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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>
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Andrea Righi authored and torvalds committed Aug 19, 2010
1 parent d83a71c commit a25effa4d265eb5028c7d4a92a0ddd9267c3c43d
Showing with 144 additions and 51 deletions.
  1. +6 −1 samples/kfifo/bytestream-example.c
  2. +67 −39 samples/kfifo/dma-example.c
  3. +35 −8 samples/kfifo/inttype-example.c
  4. +36 −3 samples/kfifo/record-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;
View
@@ -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;
}
@@ -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");
@@ -66,19 +73,34 @@ 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));
/* show the first value without removing from the fifo */
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
@@ -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];
@@ -75,18 +88,33 @@ 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 */
ret = kfifo_out_peek(&test, buf, sizeof(buf));
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

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