kfifo: add explicit error checking in byte stream example

Provide a static array of expected items that kfifo should contain at the
end of the test to validate it.

Signed-off-by: Andrea Righi <arighi@develer.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 27 insertions, 6 deletions

diff --git a/samples/kfifo/bytestream-example.c b/samples/kfifo/bytestream-example.c
index 2e3a7a8128a2..a94e6948b30d 100644
--- a/samples/kfifo/bytestream-example.c
+++ b/samples/kfifo/bytestream-example.c
@@ -44,10 +44,17 @@ static struct kfifo test;
 static DECLARE_KFIFO(test, unsigned char, FIFO_SIZE);
 #endif
 
+static unsigned char expected_result[FIFO_SIZE] = {
+         3,  4,  5,  6,  7,  8,  9,  0,
+         1, 20, 21, 22, 23, 24, 25, 26,
+        27, 28, 29, 30, 31, 32, 33, 34,
+        35, 36, 37, 38, 39, 40, 41, 42,
+};
+
 static int __init testfunc(void)
 {
         unsigned char   buf[6];
-        unsigned char   i;
+        unsigned char   i, j;
         unsigned int    ret;
 
         printk(KERN_INFO "byte stream fifo test start\n");
@@ -83,10 +90,19 @@ static int __init testfunc(void)
 
         printk(KERN_INFO "queue len: %u\n", kfifo_len(&test));
 
-        /* print out all values in the fifo */
-        while (kfifo_get(&test, &i))
-                printk("%d ", i);
-        printk("\n");
+        /* check the correctness of all values in the fifo */
+        j = 0;
+        while (kfifo_get(&test, &i)) {
+                if (i != expected_result[j++]) {
+                        printk(KERN_WARNING "value mismatch: test failed\n");
+                        return -EIO;
+                }
+        }
+        if (j != ARRAY_SIZE(expected_result)) {
+                printk(KERN_WARNING "size mismatch: test failed\n");
+                return -EIO;
+        }
+        printk(KERN_INFO "test passed\n");
 
         return 0;
 }
@@ -142,7 +158,12 @@ static int __init example_init(void)
 #else
         INIT_KFIFO(test);
 #endif
-        testfunc();
+        if (testfunc() < 0) {
+#ifdef DYNAMIC
+                kfifo_free(&test);
+#endif
+                return -EIO;
+        }
 
         if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) {
 #ifdef DYNAMIC