rcu: Inline RCU task stall-warning helper functions

The rcu_print_detail_task_stall(), rcu_print_task_stall_begin(), and
rcu_print_task_stall_end() functions were defined to allow long-gone
Kconfig options to provide an abbreviated RCU CPU stall warning printout.
This commit saves a few lines of code by inlining them into their sole
callers.

While in the area, a useless call of rcu_print_detail_task_stall_rnp()
on the root rcu_node structure was eliminated.  If there is only one
rcu_node structure, its tasks get printed twice, but if there are more,
the root rcu_node structure is guaranteed to have an empty list of blocked
tasks, hence the uselessness.  (Long ago, root rcu_node structures with
non-empty ->blkd_tasks lists could happen, but no longer.)

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 3c4e26fff80697fc5229f61e687a5481bde53ab4..c6df9a13dd06c90f4fd5ed26e3533f625f07245e 100644 (file)
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -445,7 +445,6 @@ static void rcu_dynticks_task_enter(void);
 static void rcu_dynticks_task_exit(void);
 
 /* Forward declarations for tree_stall.h */
-static void rcu_print_detail_task_stall(void);
 static int rcu_print_task_stall(struct rcu_node *rnp);
 static void record_gp_stall_check_time(void);
 static void check_cpu_stall(struct rcu_data *rdp);

diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index e0e73f493363915f7b9f30a67dd76617c3ec34ae..b476786b8ef731cf02cc81c665430e66621b2ee4 100644 (file)
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -94,30 +94,6 @@ static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
        raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 }
 
-/*
- * Dump detailed information for all tasks blocking the current RCU
- * grace period.
- */
-static void rcu_print_detail_task_stall(void)
-{
-       struct rcu_node *rnp = rcu_get_root();
-
-       rcu_print_detail_task_stall_rnp(rnp);
-       rcu_for_each_leaf_node(rnp)
-               rcu_print_detail_task_stall_rnp(rnp);
-}
-
-static void rcu_print_task_stall_begin(struct rcu_node *rnp)
-{
-       pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):",
-              rnp->level, rnp->grplo, rnp->grphi);
-}
-
-static void rcu_print_task_stall_end(void)
-{
-       pr_cont("\n");
-}
-
 /*
  * Scan the current list of tasks blocked within RCU read-side critical
  * sections, printing out the tid of each.
@@ -129,14 +105,15 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
 
        if (!rcu_preempt_blocked_readers_cgp(rnp))
                return 0;
-       rcu_print_task_stall_begin(rnp);
+       pr_err("\tTasks blocked on level-%d rcu_node (CPUs %d-%d):",
+              rnp->level, rnp->grplo, rnp->grphi);
        t = list_entry(rnp->gp_tasks->prev,
                       struct task_struct, rcu_node_entry);
        list_for_each_entry_continue(t, &rnp->blkd_tasks, rcu_node_entry) {
                pr_cont(" P%d", t->pid);
                ndetected++;
        }
-       rcu_print_task_stall_end();
+       pr_cont("\n");
        return ndetected;
 }
 
@@ -146,7 +123,7 @@ static int rcu_print_task_stall(struct rcu_node *rnp)
  * Because preemptible RCU does not exist, we never have to check for
  * tasks blocked within RCU read-side critical sections.
  */
-static void rcu_print_detail_task_stall(void)
+static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
 {
 }
 
@@ -253,7 +230,7 @@ static void print_other_cpu_stall(unsigned long gp_seq)
        unsigned long gpa;
        unsigned long j;
        int ndetected = 0;
-       struct rcu_node *rnp = rcu_get_root();
+       struct rcu_node *rnp;
        long totqlen = 0;
 
        /* Kick and suppress, if so configured. */
@@ -291,7 +268,8 @@ static void print_other_cpu_stall(unsigned long gp_seq)
                rcu_dump_cpu_stacks();
 
                /* Complain about tasks blocking the grace period. */
-               rcu_print_detail_task_stall();
+               rcu_for_each_leaf_node(rnp)
+                       rcu_print_detail_task_stall_rnp(rnp);
        } else {
                if (rcu_seq_current(&rcu_state.gp_seq) != gp_seq) {
                        pr_err("INFO: Stall ended before state dump start\n");