[cc: linux-user-rt, Thomas and Sebastian] On Mon, Nov 11, 2019 at 08:59:44AM -0500, Mikulas Patocka wrote: > list_bl.h would crash with BUG() if we used it without locking. > dm-snapshot uses its own locking on readltime kernels, so to avoid this > BUG, we must set LIST_BL_LOCKMASK = 0. > > Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> > > Index: linux-rt-devel/include/linux/list_bl.h > =================================================================== > --- linux-rt-devel.orig/include/linux/list_bl.h 2019-11-07 14:01:51.000000000 +0100 > +++ linux-rt-devel/include/linux/list_bl.h 2019-11-08 10:12:49.000000000 +0100 > @@ -19,7 +19,7 @@ > * some fast and compact auxiliary data. > */ > > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > +#if (defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)) && !defined(CONFIG_PREEMPT_RT_BASE) CONFIG_PREEMPT_RT_BASE is only available in the out of tree -rt patch set, therefore I assume it's not for mainline, right? > #define LIST_BL_LOCKMASK 1UL > #else > #define LIST_BL_LOCKMASK 0UL > @@ -161,9 +161,6 @@ static inline void hlist_bl_lock(struct > bit_spin_lock(0, (unsigned long *)b); > #else > raw_spin_lock(&b->lock); > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > - __set_bit(0, (unsigned long *)b); > -#endif > #endif > } > > @@ -172,9 +169,6 @@ static inline void hlist_bl_unlock(struc > #ifndef CONFIG_PREEMPT_RT_BASE > __bit_spin_unlock(0, (unsigned long *)b); > #else > -#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) > - __clear_bit(0, (unsigned long *)b); > -#endif > raw_spin_unlock(&b->lock); > #endif > } > > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel > Thanks, Daniel
