[PATCH v2 7/8] firmware: arm_scmi: make notify_priv really private

From: Cristian Marussi
Date: Wed Oct 28 2020 - 17:47:21 EST


Notification private data is currently accessible via handle->notify_priv;
this data was indeed meant to be private to the notification core support
and not to be accessible to SCMI drivers: make it private hiding it inside
instance descriptor struct scmi_info.

Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
---
drivers/firmware/arm_scmi/common.h | 4 +++
drivers/firmware/arm_scmi/driver.c | 21 +++++++++++++
drivers/firmware/arm_scmi/notify.c | 49 +++++++++++-------------------
include/linux/scmi_protocol.h | 3 --
4 files changed, 43 insertions(+), 34 deletions(-)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 995f19a07b5e..9ae0e4133f31 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -342,4 +342,8 @@ void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem);
bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
struct scmi_xfer *xfer);

+void scmi_set_notification_instance_data(const struct scmi_handle *handle,
+ void *priv);
+void *scmi_get_notification_instance_data(const struct scmi_handle *handle);
+
#endif /* _SCMI_COMMON_H */
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 87ceb235194b..d6a975992136 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -113,6 +113,7 @@ struct scmi_protocol_instance {
* @protocols_mtx: A mutex to protect protocols instances initialization.
* @protocols_imp: List of protocols implemented, currently maximum of
* MAX_PROTOCOLS_IMP elements allocated by the base protocol
+ * @notify_priv: Pointer to private data structure specific to notifications.
* @node: List head
* @users: Number of users of this instance
*/
@@ -129,6 +130,7 @@ struct scmi_info {
/* Ensure mutual exclusive access to protocols instance array */
struct mutex protocols_mtx;
u8 *protocols_imp;
+ void *notify_priv;
struct list_head node;
int users;
};
@@ -170,6 +172,25 @@ static inline void scmi_dump_header_dbg(struct device *dev,
hdr->id, hdr->seq, hdr->protocol_id);
}

+void scmi_set_notification_instance_data(const struct scmi_handle *handle,
+ void *priv)
+{
+ struct scmi_info *info = handle_to_scmi_info(handle);
+
+ info->notify_priv = priv;
+ /* Ensure updated protocol private date are visible */
+ smp_wmb();
+}
+
+void *scmi_get_notification_instance_data(const struct scmi_handle *handle)
+{
+ struct scmi_info *info = handle_to_scmi_info(handle);
+
+ /* Ensure protocols_private_data has been updated */
+ smp_rmb();
+ return info->notify_priv;
+}
+
/**
* scmi_xfer_get() - Allocate one message
*
diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c
index 6d4a1d78c22e..1c0126f41756 100644
--- a/drivers/firmware/arm_scmi/notify.c
+++ b/drivers/firmware/arm_scmi/notify.c
@@ -580,11 +580,9 @@ int scmi_notify(const struct scmi_handle *handle, u8 proto_id, u8 evt_id,
struct scmi_event_header eh;
struct scmi_notify_instance *ni;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return 0;
- ni = handle->notify_priv;

r_evt = SCMI_GET_REVT(ni, proto_id, evt_id);
if (!r_evt)
@@ -760,11 +758,9 @@ int scmi_register_protocol_events(const struct scmi_handle *handle, u8 proto_id,
(!ee->num_sources && !ee->ops->get_num_sources))
return -EINVAL;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return -ENOMEM;
- ni = handle->notify_priv;

/* num_sources cannot be <= 0 */
if (ee->num_sources) {
@@ -849,12 +845,10 @@ void scmi_deregister_protocol_events(const struct scmi_handle *handle,
struct scmi_notify_instance *ni;
struct scmi_registered_events_desc *pd;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return;

- ni = handle->notify_priv;
pd = ni->registered_protocols[proto_id];
if (!pd)
return;
@@ -1357,11 +1351,9 @@ static int scmi_register_notifier(const struct scmi_handle *handle,
struct scmi_event_handler *hndl;
struct scmi_notify_instance *ni;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return -ENODEV;
- ni = handle->notify_priv;

evt_key = MAKE_HASH_KEY(proto_id, evt_id,
src_id ? *src_id : SRC_ID_MASK);
@@ -1405,11 +1397,9 @@ static int scmi_unregister_notifier(const struct scmi_handle *handle,
struct scmi_event_handler *hndl;
struct scmi_notify_instance *ni;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return -ENODEV;
- ni = handle->notify_priv;

evt_key = MAKE_HASH_KEY(proto_id, evt_id,
src_id ? *src_id : SRC_ID_MASK);
@@ -1682,8 +1672,8 @@ int scmi_notification_init(struct scmi_handle *handle)

INIT_WORK(&ni->init_work, scmi_protocols_late_init);

+ scmi_set_notification_instance_data(handle, ni);
handle->notify_ops = &notify_ops;
- handle->notify_priv = ni;
/* Ensure handle is up to date */
smp_wmb();

@@ -1695,7 +1685,7 @@ int scmi_notification_init(struct scmi_handle *handle)

err:
dev_warn(handle->dev, "Initialization Failed.\n");
- devres_release_group(handle->dev, NULL);
+ devres_release_group(handle->dev, gid);
return -ENOMEM;
}

@@ -1706,19 +1696,16 @@ int scmi_notification_init(struct scmi_handle *handle)
void scmi_notification_exit(struct scmi_handle *handle)
{
struct scmi_notify_instance *ni;
+ void *gid;

- /* Ensure notify_priv is updated */
- smp_rmb();
- if (!handle->notify_priv)
+ ni = scmi_get_notification_instance_data(handle);
+ if (!ni)
return;
- ni = handle->notify_priv;
-
- handle->notify_priv = NULL;
- /* Ensure handle is up to date */
- smp_wmb();
+ scmi_set_notification_instance_data(handle, NULL);

/* Destroy while letting pending work complete */
destroy_workqueue(ni->notify_wq);

- devres_release_group(ni->handle->dev, ni->gid);
+ gid = ni->gid;
+ devres_release_group(ni->handle->dev, gid);
}
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index 383b3d0ca383..66625aedd3a7 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -279,8 +279,6 @@ struct scmi_notify_ops {
* dedicated protocol handler
* @put_ops: method to release a protocol
* @notify_ops: pointer to set of notifications related operations
- * @notify_priv: pointer to private data structure specific to notifications
- * (for internal use only)
*/
struct scmi_handle {
struct device *dev;
@@ -297,7 +295,6 @@ struct scmi_handle {
void (*put_ops)(const struct scmi_handle *handle, u8 proto);

const struct scmi_notify_ops *notify_ops;
- void *notify_priv;
};

enum scmi_std_protocol {
--
2.17.1