All of lore.kernel.org
 help / color / mirror / Atom feed
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Will Deacon <will@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Vinayak Menon <vinmenon@codeaurora.org>,
	Hugh Dickins <hughd@google.com>,
	Android Kernel Team <kernel-team@android.com>
Subject: Re: [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault'
Date: Thu, 14 Jan 2021 11:09:01 -0800	[thread overview]
Message-ID: <CAHk-=wjdJmL22+zk3_rWAfEJJCf=oDxiJ530qk-WNk_Ji0qhxw@mail.gmail.com> (raw)
In-Reply-To: <20210114190021.GB13135@willie-the-truck>

On Thu, Jan 14, 2021 at 11:00 AM Will Deacon <will@kernel.org> wrote:
>
> I tried that initially, but I found that I had to make all of the
> members const to get it to work, at which point the anonymous struct
> wasn't really adding anything. Did I just botch the syntax?

I'm not sure what you tried. But this stupid test-case sure works for me:

    struct hello {
        const struct {
                unsigned long address;
        };
        unsigned int flags;
    };

    extern int fn(struct hello *);

    int test(void)
    {
        struct hello a = {
                .address = 1,
        };
        a.flags = 0;
        return fn(&a);
    }

and because "address" is in that unnamed constant struct, you can only
set it within that initializer, and cannot do

        a.address = 0;

without an error (the way you _can_ do "a.flags = 0").

I don't see naming the struct making a difference - apart from forcing
that big rename patch, of course.

But maybe we're talking about different issues?

            Linus

WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Will Deacon <will@kernel.org>
Cc: Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Hugh Dickins <hughd@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>,
	Vinayak Menon <vinmenon@codeaurora.org>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Android Kernel Team <kernel-team@android.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault'
Date: Thu, 14 Jan 2021 11:09:01 -0800	[thread overview]
Message-ID: <CAHk-=wjdJmL22+zk3_rWAfEJJCf=oDxiJ530qk-WNk_Ji0qhxw@mail.gmail.com> (raw)
In-Reply-To: <20210114190021.GB13135@willie-the-truck>

On Thu, Jan 14, 2021 at 11:00 AM Will Deacon <will@kernel.org> wrote:
>
> I tried that initially, but I found that I had to make all of the
> members const to get it to work, at which point the anonymous struct
> wasn't really adding anything. Did I just botch the syntax?

I'm not sure what you tried. But this stupid test-case sure works for me:

    struct hello {
        const struct {
                unsigned long address;
        };
        unsigned int flags;
    };

    extern int fn(struct hello *);

    int test(void)
    {
        struct hello a = {
                .address = 1,
        };
        a.flags = 0;
        return fn(&a);
    }

and because "address" is in that unnamed constant struct, you can only
set it within that initializer, and cannot do

        a.address = 0;

without an error (the way you _can_ do "a.flags = 0").

I don't see naming the struct making a difference - apart from forcing
that big rename patch, of course.

But maybe we're talking about different issues?

            Linus

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-01-14 19:10 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-14 17:59 [PATCH v3 0/8] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag Will Deacon
2021-01-14 17:59 ` Will Deacon
2021-01-14 17:59 ` [PATCH v3 1/8] mm: Cleanup faultaround and finish_fault() codepaths Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-02-09 20:24   ` Guenter Roeck
2021-02-09 20:24     ` Guenter Roeck
2021-02-10 11:44     ` Will Deacon
2021-02-10 11:44       ` Will Deacon
2021-02-10 14:57       ` Guenter Roeck
2021-02-10 14:57         ` Guenter Roeck
2021-01-14 17:59 ` [PATCH v3 2/8] mm: Allow architectures to request 'old' entries when prefaulting Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 17:59 ` [PATCH v3 3/8] arm64: mm: Implement arch_wants_old_prefaulted_pte() Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault' Will Deacon
2021-01-14 18:16   ` Linus Torvalds
2021-01-14 18:16     ` Linus Torvalds
2021-01-14 18:16     ` Linus Torvalds
2021-01-14 19:00     ` Will Deacon
2021-01-14 19:00       ` Will Deacon
2021-01-14 19:09       ` Linus Torvalds [this message]
2021-01-14 19:09         ` Linus Torvalds
2021-01-14 19:09         ` Linus Torvalds
2021-01-14 19:41         ` Will Deacon
2021-01-14 19:41           ` Will Deacon
2021-01-14 20:09           ` Nick Desaulniers
2021-01-14 20:09             ` Nick Desaulniers
2021-01-14 20:09             ` Nick Desaulniers
2021-01-14 21:11           ` Linus Torvalds
2021-01-14 21:11             ` Linus Torvalds
2021-01-14 21:11             ` Linus Torvalds
2021-01-15  9:23             ` Will Deacon
2021-01-15  9:23               ` Will Deacon
2021-01-15 21:32               ` Linus Torvalds
2021-01-15 21:32                 ` Linus Torvalds
2021-01-15 21:32                 ` Linus Torvalds
2021-01-20  0:00                 ` Nick Desaulniers
2021-01-20  0:00                   ` Nick Desaulniers
2021-01-20  0:00                   ` Nick Desaulniers
2021-01-14 17:59 ` [RFC PATCH 5/8] mm: Pass 'address' to map to do_set_pte() and drop FAULT_FLAG_PREFAULT Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 18:17   ` Linus Torvalds
2021-01-14 18:17     ` Linus Torvalds
2021-01-14 18:17     ` Linus Torvalds
2021-01-15 10:24     ` Will Deacon
2021-01-15 10:24       ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 6/8] mm: Avoid modifying vmf.info.address in __collapse_huge_page_swapin() Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 7/8] mm: Use static initialisers for 'info' field of 'struct vm_fault' Will Deacon
2021-01-14 17:59   ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 8/8] mm: Mark 'info' field of 'struct vm_fault' as 'const' Will Deacon
2021-01-14 17:59   ` Will Deacon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAHk-=wjdJmL22+zk3_rWAfEJJCf=oDxiJ530qk-WNk_Ji0qhxw@mail.gmail.com' \
    --to=torvalds@linux-foundation.org \
    --cc=akpm@linux-foundation.org \
    --cc=catalin.marinas@arm.com \
    --cc=hughd@google.com \
    --cc=jack@suse.cz \
    --cc=kernel-team@android.com \
    --cc=kirill.shutemov@linux.intel.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=minchan@kernel.org \
    --cc=vinmenon@codeaurora.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.