Re: [PATCH v4 1/3] xen/console: cleanup conring management

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 16 May 2025, dmkhn@xxxxxxxxx wrote:
> From: Denis Mukhin <dmukhin@xxxxxxxx>
> 
> Move conring tasklet code close to conring definitions in the console driver
> and rename conring tasklet variables by adding conring_ prefix for better
> readability.
> 
> No functional change.
> 
> Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> Changes since v3:
> - dropped 3rd argument from conring_puts()
> ---
>  xen/drivers/char/console.c | 28 ++++++++++++++--------------
>  1 file changed, 14 insertions(+), 14 deletions(-)
> 
> diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
> index c3150fbdb7..b4757844e6 100644
> --- a/xen/drivers/char/console.c
> +++ b/xen/drivers/char/console.c
> @@ -325,6 +325,16 @@ static void cf_check do_dec_thresh(unsigned char key, 
> bool unused)
>   * ********************************************************
>   */
>  
> +static void cf_check conring_notify(void *unused)
> +{
> +    send_global_virq(VIRQ_CON_RING);
> +}
> +
> +static DECLARE_SOFTIRQ_TASKLET(conring_tasklet, conring_notify, NULL);
> +
> +/* NB: Do not send conring VIRQs during panic. */
> +static bool conring_no_notify;
> +
>  static void conring_puts(const char *str, size_t len)
>  {
>      ASSERT(rspin_is_locked(&console_lock));
> @@ -594,13 +604,6 @@ static void cf_check serial_rx(char c)
>      __serial_rx(c);
>  }
>  
> -static void cf_check notify_dom0_con_ring(void *unused)
> -{
> -    send_global_virq(VIRQ_CON_RING);
> -}
> -static DECLARE_SOFTIRQ_TASKLET(notify_dom0_con_ring_tasklet,
> -                               notify_dom0_con_ring, NULL);
> -
>  #ifdef CONFIG_X86
>  static inline void xen_console_write_debug_port(const char *buf, size_t len)
>  {
> @@ -650,7 +653,7 @@ static long 
> guest_console_write(XEN_GUEST_HANDLE_PARAM(char) buffer,
>              if ( opt_console_to_ring )
>              {
>                  conring_puts(kbuf, kcount);
> -                tasklet_schedule(&notify_dom0_con_ring_tasklet);
> +                tasklet_schedule(&conring_tasklet);
>              }
>  
>              nrspin_unlock_irq(&console_lock);
> @@ -753,8 +756,6 @@ long do_console_io(
>   * *****************************************************
>   */
>  
> -static bool console_locks_busted;
> -
>  static void __putstr(const char *str)
>  {
>      size_t len = strlen(str);
> @@ -775,9 +776,8 @@ static void __putstr(const char *str)
>  #endif
>  
>      conring_puts(str, len);
> -
> -    if ( !console_locks_busted )
> -        tasklet_schedule(&notify_dom0_con_ring_tasklet);
> +    if ( !conring_no_notify )
> +        tasklet_schedule(&conring_tasklet);
>  }
>  
>  static int printk_prefix_check(char *p, char **pp)
> @@ -1171,7 +1171,7 @@ void console_force_unlock(void)
>      spin_debug_disable();
>      rspin_lock_init(&console_lock);
>      serial_force_unlock(sercon_handle);
> -    console_locks_busted = 1;
> +    conring_no_notify = true;
>      console_start_sync();
>  }
>  
> -- 
> 2.34.1
> 
>