diff options
author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-02-23 01:04:46 (GMT) |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2010-02-25 08:41:00 (GMT) |
commit | c26d34a5858f96a564c45048bf5f09319d2abad1 (patch) | |
tree | 644941c0005b8ecda4f5af3fd9f9c385f911f146 /include | |
parent | 632ee200130899252508c478ad0e808222573fbc (diff) | |
download | linux-fsl-qoriq-c26d34a5858f96a564c45048bf5f09319d2abad1.tar.xz |
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>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/rcupdate.h | 41 | ||||
-rw-r--r-- | include/linux/srcu.h | 8 |
2 files changed, 42 insertions, 7 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index e3d37ef..839d296 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -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 */ @@ -325,22 +325,49 @@ 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 * critical sections. Returns the value assigned. diff --git a/include/linux/srcu.h b/include/linux/srcu.h index adbe167..3084f80 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -106,6 +106,14 @@ 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. * |