[PATCH 3/6] mm: implement access_remote_vm

From: Stephen Wilson
Date: Tue Mar 08 2011 - 19:45:08 EST


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@xxxxxxxx>
---
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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