[tip:x86/vdso] mm: Add new func _install_special_mapping() to mmap.c

From: tip-bot for Stefani Seibold
Date: Sun Feb 16 2014 - 19:53:24 EST


Commit-ID: 48be0cb586e850e3ff5c37fe9339f233f9c893e4
Gitweb: http://git.kernel.org/tip/48be0cb586e850e3ff5c37fe9339f233f9c893e4
Author: Stefani Seibold <stefani@xxxxxxxxxxx>
AuthorDate: Sun, 16 Feb 2014 22:52:40 +0100
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Sun, 16 Feb 2014 15:04:23 -0800

mm: Add new func _install_special_mapping() to mmap.c

The _install_special_mapping() is the new base function for
install_special_mapping(). This function will return a pointer of the
created VMA or a error code in an ERR_PTR().

This new function will be needed by the for the x86 vdso 32-bit
support to map the additonal vvar and hpet pages into the 32 bit
address space. This will be done with io_remap_pfn_range() and
remap_pfn_range, which requieres a vm_area_struct.

Signed-off-by: Stefani Seibold <stefani@xxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1392587568-7325-3-git-send-email-stefani@xxxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
include/linux/mm.h | 3 +++
mm/mmap.c | 20 ++++++++++++++++----
2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f28f46e..55342aa 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1740,6 +1740,9 @@ extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
extern struct file *get_mm_exe_file(struct mm_struct *mm);

extern int may_expand_vm(struct mm_struct *mm, unsigned long npages);
+extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
+ unsigned long addr, unsigned long len,
+ unsigned long flags, struct page **pages);
extern int install_special_mapping(struct mm_struct *mm,
unsigned long addr, unsigned long len,
unsigned long flags, struct page **pages);
diff --git a/mm/mmap.c b/mm/mmap.c
index 20ff0c3..81ba54f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2918,7 +2918,7 @@ static const struct vm_operations_struct special_mapping_vmops = {
* The array pointer and the pages it points to are assumed to stay alive
* for as long as this mapping might exist.
*/
-int install_special_mapping(struct mm_struct *mm,
+struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
unsigned long addr, unsigned long len,
unsigned long vm_flags, struct page **pages)
{
@@ -2927,7 +2927,7 @@ int install_special_mapping(struct mm_struct *mm,

vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
if (unlikely(vma == NULL))
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);

INIT_LIST_HEAD(&vma->anon_vma_chain);
vma->vm_mm = mm;
@@ -2948,11 +2948,23 @@ int install_special_mapping(struct mm_struct *mm,

perf_event_mmap(vma);

- return 0;
+ return vma;

out:
kmem_cache_free(vm_area_cachep, vma);
- return ret;
+ return ERR_PTR(ret);
+}
+
+int install_special_mapping(struct mm_struct *mm,
+ unsigned long addr, unsigned long len,
+ unsigned long vm_flags, struct page **pages)
+{
+ struct vm_area_struct *vma = _install_special_mapping(mm,
+ addr, len, vm_flags, pages);
+
+ if (IS_ERR(vma))
+ return PTR_ERR(vma);
+ return 0;
}

static DEFINE_MUTEX(mm_all_locks_mutex);
--
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