Hey Bjorn,
Thanks for taking time to review
the series.
On 2020-01-03 02:15, Bjorn Andersson wrote:
On Sun 29 Dec 21:00 PST 2019, Sibi Sankar wrote:
[..]
diff --git a/drivers/soc/qcom/pdr_interface.c
b/drivers/soc/qcom/pdr_interface.c
[..]
+static int servreg_locator_new_server(struct qmi_handle *qmi,
+ struct qmi_service *svc)
+{
+ struct pdr_handle *pdr = container_of(qmi, struct pdr_handle,
+ servloc_client);
+ struct pdr_service *pds, *tmp;
+
+ /* Create a Local client port for QMI communication */
+ pdr->servloc_addr.sq_family = AF_QIPCRTR;
+ pdr->servloc_addr.sq_node = svc->node;
+ pdr->servloc_addr.sq_port = svc->port;
+
+ mutex_lock(&pdr->locator_lock);
+ pdr->locator_available = true;
+ mutex_unlock(&pdr->locator_lock);
+
+ /* Service pending lookup requests */
+ mutex_lock(&pdr->list_lock);
+ list_for_each_entry_safe(pds, tmp, &pdr->lookups, node) {
No need to make this _safe, as you're not modifying the list in the
loop.
sure I'll do that
+ if (pds->need_servreg_lookup)
+ schedule_work(&pdr->servloc_work);
+ }
+ mutex_unlock(&pdr->list_lock);
+
+ return 0;
+}
[..]
+static void pdr_servreg_link_create(struct pdr_handle *pdr,
+ struct pdr_service *pds)
+{
+ struct pdr_service *pds_iter, *tmp;
+ bool link_exists = false;
+
+ /* Check if a QMI link to SERVREG instance already exists */
+ mutex_lock(&pdr->list_lock);
+ list_for_each_entry_safe(pds_iter, tmp, &pdr->lookups, node) {
+ if (pds_iter->instance == pds->instance &&
Flip this condition around and continue if it's not a match, to save
indentation and to split the two expressions into two distinct checks.
sure I'll do that
+ strcmp(pds_iter->service_path, pds->service_path)) {
Isn't this just saying:
if (pds_iter == pds)
continue;
With the purpose of link_exists to be !empty(set(lookups) - pds) ?
More like:
!empty(set(lookups_with_same_instance) - pds)
servreg_link_create was added to re-use
an existing qmi_lookup i.e deal with
PDs running on the same remote processor.
This can be identified by looking for
a lookup with the same instance value
but with a different service path. We
still need to register the service_path
with the servreg service once its up.
But if I read pdr_add_lookup() correctly it's possible that a client
could call pdr_add_lookup() more than once before pdr_servloc_work() is
scheduled, in which case "set(lookup) - pds" isn't empty and as such
you
won't add the lookup?
holding the lock over entire servloc_work
should handle that scenario? That way we
can ensure qmi_lookup is called atleast
once.
+ link_exists = true;
+ pds->service_connected = pds_iter->service_connected;
+ if (pds_iter->service_connected)
+ pds->need_servreg_register = true;
+ else
+ pds->need_servreg_remove = true;
+ queue_work(pdr->servreg_wq, &pdr->servreg_work);
+ break;
+ }
+ }
[..]
+static void pdr_servloc_work(struct work_struct *work)
+{
+ struct pdr_handle *pdr = container_of(work, struct pdr_handle,
+ servloc_work);
+ struct pdr_service *pds, *tmp;
+ int ret;
+
+ /* Bail out early if PD Mapper is not up */
+ mutex_lock(&pdr->locator_lock);
+ if (!pdr->locator_available) {
+ mutex_unlock(&pdr->locator_lock);
+ pr_warn("PDR: SERVICE LOCATOR service not available\n");
+ return;
+ }
+ mutex_unlock(&pdr->locator_lock);
+
+ mutex_lock(&pdr->list_lock);
+ list_for_each_entry_safe(pds, tmp, &pdr->lookups, node) {
As written right now you don't need _safe here, because in the only
case
you're modifying the list you end up exiting the loop.
sure
+ if (!pds->need_servreg_lookup)
+ continue;
+
+ pds->need_servreg_lookup = false;
+ mutex_unlock(&pdr->list_lock);
You should probably just hold on to list_lock over this entire loop.
+
+ ret = pdr_locate_service(pdr, pds);
+ if (ret < 0) {
+ if (ret == -ENXIO)
+ pds->state = SERVREG_LOCATOR_UNKNOWN_SERVICE;
+ else if (ret == -EAGAIN)
+ pds->state = SERVREG_LOCATOR_DB_UPDATED;
Isn't this something that we should recover from?
yes its a case where the json
referenced by pd-mapper has been
updated mid lookup. Calling lookup
again should ideally fix this but
we'll have to decide on the max
number of retries. I guess I can
simulate such a scenario with
a custom json file and pd-mapper
changes.
+ else
+ pds->state = SERVREG_LOCATOR_ERR;
+
+ pr_err("PDR: service lookup for %s failed: %d\n",
+ pds->service_name, ret);
+
+ /* Remove from lookup list */
+ mutex_lock(&pdr->list_lock);
+ list_del(&pds->node);
What should I do in my driver when this happens?
db_updated -> retry should fix
this error
unknown_service -> lookup not found.
^^ With the way pd-mapper is implemented
its not really recoverable until pd-mapper
is restarted with different args.
locator_err -> not really recoverable
+ mutex_unlock(&pdr->list_lock);
+
+ /* Notify Lookup failed */
+ mutex_lock(&pdr->status_lock);
+ pdr->status(pdr, pds);
+ mutex_unlock(&pdr->status_lock);
+ kfree(pds);
+ } else {
+ pdr_servreg_link_create(pdr, pds);
+ }
+
+ return;
There might be more pds entries with need_servreg_lookup in the list,
shouldn't we allow this to continue?
but we've already scheduled a
number of workers to deal with
this.
This would though imply that you should hold onto the list_lock over
the
entire loop, which I think looks fine.
sure
+ }
+ mutex_unlock(&pdr->list_lock);
+}
+
+/**
+ * pdr_add_lookup() - register a tracking request for a PD
+ * @pdr: PDR client handle
+ * @service_name: service name of the tracking request
+ * @service_path: service path of the tracking request
+ *
+ * Registering a pdr lookup allows for tracking the life cycle of the
PD.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int pdr_add_lookup(struct pdr_handle *pdr, const char *service_name,
+ const char *service_path)
+{
+ struct pdr_service *pds, *pds_iter, *tmp;
+ int ret;
+
+ if (!service_name || strlen(service_name) > SERVREG_NAME_LENGTH ||
+ !service_path || strlen(service_path) > SERVREG_NAME_LENGTH)
+ return -EINVAL;
+
+ pds = kzalloc(sizeof(*pds), GFP_KERNEL);
+ if (!pds)
+ return -ENOMEM;
+
+ pds->service = SERVREG_NOTIFIER_SERVICE;
+ strcpy(pds->service_name, service_name);
+ strcpy(pds->service_path, service_path);
+ pds->need_servreg_lookup = true;
+
+ mutex_lock(&pdr->list_lock);
+ list_for_each_entry_safe(pds_iter, tmp, &pdr->lookups, node) {
No _safe
Thanks will update
+ if (!strcmp(pds_iter->service_path, service_path)) {
+ mutex_unlock(&pdr->list_lock);
+ ret = -EALREADY;
+ goto err;
+ }
+ }
+
+ list_add(&pds->node, &pdr->lookups);
+ mutex_unlock(&pdr->list_lock);
+
+ schedule_work(&pdr->servloc_work);
+
+ return 0;
+err:
+ kfree(pds);
+
+ return ret;
+}
+EXPORT_SYMBOL(pdr_add_lookup);
+
+/**
+ * pdr_restart_pd() - restart PD
+ * @pdr: PDR client handle
+ * @service_path: service path of restart request
+ *
+ * Restarts the PD tracked by the PDR client handle for a given
service path.
+ *
+ * Return: 0 on success, negative errno on failure.
+ */
+int pdr_restart_pd(struct pdr_handle *pdr, const char *service_path)
+{
+ struct servreg_restart_pd_req req;
+ struct servreg_restart_pd_resp resp;
+ struct pdr_service *pds = NULL, *pds_iter, *tmp;
+ struct qmi_txn txn;
+ int ret;
+
+ if (!service_path || strlen(service_path) > SERVREG_NAME_LENGTH)
+ return -EINVAL;
+
+ mutex_lock(&pdr->list_lock);
+ list_for_each_entry_safe(pds_iter, tmp, &pdr->lookups, node) {
+ if (!pds_iter->service_connected)
+ continue;
+
+ if (!strcmp(pds_iter->service_path, service_path)) {
+ pds = pds_iter;
+ break;
+ }
+ }
+ mutex_unlock(&pdr->list_lock);
+
+ if (!pds)
Given that you may only call pdr_restart_pd() on something created by
first calling pdr_add_lookup(), how about returning the struct
pdr_service from pdr_add_lookup() instead and then have the client pass
that as an argument to this function.
Most clients doesn't care about pdr_restart_pd() so they would only
have
to IS_ERR(pdr_add_lookup()) anyways, and the ones that care can carry
the returned pointer.
Note that the struct pdr_service doesn't have to be defined in a way
that it's possible to dereference by clients.
sure will update the design in the
next re-spin.
+ return -EINVAL;
+
+ /* Prepare req message */
+ strcpy(req.service_path, pds->service_path);
+
+ ret = qmi_txn_init(&pdr->servreg_client, &txn,
+ servreg_restart_pd_resp_ei,
+ &resp);
+ if (ret < 0)
+ return ret;
+
+ ret = qmi_send_request(&pdr->servreg_client, &pdr->servreg_addr,
+ &txn, SERVREG_RESTART_PD_REQ,
+ SERVREG_RESTART_PD_REQ_MAX_LEN,
+ servreg_restart_pd_req_ei, &req);
+ if (ret < 0) {
+ qmi_txn_cancel(&txn);
+ return ret;
+ }
+
+ ret = qmi_txn_wait(&txn, 5 * HZ);
+ if (ret < 0) {
+ pr_err("PDR: %s PD restart txn wait failed: %d\n",
+ pds->service_path, ret);
+ return ret;
+ }
+
+ /* Check response if PDR is disabled */
+ if (resp.resp.result == QMI_RESULT_FAILURE_V01 &&
+ resp.resp.error == QMI_ERR_DISABLED_V01) {
+ pr_err("PDR: %s PD restart is disabled: 0x%x\n",
+ pds->service_path, resp.resp.error);
+ return -EOPNOTSUPP;
+ }
+
+ /* Check the response for other error case*/
+ if (resp.resp.result != QMI_RESULT_SUCCESS_V01) {
+ pr_err("PDR: %s request for PD restart failed: 0x%x\n",
+ pds->service_path, resp.resp.error);
+ return -EREMOTEIO;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(pdr_restart_pd);
[..]
+/**
+ * struct pdr_service - context to track lookups/restarts
+ * @service_name: name of the service running on the PD
+ * @service_path: service path of the PD
+ * @service_data_valid: indicates if service_data field has valid
data
+ * @service_data: service data provided by servreg_locator service
+ * @need_servreg_lookup: state flag for tracking servreg lookup
requests
+ * @need_servreg_register: state flag for tracking pending servreg
register
+ * @need_servreg_remove: state flag for tracking pending servreg
remove
+ * @service_connected: current state of servreg_notifier qmi service
+ * @state: current state of PD
+ * @service: servreg_notifer service type
+ * @instance: instance id of the @service
+ * @priv: handle for client's use
+ * @node: list_head for house keeping
+ */
+struct pdr_service {
This is primarily internal bookkeeping, how about not exposing it to
the
clients? This would imply that status() would have to be called with
pdr_service->priv and pdr_service->state as arguments instead.
sure will update the design in the
next re-spin.
+ char service_name[SERVREG_NAME_LENGTH + 1];
+ char service_path[SERVREG_NAME_LENGTH + 1];
+
+ u8 service_data_valid;
+ u32 service_data;
+
+ bool need_servreg_lookup;
+ bool need_servreg_register;
+ bool need_servreg_remove;
+ bool service_connected;
+ int state;
+
+ unsigned int instance;
+ unsigned int service;
+
+ void *priv;
+ struct list_head node;
+};
+
[..]
+ void (*status)(struct pdr_handle *pdr, struct pdr_service *pds);
+};
Regards,
Bjorn
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