[dm-devel] [PATCH RT 1/2 v2] dm-snapshot: fix crash with the realtime kernel

[Sebastian Andrzej Siewior]

On 2019-11-12 11:09:51 [-0500], Mikulas Patocka wrote:
> ===================================================================
> --- linux-2.6.orig/drivers/md/dm-snap.c	2019-11-12 16:44:36.000000000 +0100
> +++ linux-2.6/drivers/md/dm-snap.c	2019-11-12 17:01:46.000000000 +0100
…
>  static void dm_exception_table_lock(struct dm_exception_table_lock *lock)
>  {
> +#ifndef CONFIG_PREEMPT_RT_BASE
>  	hlist_bl_lock(lock->complete_slot);
>  	hlist_bl_lock(lock->pending_slot);
> +#else
> +	spin_lock(lock->lock);

if you also set the lowest bit for complete_slot + pending_slot then
patch 2 of this mini series wouldn't be required. That means we could
keep the debug code on -RT. Or am I missing something?

> +#endif
>  }

Sebastian