Re: [PATCH] staging: rtl8712: Add comment to lock declaration

[Dan Carpenter <dan.carpenter@oracle.com>]

On Mon, Oct 07, 2019 at 09:52:48PM +0100, Jules Irenge wrote:
> Add comment to spinlock declaration to fix warning issued by checkpatch.pl
> "CHECK: spinlock_t definition without comment".
> 
> Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
> ---
>  drivers/staging/rtl8712/drv_types.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/rtl8712/drv_types.h b/drivers/staging/rtl8712/drv_types.h
> index 0c4325073c63..960d8709aada 100644
> --- a/drivers/staging/rtl8712/drv_types.h
> +++ b/drivers/staging/rtl8712/drv_types.h
> @@ -160,7 +160,7 @@ struct _adapter {
>  	int pid; /*process id from UI*/
>  	struct work_struct wk_filter_rx_ff0;
>  	u8 blnEnableRxFF0Filter;
> -	spinlock_t lock_rx_ff0_filter;
> +	spinlock_t lock_rx_ff0_filter; /*spinlock to protect interrupt request*/

This spinlock seems to be nonsense.  It's only used one time:

drivers/staging/rtl8712/xmit_linux.c
    94  void r8712_SetFilter(struct work_struct *work)
    95  {
    96          struct _adapter *adapter = container_of(work, struct _adapter,
    97                                                  wk_filter_rx_ff0);
    98          u8  oldvalue = 0x00, newvalue = 0x00;
    99          unsigned long irqL;
   100  
   101          oldvalue = r8712_read8(adapter, 0x117);
   102          newvalue = oldvalue & 0xfe;
   103          r8712_write8(adapter, 0x117, newvalue);
   104  
   105          spin_lock_irqsave(&adapter->lock_rx_ff0_filter, irqL);
   106          adapter->blnEnableRxFF0Filter = 1;

It only protects writing to ->blnEnableRxFF0Filter but it doesn't
protect reading so it can't possibly work.

   107          spin_unlock_irqrestore(&adapter->lock_rx_ff0_filter, irqL);
   108          do {
   109                  msleep(100);
   110          } while (adapter->blnEnableRxFF0Filter == 1);
   111          r8712_write8(adapter, 0x117, oldvalue);
   112  }

Also put a space after /* and before */ so the comment looks like:
	/* spinlock to protect interrupt request */

But in this case, the comment isn't correct so please just leave it
as-is until someone can fix the locking.

regards,
dan carpenter