dmatest: replace stored results mechanism, with uniform messages

For long running tests the tracking results in a memory leak for the "ok"
results, and for the failures the kernel log should be sufficient.  Provide a
uniform format for error messages so they can be easily parsed and remove the
debugfs file.

Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

2 files changed, 46 insertions, 221 deletions

diff --git a/Documentation/dmatest.txt b/Documentation/dmatest.txt
index 8b7a5c879df9..45b8c95f1a21 100644
--- a/Documentation/dmatest.txt
+++ b/Documentation/dmatest.txt
@@ -16,9 +16,8 @@ be built as module or inside kernel. Let's consider those cases.
         Part 2 - When dmatest is built as a module...
 
 After mounting debugfs and loading the module, the /sys/kernel/debug/dmatest
-folder with nodes will be created. There are two important files located. First
-is the 'run' node that controls run and stop phases of the test, and the second
-one, 'results', is used to get the test case results.
+folder with a file named 'run' nodes will be created.  'run' controls run and
+stop phases of the test.
 
 Note that in this case test will not run on load automatically.
 
@@ -32,8 +31,9 @@ Hint: available channel list could be extracted by running the following
 command:
         % ls -1 /sys/class/dma/
 
-After a while you will start to get messages about current status or error like
-in the original code.
+Once started a message like "dmatest: Started 1 threads using dma0chan0" is
+emitted.  After that only test failure messages are reported until the test
+stops.
 
 Note that running a new test will not stop any in progress test.
 
@@ -62,19 +62,18 @@ case. You always could check them at run-time by running
 
         Part 4 - Gathering the test results
 
-The module provides a storage for the test results in the memory. The gathered
-data could be used after test is done.
+Test results are printed to the kernel log buffer with the format:
 
-The special file 'results' in the debugfs represents gathered data of the in
-progress test. The messages collected are printed to the kernel log as well.
+"dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)"
 
 Example of output:
-        % cat /sys/kernel/debug/dmatest/results
-        dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
+        % dmesg | tail -n 1
+        dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
 
 The message format is unified across the different types of errors. A number in
 the parens represents additional information, e.g. error code, error counter,
-or status.
+or status.  A test thread also emits a summary line at completion listing the
+number of tests executed, number that failed, and a result code.
 
-Note that the buffer comparison is done in the old way, i.e. data is not
-collected and just printed out.
+The details of a data miscompare error are also emitted, but do not follow the
+above format.
diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index dcb38d86550e..58b195f9d03c 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -8,6 +8,8 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
 #include <linux/dmaengine.h>
@@ -88,39 +90,6 @@ MODULE_PARM_DESC(timeout, "Transfer Timeout in msec (default: 3000), "
 #define PATTERN_OVERWRITE       0x20
 #define PATTERN_COUNT_MASK      0x1f
 
-enum dmatest_error_type {
-        DMATEST_ET_OK,
-        DMATEST_ET_MAP_SRC,
-        DMATEST_ET_MAP_DST,
-        DMATEST_ET_PREP,
-        DMATEST_ET_SUBMIT,
-        DMATEST_ET_TIMEOUT,
-        DMATEST_ET_DMA_ERROR,
-        DMATEST_ET_DMA_IN_PROGRESS,
-        DMATEST_ET_VERIFY,
-};
-
-struct dmatest_thread_result {
-        struct list_head        node;
-        unsigned int            n;
-        unsigned int            src_off;
-        unsigned int            dst_off;
-        unsigned int            len;
-        enum dmatest_error_type type;
-        union {
-                unsigned long           data;
-                dma_cookie_t            cookie;
-                enum dma_status         status;
-                int                     error;
-        };
-};
-
-struct dmatest_result {
-        struct list_head        node;
-        char                    *name;
-        struct list_head        results;
-};
-
 struct dmatest_info;
 
 struct dmatest_thread {
@@ -180,10 +149,6 @@ struct dmatest_info {
 
         /* debugfs related stuff */
         struct dentry           *root;
-
-        /* Test results */
-        struct list_head        results;
-        struct mutex            results_lock;
 };
 
 static struct dmatest_info test_info;
@@ -337,100 +302,19 @@ static unsigned int min_odd(unsigned int x, unsigned int y)
         return val % 2 ? val : val - 1;
 }
 
-static char *thread_result_get(const char *name,
-                struct dmatest_thread_result *tr)
+static void result(const char *err, unsigned int n, unsigned int src_off,
+                   unsigned int dst_off, unsigned int len, unsigned long data)
 {
-        static const char * const messages[] = {
-                [DMATEST_ET_OK]                 = "No errors",
-                [DMATEST_ET_MAP_SRC]            = "src mapping error",
-                [DMATEST_ET_MAP_DST]            = "dst mapping error",
-                [DMATEST_ET_PREP]               = "prep error",
-                [DMATEST_ET_SUBMIT]             = "submit error",
-                [DMATEST_ET_TIMEOUT]            = "test timed out",
-                [DMATEST_ET_DMA_ERROR]          =
-                        "got completion callback (DMA_ERROR)",
-                [DMATEST_ET_DMA_IN_PROGRESS]    =
-                        "got completion callback (DMA_IN_PROGRESS)",
-                [DMATEST_ET_VERIFY]             = "errors",
-        };
-        static char buf[512];
-
-        snprintf(buf, sizeof(buf) - 1,
-                 "%s: #%u: %s with src_off=0x%x ""dst_off=0x%x len=0x%x (%lu)",
-                 name, tr->n, messages[tr->type], tr->src_off, tr->dst_off,
-                 tr->len, tr->data);
-
-        return buf;
+        pr_info("%s: result #%u: '%s' with src_off=0x%x ""dst_off=0x%x len=0x%x (%lu)",
+                current->comm, n, err, src_off, dst_off, len, data);
 }
 
-static int thread_result_add(struct dmatest_info *info,
-                struct dmatest_result *r, enum dmatest_error_type type,
-                unsigned int n, unsigned int src_off, unsigned int dst_off,
-                unsigned int len, unsigned long data)
+static void dbg_result(const char *err, unsigned int n, unsigned int src_off,
+                       unsigned int dst_off, unsigned int len,
+                       unsigned long data)
 {
-        struct dmatest_thread_result *tr;
-
-        tr = kzalloc(sizeof(*tr), GFP_KERNEL);
-        if (!tr)
-                return -ENOMEM;
-
-        tr->type = type;
-        tr->n = n;
-        tr->src_off = src_off;
-        tr->dst_off = dst_off;
-        tr->len = len;
-        tr->data = data;
-
-        mutex_lock(&info->results_lock);
-        list_add_tail(&tr->node, &r->results);
-        mutex_unlock(&info->results_lock);
-
-        if (tr->type == DMATEST_ET_OK)
-                pr_debug("%s\n", thread_result_get(r->name, tr));
-        else
-                pr_warn("%s\n", thread_result_get(r->name, tr));
-
-        return 0;
-}
-
-static void result_free(struct dmatest_info *info, const char *name)
-{
-        struct dmatest_result *r, *_r;
-
-        mutex_lock(&info->results_lock);
-        list_for_each_entry_safe(r, _r, &info->results, node) {
-                struct dmatest_thread_result *tr, *_tr;
-
-                if (name && strcmp(r->name, name))
-                        continue;
-
-                list_for_each_entry_safe(tr, _tr, &r->results, node) {
-                        list_del(&tr->node);
-                        kfree(tr);
-                }
-
-                kfree(r->name);
-                list_del(&r->node);
-                kfree(r);
-        }
-
-        mutex_unlock(&info->results_lock);
-}
-
-static struct dmatest_result *result_init(struct dmatest_info *info,
-                const char *name)
-{
-        struct dmatest_result *r;
-
-        r = kzalloc(sizeof(*r), GFP_KERNEL);
-        if (r) {
-                r->name = kstrdup(name, GFP_KERNEL);
-                INIT_LIST_HEAD(&r->results);
-                mutex_lock(&info->results_lock);
-                list_add_tail(&r->node, &info->results);
-                mutex_unlock(&info->results_lock);
-        }
-        return r;
+        pr_debug("%s: result #%u: '%s' with src_off=0x%x ""dst_off=0x%x len=0x%x (%lu)",
+                 current->comm, n, err, src_off, dst_off, len, data);
 }
 
 /*
@@ -456,7 +340,6 @@ static int dmatest_func(void *data)
         struct dmatest_params   *params;
         struct dma_chan         *chan;
         struct dma_device       *dev;
-        const char              *thread_name;
         unsigned int            src_off, dst_off, len;
         unsigned int            error_count;
         unsigned int            failed_tests = 0;
@@ -469,9 +352,7 @@ static int dmatest_func(void *data)
         int                     src_cnt;
         int                     dst_cnt;
         int                     i;
-        struct dmatest_result   *result;
 
-        thread_name = current->comm;
         set_freezable();
 
         ret = -ENOMEM;
@@ -501,10 +382,6 @@ static int dmatest_func(void *data)
         } else
                 goto err_thread_type;
 
-        result = result_init(info, thread_name);
-        if (!result)
-                goto err_srcs;
-
         thread->srcs = kcalloc(src_cnt+1, sizeof(u8 *), GFP_KERNEL);
         if (!thread->srcs)
                 goto err_srcs;
@@ -576,10 +453,8 @@ static int dmatest_func(void *data)
                         ret = dma_mapping_error(dev->dev, dma_srcs[i]);
                         if (ret) {
                                 unmap_src(dev->dev, dma_srcs, len, i);
-                                thread_result_add(info, result,
-                                                  DMATEST_ET_MAP_SRC,
-                                                  total_tests, src_off, dst_off,
-                                                  len, ret);
+                                result("src mapping error", total_tests,
+                                       src_off, dst_off, len, ret);
                                 failed_tests++;
                                 continue;
                         }
@@ -594,10 +469,8 @@ static int dmatest_func(void *data)
                                 unmap_src(dev->dev, dma_srcs, len, src_cnt);
                                 unmap_dst(dev->dev, dma_dsts, params->buf_size,
                                           i);
-                                thread_result_add(info, result,
-                                                  DMATEST_ET_MAP_DST,
-                                                  total_tests, src_off, dst_off,
-                                                  len, ret);
+                                result("dst mapping error", total_tests,
+                                       src_off, dst_off, len, ret);
                                 failed_tests++;
                                 continue;
                         }
@@ -627,9 +500,8 @@ static int dmatest_func(void *data)
                         unmap_src(dev->dev, dma_srcs, len, src_cnt);
                         unmap_dst(dev->dev, dma_dsts, params->buf_size,
                                   dst_cnt);
-                        thread_result_add(info, result, DMATEST_ET_PREP,
-                                          total_tests, src_off, dst_off,
-                                          len, 0);
+                        result("prep error", total_tests, src_off,
+                               dst_off, len, ret);
                         msleep(100);
                         failed_tests++;
                         continue;
@@ -641,9 +513,8 @@ static int dmatest_func(void *data)
                 cookie = tx->tx_submit(tx);
 
                 if (dma_submit_error(cookie)) {
-                        thread_result_add(info, result, DMATEST_ET_SUBMIT,
-                                          total_tests, src_off, dst_off,
-                                          len, cookie);
+                        result("submit error", total_tests, src_off,
+                               dst_off, len, ret);
                         msleep(100);
                         failed_tests++;
                         continue;
@@ -664,17 +535,15 @@ static int dmatest_func(void *data)
                          * free it this time?" dancing.  For now, just
                          * leave it dangling.
                          */
-                        thread_result_add(info, result, DMATEST_ET_TIMEOUT,
-                                          total_tests, src_off, dst_off,
-                                          len, 0);
+                        result("test timed out", total_tests, src_off, dst_off,
+                               len, 0);
                         failed_tests++;
                         continue;
                 } else if (status != DMA_SUCCESS) {
-                        enum dmatest_error_type type = (status == DMA_ERROR) ?
-                                DMATEST_ET_DMA_ERROR : DMATEST_ET_DMA_IN_PROGRESS;
-                        thread_result_add(info, result, type,
-                                          total_tests, src_off, dst_off,
-                                          len, status);
+                        result(status == DMA_ERROR ?
+                               "completion error status" :
+                               "completion busy status", total_tests, src_off,
+                               dst_off, len, ret);
                         failed_tests++;
                         continue;
                 }
@@ -685,7 +554,7 @@ static int dmatest_func(void *data)
 
                 error_count = 0;
 
-                pr_debug("%s: verifying source buffer...\n", thread_name);
+                pr_debug("%s: verifying source buffer...\n", current->comm);
                 error_count += dmatest_verify(thread->srcs, 0, src_off,
                                 0, PATTERN_SRC, true);
                 error_count += dmatest_verify(thread->srcs, src_off,
@@ -695,8 +564,7 @@ static int dmatest_func(void *data)
                                 params->buf_size, src_off + len,
                                 PATTERN_SRC, true);
 
-                pr_debug("%s: verifying dest buffer...\n",
-                                thread->task->comm);
+                pr_debug("%s: verifying dest buffer...\n", current->comm);
                 error_count += dmatest_verify(thread->dsts, 0, dst_off,
                                 0, PATTERN_DST, false);
                 error_count += dmatest_verify(thread->dsts, dst_off,
@@ -707,14 +575,12 @@ static int dmatest_func(void *data)
                                 PATTERN_DST, false);
 
                 if (error_count) {
-                        thread_result_add(info, result, DMATEST_ET_VERIFY,
-                                          total_tests, src_off, dst_off,
-                                          len, error_count);
+                        result("data error", total_tests, src_off, dst_off,
+                               len, error_count);
                         failed_tests++;
                 } else {
-                        thread_result_add(info, result, DMATEST_ET_OK,
-                                          total_tests, src_off, dst_off,
-                                          len, 0);
+                        dbg_result("test passed", total_tests, src_off, dst_off,
+                                   len, 0);
                 }
         }
 
@@ -731,8 +597,8 @@ err_srcbuf:
 err_srcs:
         kfree(pq_coefs);
 err_thread_type:
-        pr_notice("%s: terminating after %u tests, %u failures (status %d)\n",
-                        thread_name, total_tests, failed_tests, ret);
+        pr_info("%s: terminating after %u tests, %u failures (status %d)\n",
+                current->comm, total_tests, failed_tests, ret);
 
         /* terminate all transfers on specified channels */
         if (ret)
@@ -937,9 +803,6 @@ static int __restart_threaded_test(struct dmatest_info *info, bool run)
         if (run == false)
                 return 0;
 
-        /* Clear results from previous run */
-        result_free(info, NULL);
-
         /* Copy test parameters */
         params->buf_size = test_buf_size;
         strlcpy(params->channel, strim(test_channel), sizeof(params->channel));
@@ -1024,35 +887,6 @@ static const struct file_operations dtf_run_fops = {
         .llseek = default_llseek,
 };
 
-static int dtf_results_show(struct seq_file *sf, void *data)
-{
-        struct dmatest_info *info = sf->private;
-        struct dmatest_result *result;
-        struct dmatest_thread_result *tr;
-
-        mutex_lock(&info->results_lock);
-        list_for_each_entry(result, &info->results, node) {
-                list_for_each_entry(tr, &result->results, node)
-                        seq_printf(sf, "%s\n",
-                                thread_result_get(result->name, tr));
-        }
-
-        mutex_unlock(&info->results_lock);
-        return 0;
-}
-
-static int dtf_results_open(struct inode *inode, struct file *file)
-{
-        return single_open(file, dtf_results_show, inode->i_private);
-}
-
-static const struct file_operations dtf_results_fops = {
-        .open           = dtf_results_open,
-        .read           = seq_read,
-        .llseek         = seq_lseek,
-        .release        = single_release,
-};
-
 static int dmatest_register_dbgfs(struct dmatest_info *info)
 {
         struct dentry *d;
@@ -1069,10 +903,6 @@ static int dmatest_register_dbgfs(struct dmatest_info *info)
         debugfs_create_file("run", S_IWUSR | S_IRUGO, info->root, info,
                             &dtf_run_fops);
 
-        /* Results of test in progress */
-        debugfs_create_file("results", S_IRUGO, info->root, info,
-                            &dtf_results_fops);
-
         return 0;
 
 err_root:
@@ -1090,9 +920,6 @@ static int __init dmatest_init(void)
         mutex_init(&info->lock);
         INIT_LIST_HEAD(&info->channels);
 
-        mutex_init(&info->results_lock);
-        INIT_LIST_HEAD(&info->results);
-
         ret = dmatest_register_dbgfs(info);
         if (ret)
                 return ret;
@@ -1112,7 +939,6 @@ static void __exit dmatest_exit(void)
 
         debugfs_remove_recursive(info->root);
         stop_threaded_test(info);
-        result_free(info, NULL);
 }
 module_exit(dmatest_exit);