| Message ID | 20240819165939.745801-6-kent.overstreet@linux.dev (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | rcu_pending | expand |
On Mon, Aug 19, 2024 at 12:59:31PM -0400, Kent Overstreet wrote: > this assertion appears to have been entirely unnecessary > > Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev> Please also adjust the comments. Or just take this from the -rcu tree's "dev" branch, which is shown at the end of this email: e0a917e08b9b ("rcu: Permit start_poll_synchronize_rcu*() with interrupts disabled") > --- > kernel/rcu/tree.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index e641cc681901..52f9f0bf1b8e 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -4119,7 +4119,6 @@ static void start_poll_synchronize_rcu_common(void) > struct rcu_data *rdp; > struct rcu_node *rnp; > > - lockdep_assert_irqs_enabled(); > local_irq_save(flags); > rdp = this_cpu_ptr(&rcu_data); > rnp = rdp->mynode; > -- > 2.45.2 > ------------------------------------------------------------------------ commit e0a917e08b9b39eee5870738250d0b8b10272dbe Author: Paul E. McKenney <paulmck@kernel.org> Date: Fri Aug 16 14:22:48 2024 -0700 rcu: Permit start_poll_synchronize_rcu*() with interrupts disabled The header comment for both start_poll_synchronize_rcu() and start_poll_synchronize_rcu_full() state that interrupts must be enabled when calling these two functions, and there is a lockdep assertion in start_poll_synchronize_rcu_common() enforcing this restriction. However, there is no need for this restrictions, as can be seen in call_rcu(), which does wakeups when interrupts are disabled. This commit therefore removes the lockdep assertion and the comments. Reported-by: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 36b207918158c..47c753ae9bbcd 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4103,7 +4103,6 @@ static void start_poll_synchronize_rcu_common(void) struct rcu_data *rdp; struct rcu_node *rnp; - lockdep_assert_irqs_enabled(); local_irq_save(flags); rdp = this_cpu_ptr(&rcu_data); rnp = rdp->mynode; @@ -4128,9 +4127,6 @@ static void start_poll_synchronize_rcu_common(void) * grace period has elapsed in the meantime. If the needed grace period * is not already slated to start, notifies RCU core of the need for that * grace period. - * - * Interrupts must be enabled for the case where it is necessary to awaken - * the grace-period kthread. */ unsigned long start_poll_synchronize_rcu(void) { @@ -4151,9 +4147,6 @@ EXPORT_SYMBOL_GPL(start_poll_synchronize_rcu); * grace period (whether normal or expedited) has elapsed in the meantime. * If the needed grace period is not already slated to start, notifies * RCU core of the need for that grace period. - * - * Interrupts must be enabled for the case where it is necessary to awaken - * the grace-period kthread. */ void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) {
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index e641cc681901..52f9f0bf1b8e 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4119,7 +4119,6 @@ static void start_poll_synchronize_rcu_common(void) struct rcu_data *rdp; struct rcu_node *rnp; - lockdep_assert_irqs_enabled(); local_irq_save(flags); rdp = this_cpu_ptr(&rcu_data); rnp = rdp->mynode;
this assertion appears to have been entirely unnecessary Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev> --- kernel/rcu/tree.c | 1 - 1 file changed, 1 deletion(-)