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Subject[PATCH 17/41] copy_regset_to_user(): do all copyout at once.
Date
From: Al Viro <viro@zeniv.linux.org.uk>

Turn copy_regset_to_user() into regset_get_alloc() + copy_to_user().
Now all ->get() calls have a kernel buffer as destination.

Note that we'd already eliminated the callers of copy_regset_to_user()
with non-zero offset; now that argument is simply unused.

Uninlined, while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
include/linux/regset.h | 29 ++++-------------------------
kernel/regset.c | 26 ++++++++++++++++++++++++++
2 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/include/linux/regset.h b/include/linux/regset.h
index 968a032922d5..af57c1db1924 100644
--- a/include/linux/regset.h
+++ b/include/linux/regset.h
@@ -362,31 +362,10 @@ extern int regset_get_alloc(struct task_struct *target,
unsigned int size,
void **data);

-/**
- * copy_regset_to_user - fetch a thread's user_regset data into user memory
- * @target: thread to be examined
- * @view: &struct user_regset_view describing user thread machine state
- * @setno: index in @view->regsets
- * @offset: offset into the regset data, in bytes
- * @size: amount of data to copy, in bytes
- * @data: user-mode pointer to copy into
- */
-static inline int copy_regset_to_user(struct task_struct *target,
- const struct user_regset_view *view,
- unsigned int setno,
- unsigned int offset, unsigned int size,
- void __user *data)
-{
- const struct user_regset *regset = &view->regsets[setno];
-
- if (!regset->get)
- return -EOPNOTSUPP;
-
- if (!access_ok(data, size))
- return -EFAULT;
-
- return regset->get(target, regset, offset, size, NULL, data);
-}
+extern int copy_regset_to_user(struct task_struct *target,
+ const struct user_regset_view *view,
+ unsigned int setno, unsigned int offset,
+ unsigned int size, void __user *data);

/**
* copy_regset_from_user - store into thread's user_regset data from user memory
diff --git a/kernel/regset.c b/kernel/regset.c
index 6b39fa0993ec..0a610983ce43 100644
--- a/kernel/regset.c
+++ b/kernel/regset.c
@@ -52,3 +52,29 @@ int regset_get_alloc(struct task_struct *target,
return __regset_get(target, regset, size, data);
}
EXPORT_SYMBOL(regset_get_alloc);
+
+/**
+ * copy_regset_to_user - fetch a thread's user_regset data into user memory
+ * @target: thread to be examined
+ * @view: &struct user_regset_view describing user thread machine state
+ * @setno: index in @view->regsets
+ * @offset: offset into the regset data, in bytes
+ * @size: amount of data to copy, in bytes
+ * @data: user-mode pointer to copy into
+ */
+int copy_regset_to_user(struct task_struct *target,
+ const struct user_regset_view *view,
+ unsigned int setno,
+ unsigned int offset, unsigned int size,
+ void __user *data)
+{
+ const struct user_regset *regset = &view->regsets[setno];
+ void *buf;
+ int ret;
+
+ ret = regset_get_alloc(target, regset, size, &buf);
+ if (ret > 0)
+ ret = copy_to_user(data, buf, ret) ? -EFAULT : 0;
+ kfree(buf);
+ return ret;
+}
--
2.11.0
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