rcutorture: Add reader_flavor parameter for SRCU readers

This commit adds an rcutorture.reader_flavor parameter whose bits
correspond to reader flavors.  For example, SRCU's readers are 0x1 for
normal and 0x2 for NMI-safe.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1518343bbe2237f1d577df5656339d6224b769be..52922727006fcfb95aaa1319ee4e9653ead85428 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5426,6 +5426,14 @@
                        The delay, in seconds, between successive
                        read-then-exit testing episodes.
 
+       rcutorture.reader_flavor= [KNL]
+                       A bit mask indicating which readers to use.
+                       If there is more than one bit set, the readers
+                       are entered from low-order bit up, and are
+                       exited in the opposite order.  For SRCU, the
+                       0x1 bit is normal readers and the 0x2 bit is
+                       for NMI-safe readers.
+
        rcutorture.shuffle_interval= [KNL]
                        Set task-shuffle interval (s).  Shuffling tasks
                        allows some CPUs to go into dyntick-idle mode

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f96ab98f8182fb9dfb423397fb88c981e1c1ca9a..405decec336776ce96243b4a5fe76599ced855d5 100644 (file)
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -111,6 +111,7 @@ torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disab
 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
+torture_param(int, reader_flavor, 0x1, "Reader flavors to use, one per bit.");
 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
@@ -644,10 +645,20 @@ static void srcu_get_gp_data(int *flags, unsigned long *gp_seq)
 
 static int srcu_torture_read_lock(void)
 {
-       if (cur_ops == &srcud_ops)
-               return srcu_read_lock_nmisafe(srcu_ctlp);
-       else
-               return srcu_read_lock(srcu_ctlp);
+       int idx;
+       int ret = 0;
+
+       if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) {
+               idx = srcu_read_lock(srcu_ctlp);
+               WARN_ON_ONCE(idx & ~0x1);
+               ret += idx;
+       }
+       if (reader_flavor & 0x2) {
+               idx = srcu_read_lock_nmisafe(srcu_ctlp);
+               WARN_ON_ONCE(idx & ~0x1);
+               ret += idx << 1;
+       }
+       return ret;
 }
 
 static void
@@ -671,10 +682,11 @@ srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
 
 static void srcu_torture_read_unlock(int idx)
 {
-       if (cur_ops == &srcud_ops)
-               srcu_read_unlock_nmisafe(srcu_ctlp, idx);
-       else
-               srcu_read_unlock(srcu_ctlp, idx);
+       WARN_ON_ONCE((reader_flavor && (idx & ~reader_flavor)) || (!reader_flavor && (idx & ~0x1)));
+       if (reader_flavor & 0x2)
+               srcu_read_unlock_nmisafe(srcu_ctlp, (idx & 0x2) >> 1);
+       if ((reader_flavor & 0x1) || !(reader_flavor & 0x7))
+               srcu_read_unlock(srcu_ctlp, idx & 0x1);
 }
 
 static int torture_srcu_read_lock_held(void)
@@ -2389,6 +2401,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
                 "n_barrier_cbs=%d "
                 "onoff_interval=%d onoff_holdoff=%d "
                 "read_exit_delay=%d read_exit_burst=%d "
+                "reader_flavor=%x "
                 "nocbs_nthreads=%d nocbs_toggle=%d "
                 "test_nmis=%d\n",
                 torture_type, tag, nrealreaders, nfakewriters,
@@ -2401,6 +2414,7 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
                 n_barrier_cbs,
                 onoff_interval, onoff_holdoff,
                 read_exit_delay, read_exit_burst,
+                reader_flavor,
                 nocbs_nthreads, nocbs_toggle,
                 test_nmis);
 }