diff options
| -rw-r--r-- | include/uapi/linux/memfd.h | 24 | ||||
| -rw-r--r-- | mm/shmem.c | 37 |
2 files changed, 55 insertions, 6 deletions
diff --git a/include/uapi/linux/memfd.h b/include/uapi/linux/memfd.h index 534e364bda92..7f3a722dbd72 100644 --- a/include/uapi/linux/memfd.h +++ b/include/uapi/linux/memfd.h @@ -1,8 +1,32 @@ #ifndef _UAPI_LINUX_MEMFD_H #define _UAPI_LINUX_MEMFD_H +#include <asm-generic/hugetlb_encode.h> + /* flags for memfd_create(2) (unsigned int) */ #define MFD_CLOEXEC 0x0001U #define MFD_ALLOW_SEALING 0x0002U +#define MFD_HUGETLB 0x0004U + +/* + * Huge page size encoding when MFD_HUGETLB is specified, and a huge page + * size other than the default is desired. See hugetlb_encode.h. + * All known huge page size encodings are provided here. It is the + * responsibility of the application to know which sizes are supported on + * the running system. See mmap(2) man page for details. + */ +#define MFD_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT +#define MFD_HUGE_MASK HUGETLB_FLAG_ENCODE_MASK + +#define MFD_HUGE_64KB HUGETLB_FLAG_ENCODE_64KB +#define MFD_HUGE_512KB HUGETLB_FLAG_ENCODE_512KB +#define MFD_HUGE_1MB HUGETLB_FLAG_ENCODE_1MB +#define MFD_HUGE_2MB HUGETLB_FLAG_ENCODE_2MB +#define MFD_HUGE_8MB HUGETLB_FLAG_ENCODE_8MB +#define MFD_HUGE_16MB HUGETLB_FLAG_ENCODE_16MB +#define MFD_HUGE_256MB HUGETLB_FLAG_ENCODE_256MB +#define MFD_HUGE_1GB HUGETLB_FLAG_ENCODE_1GB +#define MFD_HUGE_2GB HUGETLB_FLAG_ENCODE_2GB +#define MFD_HUGE_16GB HUGETLB_FLAG_ENCODE_16GB #endif /* _UAPI_LINUX_MEMFD_H */ diff --git a/mm/shmem.c b/mm/shmem.c index 64bdc91187f7..47179bbe9ee7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -34,6 +34,7 @@ #include <linux/swap.h> #include <linux/uio.h> #include <linux/khugepaged.h> +#include <linux/hugetlb.h> #include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */ @@ -3652,7 +3653,7 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root) #define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1) #define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN) -#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING) +#define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING | MFD_HUGETLB) SYSCALL_DEFINE2(memfd_create, const char __user *, uname, @@ -3664,8 +3665,18 @@ SYSCALL_DEFINE2(memfd_create, char *name; long len; - if (flags & ~(unsigned int)MFD_ALL_FLAGS) - return -EINVAL; + if (!(flags & MFD_HUGETLB)) { + if (flags & ~(unsigned int)MFD_ALL_FLAGS) + return -EINVAL; + } else { + /* Sealing not supported in hugetlbfs (MFD_HUGETLB) */ + if (flags & MFD_ALLOW_SEALING) + return -EINVAL; + /* Allow huge page size encoding in flags. */ + if (flags & ~(unsigned int)(MFD_ALL_FLAGS | + (MFD_HUGE_MASK << MFD_HUGE_SHIFT))) + return -EINVAL; + } /* length includes terminating zero */ len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1); @@ -3696,16 +3707,30 @@ SYSCALL_DEFINE2(memfd_create, goto err_name; } - file = shmem_file_setup(name, 0, VM_NORESERVE); + if (flags & MFD_HUGETLB) { + struct user_struct *user = NULL; + + file = hugetlb_file_setup(name, 0, VM_NORESERVE, &user, + HUGETLB_ANONHUGE_INODE, + (flags >> MFD_HUGE_SHIFT) & + MFD_HUGE_MASK); + } else + file = shmem_file_setup(name, 0, VM_NORESERVE); if (IS_ERR(file)) { error = PTR_ERR(file); goto err_fd; } - info = SHMEM_I(file_inode(file)); file->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; file->f_flags |= O_RDWR | O_LARGEFILE; - if (flags & MFD_ALLOW_SEALING) + + if (flags & MFD_ALLOW_SEALING) { + /* + * flags check at beginning of function ensures + * this is not a hugetlbfs (MFD_HUGETLB) file. + */ + info = SHMEM_I(file_inode(file)); info->seals &= ~F_SEAL_SEAL; + } fd_install(fd, file); kfree(name); |