[PATCH v2 resend 08/12] mm: implement access_remote_vm

[Stephen Wilson <wilsons@start.ca>]

Provide an alternative to access_process_vm that allows the caller to obtain a
reference to the supplied mm_struct.

Signed-off-by: Stephen Wilson <wilsons@start.ca>
---
 include/linux/mm.h |    2 ++
 mm/memory.c        |   16 ++++++++++++++++
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 694512d..e5fde8a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -964,6 +964,8 @@ static inline int handle_mm_fault(struct mm_struct *mm,
 
 extern int make_pages_present(unsigned long addr, unsigned long end);
 extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
+extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
+		void *buf, int len, int write);
 
 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 			unsigned long start, int nr_pages, int write, int force,
diff --git a/mm/memory.c b/mm/memory.c
index 68eec4f..c26e4f9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3654,6 +3654,22 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
 	return buf - old_buf;
 }
 
+/**
+ * @access_remote_vm - access another process' address space
+ * @mm:		the mm_struct of the target address space
+ * @addr:	start address to access
+ * @buf:	source or destination buffer
+ * @len:	number of bytes to transfer
+ * @write:	whether the access is a write
+ *
+ * The caller must hold a reference on @mm.
+ */
+int access_remote_vm(struct mm_struct *mm, unsigned long addr,
+		void *buf, int len, int write)
+{
+	return __access_remote_vm(NULL, mm, addr, buf, len, write);
+}
+
 /*
  * Access another process' address space.
  * Source/target buffer must be kernel space,
-- 
1.7.3.5

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