Re: clear_bit_unlock_is_negative_byte

[Matthew Wilcox <willy@infradead.org>]

On Sat, Jul 22, 2023 at 08:24:34AM +0200, Andreas Schwab wrote:
> On Jul 21 2023, Michael Schmitz wrote:
> 
> > static inline bool clear_bit_unlock_is_negative_byte(unsigned int nr,
> >                 volatile unsigned long *p)
> > {
> >         unsigned char *cp = (unsigned char *) p;
> >         char result;
> >         char mask = 1 << nr;    /* nr guaranteed to be < 7 */
> >
> >         __asm__ __volatile__ ("eori.b %1, %2; smi %0"
> >                 : "=d" (result)
> >                 : "i" (mask), "o" (*(cp+3))
> 
> That should use "id" as constraint, so that the compiler can share the
> constant with other insns.  Also, the third operand is modified, so it
> needs to be marked as in/out.

The "o" constraint is shared with bfset_mem_set_bit,
bfclr_mem_test_and_clear_bit and a few other functions.  Should they
all be changed?  Some use "+m".