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| author |   Boqun Feng <boqun.feng@gmail.com> | 2018-03-07 16:49:39 +0800 |
|---|---|---|
| committer |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-05-15 10:26:01 -0700 |
| commit | 7be8c56f8f8a58af92f8791c5a09d48e342d7101 (patch) | |
| tree | 25cd6760e384e2443a51b51c04c64fb55575a0ee /kernel/rcu | |
| parent | rcu: Parallelize expedited grace-period initialization (diff) | |
| download | linux-dev-7be8c56f8f8a58af92f8791c5a09d48e342d7101.tar.xz linux-dev-7be8c56f8f8a58af92f8791c5a09d48e342d7101.zip | |
rcu: exp: Fix "must hold exp_mutex" comments for QS reporting functions
Since commit d9a3da0699b2 ("rcu: Add expedited grace-period support
for preemptible RCU"), there are comments for some funtions in
rcu_report_exp_rnp()'s call-chain saying that exp_mutex or its
predecessors needs to be held.
However, exp_mutex and its predecessors were used only to synchronize
between GPs, and it is clear that all variables visited by those functions
are under the protection of rcu_node's ->lock. Moreover, those functions
are currently called without held exp_mutex, and seems that doesn't
introduce any trouble.
So this patch fixes this problem by updating the comments to match the
current code.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Fixes: d9a3da0699b2 ("rcu: Add expedited grace-period support for preemptible RCU")
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/tree_exp.h | 10 |
1 files changed, 3 insertions, 7 deletions
diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 73e1d3dca5b1..d7622cb85aa7 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -154,7 +154,7 @@ static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp) * for the current expedited grace period. Works only for preemptible * RCU -- other RCU implementation use other means. * - * Caller must hold the rcu_state's exp_mutex. + * Caller must hold the specificed rcu_node structure's ->lock */ static bool sync_rcu_preempt_exp_done(struct rcu_node *rnp) { @@ -170,8 +170,7 @@ static bool sync_rcu_preempt_exp_done(struct rcu_node *rnp) * recursively up the tree. (Calm down, calm down, we do the recursion * iteratively!) * - * Caller must hold the rcu_state's exp_mutex and the specified rcu_node - * structure's ->lock. + * Caller must hold the specified rcu_node structure's ->lock. */ static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, bool wake, unsigned long flags) @@ -207,8 +206,6 @@ static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, /* * Report expedited quiescent state for specified node. This is a * lock-acquisition wrapper function for __rcu_report_exp_rnp(). - * - * Caller must hold the rcu_state's exp_mutex. */ static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, bool wake) @@ -221,8 +218,7 @@ static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp, /* * Report expedited quiescent state for multiple CPUs, all covered by the - * specified leaf rcu_node structure. Caller must hold the rcu_state's - * exp_mutex. + * specified leaf rcu_node structure. */ static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp, unsigned long mask, bool wake) |