Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230106220959.3398792-1-song@kernel.org> <CAPhsuW4oY6Gh2c11AvzoCrv7ZShT0E=zU0OgK8LUq_pYW9=edw@mail.gmail.com>
 <CAPhsuW44n8wzx6Ois4hNRWR9S=kB=LL+DqMTtMjAyGY2FVNoUA@mail.gmail.com>
 <20230118074047.GA27385@lst.de> <CAPhsuW7zqYgLcWoG1Wr_tBBLt-yiNYq3FLVWYMpMj=6TJawQEg@mail.gmail.com>
 <20230119053545.GA16775@lst.de> <CAPhsuW5WFEHfGrSW5nYRRohmLMAfWoZiOCBgCdgzOCmn+Q_vVA@mail.gmail.com>
In-Reply-To: <CAPhsuW5WFEHfGrSW5nYRRohmLMAfWoZiOCBgCdgzOCmn+Q_vVA@mail.gmail.com>
From:   Song Liu <song@kernel.org>
Date:   Fri, 20 Jan 2023 09:42:26 -0800
Message-ID: <CAPhsuW4snf6cBYSDRbALSNM4OE36-dusir8HQQ90Li7u067ZWA@mail.gmail.com>
Subject: Re: [PATCH/RFC] module: replace module_layout with module_memory
To:     Christoph Hellwig <hch@lst.de>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        songliubraving@fb.com, Peter Zijlstra <peterz@infradead.org>,
        linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, Jan 19, 2023 at 12:29 AM Song Liu <song@kernel.org> wrote:
>
> On Wed, Jan 18, 2023 at 9:35 PM Christoph Hellwig <hch@lst.de> wrote:
> >
> > On Wed, Jan 18, 2023 at 01:52:51PM -0800, Song Liu wrote:
> > > In this way we can use the array in the for loops, and use mod->core_text,
> > > etc. when we only need to access one of them.
> >
> > Just use the array please instead of making it too ugly.  If that
> > is the only sensible way to iterate we have a good argument for the
> > array and can live with it.
>
> Hmm.. I think it won't be ugly outside of the struct definition...
> Alternatively, how about use something like
>
> #define core_text mod_mem[MOD_MEM_TYPE_TEXT]
> ...
>
> which is similar to
>
> struct sock {
>         /*
>          * Now struct inet_timewait_sock also uses sock_common, so please just
>          * don't add nothing before this first member (__sk_common) --acme
>          */
>         struct sock_common      __sk_common;
> #define sk_node                 __sk_common.skc_node
> #define sk_nulls_node           __sk_common.skc_nulls_node
> ...
> };

So here are the two versions, both with secondary addr_[min|max] for
CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC.

v2. Just use mod_mem array:
https://git.kernel.org/pub/scm/linux/kernel/git/song/md.git/commit/?h=remotes/song-md/new_module_alloc_build_test_v2

v3. mod_mem array and the defines:
#define mod_core_text mod_mem[MOD_MEM_TYPE_TEXT]
#define mod_core_data mod_mem[MOD_MEM_TYPE_DATA]
etc.
https://git.kernel.org/pub/scm/linux/kernel/git/song/md.git/commit/?h=remotes/song-md/new_module_alloc_build_test_v3

I personally like the v3 better. Please share you
comments on this.

Thanks,
Song