On Wed, Mar 26, 2025 at 09:00:33PM +0100, Christian Lamparter wrote: > Hi, > > On Wed, Mar 26, 2025 at 4:52 PM Yury Norov <yury.norov@xxxxxxxxx> wrote: > > > > The function calls bitmap_empty() just before find_first_bit(). Both > > functions are O(N). Because find_first_bit() returns >= nbits in case of > > empty bitmap, the bitmap_empty() test may be avoided. > > > > I looked up bitmap_empty(): > <https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/bitmap.h#n423> > > apart from the small_const_nbits stuff (which carl9170 likely does not qualify > for since from what I remember it's a 128bits bitmap) the function just does: > > | return find_first_bit(src, nbits) == nbits; > > so yes, find_first_bit runs twice with same parameters... Unless the > compiler is smart > enough to detect this and (re-)use the intermediate result later. But > I haven't check > if this is the case with any current, old or future compilers. Has anyone? > > Anyway, Sure. > > > Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx> > > Acked-by: Christian Lamparter <chunkeey@xxxxxxxxx> Thanks, Chrustian. So, how is that supposed to be merged? I can move it with bitmap-for-next, unless there's no better branch. Thanks, Yury
