2021-07-30 04:18:38

by Desmond Cheong Zhi Xi

Subject: [PATCH 0/2] locking/lockdep, drm: apply new lockdep assert in drm_auth.c

Hi,

Following a discussion on the patch ("drm: use the lookup lock in
drm_is_current_master") [1], Peter Zijlstra proposed new lockdep_assert
helpers to make it convenient to compose lockdep checks together.

This series includes the patch that introduces the new lockdep helpers,
then utilizes these helpers in drm_is_current_master_locked in the
following patch.

Link: https://lore.kernel.org/lkml/[email protected]/ [1]

Best wishes,
Desmond

Desmond Cheong Zhi Xi (1):
drm: add lockdep assert to drm_is_current_master_locked

Peter Zijlstra (1):
locking/lockdep: Provide lockdep_assert{,_once}() helpers

drivers/gpu/drm/drm_auth.c | 6 +++---
include/linux/lockdep.h | 41 +++++++++++++++++++-------------------
2 files changed, 24 insertions(+), 23 deletions(-)

--
2.25.1

2021-07-30 04:18:47

by Desmond Cheong Zhi Xi

Subject: [PATCH 1/2] locking/lockdep: Provide lockdep_assert{,_once}() helpers

From: Peter Zijlstra <[email protected]>

Extract lockdep_assert{,_once}() helpers to more easily write composite
assertions like, for example:

lockdep_assert(lockdep_is_held(&drm_device.master_mutex) ||
lockdep_is_held(&drm_file.master_lookup_lock));

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Desmond Cheong Zhi Xi <[email protected]>
---
include/linux/lockdep.h | 41 +++++++++++++++++++++--------------------
1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 5cf387813754..9fe165beb0f9 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -306,31 +306,29 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);

#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)

-#define lockdep_assert_held(l) do { \
- WARN_ON(debug_locks && \
- lockdep_is_held(l) == LOCK_STATE_NOT_HELD); \
- } while (0)
+#define lockdep_assert(cond) \
+ do { WARN_ON(debug_locks && !(cond)); } while (0)

-#define lockdep_assert_not_held(l) do { \
- WARN_ON(debug_locks && \
- lockdep_is_held(l) == LOCK_STATE_HELD); \
- } while (0)
+#define lockdep_assert_once(cond) \
+ do { WARN_ON_ONCE(debug_locks && !(cond)); } while (0)

-#define lockdep_assert_held_write(l) do { \
- WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
- } while (0)
+#define lockdep_assert_held(l) \
+ lockdep_assert(lockdep_is_held(l) != LOCK_STATE_NOT_HELD)

-#define lockdep_assert_held_read(l) do { \
- WARN_ON(debug_locks && !lockdep_is_held_type(l, 1)); \
- } while (0)
+#define lockdep_assert_not_held(l) \
+ lockdep_assert(lockdep_is_held(l) != LOCK_STATE_HELD)

-#define lockdep_assert_held_once(l) do { \
- WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \
- } while (0)
+#define lockdep_assert_held_write(l) \
+ lockdep_assert(lockdep_is_held_type(l, 0))

-#define lockdep_assert_none_held_once() do { \
- WARN_ON_ONCE(debug_locks && current->lockdep_depth); \
- } while (0)
+#define lockdep_assert_held_read(l) \
+ lockdep_assert(lockdep_is_held_type(l, 1))
+
+#define lockdep_assert_held_once(l) \
+ lockdep_assert_once(lockdep_is_held(l) != LOCK_STATE_NOT_HELD)
+
+#define lockdep_assert_none_held_once() \
+ lockdep_assert_once(!current->lockdep_depth)

#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)

@@ -407,6 +405,9 @@ extern int lock_is_held(const void *);
extern int lockdep_is_held(const void *);
#define lockdep_is_held_type(l, r) (1)

+#define lockdep_assert(c) do { } while (0)
+#define lockdep_assert_once(c) do { } while (0)
+
#define lockdep_assert_held(l) do { (void)(l); } while (0)
#define lockdep_assert_not_held(l) do { (void)(l); } while (0)
#define lockdep_assert_held_write(l) do { (void)(l); } while (0)
--
2.25.1

2021-07-30 17:41:48

by Waiman Long

Subject: Re: [PATCH 0/2] locking/lockdep, drm: apply new lockdep assert in drm_auth.c

On 7/30/21 12:15 AM, Desmond Cheong Zhi Xi wrote:
> Hi,
>
> Following a discussion on the patch ("drm: use the lookup lock in
> drm_is_current_master") [1], Peter Zijlstra proposed new lockdep_assert
> helpers to make it convenient to compose lockdep checks together.
>
> This series includes the patch that introduces the new lockdep helpers,
> then utilizes these helpers in drm_is_current_master_locked in the
> following patch.
>
> Link: https://lore.kernel.org/lkml/[email protected]/ [1]
>
> Best wishes,
> Desmond
>
> Desmond Cheong Zhi Xi (1):
> drm: add lockdep assert to drm_is_current_master_locked
>
> Peter Zijlstra (1):
> locking/lockdep: Provide lockdep_assert{,_once}() helpers
>
> drivers/gpu/drm/drm_auth.c | 6 +++---
> include/linux/lockdep.h | 41 +++++++++++++++++++-------------------
> 2 files changed, 24 insertions(+), 23 deletions(-)
>
This patch series looks good to me.

Acked-by: Waiman Long <[email protected]>

Thanks!