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| author |   Joel Fernandes (Google) <joel@joelfernandes.org> | 2018-06-28 11:21:44 -0700 |
|---|---|---|
| committer |   Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-07-26 10:50:16 -0400 |
| commit | 0b764a6e4e19dc254caca636002eaa47b1d0b0af (patch) | |
| tree | 53ef602e29f6987ed13e629f2dcee617566adf5b | |
| parent | srcu: Add notrace variants of srcu_read_{lock,unlock} (diff) | |
| download | linux-dev-0b764a6e4e19dc254caca636002eaa47b1d0b0af.tar.xz linux-dev-0b764a6e4e19dc254caca636002eaa47b1d0b0af.zip | |
srcu: Add notrace variant of srcu_dereference
In the last patch in this series, we are making lockdep register hooks
onto the irq_{disable,enable} tracepoints. These tracepoints use the
_rcuidle tracepoint variant. In this series we switch the _rcuidle
tracepoint callers to use SRCU instead of sched-RCU. Inorder to
dereference the pointer to the probe functions, we could call
srcu_dereference, however this API will call back into lockdep to check
if the lock is held *before* the lockdep probe hooks have a chance to
run and annotate the IRQ enabled/disabled state.
For this reason we need a notrace variant of srcu_dereference since
otherwise we get lockdep splats. This patch adds the needed
srcu_dereference_notrace variant.
Link: http://lkml.kernel.org/r/20180628182149.226164-3-joel@joelfernandes.org
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | include/linux/srcu.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 3e72a291c401..67135d4a8a30 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -170,6 +170,11 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp) #define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0) /** + * srcu_dereference_notrace - no tracing and no lockdep calls from here + */ +#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1) + +/** * srcu_read_lock - register a new reader for an SRCU-protected structure. * @sp: srcu_struct in which to register the new reader. * |