Re: [PATCH][trivial] mISDN: l1oip - reduce stack memory footprint

Andrew Morton
2009-02-26T22:18:20Z

On Wed, 25 Feb 2009 16:54:56 +0100
Frank Seidel <fseidel@suse.de> wrote:

> From: Frank Seidel <frank@f-seidel.de>
>
> Applying kernel janitors todos (reduce stack
> footprint where possible) to l1oip mISDN driver.
> (Before 1656 bytes on i386, now 164)
>
> Signed-off-by: Frank Seidel <frank@f-seidel.de>
> ---
> drivers/isdn/mISDN/l1oip_core.c | 21 +++++++++++++++++----
> 1 file changed, 17 insertions(+), 4 deletions(-)
>
> --- a/drivers/isdn/mISDN/l1oip_core.c
> +++ b/drivers/isdn/mISDN/l1oip_core.c
> @@ -663,18 +663,28 @@ l1oip_socket_thread(void *data)
> struct iovec iov;
> mm_segment_t oldfs;
> struct sockaddr_in sin_rx;
> - unsigned char recvbuf[1500];
> + unsigned char *recvbuf;
> + size_t recvbuf_size = 1500;
> int recvlen;
> struct socket *socket = NULL;
> DECLARE_COMPLETION(wait);
>
> + /* allocate buffer memory */
> + recvbuf = kmalloc(recvbuf_size * sizeof(*recvbuf), GFP_KERNEL);

It's rather pointless to multiply by sizeof(*recvbuf) here

> - iov.iov_len = sizeof(recvbuf);
> + iov.iov_len = recvbuf_size;
> oldfs = get_fs();
> set_fs(KERNEL_DS);
> - recvlen = sock_recvmsg(socket, &msg, sizeof(recvbuf), 0);
> + recvlen = sock_recvmsg(socket, &msg, recvbuf_size, 0);

but not here.