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SubjectRe: [PATCH v11 26/33] counter: Add character device interface
On Wed, Jun 09, 2021 at 10:31:29AM +0900, William Breathitt Gray wrote:
> +static int counter_set_event_node(struct counter_device *const counter,
> + struct counter_watch *const watch,
> + const struct counter_comp_node *const cfg)
> +{
> + struct counter_event_node *event_node;
> + struct counter_comp_node *comp_node;
> +

The caller should be holding the counter->events_list_lock lock but it's
not.


> + /* Search for event in the list */
> + list_for_each_entry(event_node, &counter->next_events_list, l)
> + if (event_node->event == watch->event &&
> + event_node->channel == watch->channel)
> + break;
> +
> + /* If event is not already in the list */
> + if (&event_node->l == &counter->next_events_list) {
> + /* Allocate new event node */
> + event_node = kmalloc(sizeof(*event_node), GFP_ATOMIC);
> + if (!event_node)
> + return -ENOMEM;
> +
> + /* Configure event node and add to the list */
> + event_node->event = watch->event;
> + event_node->channel = watch->channel;
> + INIT_LIST_HEAD(&event_node->comp_list);
> + list_add(&event_node->l, &counter->next_events_list);
> + }
> +
> + /* Check if component watch has already been set before */
> + list_for_each_entry(comp_node, &event_node->comp_list, l)
> + if (comp_node->parent == cfg->parent &&
> + comp_node->comp.count_u8_read == cfg->comp.count_u8_read)
> + return -EINVAL;
> +
> + /* Allocate component node */
> + comp_node = kmalloc(sizeof(*comp_node), GFP_ATOMIC);
> + if (!comp_node) {
> + /* Free event node if no one else is watching */
> + if (list_empty(&event_node->comp_list)) {
> + list_del(&event_node->l);
> + kfree(event_node);
> + }
> + return -ENOMEM;
> + }
> + *comp_node = *cfg;
> +
> + /* Add component node to event node */
> + list_add_tail(&comp_node->l, &event_node->comp_list);
> +
> + return 0;
> +}
> +
> +static int counter_disable_events(struct counter_device *const counter)
> +{
> + unsigned long flags;
> + int err = 0;
> +
> + spin_lock_irqsave(&counter->events_list_lock, flags);
> +
> + counter_events_list_free(&counter->events_list);
> +
> + if (counter->ops->events_configure)
> + err = counter->ops->events_configure(counter);
> +
> + spin_unlock_irqrestore(&counter->events_list_lock, flags);
> +
> + counter_events_list_free(&counter->next_events_list);
> +
> + return err;
> +}
> +
> +static int counter_add_watch(struct counter_device *const counter,
> + const unsigned long arg)
> +{
> + void __user *const uwatch = (void __user *)arg;
> + struct counter_watch watch;
> + struct counter_comp_node comp_node = {0};

Always use = {};. It's the new hotness, and it avoids a Sparse warning
for using 0 instead of NULL. #IDidNotTest #CouldBeWrongAboutSparse

> + size_t parent, id;
> + struct counter_comp *ext;
> + size_t num_ext;
> + int err;
> +

regards,
dan carpenter

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