From: Andrew Morton <akpm@linux-foundation•org>
To: Oleg Nesterov <oleg@redhat•com>
Cc: Joonsoo Kim <js1304@gmail•com>, Benjamin LaHaise <bcrl@kvack•org>,
Fengguang Wu <fengguang.wu@intel•com>,
Jeff Moyer <jmoyer@redhat•com>,
Johannes Weiner <hannes@cmpxchg•org>,
Stephen Rothwell <sfr@canb•auug.org.au>,
linux-next@vger•kernel.org, linux-kernel@vger•kernel.org
Subject: Re: [PATCH] mm-move-mremap-from-file_operations-to-vm_operations_struct-fix
Date: Thu, 16 Jul 2015 16:24:44 -0700 [thread overview]
Message-ID: <20150716162444.26425f5e227387f1166a6d16@linux-foundation.org> (raw)
In-Reply-To: <20150716231405.GA25147@redhat.com>
On Fri, 17 Jul 2015 01:14:05 +0200 Oleg Nesterov <oleg@redhat•com> wrote:
> fs/aio.c can't be compiled if CONFIG_MMU=n, filemap_page_mkwrite()
> is not defined in this case. Add yet another "must not be called"
> helper into nommu.c to make the linker happy.
>
> I still think this is pointless, afaics sys_io_setup() simply can't
> succeed if CONFIG_MMU=n. Instead we should make CONFIG_AIO depend
> on CONFIG_MMU.
>
> ..
>
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -2008,6 +2008,12 @@ void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
> }
> EXPORT_SYMBOL(filemap_map_pages);
>
> +int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
> +{
> + BUG();
> + return 0;
> +}
> +
> static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
> unsigned long addr, void *buf, int len, int write)
> {
So if anyone starts testing aio on NOMMU, this patch will make the
whole thing immediately go BUG. This isn't helpful :(
Yes, making AIO depend on MMU sounds better. Because if it wasn't
busted before, it sure is now!
next prev parent reply other threads:[~2015-07-16 23:24 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-16 23:14 [PATCH] mm-move-mremap-from-file_operations-to-vm_operations_struct-fix Oleg Nesterov
2015-07-16 23:22 ` Stephen Rothwell
2015-07-16 23:24 ` Andrew Morton [this message]
2015-07-16 23:52 ` Oleg Nesterov
2015-07-17 14:06 ` Benjamin LaHaise
2015-07-17 17:27 ` Oleg Nesterov
2015-07-17 17:37 ` Benjamin LaHaise
2015-07-17 17:55 ` Oleg Nesterov
2015-07-17 18:12 ` Austin S Hemmelgarn
2015-07-17 18:19 ` Oleg Nesterov
2015-07-17 18:39 ` Austin S Hemmelgarn
2015-07-17 18:54 ` Oleg Nesterov
2015-07-17 19:09 ` Austin S Hemmelgarn
2015-07-17 22:56 ` Oleg Nesterov
2015-07-17 22:31 ` Oleg Nesterov
2015-07-20 14:22 ` Jeff Moyer
2015-07-20 17:33 ` Oleg Nesterov
2015-07-20 17:51 ` Benjamin LaHaise
2015-07-20 18:30 ` Jeff Moyer
2015-07-20 18:31 ` Oleg Nesterov
2015-07-20 19:24 ` Oleg Nesterov
2015-07-20 19:39 ` Benjamin LaHaise
2015-07-20 20:03 ` Oleg Nesterov
2015-07-21 15:29 ` [PATCH v2] mm-move-mremap-from-file_operations-to-vm_operations_struct-fix Oleg Nesterov
2015-07-21 15:38 ` Benjamin LaHaise
2015-07-21 16:18 ` Oleg Nesterov
2015-07-21 16:20 ` [PATCH v3] mm-move-mremap-from-file_operations-to-vm_operations_struct-fix Oleg Nesterov
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