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staging: vc04_services: don't increment service refcount when it's not needed 

There are a few places where a service's reference count is incremented,
something quick is done, and the refcount is dropped. This can be made
a little simpler/faster by not grabbing a reference in these cases.

Signed-off-by: Marcelo Diop-Gonzalez <marcgonzalez@google.com>
Link: https://lore.kernel.org/r/ac6186ac888f1acf489b5b504efcba8b0d6a8b25.1581532523.git.marcgonzalez@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Marcelo Diop-Gonzalez 2020-02-12 13:43:33 -05:00 committed by Greg Kroah-Hartman
parent 3c27a36f27
commit a2203cfe0d
3 changed files with 40 additions and 20 deletions
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16
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
View File

@ -2497,11 +2497,11 @@ vchiq_instance_get_use_count(struct vchiq_instance *instance)
int use_count = 0, i;
i = 0;
while ((service = next_service_by_instance(instance->state,
instance, &i))) {
rcu_read_lock();
while ((service = __next_service_by_instance(instance->state,
instance, &i)))
use_count += service->service_use_count;
unlock_service(service);
}
rcu_read_unlock();
return use_count;
}
@ -2524,11 +2524,11 @@ vchiq_instance_set_trace(struct vchiq_instance *instance, int trace)
int i;
i = 0;
while ((service = next_service_by_instance(instance->state,
instance, &i))) {
rcu_read_lock();
while ((service = __next_service_by_instance(instance->state,
instance, &i)))
service->trace = trace;
unlock_service(service);
}
rcu_read_unlock();
instance->trace = (trace != 0);
}

36
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
View File

@ -222,28 +222,42 @@ find_closed_service_for_instance(struct vchiq_instance *instance,
}
struct vchiq_service *
next_service_by_instance(struct vchiq_state *state, struct vchiq_instance *instance,
int *pidx)
__next_service_by_instance(struct vchiq_state *state,
struct vchiq_instance *instance,
int *pidx)
{
struct vchiq_service *service = NULL;
int idx = *pidx;
rcu_read_lock();
while (idx < state->unused_service) {
struct vchiq_service *srv;
srv = rcu_dereference(state->services[idx++]);
if (srv && srv->srvstate != VCHIQ_SRVSTATE_FREE &&
srv->instance == instance &&
kref_get_unless_zero(&srv->ref_count)) {
service = rcu_pointer_handoff(srv);
srv->instance == instance) {
service = srv;
break;
}
}
rcu_read_unlock();
*pidx = idx;
return service;
}
struct vchiq_service *
next_service_by_instance(struct vchiq_state *state,
struct vchiq_instance *instance,
int *pidx)
{
struct vchiq_service *service;
rcu_read_lock();
service = __next_service_by_instance(state, instance, pidx);
if (service && kref_get_unless_zero(&service->ref_count))
service = rcu_pointer_handoff(service);
else
service = NULL;
rcu_read_unlock();
return service;
}
@ -283,13 +297,13 @@ unlock_service(struct vchiq_service *service)
int
vchiq_get_client_id(unsigned int handle)
{
struct vchiq_service *service = find_service_by_handle(handle);
struct vchiq_service *service;
int id;
rcu_read_lock();
service = handle_to_service(handle);
id = service ? service->client_id : 0;
if (service)
unlock_service(service);
rcu_read_unlock();
return id;
}

8
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h
View File

@ -572,7 +572,13 @@ find_closed_service_for_instance(struct vchiq_instance *instance,
unsigned int handle);
extern struct vchiq_service *
next_service_by_instance(struct vchiq_state *state, struct vchiq_instance *instance,
__next_service_by_instance(struct vchiq_state *state,
struct vchiq_instance *instance,
int *pidx);
extern struct vchiq_service *
next_service_by_instance(struct vchiq_state *state,
struct vchiq_instance *instance,
int *pidx);
extern void