linux-kernel - Re: [PATCH v2 2/3] lib/find_bit: create find_first_zero_bit

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Message-ID: <YwZmsvlFR0cOxvnD@shell.armlinux.org.uk>
Date:   Wed, 24 Aug 2022 18:58:10 +0100
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     Yury Norov <yury.norov@...il.com>
Cc:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Dennis Zhou <dennis@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Alexey Klimov <aklimov@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Andy Whitcroft <apw@...onical.com>
Subject: Re: [PATCH v2 2/3] lib/find_bit: create find_first_zero_bit_le()

On Wed, Aug 24, 2022 at 06:37:45AM -0700, Yury Norov wrote:
> Because there is a codebase that relies on existing types, mostly in
> filesystem code. And those fs fixes would require 5 or 6 patches.

Does that mean that are there filesystems that are passing pointers to
the find_bit functions which are _not_ aligned to an "unsigned long" ?

If there are, we should _not_ convert 32-bit ARM to use word loads or
use the generic code; unaligned loads are expensive on older ARM CPUs,
at least not the code for older ARM CPUs.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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