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>

diff --git a/samples/kfifo/bytestream-example.c b/samples/kfifo/bytestream-example.c
index 2e3a7a8..a94e694 100644 (file)
--- 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