Pretty crude for now...
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/ext4/file.c | 2 ++
include/linux/mm.h | 1 +
include/linux/mman.h | 3 ++-
include/uapi/asm-generic/mman.h | 1 +
mm/mmap.c | 5 +++++
5 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index f84bb29e941e..850037e140d7 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -340,6 +340,8 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
} else {
vma->vm_ops = &ext4_file_vm_ops;
+ if (vma->vm_flags & VM_SYNC)
+ return -EOPNOTSUPP;
}
return 0;
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fa036093e76c..d0fb385414a4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -188,6 +188,7 @@ extern unsigned int kobjsize(const void *objp);
#define VM_ACCOUNT 0x00100000 /* Is a VM accounted object */
#define VM_NORESERVE 0x00200000 /* should the VM suppress accounting */
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
+#define VM_SYNC 0x00800000 /* Synchronous page faults */
#define VM_ARCH_1 0x01000000 /* Architecture-specific flag */
#define VM_ARCH_2 0x02000000
#define VM_DONTDUMP 0x04000000 /* Do not include in the core dump */
diff --git a/include/linux/mman.h b/include/linux/mman.h
index c8367041fafd..c38279b651e5 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -86,7 +86,8 @@ calc_vm_flag_bits(unsigned long flags)
{
return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
_calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) |
- _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED );
+ _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) |
+ _calc_vm_trans(flags, MAP_SYNC, VM_SYNC );
}
unsigned long vm_commit_limit(void);
diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
index 7162cd4cca73..00e55627d2df 100644
--- a/include/uapi/asm-generic/mman.h
+++ b/include/uapi/asm-generic/mman.h
@@ -12,6 +12,7 @@
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x40000 /* create a huge page mapping */
+#define MAP_SYNC 0x80000 /* perform synchronous page faults for the mapping */
/* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */
diff --git a/mm/mmap.c b/mm/mmap.c
index f19efcf75418..18453c04b09f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1423,12 +1423,17 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
return -ENODEV;
if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
return -EINVAL;
+ if (!(vm_flags & VM_SHARED) && (vm_flags & VM_SYNC))
+ return -EINVAL;
break;
default:
return -EINVAL;
}
} else {
+ if (vm_flags & VM_SYNC)
+ return -EINVAL;
+
switch (flags & MAP_TYPE) {
case MAP_SHARED:
if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
--
2.12.3
