kfifo: add explicit error checking in all the examples

Provide a check in all the kfifo examples to validate the correct
execution of each testcase.

Signed-off-by: Andrea Righi <arighi@develer.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
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 a94e694..178061e 100644 (file)
--- a/samples/kfifo/bytestream-example.c
+++ b/samples/kfifo/bytestream-example.c
@@ -44,7 +44,7 @@ static struct kfifo test;
 static DECLARE_KFIFO(test, unsigned char, FIFO_SIZE);
 #endif
 
-static unsigned char expected_result[FIFO_SIZE] = {
+static const 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,
@@ -90,9 +90,14 @@ static int __init testfunc(void)
 
        printk(KERN_INFO "queue len: %u\n", kfifo_len(&test));
 
+       /* show the first value without removing from the fifo */
+       if (kfifo_peek(&test, &i))
+               printk(KERN_INFO "%d\n", i);
+
        /* check the correctness of all values in the fifo */
        j = 0;
        while (kfifo_get(&test, &i)) {
+               printk(KERN_INFO "item = %d\n", i);
                if (i != expected_result[j++]) {
                        printk(KERN_WARNING "value mismatch: test failed\n");
                        return -EIO;

diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c
index 3682278..ee03a4f 100644 (file)
--- a/samples/kfifo/dma-example.c
+++ b/samples/kfifo/dma-example.c
@@ -29,8 +29,8 @@ static int __init example_init(void)
        printk(KERN_INFO "DMA fifo test start\n");
 
        if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) {
-               printk(KERN_ERR "error kfifo_alloc\n");
-               return 1;
+               printk(KERN_WARNING "error kfifo_alloc\n");
+               return -ENOMEM;
        }
 
        printk(KERN_INFO "queue size: %u\n", kfifo_size(&fifo));
@@ -41,65 +41,93 @@ static int __init example_init(void)
                kfifo_put(&fifo, &i);
 
        /* kick away first byte */
-       ret = kfifo_get(&fifo, &i);
+       kfifo_skip(&fifo);
 
        printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
 
+       /*
+        * Configure the kfifo buffer to receive data from DMA input.
+        *
+        *  .--------------------------------------.
+        *  | 0 | 1 | 2 | ... | 12 | 13 | ... | 31 |
+        *  |---|------------------|---------------|
+        *   \_/ \________________/ \_____________/
+        *    \          \                  \
+        *     \          \_allocated data   \
+        *      \_*free space*                \_*free space*
+        *
+        * We need two different SG entries: one for the free space area at the
+        * end of the kfifo buffer (19 bytes) and another for the first free
+        * byte at the beginning, after the kfifo_skip().
+        */
        sg_init_table(sg, ARRAY_SIZE(sg));
        ret = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE);
        printk(KERN_INFO "DMA sgl entries: %d\n", ret);
+       if (!ret) {
+               /* fifo is full and no sgl was created */
+               printk(KERN_WARNING "error kfifo_dma_in_prepare\n");
+               return -EIO;
+       }
 
-       /* if 0 was returned, fifo is full and no sgl was created */
-       if (ret) {
-               printk(KERN_INFO "scatterlist for receive:\n");
-               for (i = 0; i < ARRAY_SIZE(sg); i++) {
-                       printk(KERN_INFO
-                       "sg[%d] -> "
-                       "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
-                               i, sg[i].page_link, sg[i].offset, sg[i].length);
+       /* receive data */
+       printk(KERN_INFO "scatterlist for receive:\n");
+       for (i = 0; i < ARRAY_SIZE(sg); i++) {
+               printk(KERN_INFO
+               "sg[%d] -> "
+               "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
+                       i, sg[i].page_link, sg[i].offset, sg[i].length);
 
-                       if (sg_is_last(&sg[i]))
-                               break;
-               }
+               if (sg_is_last(&sg[i]))
+                       break;
+       }
 
-               /* but here your code to setup and exectute the dma operation */
-               /* ... */
+       /* put here your code to setup and exectute the dma operation */
+       /* ... */
 
-               /* example: zero bytes received */
-               ret = 0;
+       /* example: zero bytes received */
+       ret = 0;
 
-               /* finish the dma operation and update the received data */
-               kfifo_dma_in_finish(&fifo, ret);
-       }
+       /* finish the dma operation and update the received data */
+       kfifo_dma_in_finish(&fifo, ret);
 
+       /* Prepare to transmit data, example: 8 bytes */
        ret = kfifo_dma_out_prepare(&fifo, sg, ARRAY_SIZE(sg), 8);
        printk(KERN_INFO "DMA sgl entries: %d\n", ret);
+       if (!ret) {
+               /* no data was available and no sgl was created */
+               printk(KERN_WARNING "error kfifo_dma_out_prepare\n");
+               return -EIO;
+       }
 
-       /* if 0 was returned, no data was available and no sgl was created */
-       if (ret) {
-               printk(KERN_INFO "scatterlist for transmit:\n");
-               for (i = 0; i < ARRAY_SIZE(sg); i++) {
-                       printk(KERN_INFO
-                       "sg[%d] -> "
-                       "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
-                               i, sg[i].page_link, sg[i].offset, sg[i].length);
+       printk(KERN_INFO "scatterlist for transmit:\n");
+       for (i = 0; i < ARRAY_SIZE(sg); i++) {
+               printk(KERN_INFO
+               "sg[%d] -> "
+               "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n",
+                       i, sg[i].page_link, sg[i].offset, sg[i].length);
 
-                       if (sg_is_last(&sg[i]))
-                               break;
-               }
+               if (sg_is_last(&sg[i]))
+                       break;
+       }
 
-               /* but here your code to setup and exectute the dma operation */
-               /* ... */
+       /* put here your code to setup and exectute the dma operation */
+       /* ... */
 
-               /* example: 5 bytes transmitted */
-               ret = 5;
+       /* example: 5 bytes transmitted */
+       ret = 5;
 
-               /* finish the dma operation and update the transmitted data */
-               kfifo_dma_out_finish(&fifo, ret);
-       }
+       /* finish the dma operation and update the transmitted data */
+       kfifo_dma_out_finish(&fifo, ret);
 
+       ret = kfifo_len(&fifo);
        printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
 
+       if (ret != 7) {
+               printk(KERN_WARNING "size mismatch: test failed");
+               return -EIO;
+       }
+       printk(KERN_INFO "test passed\n");
+
        return 0;
 }
 

diff --git a/samples/kfifo/inttype-example.c b/samples/kfifo/inttype-example.c
index d6c5b7d..71b2aab 100644 (file)
--- a/samples/kfifo/inttype-example.c
+++ b/samples/kfifo/inttype-example.c
@@ -44,10 +44,17 @@ static DECLARE_KFIFO_PTR(test, int);
 static DEFINE_KFIFO(test, int, FIFO_SIZE);
 #endif
 
+static const int 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)
 {
        int             buf[6];
-       int             i;
+       int             i, j;
        unsigned int    ret;
 
        printk(KERN_INFO "int fifo test start\n");
@@ -66,8 +73,13 @@ static int __init testfunc(void)
        ret = kfifo_in(&test, buf, ret);
        printk(KERN_INFO "ret: %d\n", ret);
 
-       for (i = 20; i != 30; i++)
-               kfifo_put(&test, &i);
+       /* skip first element of the fifo */
+       printk(KERN_INFO "skip 1st element\n");
+       kfifo_skip(&test);
+
+       /* put values into the fifo until is full */
+       for (i = 20; kfifo_put(&test, &i); i++)
+               ;
 
        printk(KERN_INFO "queue len: %u\n", kfifo_len(&test));
 
@@ -75,10 +87,20 @@ static int __init testfunc(void)
        if (kfifo_peek(&test, &i))
                printk(KERN_INFO "%d\n", i);
 
-       /* 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)) {
+               printk(KERN_INFO "item = %d\n", 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;
 }
@@ -132,7 +154,12 @@ static int __init example_init(void)
                return ret;
        }
 #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

diff --git a/samples/kfifo/record-example.c b/samples/kfifo/record-example.c
index 32c6e0b..e68bd16 100644 (file)
--- a/samples/kfifo/record-example.c
+++ b/samples/kfifo/record-example.c
@@ -55,6 +55,19 @@ typedef STRUCT_KFIFO_REC_1(FIFO_SIZE) mytest;
 static mytest test;
 #endif
 
+static const char *expected_result[] = {
+       "a",
+       "bb",
+       "ccc",
+       "dddd",
+       "eeeee",
+       "ffffff",
+       "ggggggg",
+       "hhhhhhhh",
+       "iiiiiiiii",
+       "jjjjjjjjjj",
+};
+
 static int __init testfunc(void)
 {
        char            buf[100];
@@ -75,6 +88,10 @@ static int __init testfunc(void)
                kfifo_in(&test, buf, i + 1);
        }
 
+       /* skip first element of the fifo */
+       printk(KERN_INFO "skip 1st element\n");
+       kfifo_skip(&test);
+
        printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test));
 
        /* show the first record without removing from the fifo */
@@ -82,11 +99,22 @@ static int __init testfunc(void)
        if (ret)
                printk(KERN_INFO "%.*s\n", ret, buf);
 
-       /* print out all records in the fifo */
+       /* check the correctness of all values in the fifo */
+       i = 0;
        while (!kfifo_is_empty(&test)) {
                ret = kfifo_out(&test, buf, sizeof(buf));
-               printk(KERN_INFO "%.*s\n", ret, buf);
+               buf[ret] = '\0';
+               printk(KERN_INFO "item = %.*s\n", ret, buf);
+               if (strcmp(buf, expected_result[i++])) {
+                       printk(KERN_WARNING "value mismatch: test failed\n");
+                       return -EIO;
+               }
+       }
+       if (i != ARRAY_SIZE(expected_result)) {
+               printk(KERN_WARNING "size mismatch: test failed\n");
+               return -EIO;
        }
+       printk(KERN_INFO "test passed\n");
 
        return 0;
 }
@@ -142,7 +170,12 @@ 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