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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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