Commit 626e98cb authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Andrew Morton
Browse files

mm: make MEMFD_CREATE into a selectable config option 

The memfd_create() syscall, enabled by CONFIG_MEMFD_CREATE, is useful on
its own even when not required by CONFIG_TMPFS or CONFIG_HUGETLBFS.

Split it into its own proper bool option that can be enabled by users.

Move that option into mm/ where the code itself also lies.  Also add
"select" statements to CONFIG_TMPFS and CONFIG_HUGETLBFS so they
automatically enable CONFIG_MEMFD_CREATE as before.

Link: https://lkml.kernel.org/r/20230630-config-memfd-v1-1-9acc3ae38b5a@weissschuh.net


Signed-off-by: default avatarThomas Weißschuh <linux@weissschuh.net>
Tested-by: default avatarZhangjin Wu <falcon@tinylab.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent fc1878ec

fs/Kconfig

+2 −3
Original line number Diff line number Diff line
@@ -169,6 +169,7 @@ source "fs/sysfs/Kconfig" 
config TMPFS

	bool "Tmpfs virtual memory file system support (former shm fs)"

	depends on SHMEM

	select MEMFD_CREATE

	help

	  Tmpfs is a file system which keeps all files in virtual memory.
@@ -240,6 +241,7 @@ config HUGETLBFS 
	bool "HugeTLB file system support"

	depends on X86 || IA64 || SPARC64 || ARCH_SUPPORTS_HUGETLBFS || BROKEN

	depends on (SYSFS || SYSCTL)

	select MEMFD_CREATE

	help

	  hugetlbfs is a filesystem backing for HugeTLB pages, based on

	  ramfs. For architectures that support it, say Y here and read
@@ -264,9 +266,6 @@ config HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON 
	  enable HVO by default. It can be disabled via hugetlb_free_vmemmap=off

	  (boot command line) or hugetlb_optimize_vmemmap (sysctl).



config MEMFD_CREATE

	def_bool TMPFS || HUGETLBFS



config ARCH_HAS_GIGANTIC_PAGE

	bool

mm/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -1144,6 +1144,9 @@ config KMAP_LOCAL_NON_LINEAR_PTE_ARRAY 
config IO_MAPPING

	bool



config MEMFD_CREATE

	bool "Enable memfd_create() system call" if EXPERT



config SECRETMEM

	default y

	bool "Enable memfd_secret() system call" if EXPERT