;
>> +
>> + aggregate_provider(p);
>> +
>> + if (p->set) {
>> + /* set the constraints */
>> + ret = p->set(prev, next, p->avg_bw, p->peak_bw);
>> + }
>
> remove curly brackets
>
> EDIT: actually the condition can be removed, icc_provider_add() fails
> when p->set is NULL.

Agree!

>
>> +int icc_set(struct icc_path *path, u32 avg_bw, u32 peak_bw)
>> +{
>> + struct icc_node *node;
>> + struct icc_provider *p;
>> + size_t i;
>> + int ret = 0;
>
> initialization is not necessary
>

Ok.

>> +struct icc_path *icc_get(struct device *dev, const int src_id, const int dst_id)
>> +{
>> + struct icc_node *src, *dst;
>> + struct icc_path *path = ERR_PTR(-EPROBE_DEFER);
>> +
>> + src = node_find(src_id);
>> + if (!src) {
>> + dev_err(dev, "%s: invalid src=%d\n", __func__, src_id);
>> + goto out;
>> + }
>> +
>> + dst = node_find(dst_id);
>> + if (!dst) {
>> + dev_err(dev, "%s: invalid dst=%d\n", __func__, dst_id);
>> + goto out;
>> + }
>> +
>> + mutex_lock(&icc_lock);
>> + path = path_find(dev, src, dst);
>> + mutex_unlock(&icc_lock);
>> + if (IS_ERR(path)) {
>> + dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
>> + goto out;
>
> this goto isn't really needed

Ok.

>> +struct icc_node *icc_node_create(int id)
>> +{
>> + struct icc_node *node;
>> +
>> + /* check if node already exists */
>> + node = node_find(id);
>> + if (node)
>> + goto out;
>> +
>> + node = kzalloc(sizeof(*node), GFP_KERNEL);
>> + if (!node) {
>> + node = ERR_PTR(-ENOMEM);
>> + goto out;
>> + }
>> +
>> + mutex_lock(&icc_lock);
>> +
>> + id = idr_alloc(&icc_idr, node, id, id + 1, GFP_KERNEL);
>> + if (WARN(id < 0, "couldn't get idr")) {
>
> kfree(node);

Thanks!

>> +int icc_node_add(struct icc_node *node, struct icc_provider *provider)
>> +{
>> + mutex_lock(&icc_lock);
>> +
>> + node->provider = provider;
>> + list_add(&node->node_list, &provider->nodes);
>> +
>> + mutex_unlock(&icc_lock);
>> +
>> + return 0;
>> +}
>
> The function returns always 0. Should probably be void so callers
> don't add pointless checks of the return value.

Agree, will change it!

>> +int icc_provider_add(struct icc_provider *provider)
>> +{
>> + if (WARN_ON(!provider->set))
>> + return -EINVAL;
>> +
>> + mutex_init(&icc_lock);
>
> Shouldn't this be mutex_lock()?

Yes, right!

>> +int icc_provider_del(struct icc_provider *provider)
>> +{
>> + mutex_lock(&icc_lock);
>> + if (provider->users) {
>> + pr_warn("interconnect provider still has %d users\n",
>> + provider->users);
>> + mutex_unlock(&icc_lock);
>> + return -EBUSY;
>> + }
>> +
>> + if (!list_empty_careful(&provider->nodes)) {
>> + pr_warn("interconnect provider still has nodes\n");
>> + mutex_unlock(&icc_lock);
>> + return -EEXIST;
>> + }
>
> Could this be just list_empty()? If I didn't miss something icc_lock
> is held in all paths that change p->nodes (assuming that all changes
> should be done through the interfaces in this file).

It could be. Will update it. I just always want to be careful!

> Actually this check will always fail if icc_node_add() was called for
> this provider, it doesn't seem nodes are ever removed.
>

The provider driver is responsible for the node removal.

Thanks,
Georgi

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