| Message ID | 20241007101415.466155-1-mschmidt@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | rcu/srcutiny: don't return before reenabling preemption | expand |
On Mon, Oct 07, 2024 at 12:14:15PM +0200, Michal Schmidt wrote: > Code after the return statement is dead. Enable preemption before > returning from srcu_drive_gp(). > > This will be important when/if PREEMPT_AUTO (lazy resched) gets merged. > > Fixes: 65b4a59557f6 ("srcu: Make Tiny SRCU explicitly disable preemption") > Signed-off-by: Michal Schmidt <mschmidt@redhat.com> Good catch! Reviewed-by: Paul E. McKenney <paulmck@kernel.org> > --- > kernel/rcu/srcutiny.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c > index 549c03336ee9..4dcbf8aa80ff 100644 > --- a/kernel/rcu/srcutiny.c > +++ b/kernel/rcu/srcutiny.c > @@ -122,8 +122,8 @@ void srcu_drive_gp(struct work_struct *wp) > ssp = container_of(wp, struct srcu_struct, srcu_work); > preempt_disable(); // Needed for PREEMPT_AUTO > if (ssp->srcu_gp_running || ULONG_CMP_GE(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max))) { > - return; /* Already running or nothing to do. */ > preempt_enable(); > + return; /* Already running or nothing to do. */ > } > > /* Remove recently arrived callbacks and wait for readers. */ > -- > 2.46.2 >
Le Wed, Oct 09, 2024 at 10:19:01AM -0700, Paul E. McKenney a écrit : > On Mon, Oct 07, 2024 at 12:14:15PM +0200, Michal Schmidt wrote: > > Code after the return statement is dead. Enable preemption before > > returning from srcu_drive_gp(). > > > > This will be important when/if PREEMPT_AUTO (lazy resched) gets merged. > > > > Fixes: 65b4a59557f6 ("srcu: Make Tiny SRCU explicitly disable preemption") > > Signed-off-by: Michal Schmidt <mschmidt@redhat.com> > > Good catch! > > Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Applied! Thanks.
diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 549c03336ee9..4dcbf8aa80ff 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -122,8 +122,8 @@ void srcu_drive_gp(struct work_struct *wp) ssp = container_of(wp, struct srcu_struct, srcu_work); preempt_disable(); // Needed for PREEMPT_AUTO if (ssp->srcu_gp_running || ULONG_CMP_GE(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max))) { - return; /* Already running or nothing to do. */ preempt_enable(); + return; /* Already running or nothing to do. */ } /* Remove recently arrived callbacks and wait for readers. */
Code after the return statement is dead. Enable preemption before returning from srcu_drive_gp(). This will be important when/if PREEMPT_AUTO (lazy resched) gets merged. Fixes: 65b4a59557f6 ("srcu: Make Tiny SRCU explicitly disable preemption") Signed-off-by: Michal Schmidt <mschmidt@redhat.com> --- kernel/rcu/srcutiny.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)