Re: [PATCH 1/9] tty: move the non-file related parts of tty_release to new tty_release_struct

Sebastian Reichel
2017-01-08T22:42:48Z

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Hi,

On Fri, Jan 06, 2017 at 10:26:27AM -0600, Rob Herring wrote:
> For in-kernel tty users, we need to be able to create and destroy
> 'struct tty' that are not associated with a file. The creation side is
> fine, but tty_release() needs to be split into the file handle portion
> and the struct tty portion. Introduce a new function, tty_release_struct,
> to handle just the destroying of a struct tty.
>
> Signed-off-by: Rob Herring <robh@kernel.org>
> ---
> drivers/tty/tty_io.c | 42 ++++++++++++++++++++++++------------------
> include/linux/tty.h | 1 +
> 2 files changed, 25 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
> index 734a635e7363..5ebc090ec47f 100644
> --- a/drivers/tty/tty_io.c
> +++ b/drivers/tty/tty_io.c
> @@ -1744,6 +1744,29 @@ static int tty_release_checks(struct tty_struct *tty, int idx)
> return 0;
> }
>
> +void tty_release_struct(struct tty_struct *tty, int idx)
> +{
> + /*
> + * Ask the line discipline code to release its structures
> + */
> + tty_ldisc_release(tty);
> +
> + /* Wait for pending work before tty destruction commmences */
> + tty_flush_works(tty);
> +
> + tty_debug_hangup(tty, "freeing structure\n");
> + /*
> + * The release_tty function takes care of the details of clearing
> + * the slots and preserving the termios structure. The tty_unlock_pair
> + * should be safe as we keep a kref while the tty is locked (so the
> + * unlock never unlocks a freed tty).
> + */
> + mutex_lock(&tty_mutex);
> + release_tty(tty, idx);
> + mutex_unlock(&tty_mutex);
> +}
> +EXPORT_SYMBOL_GPL(tty_release_struct);

tty_release_struct() is missing kernel docs.

> [...]

-- Sebastian

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