Commit 8aea7f82 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Sasha Levin
Browse files

drivers/hv: Replace binary semaphore with mutex 



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: default avatarDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent d7f0b2e4

drivers/hv/vmbus_drv.c

+5 −5
Original line number Diff line number Diff line
@@ -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)

{
@@ -2018,7 +2018,7 @@ 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
@@ -2065,7 +2065,7 @@ 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);
@@ -2082,7 +2082,7 @@ 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;
@@ -2090,7 +2090,7 @@ 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);

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