Re: [PATCH v2 15/17] sysfs: Support zapping of binary attr mmaps

Greg Kroah-Hartman
2020-10-09T10:57:22Z

On Fri, Oct 09, 2020 at 09:59:32AM +0200, Daniel Vetter wrote:
> We want to be able to revoke pci mmaps so that the same access rules
> applies as for /dev/kmem. Revoke support for devmem was added in
> 3234ac664a87 ("/dev/mem: Revoke mappings when a driver claims the
> region").
>
> The simplest way to achieve this is by having the same filp->f_mapping
> for all mappings, so that unmap_mapping_range can find them all, no
> matter through which file they've been created. Since this must be set
> at open time we need sysfs support for this.
>
> Add an optional mapping parameter bin_attr, which is only consulted
> when there's also an mmap callback, since without mmap support
> allowing to adjust the ->f_mapping makes no sense.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Jérôme Glisse <jglisse@redhat.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: linux-mm@kvack.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-samsung-soc@vger.kernel.org
> Cc: linux-media@vger.kernel.org
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-pci@vger.kernel.org
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Christian Brauner <christian.brauner@ubuntu.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Cc: Nayna Jain <nayna@linux.ibm.com>
> ---
> fs/sysfs/file.c | 11 +++++++++++
> include/linux/sysfs.h | 2 ++
> 2 files changed, 13 insertions(+)

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>