From 5ddf83912c8b49a24ab0841f6d77f33781dcf10f Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Thu, 19 Aug 2010 14:13:28 -0700 Subject: kfifo: add kfifo_skip() testcase Add a testcase for kfifo_skip() to the byte stream fifo example. Signed-off-by: Andrea Righi Cc: Greg KH Acked-by: Stefani Seibold Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- samples/kfifo/bytestream-example.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'samples') diff --git a/samples/kfifo/bytestream-example.c b/samples/kfifo/bytestream-example.c index 642eef3f6336..2e3a7a8128a2 100644 --- a/samples/kfifo/bytestream-example.c +++ b/samples/kfifo/bytestream-example.c @@ -73,6 +73,10 @@ static int __init testfunc(void) ret = kfifo_in(&test, buf, ret); printk(KERN_INFO "ret: %d\n", ret); + /* 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++) ; -- cgit v1.2.3 From 2aaf2092c168fc02df0645415f524b357ee7ec2e Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Thu, 19 Aug 2010 14:13:29 -0700 Subject: 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 Cc: Stefani Seibold Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- samples/kfifo/bytestream-example.c | 33 +++++++++++++++++++++++++++------ 1 file changed, 27 insertions(+), 6 deletions(-) (limited to 'samples') 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 -- cgit v1.2.3 From 7b34d5257a90c419d67c1c3b52f87a679845ef1e Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Thu, 19 Aug 2010 14:13:29 -0700 Subject: kfifo: fix kernel BUG in dma example The scatterlist is used uninitialized in kfifo_dma_in_prepare(). This triggers the following bug if CONFIG_DEBUG_SG=y: ------------[ cut here ]------------ kernel BUG at include/linux/scatterlist.h:65! invalid opcode: 0000 [#1] PREEMPT SMP ... Call Trace: [] setup_sgl+0x6b/0xe0 [] ? example_init+0x0/0x265 [dma_example] [] __kfifo_dma_in_prepare+0x21/0x30 [] example_init+0x124/0x265 [dma_example] [] ? trace_module_notify+0x25/0x370 [] ? free_pages_prepare+0x11e/0x1e0 [] ? get_parent_ip+0x11/0x50 [] ? trace_module_notify+0x25/0x370 [] ? trace_hardirqs_on+0xd/0x10 [] ? mutex_unlock+0xe/0x10 [] ? trace_module_notify+0x41/0x370 [] ? __blocking_notifier_call_chain+0x45/0x80 [] ? vfree+0x2a/0x30 [] ? up_read+0x23/0x40 [] ? __blocking_notifier_call_chain+0x65/0x80 [] do_one_initcall+0x43/0x180 [] sys_init_module+0xba/0x200 [] system_call_fastpath+0x16/0x1b RIP [] setup_sgl_buf+0x1a1/0x1b0 RSP ---[ end trace a72b979fd3c1d3a5 ]--- Add the proper initialization to avoid the bug. Signed-off-by: Andrea Righi Acked-by: Stefani Seibold Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- samples/kfifo/dma-example.c | 1 + 1 file changed, 1 insertion(+) (limited to 'samples') diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c index b9482c28b41a..03433ca5bdad 100644 --- a/samples/kfifo/dma-example.c +++ b/samples/kfifo/dma-example.c @@ -45,6 +45,7 @@ static int __init example_init(void) printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo)); + 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); -- cgit v1.2.3 From d83a71c4219191a9a881318ae5ca9b39aa1d0540 Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Thu, 19 Aug 2010 14:13:30 -0700 Subject: kfifo: fix a memory leak in dma example We use a dynamically allocated kfifo in the dma example, so we need to free it when unloading the module. Signed-off-by: Andrea Righi Acked-by: Stefani Seibold Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- samples/kfifo/dma-example.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'samples') diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c index 03433ca5bdad..3682278785f7 100644 --- a/samples/kfifo/dma-example.c +++ b/samples/kfifo/dma-example.c @@ -105,9 +105,7 @@ static int __init example_init(void) static void __exit example_exit(void) { -#ifdef DYNAMIC - kfifo_free(&test); -#endif + kfifo_free(&fifo); } module_init(example_init); -- cgit v1.2.3 From a25effa4d265eb5028c7d4a92a0ddd9267c3c43d Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Thu, 19 Aug 2010 14:13:30 -0700 Subject: 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 Acked-by: Stefani Seibold Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- samples/kfifo/bytestream-example.c | 7 ++- samples/kfifo/dma-example.c | 106 +++++++++++++++++++++++-------------- samples/kfifo/inttype-example.c | 43 ++++++++++++--- samples/kfifo/record-example.c | 39 ++++++++++++-- 4 files changed, 144 insertions(+), 51 deletions(-) (limited to 'samples') diff --git a/samples/kfifo/bytestream-example.c b/samples/kfifo/bytestream-example.c index a94e6948b30d..178061e87ffe 100644 --- 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 3682278785f7..ee03a4f0b64f 100644 --- 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 d6c5b7d9df64..71b2aabca96a 100644 --- 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 32c6e0bda744..e68bd16a5da4 100644 --- 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 -- cgit v1.2.3 From 399f1e30ac17b77d383444aff480c7390f5adf2a Mon Sep 17 00:00:00 2001 From: "Ira W. Snyder" Date: Thu, 30 Sep 2010 15:15:27 -0700 Subject: kfifo: fix scatterlist usage The kfifo_dma family of functions use sg_mark_end() on the last element in their scatterlist. This forces use of a fresh scatterlist for each DMA operation, which makes recycling a single scatterlist impossible. Change the behavior of the kfifo_dma functions to match the usage of the dma_map_sg function. This means that users must respect the returned nents value. The sample code is updated to reflect the change. This bug is trivial to cause: call kfifo_dma_in_prepare() such that it prepares a scatterlist with a single entry comprising the whole fifo. This is the case when you map the entirety of a newly created empty fifo. This causes the setup_sgl() function to mark the first scatterlist entry as the end of the chain, no matter what comes after it. Afterwards, add and remove some data from the fifo such that another call to kfifo_dma_in_prepare() will create two scatterlist entries. It returns nents=2. However, due to the previous sg_mark_end() call, sg_is_last() will now return true for the first scatterlist element. This causes the sample code to print a single scatterlist element when it should print two. By removing the call to sg_mark_end(), we make the API as similar as possible to the DMA mapping API. All users are required to respect the returned nents. Signed-off-by: Ira W. Snyder Cc: Stefani Seibold Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kfifo.c | 2 -- samples/kfifo/dma-example.c | 17 +++++++++-------- 2 files changed, 9 insertions(+), 10 deletions(-) (limited to 'samples') diff --git a/kernel/kfifo.c b/kernel/kfifo.c index 6b5580c57644..01a0700e873f 100644 --- a/kernel/kfifo.c +++ b/kernel/kfifo.c @@ -365,8 +365,6 @@ static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl, n = setup_sgl_buf(sgl, fifo->data + off, nents, l); n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l); - if (n) - sg_mark_end(sgl + n - 1); return n; } diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c index ee03a4f0b64f..06473791c08a 100644 --- a/samples/kfifo/dma-example.c +++ b/samples/kfifo/dma-example.c @@ -24,6 +24,7 @@ static int __init example_init(void) { int i; unsigned int ret; + unsigned int nents; struct scatterlist sg[10]; printk(KERN_INFO "DMA fifo test start\n"); @@ -61,9 +62,9 @@ static int __init example_init(void) * 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) { + nents = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE); + printk(KERN_INFO "DMA sgl entries: %d\n", nents); + if (!nents) { /* fifo is full and no sgl was created */ printk(KERN_WARNING "error kfifo_dma_in_prepare\n"); return -EIO; @@ -71,7 +72,7 @@ static int __init example_init(void) /* receive data */ printk(KERN_INFO "scatterlist for receive:\n"); - for (i = 0; i < ARRAY_SIZE(sg); i++) { + for (i = 0; i < nents; i++) { printk(KERN_INFO "sg[%d] -> " "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n", @@ -91,16 +92,16 @@ static int __init example_init(void) 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) { + nents = kfifo_dma_out_prepare(&fifo, sg, ARRAY_SIZE(sg), 8); + printk(KERN_INFO "DMA sgl entries: %d\n", nents); + if (!nents) { /* no data was available and no sgl was created */ printk(KERN_WARNING "error kfifo_dma_out_prepare\n"); return -EIO; } printk(KERN_INFO "scatterlist for transmit:\n"); - for (i = 0; i < ARRAY_SIZE(sg); i++) { + for (i = 0; i < nents; i++) { printk(KERN_INFO "sg[%d] -> " "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n", -- cgit v1.2.3