MIME-Version: 1.0
In-Reply-To: <CAHk-=wiRtgOweogzkky6phOSCySWRzWmDQ1S7J5xxQR2UCJ+dg@mail.gmail.com>
References: <20230118150703.4024-1-ubizjak@gmail.com> <20230118131825.c6daea81ea1e2dc6aa014f38@linux-foundation.org>
 <CAFULd4ZQGG+N3f7xDuoiNG1jY128pqaH0F4eLKO+fhvSNAbKfA@mail.gmail.com>
 <CAFULd4b5szcTHTVbGJ9WiciG_+8kANiPZYP_pkEZUhnz_HHy-g@mail.gmail.com>
 <913c01d41f824fa8b3400384437fa0d8@AcuMS.aculab.com> <CAFULd4aDORSrq7zf_LcAZRP8HOHcrq2-rGMaroKyG2zQDHNpOA@mail.gmail.com>
 <CAGudoHF6zbyzza6xysuCjcxjHAUgeAVvgW0sqxDAFQNwz9u7wg@mail.gmail.com>
 <CAHk-=whUSZk1dZrJuhxeb4qB3POstVRwOZCN8PXd3W7ztbqQBg@mail.gmail.com>
 <CAGudoHH+SmRoyXvppjBEoK=dvVdy1jvKNHDLEVf9mLnzsEds6Q@mail.gmail.com> <CAHk-=wiRtgOweogzkky6phOSCySWRzWmDQ1S7J5xxQR2UCJ+dg@mail.gmail.com>
From:   Mateusz Guzik <mjguzik@gmail.com>
Date:   Tue, 24 Jan 2023 07:48:51 +0100
Message-ID: <CAGudoHHD3ZpYhx+wLSCeQV_bEkBysLahAO-ovXhbPDc4vWeO5A@mail.gmail.com>
Subject: Re: [PATCH] lib/genalloc: use try_cmpxchg in {set,clear}_bits_ll
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Al Viro <viro@zeniv.linux.org.uk>, Uros Bizjak <ubizjak@gmail.com>,
        David Laight <David.Laight@aculab.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On 1/24/23, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Mon, Jan 23, 2023 at 4:11 PM Mateusz Guzik <mjguzik@gmail.com> wrote:
>>
>> On another point how to end up dealing with lockref less, I have to
>> note glibc switched fstat(fd, buf) to use newfstatat(fd, "", buf,
>> AT_EMPTY_PATH) internally.
>
> Yeah, that's just plain stupid.
>
> I don't know what the thinking (or rather, lack-thereof) was inside
> glibc for that one.
>

To my reading the fstat system call is now legacy so they switched to
something else. There is a lot to say about the stat situation (going
past the fd vs lookup issue), which I'm going to do on fsdevel (perhaps
next week).

All flaming aside, I think Uros is still waiting for an answer what
should be done in cmpxchg loops and someone else will have to provide
it.

I stated my case for the best course of action being to do nothing
(for x86-64 anyway), but I'm not an authority figure.

-- 
Mateusz Guzik <mjguzik gmail.com>