From: Christoph Hellwig <hch@infradead.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: akpm@linux-foundation.org, Jan Kara <jack@suse.cz>,
linux-nvdimm@lists.01.org, David Airlie <airlied@linux.ie>,
linux-api@vger.kernel.org, Takashi Iwai <tiwai@suse.com>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
linux-xfs@vger.kernel.org, Julia Lawall <julia.lawall@lip6.fr>,
luto@kernel.org, linux-fsdevel@vger.kernel.org,
Daniel Vetter <daniel.vetter@intel.com>,
linux-mm@kvack.org
Subject: Re: [PATCH v6 1/5] vfs: add flags parameter to ->mmap() in 'struct file_operations'
Date: Thu, 24 Aug 2017 09:58:38 -0700 [thread overview]
Message-ID: <20170824165838.GB3121@infradead.org> (raw)
In-Reply-To: <150353211985.5039.4333061601382775843.stgit@dwillia2-desk3.amr.corp.intel.com>
On Wed, Aug 23, 2017 at 04:48:40PM -0700, Dan Williams wrote:
> We are running running short of vma->vm_flags. We can avoid needing a
> new VM_* flag in some cases if the original @flags submitted to mmap(2)
> is made available to the ->mmap() 'struct file_operations'
> implementation. For example, the proposed addition of MAP_DIRECT can be
> implemented without taking up a new vm_flags bit. Another motivation to
> avoid vm_flags is that they appear in /proc/$pid/smaps, and we have seen
> software that tries to dangerously (TOCTOU) read smaps to infer the
> behavior of a virtual address range.
>
> This conversion was performed by the following semantic patch. There
> were a few manual edits for oddities like proc_reg_mmap.
>
> Thanks to Julia for helping me with coccinelle iteration to cover cases
> where the mmap routine is defined in a separate file from the 'struct
> file_operations' instance that consumes it.
How are we going to check that an instance actually supports any
of those flags?
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next prev parent reply other threads:[~2017-08-24 16:58 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-23 23:48 [PATCH v6 0/5] MAP_DIRECT and block-map-atomic files Dan Williams
2017-08-23 23:48 ` [PATCH v6 1/5] vfs: add flags parameter to ->mmap() in 'struct file_operations' Dan Williams
2017-08-24 16:58 ` Christoph Hellwig [this message]
2017-08-24 17:42 ` Dan Williams
2017-08-23 23:48 ` [PATCH v6 2/5] fs, xfs: introduce S_IOMAP_SEALED Dan Williams
2017-08-24 16:13 ` Christoph Hellwig
2017-08-25 6:00 ` Dan Williams
2017-08-25 19:44 ` Dan Williams
2017-08-23 23:48 ` [PATCH v6 3/5] mm: introduce mmap3 for safely defining new mmap flags Dan Williams
2017-08-24 13:04 ` Jan Kara
2017-08-24 16:55 ` Christoph Hellwig
2017-08-24 17:36 ` Dan Williams
2017-08-25 13:00 ` Christoph Hellwig
2017-08-25 15:58 ` Kirill A. Shutemov
2017-08-25 16:02 ` Christoph Hellwig
2017-08-25 16:16 ` Kirill A. Shutemov
2017-08-25 16:19 ` Helge Deller
2017-08-25 16:56 ` Kirill A. Shutemov
2017-08-25 20:24 ` Dan Williams
2017-08-26 7:40 ` Helge Deller
2017-08-26 15:15 ` Dan Williams
2017-08-26 19:50 ` Helge Deller
2017-08-26 22:46 ` Dan Williams
2017-08-26 23:56 ` Kirill A. Shutemov
2017-08-23 23:48 ` [PATCH v6 4/5] fs, xfs: introduce MAP_DIRECT for creating block-map-atomic file ranges Dan Williams
2017-08-24 16:11 ` Christoph Hellwig
2017-08-24 16:31 ` Dan Williams
2017-08-24 16:39 ` Christoph Hellwig
2017-08-24 20:26 ` Dan Williams
2017-08-23 23:49 ` [PATCH v6 5/5] fs, fcntl: add F_MAP_DIRECT Dan Williams
2017-08-24 16:08 ` [PATCH v6 0/5] MAP_DIRECT and block-map-atomic files Christoph Hellwig
2017-08-24 16:25 ` Dan Williams
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