diff --git a/src/add-ons/kernel/bus_managers/usb/PhysicalMemoryAllocator.cpp b/src/add-ons/kernel/bus_managers/usb/PhysicalMemoryAllocator.cpp
index a1f09e0167..e864080765 100644
--- a/src/add-ons/kernel/bus_managers/usb/PhysicalMemoryAllocator.cpp
+++ b/src/add-ons/kernel/bus_managers/usb/PhysicalMemoryAllocator.cpp
@@ -10,6 +10,7 @@
 #include <string.h>
 #include <KernelExport.h>
 #include <SupportDefs.h>
+#include <util/AutoLock.h>
 #include <util/kernel_cpp.h>
 
 #include "PhysicalMemoryAllocator.h"
@@ -97,7 +98,7 @@ PhysicalMemoryAllocator::PhysicalMemoryAllocator(const char *name,
 
 PhysicalMemoryAllocator::~PhysicalMemoryAllocator()
 {
-	_Lock();
+	mutex_lock(&fLock);
 
 	for (int32 i = 0; i < fArrayCount; i++)
 		free(fArray[i]);
@@ -113,20 +114,6 @@ PhysicalMemoryAllocator::~PhysicalMemoryAllocator()
 }
 
 
-bool
-PhysicalMemoryAllocator::_Lock()
-{
-	return (mutex_lock(&fLock) == B_OK);
-}
-
-
-void
-PhysicalMemoryAllocator::_Unlock()
-{
-	mutex_unlock(&fLock);
-}
-
-
 status_t
 PhysicalMemoryAllocator::Allocate(size_t size, void **logicalAddress,
 	phys_addr_t *physicalAddress)
@@ -169,7 +156,8 @@ PhysicalMemoryAllocator::Allocate(size_t size, void **logicalAddress,
 		}
 	}
 
-	if (!_Lock())
+	MutexLocker locker(&fLock);
+	if (!locker.IsLocked())
 		return B_ERROR;
 
 	while (true) {
@@ -203,7 +191,6 @@ PhysicalMemoryAllocator::Allocate(size_t size, void **logicalAddress,
 					arrayIndex >>= 1;
 				}
 
-				_Unlock();
 				size_t offset = fBlockSize[arrayToUse] * i;
 				*logicalAddress = (void *)((uint8 *)fLogicalBase + offset);
 				*physicalAddress = (phys_addr_t)(fPhysicalBase + offset);
@@ -217,7 +204,7 @@ PhysicalMemoryAllocator::Allocate(size_t size, void **logicalAddress,
 		fNoMemoryCondition.Add(&entry);
 		fMemoryWaitersCount++;
 
-		_Unlock();
+		locker.Unlock();
 
 		TRACE_ERROR(("PMA: found no free slot to store %ld bytes, waiting\n",
 			size));
@@ -227,7 +214,7 @@ PhysicalMemoryAllocator::Allocate(size_t size, void **logicalAddress,
 			break;
 		}
 
-		if (!_Lock())
+		if (!locker.Lock())
 			return B_ERROR;
 
 		fMemoryWaitersCount--;
@@ -283,7 +270,8 @@ PhysicalMemoryAllocator::Deallocate(size_t size, void *logicalAddress,
 		return B_BAD_VALUE;
 	}
 
-	if (!_Lock())
+	MutexLocker _(&fLock);
+	if (!_.IsLocked())
 		return B_ERROR;
 
 	// clear upwards to the smallest block
@@ -308,7 +296,6 @@ PhysicalMemoryAllocator::Deallocate(size_t size, void *logicalAddress,
 	if (fMemoryWaitersCount > 0)
 		fNoMemoryCondition.NotifyAll();
 
-	_Unlock();
 	return B_OK;
 }
 
diff --git a/src/add-ons/kernel/bus_managers/usb/PhysicalMemoryAllocator.h b/src/add-ons/kernel/bus_managers/usb/PhysicalMemoryAllocator.h
index 053dcddcef..9fc27f7330 100644
--- a/src/add-ons/kernel/bus_managers/usb/PhysicalMemoryAllocator.h
+++ b/src/add-ons/kernel/bus_managers/usb/PhysicalMemoryAllocator.h
@@ -39,9 +39,6 @@ public:
 		void						DumpFreeSlots();
 
 private:
-		bool						_Lock();
-		void						_Unlock();
-
 		char						*fName;
 
 		size_t						fOverhead;