rcu: Use pr_alert/pr_cont for printing logs

User pr_alert/pr_cont for printing the logs from rcutorture module directly
instead of writing it to a buffer and then printing it. This allows us from not
having to allocate such buffers. Also remove a resulting empty function.

I tested this using the parse-torture.sh script as follows:

$ dmesg | grep torture > log.txt
$ bash parse-torture.sh log.txt test
$

There were no warnings which means that parsing went fine.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

3 files changed, 64 insertions, 81 deletions

diff --git a/include/linux/torture.h b/include/linux/torture.h
index 5ca58fcbaf1b..fec46f8c08eb 100644
--- a/include/linux/torture.h
+++ b/include/linux/torture.h
@@ -51,7 +51,7 @@
 
 /* Definitions for online/offline exerciser. */
 int torture_onoff_init(long ooholdoff, long oointerval);
-char *torture_onoff_stats(char *page);
+void torture_onoff_stats(void);
 bool torture_onoff_failures(void);
 
 /* Low-rider random number generator. */
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 7e67711cbae8..ff4f0c756dee 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -242,7 +242,7 @@ struct rcu_torture_ops {
         void (*call)(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
         void (*cb_barrier)(void);
         void (*fqs)(void);
-        void (*stats)(char *page);
+        void (*stats)(void);
         int irq_capable;
         int can_boost;
         const char *name;
@@ -525,21 +525,21 @@ static void srcu_torture_barrier(void)
         srcu_barrier(&srcu_ctl);
 }
 
-static void srcu_torture_stats(char *page)
+static void srcu_torture_stats(void)
 {
         int cpu;
         int idx = srcu_ctl.completed & 0x1;
 
-        page += sprintf(page, "%s%s per-CPU(idx=%d):",
-                       torture_type, TORTURE_FLAG, idx);
+        pr_alert("%s%s per-CPU(idx=%d):",
+                 torture_type, TORTURE_FLAG, idx);
         for_each_possible_cpu(cpu) {
                 long c0, c1;
 
                 c0 = (long)per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[!idx];
                 c1 = (long)per_cpu_ptr(srcu_ctl.per_cpu_ref, cpu)->c[idx];
-                page += sprintf(page, " %d(%ld,%ld)", cpu, c0, c1);
+                pr_cont(" %d(%ld,%ld)", cpu, c0, c1);
         }
-        sprintf(page, "\n");
+        pr_cont("\n");
 }
 
 static void srcu_torture_synchronize_expedited(void)
@@ -1031,10 +1031,15 @@ rcu_torture_reader(void *arg)
 }
 
 /*
- * Create an RCU-torture statistics message in the specified buffer.
+ * Print torture statistics.  Caller must ensure that there is only
+ * one call to this function at a given time!!!  This is normally
+ * accomplished by relying on the module system to only have one copy
+ * of the module loaded, and then by giving the rcu_torture_stats
+ * kthread full control (or the init/cleanup functions when rcu_torture_stats
+ * thread is not running).
  */
 static void
-rcu_torture_printk(char *page)
+rcu_torture_stats_print(void)
 {
         int cpu;
         int i;
@@ -1052,55 +1057,60 @@ rcu_torture_printk(char *page)
                 if (pipesummary[i] != 0)
                         break;
         }
-        page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
-        page += sprintf(page,
-                       "rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
-                       rcu_torture_current,
-                       rcu_torture_current_version,
-                       list_empty(&rcu_torture_freelist),
-                       atomic_read(&n_rcu_torture_alloc),
-                       atomic_read(&n_rcu_torture_alloc_fail),
-                       atomic_read(&n_rcu_torture_free));
-        page += sprintf(page, "rtmbe: %d rtbke: %ld rtbre: %ld ",
-                       atomic_read(&n_rcu_torture_mberror),
-                       n_rcu_torture_boost_ktrerror,
-                       n_rcu_torture_boost_rterror);
-        page += sprintf(page, "rtbf: %ld rtb: %ld nt: %ld ",
-                       n_rcu_torture_boost_failure,
-                       n_rcu_torture_boosts,
-                       n_rcu_torture_timers);
-        page = torture_onoff_stats(page);
-        page += sprintf(page, "barrier: %ld/%ld:%ld",
-                       n_barrier_successes,
-                       n_barrier_attempts,
-                       n_rcu_torture_barrier_error);
-        page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
+
+        pr_alert("%s%s ", torture_type, TORTURE_FLAG);
+        pr_cont("rtc: %p ver: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
+                rcu_torture_current,
+                rcu_torture_current_version,
+                list_empty(&rcu_torture_freelist),
+                atomic_read(&n_rcu_torture_alloc),
+                atomic_read(&n_rcu_torture_alloc_fail),
+                atomic_read(&n_rcu_torture_free));
+        pr_cont("rtmbe: %d rtbke: %ld rtbre: %ld ",
+                atomic_read(&n_rcu_torture_mberror),
+                n_rcu_torture_boost_ktrerror,
+                n_rcu_torture_boost_rterror);
+        pr_cont("rtbf: %ld rtb: %ld nt: %ld ",
+                n_rcu_torture_boost_failure,
+                n_rcu_torture_boosts,
+                n_rcu_torture_timers);
+        torture_onoff_stats();
+        pr_cont("barrier: %ld/%ld:%ld\n",
+                n_barrier_successes,
+                n_barrier_attempts,
+                n_rcu_torture_barrier_error);
+
+        pr_alert("%s%s ", torture_type, TORTURE_FLAG);
         if (atomic_read(&n_rcu_torture_mberror) != 0 ||
             n_rcu_torture_barrier_error != 0 ||
             n_rcu_torture_boost_ktrerror != 0 ||
             n_rcu_torture_boost_rterror != 0 ||
             n_rcu_torture_boost_failure != 0 ||
             i > 1) {
-                page += sprintf(page, "!!! ");
+                pr_cont("%s", "!!! ");
                 atomic_inc(&n_rcu_torture_error);
                 WARN_ON_ONCE(1);
         }
-        page += sprintf(page, "Reader Pipe: ");
+        pr_cont("Reader Pipe: ");
         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
-                page += sprintf(page, " %ld", pipesummary[i]);
-        page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
-        page += sprintf(page, "Reader Batch: ");
+                pr_cont(" %ld", pipesummary[i]);
+        pr_cont("\n");
+
+        pr_alert("%s%s ", torture_type, TORTURE_FLAG);
+        pr_cont("Reader Batch: ");
         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
-                page += sprintf(page, " %ld", batchsummary[i]);
-        page += sprintf(page, "\n%s%s ", torture_type, TORTURE_FLAG);
-        page += sprintf(page, "Free-Block Circulation: ");
+                pr_cont(" %ld", batchsummary[i]);
+        pr_cont("\n");
+
+        pr_alert("%s%s ", torture_type, TORTURE_FLAG);
+        pr_cont("Free-Block Circulation: ");
         for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
-                page += sprintf(page, " %d",
-                               atomic_read(&rcu_torture_wcount[i]));
+                pr_cont(" %d", atomic_read(&rcu_torture_wcount[i]));
         }
-        page += sprintf(page, "\n");
+        pr_cont("\n");
+
         if (cur_ops->stats)
-                cur_ops->stats(page);
+                cur_ops->stats();
         if (rtcv_snap == rcu_torture_current_version &&
             rcu_torture_current != NULL) {
                 int __maybe_unused flags;
@@ -1109,10 +1119,9 @@ rcu_torture_printk(char *page)
 
                 rcutorture_get_gp_data(cur_ops->ttype,
                                        &flags, &gpnum, &completed);
-                page += sprintf(page,
-                                "??? Writer stall state %d g%lu c%lu f%#x\n",
-                                rcu_torture_writer_state,
-                                gpnum, completed, flags);
+                pr_alert("??? Writer stall state %d g%lu c%lu f%#x\n",
+                         rcu_torture_writer_state,
+                         gpnum, completed, flags);
                 show_rcu_gp_kthreads();
                 rcutorture_trace_dump();
         }
@@ -1120,30 +1129,6 @@ rcu_torture_printk(char *page)
 }
 
 /*
- * Print torture statistics.  Caller must ensure that there is only
- * one call to this function at a given time!!!  This is normally
- * accomplished by relying on the module system to only have one copy
- * of the module loaded, and then by giving the rcu_torture_stats
- * kthread full control (or the init/cleanup functions when rcu_torture_stats
- * thread is not running).
- */
-static void
-rcu_torture_stats_print(void)
-{
-        int size = nr_cpu_ids * 200 + 8192;
-        char *buf;
-
-        buf = kmalloc(size, GFP_KERNEL);
-        if (!buf) {
-                pr_err("rcu-torture: Out of memory, need: %d", size);
-                return;
-        }
-        rcu_torture_printk(buf);
-        pr_alert("%s", buf);
-        kfree(buf);
-}
-
-/*
  * Periodically prints torture statistics, if periodic statistics printing
  * was specified via the stat_interval module parameter.
  */
diff --git a/kernel/torture.c b/kernel/torture.c
index d600af21f022..ede8b25ec1ae 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -211,18 +211,16 @@ EXPORT_SYMBOL_GPL(torture_onoff_cleanup);
 /*
  * Print online/offline testing statistics.
  */
-char *torture_onoff_stats(char *page)
+void torture_onoff_stats(void)
 {
 #ifdef CONFIG_HOTPLUG_CPU
-        page += sprintf(page,
-                       "onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
-                       n_online_successes, n_online_attempts,
-                       n_offline_successes, n_offline_attempts,
-                       min_online, max_online,
-                       min_offline, max_offline,
-                       sum_online, sum_offline, HZ);
+        pr_cont("onoff: %ld/%ld:%ld/%ld %d,%d:%d,%d %lu:%lu (HZ=%d) ",
+                n_online_successes, n_online_attempts,
+                n_offline_successes, n_offline_attempts,
+                min_online, max_online,
+                min_offline, max_offline,
+                sum_online, sum_offline, HZ);
 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
-        return page;
 }
 EXPORT_SYMBOL_GPL(torture_onoff_stats);