On Fri, Nov 22, 2013 at 12:09:58PM -0500, Peter Hurley wrote:
> tty flip buffers use GFP_ATOMIC allocations for received data
> which is to be processed by the line discipline. For each byte
> received, an extra byte is used to indicate the error status of
> that byte.
>
> Instead, if the received data is error-free, encode the entire
> buffer without status bytes.
>
> Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/tty/tty_buffer.c | 45 +++++++++++++++++++++++++++++++++++----------
> include/linux/tty.h | 4 ++++
> include/linux/tty_flip.h | 8 ++++++--
> 3 files changed, 45 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
> index 6a3620e..c4fe20e 100644
> --- a/drivers/tty/tty_buffer.c
> +++ b/drivers/tty/tty_buffer.c
> @@ -100,6 +100,7 @@ static void tty_buffer_reset(struct tty_buffer *p, size_t size)
> p->next = NULL;
> p->commit = 0;
> p->read = 0;
> + p->flags = 0;
> }
>
> /**
> @@ -230,31 +231,49 @@ void tty_buffer_flush(struct tty_struct *tty)
> * tty_buffer_request_room - grow tty buffer if needed
> * @tty: tty structure
> * @size: size desired
> + * @flags: buffer flags if new buffer allocated (default = 0)
> *
> * Make at least size bytes of linear space available for the tty
> * buffer. If we fail return the size we managed to find.
> + *
> + * Will change over to a new buffer if the current buffer is encoded as
> + * TTY_NORMAL (so has no flags buffer) and the new buffer requires
> + * a flags buffer.
> */
> -int tty_buffer_request_room(struct tty_port *port, size_t size)
> +int __tty_buffer_request_room(struct tty_port *port, size_t size, int flags)
> {
> struct tty_bufhead *buf = &port->buf;
> struct tty_buffer *b, *n;
> - int left;
> + int left, change;
>
> b = buf->tail;
> - left = b->size - b->used;
> + if (b->flags & TTYB_NORMAL)
> + left = 2 * b->size - b->used;
> + else
> + left = b->size - b->used;
>
> - if (left < size) {
> + change = (b->flags & TTYB_NORMAL) && (~flags & TTYB_NORMAL);
> + if (change || left < size) {
> /* This is the slow path - looking for new buffers to use */
> if ((n = tty_buffer_alloc(port, size)) != NULL) {
> + n->flags = flags;
> buf->tail = n;
> b->commit = b->used;
> smp_mb();
> b->next = n;
> - } else
> + } else if (change)
> + size = 0;
> + else
> size = left;
> }
> return size;
> }
> +EXPORT_SYMBOL_GPL(__tty_buffer_request_room);
Why are you exporting this? There is no function prototype anywhere, so
no one can even try to call it, it should just be static, right?
I've applied the first 4 patches in this series, care to fix this one
up?
thanks,
greg k-h
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