Commit 4afb7fd0 authored by Alex Elder's avatar Alex Elder Committed by Greg Kroah-Hartman
Browse files

greybus: make op_cycle atomic (again) 



There's no need to protect updating a connections operation id cycle
counter with the operations spinlock.   That spinlock protects
connection lists, which do not interact with the cycle counter.
All that we require is that it gets updated atomically, and we
can express that requirement in its type.

Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <greg@kroah.com>
parent afb2e134

drivers/staging/greybus/connection.c

+1 −0
Original line number Diff line number Diff line
@@ -191,6 +191,7 @@ struct gb_connection *gb_connection_create(struct gb_interface *interface, 
	list_add_tail(&connection->interface_links, &interface->connections);

	spin_unlock_irq(&gb_connections_lock);



	atomic_set(&connection->op_cycle, 0);

	INIT_LIST_HEAD(&connection->operations);



	return connection;

drivers/staging/greybus/connection.h

+1 −1
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ struct gb_connection { 


	enum gb_connection_state	state;



	u16				op_cycle;

	atomic_t			op_cycle;

	struct list_head		operations;



	void				*private;

drivers/staging/greybus/operation.c

+3 −3
Original line number Diff line number Diff line
@@ -640,6 +640,7 @@ int gb_operation_request_send(struct gb_operation *operation, 
	struct gb_connection *connection = operation->connection;

	struct gb_operation_msg_hdr *header;

	unsigned long timeout;

	unsigned int cycle;

	int ret;



	if (connection->state != GB_CONNECTION_STATE_ENABLED)
@@ -661,9 +662,8 @@ int gb_operation_request_send(struct gb_operation *operation, 
	 * Assign the operation's id, and store it in the request header.

	 * Zero is a reserved operation id.

	 */

	spin_lock_irq(&gb_operations_lock);

	operation->id = ++connection->op_cycle % U16_MAX + 1;

	spin_unlock_irq(&gb_operations_lock);

	cycle = (unsigned int)atomic_inc_return(&connection->op_cycle);

	operation->id = (u16)(cycle % U16_MAX + 1);

	header = operation->request->header;

	header->operation_id = cpu_to_le16(operation->id);