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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-04-14 03:11:44 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-05-15 20:28:07 +0300 |
| commit | 5b4c11d54b1b8d0714702006e00441ada59889a9 (patch) | |
| tree | 49e052b1402d46a7a283f29913c045ee6e36b153 /kernel/rcu | |
| parent | 4317228ad9b86f094d70c951f9210a8a9b2816be (diff) | |
| download | linux-5b4c11d54b1b8d0714702006e00441ada59889a9.tar.xz | |
rcu: Add leaf-node macros
This commit adds rcu_first_leaf_node() that returns a pointer to
the first leaf rcu_node structure in the specified RCU flavor and an
rcu_is_leaf_node() that returns true iff the specified rcu_node structure
is a leaf. This commit also uses these macros where appropriate.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/rcu.h | 11 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 4 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 4 |
3 files changed, 12 insertions, 7 deletions
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 7a693e31184a..5b5bb9ee2e20 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -270,6 +270,12 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt) } } +/* Returns first leaf rcu_node of the specified RCU flavor. */ +#define rcu_first_leaf_node(rsp) ((rsp)->level[rcu_num_lvls - 1]) + +/* Is this rcu_node a leaf? */ +#define rcu_is_leaf_node(rnp) ((rnp)->level == rcu_num_lvls - 1) + /* * Do a full breadth-first scan of the rcu_node structures for the * specified rcu_state structure. @@ -284,8 +290,7 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt) * rcu_node tree with but one rcu_node structure, this loop is a no-op. */ #define rcu_for_each_nonleaf_node_breadth_first(rsp, rnp) \ - for ((rnp) = &(rsp)->node[0]; \ - (rnp) < (rsp)->level[rcu_num_lvls - 1]; (rnp)++) + for ((rnp) = &(rsp)->node[0]; !rcu_is_leaf_node(rsp, rnp); (rnp)++) /* * Scan the leaves of the rcu_node hierarchy for the specified rcu_state @@ -294,7 +299,7 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt) * It is still a leaf node, even if it is also the root node. */ #define rcu_for_each_leaf_node(rsp, rnp) \ - for ((rnp) = (rsp)->level[rcu_num_lvls - 1]; \ + for ((rnp) = rcu_first_leaf_node(rsp); \ (rnp) < &(rsp)->node[rcu_num_nodes]; (rnp)++) /* diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c4db0e20b035..b22d2e1ca5c0 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2398,7 +2398,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, return; } WARN_ON_ONCE(oldmask); /* Any child must be all zeroed! */ - WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1 && + WARN_ON_ONCE(!rcu_is_leaf_node(rnp) && rcu_preempt_blocked_readers_cgp(rnp)); rnp->qsmask &= ~mask; trace_rcu_quiescent_state_report(rsp->name, rnp->gpnum, @@ -4056,7 +4056,7 @@ static void __init rcu_init_one(struct rcu_state *rsp) init_swait_queue_head(&rsp->gp_wq); init_swait_queue_head(&rsp->expedited_wq); - rnp = rsp->level[rcu_num_lvls - 1]; + rnp = rcu_first_leaf_node(rsp); for_each_possible_cpu(i) { while (i > rnp->grphi) rnp++; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index d37b9bb3f481..b999032e9466 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -182,7 +182,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp) raw_lockdep_assert_held_rcu_node(rnp); WARN_ON_ONCE(rdp->mynode != rnp); - WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1); + WARN_ON_ONCE(!rcu_is_leaf_node(rnp)); /* * Decide where to queue the newly blocked task. In theory, @@ -533,7 +533,7 @@ void rcu_read_unlock_special(struct task_struct *t) rnp = t->rcu_blocked_node; raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ WARN_ON_ONCE(rnp != t->rcu_blocked_node); - WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1); + WARN_ON_ONCE(!rcu_is_leaf_node(rnp)); empty_norm = !rcu_preempt_blocked_readers_cgp(rnp); empty_exp = sync_rcu_preempt_exp_done(rnp); smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ |