[RFC PATCH v3 09/10] mm: create __do_mmap() to take an mm_struct * arg

[Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>]

In preparation for mapping objects into an mshare region, create
__do_mmap() to allow mapping into a specified mm. There are no
functional changes otherwise.

Signed-off-by: Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>
---
 include/linux/mm.h | 18 +++++++++++++++++-
 mm/mmap.c          | 12 +++++-------
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 3aa0b3322284..a9afbda73cb0 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3409,11 +3409,27 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 
 extern unsigned long mmap_region(struct file *file, unsigned long addr,
 	unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
-	struct list_head *uf);
+	struct list_head *uf, struct mm_struct *mm);
+#ifdef CONFIG_MMU
+extern 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 list_head *uf, struct mm_struct *mm);
+static inline 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 list_head *uf)
+{
+	return __do_mmap(file, addr, len, prot, flags, vm_flags, pgoff,
+			 populate, uf, current->mm);
+}
+#else
 extern 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 list_head *uf);
+#endif
+
 extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm,
 			 unsigned long start, size_t len, struct list_head *uf,
 			 bool unlock);
diff --git a/mm/mmap.c b/mm/mmap.c
index d0dfc85b209b..4112f18e7302 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1250,15 +1250,14 @@ static inline bool file_mmap_ok(struct file *file, struct inode *inode,
 }
 
 /*
- * The caller must write-lock current->mm->mmap_lock.
+ * The caller must write-lock mm->mmap_lock.
  */
-unsigned long do_mmap(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, vm_flags_t vm_flags,
 			unsigned long pgoff, unsigned long *populate,
-			struct list_head *uf)
+			struct list_head *uf, struct mm_struct *mm)
 {
-	struct mm_struct *mm = current->mm;
 	int pkey = 0;
 
 	*populate = 0;
@@ -1465,7 +1464,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
 			vm_flags |= VM_NORESERVE;
 	}
 
-	addr = mmap_region(file, addr, len, vm_flags, pgoff, uf);
+	addr = mmap_region(file, addr, len, vm_flags, pgoff, uf, mm);
 	if (!IS_ERR_VALUE(addr) &&
 	    ((vm_flags & VM_LOCKED) ||
 	     (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE))
@@ -2848,9 +2847,8 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
 
 unsigned long mmap_region(struct file *file, unsigned long addr,
 		unsigned long len, vm_flags_t vm_flags, unsigned long pgoff,
-		struct list_head *uf)
+		struct list_head *uf, struct mm_struct *mm)
 {
-	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma = NULL;
 	struct vm_area_struct *next, *prev, *merge;
 	pgoff_t pglen = len >> PAGE_SHIFT;
-- 
2.43.5