Mutual exclusion at the record level with priority inheritance for embedded systems using one semaphore

A method to be performed by a software routine that is comprised of a plurality of tasks that may desire to lock or unlock any of plurality of resources, said method comprising:

• maintaining a first list, said first list listing a first group of said tasks, wherein, each task listed within said first group of tasks is waiting in a suspended state for at least one of said resources to be freed;
• maintaining a second list, said second list listing a second group of said tasks, wherein, each task listed within said second group of tasks is holding at least one of said resources;
• suspending a first task and expanding said first list to include said first task upon said first task desiring to lock a resource that is being held by a second task, said second task being listed on said second list, said first task having a priority, said resource having any one of a plurality of different levels;
• setting a flag to a first state as a consequence of said first task said desiring to lock said resource;
• comparing said priority of said first task with the priority of said second task;
• and
• increasing the priority level of said second task to that of said first task if said second task has a lower priority than said first task.