linux-kernel - Re: [PATCH v4 00/40] lib/find: add atomic find

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAHk-=wi2R7-jyoOw27Svf1PmfDFQgBWVAH3DP5CXO+JF-BeFZA@mail.gmail.com>
Date: Thu, 20 Jun 2024 13:32:05 -0700
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: Yury Norov <yury.norov@...il.com>
Cc: linux-kernel@...r.kernel.org, "David S. Miller" <davem@...emloft.net>, 
	"H. Peter Anvin" <hpa@...or.com>, "James E.J. Bottomley" <jejb@...ux.ibm.com>, 
	"K. Y. Srinivasan" <kys@...rosoft.com>, "Md. Haris Iqbal" <haris.iqbal@...os.com>, 
	Akinobu Mita <akinobu.mita@...il.com>, Andrew Morton <akpm@...ux-foundation.org>, 
	Bjorn Andersson <andersson@...nel.org>, Borislav Petkov <bp@...en8.de>, Chaitanya Kulkarni <kch@...dia.com>, 
	Christian Brauner <brauner@...nel.org>, Damien Le Moal <damien.lemoal@...nsource.wdc.com>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, David Disseldorp <ddiss@...e.de>, 
	Edward Cree <ecree.xilinx@...il.com>, Eric Dumazet <edumazet@...gle.com>, 
	Fenghua Yu <fenghua.yu@...el.com>, Geert Uytterhoeven <geert@...ux-m68k.org>, 
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Gregory Greenman <gregory.greenman@...el.com>, 
	Hans Verkuil <hverkuil@...all.nl>, Hans de Goede <hdegoede@...hat.com>, 
	Hugh Dickins <hughd@...gle.com>, Ingo Molnar <mingo@...hat.com>, Jakub Kicinski <kuba@...nel.org>, 
	Jaroslav Kysela <perex@...ex.cz>, Jason Gunthorpe <jgg@...pe.ca>, Jens Axboe <axboe@...nel.dk>, 
	Jiri Pirko <jiri@...nulli.us>, Jiri Slaby <jirislaby@...nel.org>, Kalle Valo <kvalo@...nel.org>, 
	Karsten Graul <kgraul@...ux.ibm.com>, Karsten Keil <isdn@...ux-pingi.de>, 
	Kees Cook <keescook@...omium.org>, Leon Romanovsky <leon@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, Martin Habets <habetsm.xilinx@...il.com>, 
	Mauro Carvalho Chehab <mchehab@...nel.org>, Michael Ellerman <mpe@...erman.id.au>, Michal Simek <monstr@...str.eu>, 
	Nicholas Piggin <npiggin@...il.com>, Oliver Neukum <oneukum@...e.com>, Paolo Abeni <pabeni@...hat.com>, 
	Paolo Bonzini <pbonzini@...hat.com>, Peter Zijlstra <peterz@...radead.org>, 
	Ping-Ke Shih <pkshih@...ltek.com>, Rich Felker <dalias@...c.org>, Rob Herring <robh@...nel.org>, 
	Robin Murphy <robin.murphy@....com>, Sean Christopherson <seanjc@...gle.com>, 
	Shuai Xue <xueshuai@...ux.alibaba.com>, Stanislaw Gruszka <stf_xl@...pl>, 
	Steven Rostedt <rostedt@...dmis.org>, Thomas Bogendoerfer <tsbogend@...ha.franken.de>, 
	Thomas Gleixner <tglx@...utronix.de>, Valentin Schneider <vschneid@...hat.com>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>, Wenjia Zhang <wenjia@...ux.ibm.com>, 
	Will Deacon <will@...nel.org>, Yoshinori Sato <ysato@...rs.sourceforge.jp>, 
	GR-QLogic-Storage-Upstream@...vell.com, alsa-devel@...a-project.org, 
	ath10k@...ts.infradead.org, dmaengine@...r.kernel.org, iommu@...ts.linux.dev, 
	kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-arm-msm@...r.kernel.org, linux-block@...r.kernel.org, 
	linux-bluetooth@...r.kernel.org, linux-hyperv@...r.kernel.org, 
	linux-m68k@...ts.linux-m68k.org, linux-media@...r.kernel.org, 
	linux-mips@...r.kernel.org, linux-net-drivers@....com, 
	linux-pci@...r.kernel.org, linux-rdma@...r.kernel.org, 
	linux-s390@...r.kernel.org, linux-scsi@...r.kernel.org, 
	linux-serial@...r.kernel.org, linux-sh@...r.kernel.org, 
	linux-sound@...r.kernel.org, linux-usb@...r.kernel.org, 
	linux-wireless@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org, 
	mpi3mr-linuxdrv.pdl@...adcom.com, netdev@...r.kernel.org, 
	sparclinux@...r.kernel.org, x86@...nel.org, 
	Alexey Klimov <alexey.klimov@...aro.org>, Bart Van Assche <bvanassche@....org>, Jan Kara <jack@...e.cz>, 
	Matthew Wilcox <willy@...radead.org>, Mirsad Todorovac <mirsad.todorovac@....unizg.hr>, 
	Rasmus Villemoes <linux@...musvillemoes.dk>, Sergey Shtylyov <s.shtylyov@....ru>
Subject: Re: [PATCH v4 00/40] lib/find: add atomic find_bit() primitives

On Thu, 20 Jun 2024 at 13:20, Yury Norov <yury.norov@...il.com> wrote:
>
> FORCE_NR_CPUS helped to generate a better code for me back then. I'll
> check again against the current kernel.

Of _course_ it generates better code.

But when "better code" is a source of bugs, and isn't actually useful
in general, it's not better, is it.

> The 5d272dd1b343 is wrong. Limiting FORCE_NR_CPUS to UP case makes no
> sense because in UP case nr_cpu_ids is already a compile-time macro:

Yury, I'm very aware. That was obviously intentional. the whole point
of the commit is to just disable the the whole thing as useless and
problematic.

I could have just ripped it out entirely. I ended up doing a one-liner instead.

                Linus