From 64acb6611f3c17251347870e73ddc106fed807cb Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 9 Mar 2016 12:20:40 +0100 Subject: [PATCH] greybus: interface: remove useless spinlock Remove useless global interface spinlock that appeared to protect the host-device interface list, but really did not as we are doing lock-less look-ups by relying on the single-threaded SVC workqueue. Document the locking assumptions. Signed-off-by: Johan Hovold Reviewed-by: Viresh Kumar Signed-off-by: Greg Kroah-Hartman --- drivers/staging/greybus/interface.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/staging/greybus/interface.c b/drivers/staging/greybus/interface.c index 2654fa8a1f0b..4671f4092a17 100644 --- a/drivers/staging/greybus/interface.c +++ b/drivers/staging/greybus/interface.c @@ -54,9 +54,6 @@ static struct attribute *interface_attrs[] = { ATTRIBUTE_GROUPS(interface); -/* XXX This could be per-host device */ -static DEFINE_SPINLOCK(gb_interfaces_lock); - // FIXME, odds are you don't want to call this function, rework the caller to // not need it please. struct gb_interface *gb_interface_find(struct gb_host_device *hd, @@ -100,6 +97,9 @@ struct device_type greybus_interface_type = { * * Returns a pointer to the new interfce or a null pointer if a * failure occurs due to memory exhaustion. + * + * Locking: Caller ensures serialisation with gb_interface_remove and + * gb_interface_find. */ struct gb_interface *gb_interface_create(struct gb_host_device *hd, u8 interface_id) @@ -132,9 +132,7 @@ struct gb_interface *gb_interface_create(struct gb_host_device *hd, return NULL; } - spin_lock_irq(&gb_interfaces_lock); list_add(&intf->links, &hd->interfaces); - spin_unlock_irq(&gb_interfaces_lock); return intf; } @@ -164,9 +162,7 @@ void gb_interface_remove(struct gb_interface *intf) gb_control_disable(intf->control); - spin_lock_irq(&gb_interfaces_lock); list_del(&intf->links); - spin_unlock_irq(&gb_interfaces_lock); put_device(&intf->dev); } -- 2.20.1