From: Zqiang Date: Thu, 11 Sep 2025 12:51:55 +0000 (+0800) Subject: srcu/tiny: Remove preempt_disable/enable() in srcu_gp_start_if_needed() X-Git-Tag: v6.18-rc1~86^2~1^2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=e6a43aeb71852a39432332dcc3a6d11bb464b075;p=thirdparty%2Fkernel%2Flinux.git srcu/tiny: Remove preempt_disable/enable() in srcu_gp_start_if_needed() 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: 65b4a59557f6 ("srcu: Make Tiny SRCU explicitly disable preemption") Signed-off-by: Zqiang Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 6e9fe2ce1075..e3b64a5e0ec7 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -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(); } /*