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| author | Nicholas Mc Guire <der.herr@hofr.at> | 2014-01-02 09:18:42 (GMT) |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2015-02-13 22:20:45 (GMT) |
| commit | 937634f2854358d3cf38e95e2fd271cf0c24c7fe (patch) | |
| tree | a904e05790b9c557c29b96d30b87a27051cb5a1b /include | |
| parent | 805d5a3b8703a518c76fd7a6b14a46af251de054 (diff) | |
| download | linux-fsl-qoriq-937634f2854358d3cf38e95e2fd271cf0c24c7fe.tar.xz | |
write_lock migrate_disable pushdown to rt_write_lock
pushdown of migrate_disable/enable from write_*lock* to the rt_write_*lock*
api level
general mapping of write_*lock* to mutexes:
write_*lock*
`-> rt_write_*lock*
`-> __spin_lock (the sleeping __spin_lock)
`-> rt_mutex
write_*lock*s are non-recursive so we have two lock chains to consider
- write_trylock*/write_unlock
- write_lock*/wirte_unlock
for both paths the migration_disable/enable must be balanced.
write_trylock* mapping:
write_trylock_irqsave
`-> rt_write_trylock_irqsave
write_trylock \
`--------> rt_write_trylock
ret = rt_mutex_trylock
rt_mutex_fasttrylock
rt_mutex_cmpxchg
if (ret)
migrate_disable
write_lock* mapping:
write_lock_irqsave
`-> rt_write_lock_irqsave
write_lock_irq -> write_lock ----. \
write_lock_bh -+ \
`-> rt_write_lock
__rt_spin_lock()
rt_spin_lock_fastlock()
rt_mutex_cmpxchg()
migrate_disable()
write_unlock* mapping:
write_unlock_irqrestore.
write_unlock_bh -------+
write_unlock_irq -> write_unlock ----------+
`-> rt_write_unlock()
__rt_spin_unlock()
rt_spin_lock_fastunlock()
rt_mutex_cmpxchg()
migrate_enable()
So calls to migrate_disable/enable() are better placed at the rt_write_*
level of lock/trylock/unlock as all of the write_*lock* API has this as a
common path.
This approach to write_*_bh also eliminates the concerns raised with
regards to api inbalances (write_lock_bh -> write_unlock+local_bh_enable)
Tested-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/rwlock_rt.h | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/include/linux/rwlock_rt.h b/include/linux/rwlock_rt.h index 853ee36..a276fae 100644 --- a/include/linux/rwlock_rt.h +++ b/include/linux/rwlock_rt.h @@ -40,7 +40,6 @@ extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key #define write_lock_irqsave(lock, flags) \ do { \ typecheck(unsigned long, flags); \ - migrate_disable(); \ flags = rt_write_lock_irqsave(lock); \ } while (0) @@ -61,14 +60,12 @@ extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key #define write_lock(lock) \ do { \ - migrate_disable(); \ rt_write_lock(lock); \ } while (0) #define write_lock_bh(lock) \ do { \ local_bh_disable(); \ - migrate_disable(); \ rt_write_lock(lock); \ } while (0) @@ -92,13 +89,11 @@ extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key #define write_unlock(lock) \ do { \ rt_write_unlock(lock); \ - migrate_enable(); \ } while (0) #define write_unlock_bh(lock) \ do { \ rt_write_unlock(lock); \ - migrate_enable(); \ local_bh_enable(); \ } while (0) @@ -117,7 +112,6 @@ extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key typecheck(unsigned long, flags); \ (void) flags; \ rt_write_unlock(lock); \ - migrate_enable(); \ } while (0) #endif |