At a slight footprint cost (24 vs 32 bytes), mutexes are more optimal
than semaphores; it's also a nicer interface for mutual exclusion,
which is why they are encouraged over binary semaphores, when possible.
Replace the hyperv_mmio_lock, its semantics implies traditional lock
ownership; that is, the lock owner is the same for both lock/unlock
operations. Therefore it is safe to convert.
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
This is part of reducing the amount of semaphore users in the kernel.
Compile-tested only.
drivers/hv/vmbus_drv.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 391f0b225c9a..5c606dc4a3f7 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -79,7 +79,7 @@ static struct notifier_block hyperv_panic_block = {
static const char *fb_mmio_name = "fb_range";
static struct resource *fb_mmio;
static struct resource *hyperv_mmio;
-static DEFINE_SEMAPHORE(hyperv_mmio_lock);
+static DEFINE_MUTEX(hyperv_mmio_lock);
static int vmbus_exists(void)
{
@@ -2011,7 +2011,7 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
int retval;
retval = -ENXIO;
- down(&hyperv_mmio_lock);
+ mutex_lock(&hyperv_mmio_lock);
/*
* If overlaps with frame buffers are allowed, then first attempt to
@@ -2058,7 +2058,7 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
}
exit:
- up(&hyperv_mmio_lock);
+ mutex_unlock(&hyperv_mmio_lock);
return retval;
}
EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
@@ -2075,7 +2075,7 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size)
{
struct resource *iter;
- down(&hyperv_mmio_lock);
+ mutex_lock(&hyperv_mmio_lock);
for (iter = hyperv_mmio; iter; iter = iter->sibling) {
if ((iter->start >= start + size) || (iter->end <= start))
continue;
@@ -2083,7 +2083,7 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size)
__release_region(iter, start, size);
}
release_mem_region(start, size);
- up(&hyperv_mmio_lock);
+ mutex_unlock(&hyperv_mmio_lock);
}
EXPORT_SYMBOL_GPL(vmbus_free_mmio);
--
2.16.4
