The patch titled
Subject: shmem: add sealing support to hugetlb-backed memfd
has been added to the -mm tree. Its filename is
shmem-add-sealing-support-to-hugetlb-backed-memfd.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/shmem-add-sealing-support-to-hugetlb-backed-memfd.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/shmem-add-sealing-support-to-hugetlb-backed-memfd.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
Subject: shmem: add sealing support to hugetlb-backed memfd
Adapt add_seals()/get_seals() to work with hugetbfs-backed memory.
Teach memfd_create() to allow sealing operations on MFD_HUGETLB.
Link: http://lkml.kernel.org/r/20171107122800.25517-6-marcandre.lureau@xxxxxxxxxx
Signed-off-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: David Herrmann <dh.herrmann@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 47 ++++++++++++++++++++++++++++-------------------
1 file changed, 28 insertions(+), 19 deletions(-)
diff -puN mm/shmem.c~shmem-add-sealing-support-to-hugetlb-backed-memfd mm/shmem.c
--- a/mm/shmem.c~shmem-add-sealing-support-to-hugetlb-backed-memfd
+++ a/mm/shmem.c
@@ -2720,6 +2720,19 @@ continue_resched:
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 | \
@@ -2728,7 +2741,7 @@ continue_resched:
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;
/*
@@ -2761,8 +2774,6 @@ static int memfd_add_seals(struct file *
* 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)
@@ -2770,12 +2781,18 @@ static int memfd_add_seals(struct file *
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;
@@ -2787,7 +2804,7 @@ static int memfd_add_seals(struct file *
}
}
- info->seals |= seals;
+ *file_seals |= seals;
error = 0;
unlock:
@@ -2797,10 +2814,9 @@ unlock:
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)
@@ -3658,7 +3674,7 @@ 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;
@@ -3668,9 +3684,6 @@ 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)))
@@ -3723,12 +3736,8 @@ 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);
_
Patches currently in -mm which might be from marcandre.lureau@xxxxxxxxxx are
shmem-unexport-shmem_add_seals-shmem_get_seals.patch
shmem-rename-functions-that-are-memfd-related.patch
hugetlb-expose-hugetlbfs_inode_info-in-header.patch
hugetlb-implement-memfd-sealing.patch
shmem-add-sealing-support-to-hugetlb-backed-memfd.patch
memfd-test-test-hugetlbfs-sealing.patch
memfd-test-add-memfd-hugetlb-prefix-when-testing-hugetlbfs.patch
memfd-test-move-common-code-to-a-shared-unit.patch
memfd-test-run-fuse-test-on-hugetlb-backend-memory.patch
mm-page_owner-align-with-pageblock_nr_pages.patch
--
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