Adapt add_seals()/get_seals() to work with hugetbfs-backed memory.
Teach memfd_create() to allow sealing operations on MFD_HUGETLB.
Signed-off-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
---
mm/shmem.c | 47 ++++++++++++++++++++++++++++-------------------
1 file changed, 28 insertions(+), 19 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index b7811979611f..b08ba5d84d84 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2717,6 +2717,19 @@ static int shmem_wait_for_pins(struct address_space *mapping)
return error;
}
+static unsigned int *memfd_file_seals_ptr(struct file *file)
+{
+ if (file->f_op == &shmem_file_operations)
+ return &SHMEM_I(file_inode(file))->seals;
+
+#ifdef CONFIG_HUGETLBFS
+ if (file->f_op == &hugetlbfs_file_operations)
+ return &HUGETLBFS_I(file_inode(file))->seals;
+#endif
+
+ return NULL;
+}
+
#define F_ALL_SEALS (F_SEAL_SEAL | \
F_SEAL_SHRINK | \
F_SEAL_GROW | \
@@ -2725,7 +2738,7 @@ static int shmem_wait_for_pins(struct address_space *mapping)
static int memfd_add_seals(struct file *file, unsigned int seals)
{
struct inode *inode = file_inode(file);
- struct shmem_inode_info *info = SHMEM_I(inode);
+ unsigned int *file_seals;
int error;
/*
@@ -2758,8 +2771,6 @@ static int memfd_add_seals(struct file *file, unsigned int seals)
* other file types.
*/
- if (file->f_op != &shmem_file_operations)
- return -EINVAL;
if (!(file->f_mode & FMODE_WRITE))
return -EPERM;
if (seals & ~(unsigned int)F_ALL_SEALS)
@@ -2767,12 +2778,18 @@ static int memfd_add_seals(struct file *file, unsigned int seals)
inode_lock(inode);
- if (info->seals & F_SEAL_SEAL) {
+ file_seals = memfd_file_seals_ptr(file);
+ if (!file_seals) {
+ error = -EINVAL;
+ goto unlock;
+ }
+
+ if (*file_seals & F_SEAL_SEAL) {
error = -EPERM;
goto unlock;
}
- if ((seals & F_SEAL_WRITE) && !(info->seals & F_SEAL_WRITE)) {
+ if ((seals & F_SEAL_WRITE) && !(*file_seals & F_SEAL_WRITE)) {
error = mapping_deny_writable(file->f_mapping);
if (error)
goto unlock;
@@ -2784,7 +2801,7 @@ static int memfd_add_seals(struct file *file, unsigned int seals)
}
}
- info->seals |= seals;
+ *file_seals |= seals;
error = 0;
unlock:
@@ -2794,10 +2811,9 @@ static int memfd_add_seals(struct file *file, unsigned int seals)
static int memfd_get_seals(struct file *file)
{
- if (file->f_op != &shmem_file_operations)
- return -EINVAL;
+ unsigned int *seals = memfd_file_seals_ptr(file);
- return SHMEM_I(file_inode(file))->seals;
+ return seals ? *seals : -EINVAL;
}
long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
@@ -3657,7 +3673,7 @@ SYSCALL_DEFINE2(memfd_create,
const char __user *, uname,
unsigned int, flags)
{
- struct shmem_inode_info *info;
+ unsigned int *file_seals;
struct file *file;
int fd, error;
char *name;
@@ -3667,9 +3683,6 @@ SYSCALL_DEFINE2(memfd_create,
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)))
@@ -3722,12 +3735,8 @@ SYSCALL_DEFINE2(memfd_create,
file->f_flags |= O_RDWR | O_LARGEFILE;
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;
+ file_seals = memfd_file_seals_ptr(file);
+ *file_seals &= ~F_SEAL_SEAL;
}
fd_install(fd, file);
--
2.15.0.rc0.40.gaefcc5f6f
--
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>
