On Mon, Nov 07, 2022 at 03:22:34PM +0106, John Ogness wrote:
> configure_kgdboc() uses the console_lock for console list iteration. Use
> the console_list_lock instead because list synchronization responsibility
> will be removed from the console_lock in a later change.
>
> The SRCU iterator could have been used here, but a later change will
> relocate the locking of the console_list_lock to also provide
> synchronization against register_console().
>
> Note, the console_lock is still needed to serialize the device()
> callback with other console operations.
>
> Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
> ---
> drivers/tty/serial/kgdboc.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
> index 5be381003e58..82b4b4d67823 100644
> --- a/drivers/tty/serial/kgdboc.c
> +++ b/drivers/tty/serial/kgdboc.c
> @@ -451,6 +463,7 @@ static void kgdboc_earlycon_pre_exp_handler(void)
> {
> struct console *con;
> static bool already_warned;
> + int cookie;
>
> if (already_warned)
> return;
> @@ -463,9 +476,14 @@ static void kgdboc_earlycon_pre_exp_handler(void)
> * serial drivers might be OK with this, print a warning once per
> * boot if we detect this case.
> */
> - for_each_console(con)
> + cookie = console_srcu_read_lock();
> + for_each_console_srcu(con) {
> if (con == kgdboc_earlycon_io_ops.cons)
> - return;
> + break;
> + }
> + console_srcu_read_unlock(cookie);
> + if (con)
> + return;
This change isn't mentioned in the patch description.
Daniel.
