srcu/tiny: Remove preempt_disable/enable() in srcu_gp_start_if_needed()

[ Upstream commit e6a43aeb71 ]

Currently, the srcu_gp_start_if_needed() is always be invoked in
preempt disable's critical section, this commit therefore remove
redundant preempt_disable/enable() in srcu_gp_start_if_needed()
and adds a call to lockdep_assert_preemption_disabled() in order
to enable lockdep to diagnose mistaken invocations of this function
from preempts-enabled code.

Fixes: 65b4a59557 ("srcu: Make Tiny SRCU explicitly disable preemption")
Signed-off-by: Zqiang <qiang.zhang@linux.dev>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zqiang
2025-09-11 20:51:55 +08:00
committed by Greg Kroah-Hartman
parent 2f3f888d0d
commit d9ae3a91c4

View File

@@ -176,10 +176,9 @@ static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
{
unsigned long cookie;
preempt_disable(); // Needed for PREEMPT_LAZY
lockdep_assert_preemption_disabled(); // Needed for PREEMPT_LAZY
cookie = get_state_synchronize_srcu(ssp);
if (ULONG_CMP_GE(READ_ONCE(ssp->srcu_idx_max), cookie)) {
preempt_enable();
return;
}
WRITE_ONCE(ssp->srcu_idx_max, cookie);
@@ -189,7 +188,6 @@ static void srcu_gp_start_if_needed(struct srcu_struct *ssp)
else if (list_empty(&ssp->srcu_work.entry))
list_add(&ssp->srcu_work.entry, &srcu_boot_list);
}
preempt_enable();
}
/*