Re: [PATCH 1/2] lockdep: add lockdep_assert_not_held()
4 messages,
3 authors,
2021-02-22 · open the first message on its own page
On Mon, 2021-02-15 at 11:44 +0100, Peter Zijlstra wrote:
I think something like so will work, but please double check.
Yeah, that looks better.
quoted hunk +++ b/include/linux/lockdep.h @@ -294,11 +294,15 @@ 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 )); \+ #define lockdep_assert_held(l) do { \ + WARN_ON ( debug_locks && lockdep_is_held ( l ) == 0 )); \ } while ( 0 )
That doesn't really need to change? It's the same.
quoted hunk -#define lockdep_assert_held_write(l) do { \
+#define lockdep_assert_not_held(l) do { \
+ WARN_ON(debug_locks && lockdep_is_held(l) == 1)); \
+ } while (0)
+
+#define lockdep_assert_held_write(l) do { \
WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
} while (0)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index c1418b47f625..983ba206f7b2 100644
--- a/kernel/locking/lockdep.
+++ b/kernel/locking/lockdep.c @@ -5467,7 +5467,7 @@ noinstr int lock_is_held_type(const struct lockdep_map *lock, int read)
int ret = 0 ;
if ( unlikely ( ! lockdep_enabled ()))
- return 1 ; /* avoid false negative lockdep_assert_held() */ + return -1 ; /* avoid false negative lockdep_assert_held() */
Maybe add lockdep_assert_not_held() to the comment, to explain the -1
(vs non-zero)?
johannes
On Mon, Feb 15, 2021 at 02:12:30PM +0100, Johannes Berg wrote: On Mon, 2021-02-15 at 11:44 +0100, Peter Zijlstra wrote: quoted
I think something like so will work, but please double check.
Yeah, that looks better.
quoted +++ b/include/linux/lockdep.h @@ -294,11 +294,15 @@ 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 )); \+ #define lockdep_assert_held(l) do { \ + WARN_ON ( debug_locks && lockdep_is_held ( l ) == 0 )); \ } while ( 0 )
That doesn't really need to change? It's the same.
Correct, but I found it more symmetric vs the not implementation below.
quoted -#define lockdep_assert_held_write(l) do { \
+#define lockdep_assert_not_held(l) do { \
+ WARN_ON(debug_locks && lockdep_is_held(l) == 1)); \
+ } while (0)
+
+#define lockdep_assert_held_write(l) do { \
WARN_ON(debug_locks && !lockdep_is_held_type(l, 0)); \
} while (0)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index c1418b47f625..983ba206f7b2 100644
--- a/kernel/locking/lockdep.
+++ b/kernel/locking/lockdep.c @@ -5467,7 +5467,7 @@ noinstr int lock_is_held_type(const struct lockdep_map *lock, int read)
int ret = 0 ;
if ( unlikely ( ! lockdep_enabled ()))
- return 1 ; /* avoid false negative lockdep_assert_held() */ + return -1 ; /* avoid false negative lockdep_assert_held() */
Maybe add lockdep_assert_not_held() to the comment, to explain the -1
(vs non-zero)?
Yeah, or frob a '*' in there.
On Mon, 2021-02-15 at 17:04 +0100, Peter Zijlstra wrote: On Mon, Feb 15, 2021 at 02:12:30PM +0100, Johannes Berg wrote: quoted On Mon, 2021-02-15 at 11:44 +0100, Peter Zijlstra wrote: quoted I think something like so will work, but please double check.
Yeah, that looks better.
quoted +++ b/include/linux/lockdep.h @@ -294,11 +294,15 @@ 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 )); \+ #define lockdep_assert_held(l) do { \ + WARN_ON ( debug_locks && lockdep_is_held ( l ) == 0 )); \ } while ( 0 )
That doesn't really need to change? It's the same.
Correct, but I found it more symmetric vs the not implementation below.
Fair enough. One might argue that you should have an
enum lockdep_lock_state {
LOCK_STATE_NOT_HELD, /* 0 now */
LOCK_STATE_HELD, /* 1 now */
LOCK_STATE_UNKNOWN, /* -1 with your patch but might as well be 2 */
};
:)
johannes
On 2/15/21 9:10 AM, Johannes Berg wrote: On Mon, 2021-02-15 at 17:04 +0100, Peter Zijlstra wrote: quoted On Mon, Feb 15, 2021 at 02:12:30PM +0100, Johannes Berg wrote: quoted On Mon, 2021-02-15 at 11:44 +0100, Peter Zijlstra wrote: quoted I think something like so will work, but please double check.
Yeah, that looks better.
quoted +++ b/include/linux/lockdep.h @@ -294,11 +294,15 @@ 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 )); \+ #define lockdep_assert_held(l) do { \ + WARN_ON ( debug_locks && lockdep_is_held ( l ) == 0 )); \ } while ( 0 )
That doesn't really need to change? It's the same.
Correct, but I found it more symmetric vs the not implementation below.
Fair enough. One might argue that you should have an
enum lockdep_lock_state {
LOCK_STATE_NOT_HELD, /* 0 now */
LOCK_STATE_HELD, /* 1 now */
LOCK_STATE_UNKNOWN, /* -1 with your patch but might as well be 2 */
};
:)
Thank you both. Picking this back up. Will send v2 incorporating
your comments and suggestions.
thanks,
-- Shuah