> > +/** > > + * generic_test_bit - Determine whether a bit is set > > + * @nr: bit number to test > > + * @addr: Address to start counting from > > + */ > > Shouldn't we add in this or in separate patch a big NOTE to explain that this > is actually atomic and must be kept as a such? "atomic" isn't really the right word. The volatile access makes sure that the compiler does the test at the point that the source code asked, and doesn't move it before/after other operations. But there is no such thing as an atomic test_bit() operation: if (test_bit(5, addr)) { /* some other CPU nukes bit 5 */ /* I know it was set when I looked, but now, could be anything */ ... } -Tony