The multi-producer-single-consumer ring buffer is not lock-free (so not wait-free) #20

The used algorithm can be reduced to

producer:
    pos = write_cursor.fetch_add(num);
    write_data(blocks[pos].data)                    #1
    blocks[pos].status.store(ready, release)

consumer:
    pos = read_cursor.load(relaxed)
    if blocks[pos].status.load(acquire) == ready:   #2
        read_data(blocks[pos].data)
        blocks[pos].status.store(free, release)
        

Consumer and producers rely on a flag(status) indicating whether data is ready. If a producer is suspended at #1, then the consumer is blocked at #2, waiting the producer to finish writing. No further data from other producers can be consumed. When the ring buffer become full, all other producers are blocked by the consumer which is blocked by the suspended producer. No thread can make progress until the suspended producer finish writing.