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Subject[PATCHv2 3/6] mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()
Date
From: Oleg Nesterov <oleg@redhat.com>

Add the additional "vm_flags_t vm_flags" argument to do_mmap_pgoff(),
rename it to do_mmap(), and re-introduce do_mmap_pgoff() as a simple
wrapper on top of do_mmap(). Perhaps we should update the callers of
do_mmap_pgoff() and kill it later.

This way mpx_mmap() can simply call do_mmap(vm_flags => VM_MPX) and
do not play with vm internals.

After this change mmap_region() has a single user outside of mmap.c,
arch/tile/mm/elf.c:arch_setup_additional_pages(). It would be nice
to change arch/tile/ and unexport mmap_region().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
arch/x86/mm/mpx.c | 51 +++++++--------------------------------------------
include/linux/mm.h | 12 ++++++++++--
mm/mmap.c | 10 ++++------
mm/nommu.c | 15 ++++++++-------
4 files changed, 29 insertions(+), 59 deletions(-)

diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index 4d1c11c07fe1..fdbd3e0b1dad 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -24,58 +24,21 @@
*/
static unsigned long mpx_mmap(unsigned long len)
{
- unsigned long ret;
- unsigned long addr, pgoff;
struct mm_struct *mm = current->mm;
- vm_flags_t vm_flags;
- struct vm_area_struct *vma;
+ unsigned long addr, populate;

/* Only bounds table and bounds directory can be allocated here */
if (len != MPX_BD_SIZE_BYTES && len != MPX_BT_SIZE_BYTES)
return -EINVAL;

down_write(&mm->mmap_sem);
-
- /* Too many mappings? */
- if (mm->map_count > sysctl_max_map_count) {
- ret = -ENOMEM;
- goto out;
- }
-
- /* Obtain the address to map to. we verify (or select) it and ensure
- * that it represents a valid section of the address space.
- */
- addr = get_unmapped_area(NULL, 0, len, 0, MAP_ANONYMOUS | MAP_PRIVATE);
- if (addr & ~PAGE_MASK) {
- ret = addr;
- goto out;
- }
-
- vm_flags = VM_READ | VM_WRITE | VM_MPX |
- mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
-
- /* Set pgoff according to addr for anon_vma */
- pgoff = addr >> PAGE_SHIFT;
-
- ret = mmap_region(NULL, addr, len, vm_flags, pgoff);
- if (IS_ERR_VALUE(ret))
- goto out;
-
- vma = find_vma(mm, ret);
- if (!vma) {
- ret = -ENOMEM;
- goto out;
- }
-
- if (vm_flags & VM_LOCKED) {
- up_write(&mm->mmap_sem);
- mm_populate(ret, len);
- return ret;
- }
-
-out:
+ addr = do_mmap(NULL, 0, len, PROT_READ | PROT_WRITE,
+ MAP_ANONYMOUS | MAP_PRIVATE, VM_MPX, 0, &populate);
up_write(&mm->mmap_sem);
- return ret;
+ if (populate)
+ mm_populate(addr, populate);
+
+ return addr;
}

enum reg_type {
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c3a2b37365f6..fcf255a78b1f 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1811,11 +1811,19 @@ extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned lo

extern unsigned long mmap_region(struct file *file, unsigned long addr,
unsigned long len, vm_flags_t vm_flags, unsigned long pgoff);
-extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
+extern unsigned long do_mmap(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot, unsigned long flags,
- unsigned long pgoff, unsigned long *populate);
+ vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate);
extern int do_munmap(struct mm_struct *, unsigned long, size_t);

+static inline unsigned long
+do_mmap_pgoff(struct file *file, unsigned long addr,
+ unsigned long len, unsigned long prot, unsigned long flags,
+ unsigned long pgoff, unsigned long *populate)
+{
+ return do_mmap(file, addr, len, prot, flags, 0, pgoff, populate);
+}
+
#ifdef CONFIG_MMU
extern int __mm_populate(unsigned long addr, unsigned long len,
int ignore_errors);
diff --git a/mm/mmap.c b/mm/mmap.c
index 4f2fb700a2e5..2e98784d5b7c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1260,14 +1260,12 @@ static inline int mlock_future_check(struct mm_struct *mm,
/*
* The caller must hold down_write(&current->mm->mmap_sem).
*/
-
-unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
+unsigned long do_mmap(struct file *file, unsigned long addr,
unsigned long len, unsigned long prot,
- unsigned long flags, unsigned long pgoff,
- unsigned long *populate)
+ unsigned long flags, vm_flags_t vm_flags,
+ unsigned long pgoff, unsigned long *populate)
{
struct mm_struct *mm = current->mm;
- vm_flags_t vm_flags;

*populate = 0;

@@ -1311,7 +1309,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
* to. we assume access permissions have been handled by the open
* of the memory object, so we don't do any here.
*/
- vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
+ vm_flags |= calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;

if (flags & (MAP_LOCKED | MAP_LOCKONFAULT))
diff --git a/mm/nommu.c b/mm/nommu.c
index 05e7447d960b..18dcf48883dc 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1233,13 +1233,14 @@ enomem:
/*
* handle mapping creation for uClinux
*/
-unsigned long do_mmap_pgoff(struct file *file,
- unsigned long addr,
- unsigned long len,
- unsigned long prot,
- unsigned long flags,
- unsigned long pgoff,
- unsigned long *populate)
+unsigned long do_mmap(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long prot,
+ unsigned long flags,
+ vm_flags_t vm_flags,
+ unsigned long pgoff,
+ unsigned long *populate)
{
struct vm_area_struct *vma;
struct vm_region *region;
--
2.1.4


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