diff options
author | David Herrmann <dh.herrmann@gmail.com> | 2014-08-08 14:25:29 -0700 |
---|---|---|
committer | Maciej Wereski <m.wereski@partner.samsung.com> | 2014-12-29 09:31:35 +0100 |
commit | 5ea1e3301b22ca848fd1bf21dff65f0abe10e624 (patch) | |
tree | 9192c185297c6a4407959c36e8e42ddf1bb28753 /arch/x86 | |
parent | 57ad118090f109ea3338869cef66150cc2a9550f (diff) | |
download | linux-3.10-5ea1e3301b22ca848fd1bf21dff65f0abe10e624.tar.gz linux-3.10-5ea1e3301b22ca848fd1bf21dff65f0abe10e624.tar.bz2 linux-3.10-5ea1e3301b22ca848fd1bf21dff65f0abe10e624.zip |
shm: add memfd_create() syscall
memfd_create() is similar to mmap(MAP_ANON), but returns a file-descriptor
that you can pass to mmap(). It can support sealing and avoids any
connection to user-visible mount-points. Thus, it's not subject to quotas
on mounted file-systems, but can be used like malloc()'ed memory, but with
a file-descriptor to it.
memfd_create() returns the raw shmem file, so calls like ftruncate() can
be used to modify the underlying inode. Also calls like fstat() will
return proper information and mark the file as regular file. If you want
sealing, you can specify MFD_ALLOW_SEALING. Otherwise, sealing is not
supported (like on all other regular files).
Compared to O_TMPFILE, it does not require a tmpfs mount-point and is not
subject to a filesystem size limit. It is still properly accounted to
memcg limits, though, and to the same overcommit or no-overcommit
accounting as all user memory.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ryan Lortie <desrt@desrt.ca>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Daniel Mack <zonque@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change-Id: I2ac7e2b47a1d68d4b83680f4527e5ed2aa9a420c
Origin: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=9183df25fe7b194563db3fec6dc3202a5855839c
Backported-by: Maciej Wereski <m.wereski@partner.samsung.com>
Signed-off-by: Maciej Wereski <m.wereski@partner.samsung.com>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/syscalls/syscall_32.tbl | 1 | ||||
-rw-r--r-- | arch/x86/syscalls/syscall_64.tbl | 1 |
2 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl index aabfb8380a1..a56149e79c6 100644 --- a/arch/x86/syscalls/syscall_32.tbl +++ b/arch/x86/syscalls/syscall_32.tbl @@ -357,3 +357,4 @@ 348 i386 process_vm_writev sys_process_vm_writev compat_sys_process_vm_writev 349 i386 kcmp sys_kcmp 350 i386 finit_module sys_finit_module +356 i386 memfd_create sys_memfd_create diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl index 63a899304d2..db539117c5c 100644 --- a/arch/x86/syscalls/syscall_64.tbl +++ b/arch/x86/syscalls/syscall_64.tbl @@ -320,6 +320,7 @@ 311 64 process_vm_writev sys_process_vm_writev 312 common kcmp sys_kcmp 313 common finit_module sys_finit_module +319 common memfd_create sys_memfd_create # # x32-specific system call numbers start at 512 to avoid cache impact |