From cad09a8f8ce843aa11f9a6a8a7aa5c6d6591147b Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Tue, 14 Jul 2015 15:43:30 +0200 Subject: [PATCH] greybus: connection: add connection-state locking Add locking, and the implied barriers, to connection-state updates. This will be used to fix a number of races in the operations and connection-tear-down implementations. Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/staging/greybus/connection.c | 24 ++++++++++++++++++++---- drivers/staging/greybus/connection.h | 1 + 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/staging/greybus/connection.c b/drivers/staging/greybus/connection.c index b9f9b11b1b65..abc1f861ea28 100644 --- a/drivers/staging/greybus/connection.c +++ b/drivers/staging/greybus/connection.c @@ -65,8 +65,13 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gb_connection *connection = to_gb_connection(dev); + enum gb_connection_state state; - return sprintf(buf, "%d\n", connection->state); + spin_lock_irq(&connection->lock); + state = connection->state; + spin_unlock_irq(&connection->lock); + + return sprintf(buf, "%d\n", state); } static DEVICE_ATTR_RO(state); @@ -204,6 +209,7 @@ struct gb_connection *gb_connection_create(struct gb_bundle *bundle, spin_unlock_irq(&gb_connections_lock); atomic_set(&connection->op_cycle, 0); + spin_lock_init(&connection->lock); INIT_LIST_HEAD(&connection->operations); /* XXX Will have to establish connections to get version */ @@ -274,10 +280,16 @@ int gb_connection_init(struct gb_connection *connection) } /* Need to enable the connection to initialize it */ + spin_lock_irq(&connection->lock); connection->state = GB_CONNECTION_STATE_ENABLED; + spin_unlock_irq(&connection->lock); + ret = connection->protocol->connection_init(connection); - if (ret) + if (ret) { + spin_lock_irq(&connection->lock); connection->state = GB_CONNECTION_STATE_ERROR; + spin_unlock_irq(&connection->lock); + } return ret; } @@ -291,10 +303,14 @@ void gb_connection_exit(struct gb_connection *connection) return; } - if (connection->state != GB_CONNECTION_STATE_ENABLED) + spin_lock_irq(&connection->lock); + if (connection->state != GB_CONNECTION_STATE_ENABLED) { + spin_unlock_irq(&connection->lock); return; - + } connection->state = GB_CONNECTION_STATE_DESTROYING; + spin_unlock_irq(&connection->lock); + connection->protocol->connection_exit(connection); /* diff --git a/drivers/staging/greybus/connection.h b/drivers/staging/greybus/connection.h index ad699db0dfd8..c2b71fe7f397 100644 --- a/drivers/staging/greybus/connection.h +++ b/drivers/staging/greybus/connection.h @@ -35,6 +35,7 @@ struct gb_connection { u8 major; u8 minor; + spinlock_t lock; enum gb_connection_state state; atomic_t op_cycle; -- 2.39.2