Commit c7dcf810 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu-tasks: Fix synchronize_rcu_tasks_trace() header comment 



The synchronize_rcu_tasks_trace() header comment incorrectly claims that
any number of things delimit RCU Tasks Trace read-side critical sections,
when in fact only rcu_read_lock_trace() and rcu_read_unlock_trace() do so.
This commit therefore fixes this comment, and, while in the area, fixes
a typo in the rcu_read_lock_trace() header comment.

Reported-by: default avatarAlexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent e13ef442

include/linux/rcupdate_trace.h

+2 −2
Original line number Diff line number Diff line
@@ -36,8 +36,8 @@ void rcu_read_unlock_trace_special(struct task_struct *t, int nesting); 
/**

 * rcu_read_lock_trace - mark beginning of RCU-trace read-side critical section

 *

 * When synchronize_rcu_trace() is invoked by one task, then that task

 * is guaranteed to block until all other tasks exit their read-side

 * When synchronize_rcu_tasks_trace() is invoked by one task, then that

 * task is guaranteed to block until all other tasks exit their read-side

 * critical sections.  Similarly, if call_rcu_trace() is invoked on one

 * task while other tasks are within RCU read-side critical sections,

 * invocation of the corresponding RCU callback is deferred until after

kernel/rcu/tasks.h

+4 −5
Original line number Diff line number Diff line
@@ -1118,11 +1118,10 @@ EXPORT_SYMBOL_GPL(call_rcu_tasks_trace); 
 * synchronize_rcu_tasks_trace - wait for a trace rcu-tasks grace period

 *

 * Control will return to the caller some time after a trace rcu-tasks

 * grace period has elapsed, in other words after all currently

 * executing rcu-tasks read-side critical sections have elapsed.  These

 * read-side critical sections are delimited by calls to schedule(),

 * cond_resched_tasks_rcu_qs(), userspace execution, and (in theory,

 * anyway) cond_resched().

 * grace period has elapsed, in other words after all currently executing

 * rcu-tasks read-side critical sections have elapsed.  These read-side

 * critical sections are delimited by calls to rcu_read_lock_trace()

 * and rcu_read_unlock_trace().

 *

 * This is a very specialized primitive, intended only for a few uses in

 * tracing and other situations requiring manipulation of function preambles

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