Commit e9d586a8 authored Jan 31, 2018 by Marc-André Lureau Committed by Linus Torvalds Jan 31, 2018

shmem: unexport shmem_add_seals()/shmem_get_seals()

Patch series "memfd: add sealing to hugetlb-backed memory", v3.

Recently, Mike Kravetz added hugetlbfs support to memfd.  However, he
didn't add sealing support.  One of the reasons to use memfd is to have
shared memory sealing when doing IPC or sharing memory with another
process with some extra safety.  qemu uses shared memory & hugetables
with vhost-user (used by dpdk), so it is reasonable to use memfd now
instead for convenience and security reasons.

This patch (of 9):

The functions are called through shmem_fcntl() only.  And no danger in
removing the EXPORTs as the routines only work with shmem file structs.

Link: http://lkml.kernel.org/r/20171107122800.25517-2-marcandre.lureau@redhat.com


Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent ab8928b7

include/linux/shmem_fs.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -112,8 +112,6 @@ extern void shmem_uncharge(struct inode *inode, long pages);

		#ifdef CONFIG_TMPFS

		extern int shmem_add_seals(struct file *file, unsigned int seals);
		extern int shmem_get_seals(struct file *file);
		extern long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg);

		#else

mm/shmem.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -2722,7 +2722,7 @@ continue_resched:
		F_SEAL_GROW \| \
		F_SEAL_WRITE)

		int shmem_add_seals(struct file *file, unsigned int seals)
		static int shmem_add_seals(struct file *file, unsigned int seals)
		{
		struct inode *inode = file_inode(file);
		struct shmem_inode_info *info = SHMEM_I(inode);
		@@ -2791,16 +2791,14 @@ unlock:
		inode_unlock(inode);
		return error;
		}
		EXPORT_SYMBOL_GPL(shmem_add_seals);

		int shmem_get_seals(struct file *file)
		static int shmem_get_seals(struct file *file)
		{
		if (file->f_op != &shmem_file_operations)
		return -EINVAL;

		return SHMEM_I(file_inode(file))->seals;
		}
		EXPORT_SYMBOL_GPL(shmem_get_seals);

		long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
		{

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