Re: [PATCH v4 next 4/9] lib: Add mul_u64_add_u64_div_u64() and mul_u64_u64_div_u64_roundup()

[Andrew Morton]

On Fri, 31 Oct 2025 20:59:17 +0000 David Laight <david.laight.linux@xxxxxxxxx> wrote:

> > -static inline u64 mul_u64_u64_div_u64(u64 a, u64 mul, u64 div)
> > +static inline u64 mul_u64_add_u64_div_u64(u64 rax, u64 mul, u64 add, u64 div)
> >  {
> > -	u64 q;
> > +	u64 rdx;
> >  
> > -	asm ("mulq %2; divq %3" : "=a" (q)
> > -				: "a" (a), "rm" (mul), "rm" (div)
> > -				: "rdx");
> > +	asm ("mulq %[mul]" : "+a" (rax), "=d" (rdx) : [mul] "rm" (mul));
> >  
> > -	return q;
> > +	if (statically_true(add))
> 
> This needs to be:
> 	if (!statically_true(!add))
> 
> Do you need me to resend the full series?

I queued a fix, thanks.

--- a/arch/x86/include/asm/div64.h~lib-add-mul_u64_add_u64_div_u64-and-mul_u64_u64_div_u64_roundup-fix
+++ a/arch/x86/include/asm/div64.h
@@ -90,7 +90,7 @@ static inline u64 mul_u64_add_u64_div_u6
 
 	asm ("mulq %[mul]" : "+a" (rax), "=d" (rdx) : [mul] "rm" (mul));
 
-	if (statically_true(add))
+	if (!statically_true(add))
 		asm ("addq %[add], %[lo]; adcq $0, %[hi]" :
 			[lo] "+r" (rax), [hi] "+r" (rdx) : [add] "irm" (add));
 
_