linux-kernel - [PATCH 2/2] rslib: test: Yield to prevent RCU stall messages and fix comment typos

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Message-ID: <a309f09e07374e62a77bb84c70e6715efd288448.1583122776.git.planteen@gmail.com>
Date:   Sun, 1 Mar 2020 21:27:59 -0700
From:   Cody Planteen <planteen@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de
Subject: [PATCH 2/2] rslib: test: Yield to prevent RCU stall messages and fix
 comment typos

Without this patch, running the test leads to lots of annoying
"rcu: INFO: rcu_sched self-detected stall on CPU" messages with stack
trace.

Signed-off-by: Cody Planteen <planteen@...il.com>
---
 lib/reed_solomon/test_rslib.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/lib/reed_solomon/test_rslib.c b/lib/reed_solomon/test_rslib.c
index 4eb29f365ece..aa61ac7715de 100644
--- a/lib/reed_solomon/test_rslib.c
+++ b/lib/reed_solomon/test_rslib.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/random.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 
 enum verbosity {
@@ -169,7 +170,7 @@ static int get_rcw_we(struct rs_control *rs, struct wspace *ws,
 	memset(c + dlen, 0, nroots * sizeof(*c));
 	encode_rs16(rs, c, dlen, c + dlen, 0);
 
-	/* Make copyand add errors and erasures */
+	/* Make copy and add errors and erasures */
 	memcpy(r, c, len * sizeof(*r));
 	memset(errlocs, 0, len * sizeof(*errlocs));
 	memset(derrlocs, 0, nroots * sizeof(*derrlocs));
@@ -327,8 +328,11 @@ static int ex_rs_helper(struct rs_control *rs, struct wspace *ws,
 		pr_info("  %s\n", desc[method]);
 
 	for (errs = 0; errs <= nroots / 2; errs++)
-		for (eras = 0; eras <= nroots - 2 * errs; eras++)
+		for (eras = 0; eras <= nroots - 2 * errs; eras++) {
+			/* yield to prevent rcu stall messages */
+			cond_resched_rcu();
 			test_uc(rs, len, errs, eras, trials, &stat, ws, method);
+		}
 
 	if (v >= V_CSUMMARY) {
 		pr_info("    Decodes wrong:        %d / %d\n",
@@ -385,7 +389,7 @@ static void test_bc(struct rs_control *rs, int len, int errs,
 
 			/*
 			 * We check that the returned word is actually a
-			 * codeword. The obious way to do this would be to
+			 * codeword. The obvious way to do this would be to
 			 * compute the syndrome, but we don't want to replicate
 			 * that code here. However, all the codes are in
 			 * systematic form, and therefore we can encode the
@@ -420,8 +424,11 @@ static int exercise_rs_bc(struct rs_control *rs, struct wspace *ws,
 			eras = 0;
 
 		cutoff = nroots <= len - errs ? nroots : len - errs;
-		for (; eras <= cutoff; eras++)
+		for (; eras <= cutoff; eras++) {
+			/* yield to prevent rcu stall messages */
+			cond_resched_rcu();
 			test_bc(rs, len, errs, eras, trials, &stat, ws);
+		}
 	}
 
 	if (v >= V_CSUMMARY) {
-- 
2.20.1