On Tue, Apr 15, 2014 at 10:38 PM, David Herrmann <dh.herrmann@xxxxxxxxx> wrote: > 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() does not create a front-FD, but instead returns the raw > shmem file, so calls like ftruncate() can be used. 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 > support (like on all other regular files). > > Compared to O_TMPFILE, it does not require a tmpfs mount-point and is not > subject to quotas and alike. > > Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx> > --- <cut> > +++ b/include/linux/syscalls.h > @@ -802,6 +802,7 @@ asmlinkage long sys_timerfd_settime(int ufd, int flags, > asmlinkage long sys_timerfd_gettime(int ufd, struct itimerspec __user *otmr); > asmlinkage long sys_eventfd(unsigned int count); > asmlinkage long sys_eventfd2(unsigned int count, int flags); > +asmlinkage long sys_memfd_create(const char *uname_ptr, u64 size, u64 flags); Is it right to use u64 here? I think arguments sould be 'loff_t' and 'int'. > asmlinkage long sys_fallocate(int fd, int mode, loff_t offset, loff_t len); > asmlinkage long sys_old_readdir(unsigned int, struct old_linux_dirent __user *, unsigned int); > asmlinkage long sys_pselect6(int, fd_set __user *, fd_set __user *, -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>