linux-kernel - [PATCH next 7/8] test_hexdump: Run fixed not random tests

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Message-Id: <20250308093452.3742-8-david.laight.linux@gmail.com>
Date: Sat,  8 Mar 2025 09:34:51 +0000
From: David Laight <david.laight.linux@...il.com>
To: linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>
Cc: David Laight <david.laight.linux@...il.com>,
	Arnd Bergmann <arnd@...db.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Christophe Leroy <christophe.leroy@....fr>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	nnac123@...ux.ibm.com,
	horms@...nel.org
Subject: [PATCH next 7/8] test_hexdump: Run fixed not random tests

For reproducibilty instead of running 16 random length with two
random 'rowsize' picked from 16 and 32, run the tests with rowsize
16 and 32 and all the lengths from 1 to rowsize.
(This still includes all the cases where groupsize gets forced to 1.)

For the overflow tests increase 'len' if the data fits and 'buflen'
if it doesn't.

The is more tests than really needed but covers all the interesting
cases without generating a very large number of tests.

Signed-off-by: David Laight <david.laight.linux@...il.com>
---
 lib/test_hexdump.c | 64 +++++++++++++++++++++++-----------------------
 1 file changed, 32 insertions(+), 32 deletions(-)

diff --git a/lib/test_hexdump.c b/lib/test_hexdump.c
index 56c0dfbd075b..877033a570d4 100644
--- a/lib/test_hexdump.c
+++ b/lib/test_hexdump.c
@@ -7,7 +7,6 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/random.h>
 #include <linux/string.h>
 
 static const unsigned char data_b[] = {
@@ -109,18 +108,19 @@ static void __init test_hexdump(size_t len, size_t rowsize, size_t groupsize,
 
 static void __init test_hexdump_set(size_t rowsize, bool ascii)
 {
-	size_t d = min(sizeof(data_b), rowsize);
-	size_t len = get_random_u32_inclusive(1, d);
+	size_t len;
 
-	test_hexdump(len, rowsize, 4, ascii);
-	test_hexdump(len, rowsize, 2, ascii);
-	test_hexdump(len, rowsize, 8, ascii);
-	test_hexdump(len, rowsize, 1, ascii);
+	for (len = 1; len <= rowsize; len++) {
+		test_hexdump(len, rowsize, 4, ascii);
+		test_hexdump(len, rowsize, 2, ascii);
+		test_hexdump(len, rowsize, 8, ascii);
+		test_hexdump(len, rowsize, 1, ascii);
+	}
 }
 
-static void __init test_hexdump_overflow(size_t buflen, size_t len,
-					 size_t rowsize, size_t groupsize,
-					 bool ascii)
+static bool __init test_hexdump_overflow(size_t buflen, size_t len,
+					   size_t rowsize, size_t groupsize,
+					   bool ascii)
 {
 	char test[TEST_HEXDUMP_BUF_SIZE];
 	char buf[TEST_HEXDUMP_BUF_SIZE];
@@ -154,40 +154,40 @@ static void __init test_hexdump_overflow(size_t buflen, size_t len,
 		pr_err("Expect: %zd '%.*s'\n", expected, TEST_HEXDUMP_BUF_SIZE, test);
 		failed_tests++;
 	}
+
+	return expected < buflen;
 }
 
-static void __init test_hexdump_overflow_set(size_t buflen, bool ascii)
+static void __init test_hexdump_overflow_set(size_t rowsize, bool ascii)
 {
-	unsigned int i = 0;
-	size_t rowsize = get_random_u32_inclusive(1, 2) * 16;
-
-	do {
-		size_t groupsize = 1 << i;
-		size_t len = get_random_u32_below(rowsize) + groupsize;
-
-		test_hexdump_overflow(buflen, rounddown(len, groupsize),
-				      rowsize, groupsize, ascii);
-	} while (i++ < 3);
+	size_t groupsize, len, buflen;
+
+	for (groupsize = 1; groupsize <= 8; groupsize *= 2) {
+		len = 0;
+		buflen = 0;
+		for (; len <= rowsize && buflen <= TEST_HEXDUMP_BUF_SIZE;) {
+			if (test_hexdump_overflow(buflen, len, rowsize,
+						  groupsize, ascii))
+				len += groupsize;
+			else
+				buflen++;
+		}
+	}
 }
 
 static int __init test_hexdump_init(void)
 {
-	unsigned int i;
 	size_t rowsize;
 
-	rowsize = get_random_u32_inclusive(1, 2) * 16;
-	for (i = 0; i < 16; i++)
+	for (rowsize = 16; rowsize <= 32; rowsize += 16) {
 		test_hexdump_set(rowsize, false);
-
-	rowsize = get_random_u32_inclusive(1, 2) * 16;
-	for (i = 0; i < 16; i++)
 		test_hexdump_set(rowsize, true);
+	}
 
-	for (i = 0; i <= TEST_HEXDUMP_BUF_SIZE; i++)
-		test_hexdump_overflow_set(i, false);
-
-	for (i = 0; i <= TEST_HEXDUMP_BUF_SIZE; i++)
-		test_hexdump_overflow_set(i, true);
+	test_hexdump_overflow_set(16, false);
+	test_hexdump_overflow_set(16, true);
+	test_hexdump_overflow_set(32, false);
+	test_hexdump_overflow_set(32, true);
 
 	if (failed_tests == 0)
 		pr_info("all %u tests passed\n", total_tests);
-- 
2.39.5