From: "Paul E. McKenney" <paulmck@xxxxxxxxxx> Full testing of the new SRCU polling API requires that the fake writers also use it in order to test concurrent calls to all of the API members, especially start_poll_synchronize_srcu(). This commit prepares the ground for this by making the synctype[] and nsynctype variables be static globals so that the rcu_torture_fakewriter() function can access them. Initialization of these variables is moved from rcu_torture_writer() to a new rcu_torture_write_types() function that is invoked from rcu_torture_init() just before the first writer kthread is spawned. Link: https://lore.kernel.org/rcu/20201112201547.GF3365678@xxxxxxxxxxxxxx/ Reported-by: Kent Overstreet <kent.overstreet@xxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- kernel/rcu/rcutorture.c | 62 ++++++++++++++++++++++++++++--------------------- 1 file changed, 36 insertions(+), 26 deletions(-) diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index 1930d92..ea44a2b 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1062,37 +1062,18 @@ rcu_torture_fqs(void *arg) return 0; } +// Used by writers to randomly choose from the available grace-period +// primitives. The only purpose of the initialization is to size the array. +static int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC }; +static int nsynctypes = 0; + /* - * RCU torture writer kthread. Repeatedly substitutes a new structure - * for that pointed to by rcu_torture_current, freeing the old structure - * after a series of grace periods (the "pipeline"). + * Determine which grace-period primitives are available. */ -static int -rcu_torture_writer(void *arg) +static void rcu_torture_write_types(void) { - bool boot_ended; - bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); - unsigned long cookie; - int expediting = 0; - unsigned long gp_snap; bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal; bool gp_poll1 = gp_poll, gp_sync1 = gp_sync; - int i; - int idx; - int oldnice = task_nice(current); - struct rcu_torture *rp; - struct rcu_torture *old_rp; - static DEFINE_TORTURE_RANDOM(rand); - bool stutter_waited; - int synctype[] = { RTWS_DEF_FREE, RTWS_EXP_SYNC, - RTWS_COND_GET, RTWS_POLL_GET, RTWS_SYNC }; - int nsynctypes = 0; - - VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); - if (!can_expedite) - pr_alert("%s" TORTURE_FLAG - " GP expediting controlled from boot/sysfs for %s.\n", - torture_type, cur_ops->name); /* Initialize synctype[] array. If none set, take default. */ if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_poll1 && !gp_sync1) @@ -1127,6 +1108,34 @@ rcu_torture_writer(void *arg) } else if (gp_sync && !cur_ops->sync) { pr_alert("%s: gp_sync without primitives.\n", __func__); } +} + +/* + * RCU torture writer kthread. Repeatedly substitutes a new structure + * for that pointed to by rcu_torture_current, freeing the old structure + * after a series of grace periods (the "pipeline"). + */ +static int +rcu_torture_writer(void *arg) +{ + bool boot_ended; + bool can_expedite = !rcu_gp_is_expedited() && !rcu_gp_is_normal(); + unsigned long cookie; + int expediting = 0; + unsigned long gp_snap; + int i; + int idx; + int oldnice = task_nice(current); + struct rcu_torture *rp; + struct rcu_torture *old_rp; + static DEFINE_TORTURE_RANDOM(rand); + bool stutter_waited; + + VERBOSE_TOROUT_STRING("rcu_torture_writer task started"); + if (!can_expedite) + pr_alert("%s" TORTURE_FLAG + " GP expediting controlled from boot/sysfs for %s.\n", + torture_type, cur_ops->name); if (WARN_ONCE(nsynctypes == 0, "rcu_torture_writer: No update-side primitives.\n")) { /* @@ -2889,6 +2898,7 @@ rcu_torture_init(void) /* Start up the kthreads. */ + rcu_torture_write_types(); firsterr = torture_create_kthread(rcu_torture_writer, NULL, writer_task); if (firsterr) -- 2.9.5
