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Commit 5d752600 authored by Mike Kravetz's avatar Mike Kravetz Committed by Linus Torvalds
Browse files

mm: restructure memfd code 

With the addition of memfd hugetlbfs support, we now have the situation
where memfd depends on TMPFS -or- HUGETLBFS.  Previously, memfd was only
supported on tmpfs, so it made sense that the code resided in shmem.c.
In the current code, memfd is only functional if TMPFS is defined.  If
HUGETLFS is defined and TMPFS is not defined, then memfd functionality
will not be available for hugetlbfs.  This does not cause BUGs, just a
lack of potentially desired functionality.

Code is restructured in the following way:
- include/linux/memfd.h is a new file containing memfd specific
  definitions previously contained in shmem_fs.h.
- mm/memfd.c is a new file containing memfd specific code previously
  contained in shmem.c.
- memfd specific code is removed from shmem_fs.h and shmem.c.
- A new config option MEMFD_CREATE is added that is defined if TMPFS
  or HUGETLBFS is defined.

No functional changes are made to the code: restructuring only.

Link: http://lkml.kernel.org/r/20180415182119.4517-4-mike.kravetz@oracle.com


Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: default avatarKhalid Aziz <khalid.aziz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Marc-Andr Lureau <marcandre.lureau@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c49fcfcd

fs/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -203,6 +203,9 @@ config HUGETLBFS 
config HUGETLB_PAGE

	def_bool HUGETLBFS



config MEMFD_CREATE

	def_bool TMPFS || HUGETLBFS



config ARCH_HAS_GIGANTIC_PAGE

	bool

fs/fcntl.c

+1 −1
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ 
#include <linux/rcupdate.h>

#include <linux/pid_namespace.h>

#include <linux/user_namespace.h>

#include <linux/shmem_fs.h>

#include <linux/memfd.h>

#include <linux/compat.h>



#include <linux/poll.h>

include/linux/memfd.h

0 → 100644
+16 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef __LINUX_MEMFD_H

#define __LINUX_MEMFD_H



#include <linux/file.h>



#ifdef CONFIG_MEMFD_CREATE

extern long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg);

#else

static inline long memfd_fcntl(struct file *f, unsigned int c, unsigned long a)

{

	return -EINVAL;

}

#endif



#endif /* __LINUX_MEMFD_H */

include/linux/shmem_fs.h

+0 −13
Original line number Diff line number Diff line
@@ -110,19 +110,6 @@ static inline bool shmem_file(struct file *file) 
extern bool shmem_charge(struct inode *inode, long pages);

extern void shmem_uncharge(struct inode *inode, long pages);



#ifdef CONFIG_TMPFS



extern long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg);



#else



static inline long memfd_fcntl(struct file *f, unsigned int c, unsigned long a)

{

	return -EINVAL;

}



#endif



#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE

extern bool shmem_huge_enabled(struct vm_area_struct *vma);

#else

mm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -105,3 +105,4 @@ obj-$(CONFIG_DEBUG_PAGE_REF) += debug_page_ref.o 
obj-$(CONFIG_HARDENED_USERCOPY) += usercopy.o

obj-$(CONFIG_PERCPU_STATS) += percpu-stats.o

obj-$(CONFIG_HMM) += hmm.o

obj-$(CONFIG_MEMFD_CREATE) += memfd.o