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rcu: Add lockdep-enabled variants of rcu_dereference() 

Make rcu_dereference() check for being in an RCU read-side
critical section, and create rcu_dereference_bh(),
rcu_dereference_sched(), and srcu_dereference() to check for the
other flavors of RCU.  Also create rcu_dereference_raw() to
avoid checking, and make rcu_dereference_check() use
rcu_dereference_raw().

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-2-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul E. McKenney 2010-02-22 17:04:46 -08:00 committed by Ingo Molnar
parent 632ee20013
commit c26d34a585
2 changed files with 42 additions and 7 deletions
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41
include/linux/rcupdate.h
View File

@ -184,12 +184,12 @@ static inline int rcu_read_lock_sched_held(void)
({ \
if (debug_locks) \
WARN_ON_ONCE(!(c)); \
rcu_dereference(p); \
rcu_dereference_raw(p); \
})
#else /* #ifdef CONFIG_PROVE_RCU */
#define rcu_dereference_check(p, c) rcu_dereference(p)
#define rcu_dereference_check(p, c) rcu_dereference_raw(p)
#endif /* #else #ifdef CONFIG_PROVE_RCU */
@ -325,21 +325,48 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
/**
* rcu_dereference - fetch an RCU-protected pointer in an
* RCU read-side critical section. This pointer may later
* be safely dereferenced.
* rcu_dereference_raw - fetch an RCU-protected pointer
*
* The caller must be within some flavor of RCU read-side critical
* section, or must be otherwise preventing the pointer from changing,
* for example, by holding an appropriate lock. This pointer may later
* be safely dereferenced. It is the caller's responsibility to have
* done the right thing, as this primitive does no checking of any kind.
*
* Inserts memory barriers on architectures that require them
* (currently only the Alpha), and, more importantly, documents
* exactly which pointers are protected by RCU.
*/
#define rcu_dereference(p) ({ \
#define rcu_dereference_raw(p) ({ \
typeof(p) _________p1 = ACCESS_ONCE(p); \
smp_read_barrier_depends(); \
(_________p1); \
})
/**
* rcu_dereference - fetch an RCU-protected pointer, checking for RCU
*
* Makes rcu_dereference_check() do the dirty work.
*/
#define rcu_dereference(p) \
rcu_dereference_check(p, rcu_read_lock_held())
/**
* rcu_dereference_bh - fetch an RCU-protected pointer, checking for RCU-bh
*
* Makes rcu_dereference_check() do the dirty work.
*/
#define rcu_dereference_bh(p) \
rcu_dereference_check(p, rcu_read_lock_bh_held())
/**
* rcu_dereference_sched - fetch RCU-protected pointer, checking for RCU-sched
*
* Makes rcu_dereference_check() do the dirty work.
*/
#define rcu_dereference_sched(p) \
rcu_dereference_check(p, rcu_read_lock_sched_held())
/**
* rcu_assign_pointer - assign (publicize) a pointer to a newly
* initialized structure that will be dereferenced by RCU read-side

8
include/linux/srcu.h
View File

@ -105,6 +105,14 @@ static inline int srcu_read_lock_held(struct srcu_struct *sp)
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
/**
* srcu_dereference - fetch SRCU-protected pointer with checking
*
* Makes rcu_dereference_check() do the dirty work.
*/
#define srcu_dereference(p, sp) \
rcu_dereference_check(p, srcu_read_lock_held(sp))
/**
* srcu_read_lock - register a new reader for an SRCU-protected structure.
* @sp: srcu_struct in which to register the new reader.