This reverts commit 859247d39fb008ea812e8f0c398a58a20c12899e. Current implementation of lockdep_assert_preemption_disabled() uses per-CPU variables, which was done to untangle the existing seqlock.h<=>sched.h 'current->' task_struct circular dependency.
Using per-CPU variables did not fully untangle the dependency for various non-x86 architectures though, resulting in multiple broken builds. For the affected architectures, raw_smp_processor_id() led back to 'current->', thus having the original seqlock.h<=>sched.h dependency in full-effect. For now, revert adding lockdep_assert_preemption_disabled() to seqlock.h. Reported-by: Guenter Roeck <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] References: Commit a21ee6055c30 ("lockdep: Change hardirq{s_enabled,_context} to per-cpu variables") Signed-off-by: Ahmed S. Darwish <[email protected]> --- Notes: My apologies for the mess on this one :-( include/linux/seqlock.h | 29 ++++++----------------------- 1 file changed, 6 insertions(+), 23 deletions(-) diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index 54bc20496392..e885702d8b82 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -266,12 +266,6 @@ static inline void raw_write_seqcount_end(seqcount_t *s) kcsan_nestable_atomic_end(); } -static inline void __write_seqcount_begin_nested(seqcount_t *s, int subclass) -{ - raw_write_seqcount_begin(s); - seqcount_acquire(&s->dep_map, subclass, 0, _RET_IP_); -} - /** * write_seqcount_begin_nested() - start a seqcount_t write section with * custom lockdep nesting level @@ -282,19 +276,8 @@ static inline void __write_seqcount_begin_nested(seqcount_t *s, int subclass) */ static inline void write_seqcount_begin_nested(seqcount_t *s, int subclass) { - lockdep_assert_preemption_disabled(); - __write_seqcount_begin_nested(s, subclass); -} - -/* - * A write_seqcount_begin() variant w/o lockdep non-preemptibility checks. - * - * Use for internal seqlock.h code where it's known that preemption is - * already disabled. For example, seqlock_t write side functions. - */ -static inline void __write_seqcount_begin(seqcount_t *s) -{ - __write_seqcount_begin_nested(s, 0); + raw_write_seqcount_begin(s); + seqcount_acquire(&s->dep_map, subclass, 0, _RET_IP_); } /** @@ -592,7 +575,7 @@ static inline unsigned read_seqretry(const seqlock_t *sl, unsigned start) static inline void write_seqlock(seqlock_t *sl) { spin_lock(&sl->lock); - __write_seqcount_begin(&sl->seqcount); + write_seqcount_begin(&sl->seqcount); } /** @@ -618,7 +601,7 @@ static inline void write_sequnlock(seqlock_t *sl) static inline void write_seqlock_bh(seqlock_t *sl) { spin_lock_bh(&sl->lock); - __write_seqcount_begin(&sl->seqcount); + write_seqcount_begin(&sl->seqcount); } /** @@ -645,7 +628,7 @@ static inline void write_sequnlock_bh(seqlock_t *sl) static inline void write_seqlock_irq(seqlock_t *sl) { spin_lock_irq(&sl->lock); - __write_seqcount_begin(&sl->seqcount); + write_seqcount_begin(&sl->seqcount); } /** @@ -666,7 +649,7 @@ static inline unsigned long __write_seqlock_irqsave(seqlock_t *sl) unsigned long flags; spin_lock_irqsave(&sl->lock, flags); - __write_seqcount_begin(&sl->seqcount); + write_seqcount_begin(&sl->seqcount); return flags; } -- 2.28.0
