[PATCH 10/13] mm: Wire up MAP_SYNC
From: Jan Kara <jack@suse.cz>
Date: 2017-08-17 16:08:30
Also in:
linux-ext4, linux-fsdevel, nvdimm
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), generic include/asm header files, memory management, memory management - core, memory mapping, the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Arnd Bergmann, Andrew Morton, David Hildenbrand, Liam R. Howlett, Lorenzo Stoakes, Linus Torvalds
Pretty crude for now... Signed-off-by: Jan Kara <jack@suse.cz> --- 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