From: Oleg Nesterov <oleg@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
Benjamin LaHaise <bcrl@kvack.org>,
Hugh Dickins <hughd@google.com>, Jeff Moyer <jmoyer@redhat.com>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
Pavel Emelyanov <xemul@parallels.com>
Subject: vdso && f_op->mremap (Was: special_mapping_fault() is broken)
Date: Tue, 23 Jun 2015 02:47:44 +0200 [thread overview]
Message-ID: <20150623004744.GA11212@redhat.com> (raw)
In-Reply-To: <20150621211951.GA18593@redhat.com>
On 06/21, Oleg Nesterov wrote:
>
> Forgot to add Andy...
Add Pavel ;)
I never understood why ->mremap() lives in file_operations, not in
vm_operations_struct. To me vma->vm_file->f_op in move_vma() just
looks strange, vma->vm_ops->mremap(new_vma) looks "obviously better".
And afaics more useful. CRIU remaps vdso, but this does not update
mm->context.vdso. OK, probably this does not matter currently, CRIU
can't c/r the compat tasks, and 64-bit apps do not use context.vdso.
Afaics. Still, I think we might want to have special_mapping_remap()
and we can't do this because ->vm_file == NULL.
And perhaps other architectures can depend on the "correct" value
in >context.vdso more then x86, I dunno...
In short. Shouldn't we move ->mremap() to vm_operations_struct before
it has another user? We need to fix aio.c, but this is trivial.
No?
Oleg.
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next prev parent reply other threads:[~2015-06-23 0:49 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-21 21:07 [PATCH 0/3] special_mapping_fault() is broken Oleg Nesterov
2015-06-21 21:07 ` [PATCH 1/3] mm: introduce vma_is_anonymous(vma) helper Oleg Nesterov
2015-06-21 21:07 ` [PATCH 2/3] mmap: fix the usage of ->vm_pgoff in special_mapping paths Oleg Nesterov
2015-06-21 21:07 ` [PATCH 3/3] mremap: fix the wrong !vma->vm_file check in copy_vma() Oleg Nesterov
2015-06-21 21:19 ` [PATCH 0/3] special_mapping_fault() is broken Oleg Nesterov
2015-06-23 0:47 ` Oleg Nesterov [this message]
2015-06-23 1:09 ` vdso && f_op->mremap (Was: special_mapping_fault() is broken) Linus Torvalds
2015-06-23 1:26 ` Andy Lutomirski
2015-06-23 15:04 ` Pavel Emelyanov
2015-06-23 17:03 ` Oleg Nesterov
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