set_bit (9) - Linux Man Pages
set_bit: Atomically set a bit in memory
set_bit - Atomically set a bit in memory
nr, volatile unsigned long *addr);
- the bit to set
- the address to start counting from
there are no guarantees that this function will not be reordered on non x86 architectures, so if you are writing portable code, make sure not to rely on its reordering guarantees.