The owner field in the rw_semaphore structure is used primarily for optimistic spinning. However, identifying the rwsem owner can also be helpful in debugging as well as tracing locking related issues when analyzing crash dump. The owner field may also store state information that can be important to the operation of the rwsem. So the owner field is now made a permanent member of the rw_semaphore structure irrespective of CONFIG_RWSEM_SPIN_ON_OWNER.
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| @@ -1095,7 +1095,7 @@ config PROVE_LOCKING · 1094 unmodified lines | |||
| 1095 | select DEBUG_SPINLOCK | 1095 | select DEBUG_SPINLOCK |
| 1096 | select DEBUG_MUTEXES | 1096 | select DEBUG_MUTEXES |
| 1097 | select DEBUG_RT_MUTEXES if RT_MUTEXES | 1097 | select DEBUG_RT_MUTEXES if RT_MUTEXES |
| 1098 | select DEBUG_RWSEMS if RWSEM_SPIN_ON_OWNER | 1098 | select DEBUG_RWSEMS |
| 1099 | select DEBUG_WW_MUTEX_SLOWPATH | 1099 | select DEBUG_WW_MUTEX_SLOWPATH |
| 1100 | select DEBUG_LOCK_ALLOC | 1100 | select DEBUG_LOCK_ALLOC |
| 1101 | select TRACE_IRQFLAGS | 1101 | select TRACE_IRQFLAGS |
| @@ -1199,10 +1199,10 @@ config DEBUG_WW_MUTEX_SLOWPATH · 97 unmodified lines | |||
| 1199 | 1199 | ||
| 1200 | config DEBUG_RWSEMS | 1200 | config DEBUG_RWSEMS |
| 1201 | bool "RW Semaphore debugging: basic checks" | 1201 | bool "RW Semaphore debugging: basic checks" |
| 1202 | depends on DEBUG_KERNEL && RWSEM_SPIN_ON_OWNER | 1202 | depends on DEBUG_KERNEL |
| 1203 | help | 1203 | help |
| 1204 | This debugging feature allows mismatched rw semaphore locks and unlocks | 1204 | This debugging feature allows mismatched rw semaphore locks |
| 1205 | to be detected and reported. | 1205 | and unlocks to be detected and reported. |
| 1206 | 1206 | ||
| 1207 | config DEBUG_LOCK_ALLOC | 1207 | config DEBUG_LOCK_ALLOC |
| 1208 | bool "Lock debugging: detect incorrect freeing of live locks" | 1208 | bool "Lock debugging: detect incorrect freeing of live locks" |