On Fri, Jul 10, 2015 at 02:42:56PM +0100, Russell King - ARM Linux wrote:

The obvious question though is whether we have an established name for this
operation elsewhere in the kernel, and whether we should have consistency.

Consistency is good.

In include/linux, we already have (grepping for 'and_*not'):

include/linux/nodemask.h:#define nodes_andnot(dst, src1, src2) \
include/linux/bitmap.h:extern int __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
include/linux/cpumask.h:static inline int cpumask_andnot(struct cpumask *dstp,

We also have:

include/linux/signal.h:#define _sig_andn(x,y)       ((x) & ~(y))

which seems to be the only instance of "andn" in include/.

How about I rename the _sig_andn one to _sig_andnot, and go with
atomic_andnot, to match the *mask functions.