From: Andrew Morton <akpm@linux-foundation.org>
To: David Laight <david.laight.linux@gmail.com>
Cc: linux-kernel@vger.kernel.org, u.kleine-koenig@baylibre.com,
Nicolas Pitre <npitre@baylibre.com>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Biju Das <biju.das.jz@bp.renesas.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Li RongQing <lirongqing@baidu.com>, Yu Kuai <yukuai3@huawei.com>,
Khazhismel Kumykov <khazhy@chromium.org>,
Jens Axboe <axboe@kernel.dk>,
x86@kernel.org
Subject: Re: [PATCH v4 next 4/9] lib: Add mul_u64_add_u64_div_u64() and mul_u64_u64_div_u64_roundup()
Date: Fri, 31 Oct 2025 19:12:41 -0700 [thread overview]
Message-ID: <20251031191241.c3d0fa93219cab2a1157fe1e@linux-foundation.org> (raw)
In-Reply-To: <20251031205917.56763269@pumpkin>
On Fri, 31 Oct 2025 20:59:17 +0000 David Laight <david.laight.linux@gmail.com> 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));
_
next prev parent reply other threads:[~2025-11-01 2:12 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 17:38 [PATCH v4 next 0/9] Implement mul_u64_u64_div_u64_roundup() David Laight
2025-10-29 17:38 ` [PATCH v4 next 1/9] lib: mul_u64_u64_div_u64() rename parameter 'c' to 'd' David Laight
2025-10-29 17:38 ` [PATCH v4 next 2/9] lib: mul_u64_u64_div_u64() Combine overflow and divide by zero checks David Laight
2025-10-29 18:02 ` Nicolas Pitre
2025-10-29 17:38 ` [PATCH v4 next 3/9] lib: mul_u64_u64_div_u64() simplify check for a 64bit product David Laight
2025-10-29 18:11 ` Nicolas Pitre
2025-10-31 9:19 ` David Laight
2025-10-31 17:26 ` Nicolas Pitre
2025-10-31 18:04 ` David Laight
2025-10-31 18:45 ` Nicolas Pitre
2025-10-31 20:12 ` David Laight
2025-10-29 17:38 ` [PATCH v4 next 4/9] lib: Add mul_u64_add_u64_div_u64() and mul_u64_u64_div_u64_roundup() David Laight
2025-10-29 18:17 ` Nicolas Pitre
2025-10-31 20:59 ` David Laight
2025-11-01 2:12 ` Andrew Morton [this message]
2025-10-29 17:38 ` [PATCH v4 next 5/9] lib: Add tests for mul_u64_u64_div_u64_roundup() David Laight
2025-10-29 18:26 ` Nicolas Pitre
2025-10-29 17:38 ` [PATCH v4 next 6/9] lib: test_mul_u64_u64_div_u64: Test both generic and arch versions David Laight
2025-10-29 18:53 ` Nicolas Pitre
2025-11-01 19:35 ` kernel test robot
2025-11-01 20:59 ` kernel test robot
2025-11-02 10:36 ` David Laight
2025-10-29 17:38 ` [PATCH v4 next 7/9] lib: mul_u64_u64_div_u64() optimise multiply on 32bit x86 David Laight
2025-10-29 19:01 ` Nicolas Pitre
2025-10-29 17:38 ` [PATCH v4 next 8/9] lib: mul_u64_u64_div_u64() Optimise the divide code David Laight
2025-10-29 20:47 ` Nicolas Pitre
2025-10-29 17:38 ` [PATCH v4 next 9/9] lib: test_mul_u64_u64_div_u64: Test the 32bit code on 64bit David Laight
2025-10-29 20:48 ` Nicolas Pitre
2025-10-31 4:29 ` [PATCH v4 next 0/9] Implement mul_u64_u64_div_u64_roundup() Andrew Morton
2025-11-04 17:16 ` Nicolas Pitre
2025-10-31 13:52 ` Oleg Nesterov
2025-10-31 16:17 ` David Laight
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