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SubjectRe: [PATCH v5 1/2] IMA: Define workqueue for early boot "key" measurements
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On Wed, 2019-12-18 at 08:44 -0800, Lakshmi Ramasubramanian wrote:
> +/*
> + * ima_process_queued_keys() - process keys queued for measurement
> + *
> + * This function sets ima_process_keys to true and processes queued keys.
> + * From here on keys will be processed right away (not queued).
> + */
> +void ima_process_queued_keys(void)
> +{
> + struct ima_key_entry *entry, *tmp;
> + bool process = false;
> +
> + if (ima_process_keys)
> + return;
> +
> + /*
> + * Since ima_process_keys is set to true, any new key will be
> + * processed immediately and not be queued to ima_keys list.
> + * First one setting the ima_process_keys flag to true will
> + * process the queued keys.
> + */
> + mutex_lock(&ima_keys_mutex);
> + if (!ima_process_keys) {
> + ima_process_keys = true;
> + process = true;
> + }
> + mutex_unlock(&ima_keys_mutex);
> +
> + if (!process)
> + return;
> +
> + list_for_each_entry_safe(entry, tmp, &ima_keys, list) {
> + process_buffer_measurement(entry->payload, entry->payload_len,
> + entry->keyring_name, KEY_CHECK, 0,
> + entry->keyring_name);
> + list_del(&entry->list);
> + ima_free_key_entry(entry);
> + }
> +}
> +

Getting rid of the temporary list is definitely a big improvement.  As
James suggested, using test_and_set_bit() and test_bit() would improve
this code even more.  I think, James correct me if I'm wrong, you
would be able to get rid of both the mutex and "process".

Mimi


> /**
> * ima_post_key_create_or_update - measure asymmetric keys
> * @keyring: keyring to which the key is linked to

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