| Date | Thu, 13 Apr 2023 17:22:12 +0000 | Subject | Re: [PATCH v10 1/9] mm: Introduce memfd_restricted system call to create restricted user memory | From | Ackerley Tng <> |
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Chao Peng <chao.p.peng@linux.intel.com> writes:
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Introduce 'memfd_restricted' system call with the ability to create > memory areas that are restricted from userspace access through ordinary > MMU operations (e.g. read/write/mmap). The memory content is expected to > be used through the new in-kernel interface by a third kernel module.
> ...
> diff --git a/mm/restrictedmem.c b/mm/restrictedmem.c > new file mode 100644 > index 000000000000..56953c204e5c > --- /dev/null > +++ b/mm/restrictedmem.c > @@ -0,0 +1,318 @@ > +// SPDX-License-Identifier: GPL-2.0 > +#include "linux/sbitmap.h" > +#include <linux/pagemap.h> > +#include <linux/pseudo_fs.h> > +#include <linux/shmem_fs.h> > +#include <linux/syscalls.h> > +#include <uapi/linux/falloc.h> > +#include <uapi/linux/magic.h> > +#include <linux/restrictedmem.h> > + > +struct restrictedmem_data { > + struct mutex lock; > + struct file *memfd;
Can this be renamed to file, or lower_file (as in stacking filesystems)?
It's a little confusing because this pointer doesn't actually refer to an fd.
'memfd' is already used by udmabuf to refer to an actual fd [1], which makes this a little misleading.
[1] https://elixir.bootlin.com/linux/v6.2.10/source/tools/testing/selftests/drivers/dma-buf/udmabuf.c#L63
> + struct list_head notifiers; > +}; > + > ...
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