| Message ID | 20240613064716.WxAIvb9K@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [REPOST] drm/ttm/tests: Let ttm_bo_test consider different ww_mutex implementation. | expand |
Am 13.06.24 um 08:47 schrieb Sebastian Andrzej Siewior: > PREEMPT_RT has a different locking implementation for ww_mutex. The > base mutex of struct ww_mutex is declared as struct WW_MUTEX_BASE. The > latter is defined as `mutex' for non-PREEMPT_RT builds and `rt_mutex' > for PREEMPT_RT builds. > > Using mutex_lock() directly on the base mutex in > ttm_bo_reserve_deadlock() leads to compile error on PREEMPT_RT. > > The locking-selftest has its own defines to deal with this and it is > probably best to defines the needed one within the test program since > their usefulness is limited outside of well known selftests. > > Provide ww_mutex_base_lock() which points to the correct function for > PREEMPT_RT and non-PREEMPT_RT builds. In general good that somebody is looking into this, but I can't even judge why ww_mutex would use rt_mutex in the first place. So I don't feel well reviewing this. Regards, Christian. > > Fixes: 995279d280d1e ("drm/ttm/tests: Add tests for ttm_bo functions") > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > --- > Repost of https://lore.kernel.org/r/20240404102534.QTa80QPY@linutronix.de > > drivers/gpu/drm/ttm/tests/ttm_bo_test.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > --- a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c > +++ b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c > @@ -18,6 +18,12 @@ > > #define BO_SIZE SZ_8K > > +#ifdef CONFIG_PREEMPT_RT > +#define ww_mutex_base_lock(b) rt_mutex_lock(b) > +#else > +#define ww_mutex_base_lock(b) mutex_lock(b) > +#endif > + > struct ttm_bo_test_case { > const char *description; > bool interruptible; > @@ -142,7 +148,7 @@ static void ttm_bo_reserve_deadlock(stru > bo2 = ttm_bo_kunit_init(test, test->priv, BO_SIZE); > > ww_acquire_init(&ctx1, &reservation_ww_class); > - mutex_lock(&bo2->base.resv->lock.base); > + ww_mutex_base_lock(&bo2->base.resv->lock.base); > > /* The deadlock will be caught by WW mutex, don't warn about it */ > lock_release(&bo2->base.resv->lock.base.dep_map, 1);
On 2024-06-13 14:33:51 [+0200], Christian König wrote: > > Provide ww_mutex_base_lock() which points to the correct function for > > PREEMPT_RT and non-PREEMPT_RT builds. > > In general good that somebody is looking into this, but I can't even judge > why ww_mutex would use rt_mutex in the first place. as noted in commit message, this is already done in lib/locking-selftest.c The base mutex of struct ww_mutex is WW_MUTEX_BASE which is defined as | #ifndef CONFIG_PREEMPT_RT | #define WW_MUTEX_BASE mutex … | #else | #define WW_MUTEX_BASE rt_mutex … | #endif this is all in-tree. > So I don't feel well reviewing this. > > Regards, > Christian. Sebastian
--- a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c +++ b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c @@ -18,6 +18,12 @@ #define BO_SIZE SZ_8K +#ifdef CONFIG_PREEMPT_RT +#define ww_mutex_base_lock(b) rt_mutex_lock(b) +#else +#define ww_mutex_base_lock(b) mutex_lock(b) +#endif + struct ttm_bo_test_case { const char *description; bool interruptible; @@ -142,7 +148,7 @@ static void ttm_bo_reserve_deadlock(stru bo2 = ttm_bo_kunit_init(test, test->priv, BO_SIZE); ww_acquire_init(&ctx1, &reservation_ww_class); - mutex_lock(&bo2->base.resv->lock.base); + ww_mutex_base_lock(&bo2->base.resv->lock.base); /* The deadlock will be caught by WW mutex, don't warn about it */ lock_release(&bo2->base.resv->lock.base.dep_map, 1);
PREEMPT_RT has a different locking implementation for ww_mutex. The base mutex of struct ww_mutex is declared as struct WW_MUTEX_BASE. The latter is defined as `mutex' for non-PREEMPT_RT builds and `rt_mutex' for PREEMPT_RT builds. Using mutex_lock() directly on the base mutex in ttm_bo_reserve_deadlock() leads to compile error on PREEMPT_RT. The locking-selftest has its own defines to deal with this and it is probably best to defines the needed one within the test program since their usefulness is limited outside of well known selftests. Provide ww_mutex_base_lock() which points to the correct function for PREEMPT_RT and non-PREEMPT_RT builds. Fixes: 995279d280d1e ("drm/ttm/tests: Add tests for ttm_bo functions") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- Repost of https://lore.kernel.org/r/20240404102534.QTa80QPY@linutronix.de drivers/gpu/drm/ttm/tests/ttm_bo_test.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)