[PATCH] mmc_test: collect data and show it via sysfs by demand

[Andy Shevchenko]

TODO:
 - implement show() method based on seq_file API

Changes since v5:
 - we can't use BUG_ON at exit() method because it quite normal case when the
   module is going to be removed with card plugged in, that's why we just free
   memory there

Changes since v4:
 - BUG_ON at exit if the list of the results isn't empty

Changes since v3:
 - fix multi-line commentary style
 - protect mmc_test_free_result() by mutex
 - apply known values to newly created mmc_test_general_result structure before
   attaching it to the list
 - call list_del() before free mmc_test_transfer_result structure
 - check truncated output in show() method, return -ENOBUFS if so
 - avoid deadlock in show() method if snprintf() fails

Changes since v2:
 - move card memeber to mmc_test_general_result structrure and thus throw away
   mmc_test_overall_result which was overkill
 - check result of kmalloc and kzalloc
 - keep pointer to the actual mmc_test_general_result structure in the
   mmc_test_card

Changes since v1:
 - structrure members are described
 - save transfer results code is split to separate function
 - in mmc_test_print_rate() use count = 1 instead of 0
 - mmc_test_result keeps overall results (across all tested cards), however
   it's still global variable
 - list_head variables inside structures have a suffix _lst now

Here is a patch which brings possibility to get test results via sysfs. It
helps to do tests non-interactively.

We have the file created under sysfs already and we could use it to out test
results.

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@xxxxxxxxx>
---
 drivers/mmc/card/mmc_test.c |  171 ++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 169 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c
index 9a13957..485fb66 100644
--- a/drivers/mmc/card/mmc_test.c
+++ b/drivers/mmc/card/mmc_test.c
@@ -16,6 +16,7 @@
 
 #include <linux/scatterlist.h>
 #include <linux/swap.h>
+#include <linux/list.h>
 
 #define RESULT_OK		0
 #define RESULT_FAIL		1
@@ -66,12 +67,45 @@ struct mmc_test_area {
 };
 
 /**
+ * struct mmc_test_transfer_result - transfer results for performance tests.
+ * @link: double-linked list
+ * @count: amount of group of sectors to check
+ * @sectors: amount of sectors to check in one group
+ * @ts: time values of transfer
+ * @rate: calculated transfer rate
+ */
+struct mmc_test_transfer_result {
+	struct list_head link;
+	unsigned int count;
+	unsigned int sectors;
+	struct timespec ts;
+	unsigned int rate;
+};
+
+/**
+ * struct mmc_test_general_result - results for tests.
+ * @link: double-linked list
+ * @card: card under test
+ * @testcase: number of test case
+ * @result: result of test run
+ * @tr_lst: transfer measurements if any as mmc_test_transfer_result
+ */
+struct mmc_test_general_result {
+	struct list_head link;
+	struct mmc_card *card;
+	int testcase;
+	int result;
+	struct list_head tr_lst;
+};
+
+/**
  * struct mmc_test_card - test information.
  * @card: card under test
  * @scratch: transfer buffer
  * @buffer: transfer buffer
  * @highmem: buffer for highmem tests
  * @area: information for performance tests
+ * @gr: pointer to results of current testcase
  */
 struct mmc_test_card {
 	struct mmc_card	*card;
@@ -81,7 +115,8 @@ struct mmc_test_card {
 #ifdef CONFIG_HIGHMEM
 	struct page	*highmem;
 #endif
-	struct mmc_test_area area;
+	struct mmc_test_area		area;
+	struct mmc_test_general_result	*gr;
 };
 
 /*******************************************************************/
@@ -413,6 +448,30 @@ static unsigned int mmc_test_rate(uint64_t bytes, struct timespec *ts)
 }
 
 /*
+ * Save transfer results for future usage
+ */
+static void mmc_test_save_transfer_result(struct mmc_test_card *test,
+	unsigned int count, unsigned int sectors, struct timespec ts,
+	unsigned int rate)
+{
+	struct mmc_test_transfer_result *tr;
+
+	if (!test->gr)
+		return;
+
+	tr = kmalloc(sizeof(struct mmc_test_transfer_result), GFP_KERNEL);
+	if (!tr)
+		return;
+
+	tr->count = count;
+	tr->sectors = sectors;
+	tr->ts = ts;
+	tr->rate = rate;
+
+	list_add_tail(&tr->link, &test->gr->tr_lst);
+}
+
+/*
  * Print the transfer rate.
  */
 static void mmc_test_print_rate(struct mmc_test_card *test, uint64_t bytes,
@@ -430,6 +489,8 @@ static void mmc_test_print_rate(struct mmc_test_card *test, uint64_t bytes,
 			 mmc_hostname(test->card->host), sectors, sectors >> 1,
 			 (sectors == 1 ? ".5" : ""), (unsigned long)ts.tv_sec,
 			 (unsigned long)ts.tv_nsec, rate / 1000, rate / 1024);
+
+	mmc_test_save_transfer_result(test, 1, sectors, ts, rate);
 }
 
 /*
@@ -453,6 +514,8 @@ static void mmc_test_print_avg_rate(struct mmc_test_card *test, uint64_t bytes,
 			 sectors >> 1, (sectors == 1 ? ".5" : ""),
 			 (unsigned long)ts.tv_sec, (unsigned long)ts.tv_nsec,
 			 rate / 1000, rate / 1024);
+
+	mmc_test_save_transfer_result(test, count, sectors, ts, rate);
 }
 
 /*
@@ -1836,6 +1899,8 @@ static const struct mmc_test_case mmc_test_cases[] = {
 
 static DEFINE_MUTEX(mmc_test_lock);
 
+static LIST_HEAD(mmc_test_result);
+
 static void mmc_test_run(struct mmc_test_card *test, int testcase)
 {
 	int i, ret;
@@ -1846,6 +1911,8 @@ static void mmc_test_run(struct mmc_test_card *test, int testcase)
 	mmc_claim_host(test->card->host);
 
 	for (i = 0;i < ARRAY_SIZE(mmc_test_cases);i++) {
+		struct mmc_test_general_result *gr;
+
 		if (testcase && ((i + 1) != testcase))
 			continue;
 
@@ -1864,6 +1931,25 @@ static void mmc_test_run(struct mmc_test_card *test, int testcase)
 			}
 		}
 
+		gr = kzalloc(sizeof(struct mmc_test_general_result),
+			GFP_KERNEL);
+		if (gr) {
+			INIT_LIST_HEAD(&gr->tr_lst);
+
+			/* Assign data what we know already */
+			gr->card = test->card;
+			gr->testcase = i;
+
+			/* Append container to global one */
+			list_add_tail(&gr->link, &mmc_test_result);
+
+			/*
+			 * Save the pointer to created container in our private
+			 * structure.
+			 */
+			test->gr = gr;
+		}
+
 		ret = mmc_test_cases[i].run(test);
 		switch (ret) {
 		case RESULT_OK:
@@ -1889,6 +1975,10 @@ static void mmc_test_run(struct mmc_test_card *test, int testcase)
 				mmc_hostname(test->card->host), ret);
 		}
 
+		/* Save the result */
+		if (gr)
+			gr->result = ret;
+
 		if (mmc_test_cases[i].cleanup) {
 			ret = mmc_test_cases[i].cleanup(test);
 			if (ret) {
@@ -1906,13 +1996,80 @@ static void mmc_test_run(struct mmc_test_card *test, int testcase)
 		mmc_hostname(test->card->host));
 }
 
+static void mmc_test_free_result(struct mmc_card *card)
+{
+	struct mmc_test_general_result *gr, *grs;
+
+	mutex_lock(&mmc_test_lock);
+
+	list_for_each_entry_safe(gr, grs, &mmc_test_result, link) {
+		struct mmc_test_transfer_result *tr, *trs;
+
+		if (card && gr->card != card)
+			continue;
+
+		list_for_each_entry_safe(tr, trs, &gr->tr_lst, link) {
+			list_del(&tr->link);
+			kfree(tr);
+		}
+
+		list_del(&gr->link);
+		kfree(gr);
+	}
+
+	mutex_unlock(&mmc_test_lock);
+}
+
 static ssize_t mmc_test_show(struct device *dev,
 	struct device_attribute *attr, char *buf)
 {
+	struct mmc_card *card = mmc_dev_to_card(dev);
+	struct mmc_test_general_result *gr;
+	char *p = buf;
+	size_t len = PAGE_SIZE;
+	int ret;
+
 	mutex_lock(&mmc_test_lock);
+
+	list_for_each_entry(gr, &mmc_test_result, link) {
+		struct mmc_test_transfer_result *tr;
+
+		if (gr->card != card)
+			continue;
+
+		ret = snprintf(p, len, "Test %d: %d\n", gr->testcase + 1,
+			gr->result);
+		if (ret < 0)
+			goto err;
+		if (ret >= len) {
+			ret = -ENOBUFS;
+			goto err;
+		}
+		p += ret;
+		len -= ret;
+
+		list_for_each_entry(tr, &gr->tr_lst, link) {
+			ret = snprintf(p, len, "%u %d %lu.%09lu %u\n",
+				tr->count, tr->sectors,
+				(unsigned long)tr->ts.tv_sec,
+				(unsigned long)tr->ts.tv_nsec,
+				tr->rate);
+			if (ret < 0)
+				goto err;
+			if (ret >= len) {
+				ret = -ENOBUFS;
+				goto err;
+			}
+			p += ret;
+			len -= ret;
+		}
+	}
+
+	ret = PAGE_SIZE - len;
+err:
 	mutex_unlock(&mmc_test_lock);
 
-	return 0;
+	return ret;
 }
 
 static ssize_t mmc_test_store(struct device *dev,
@@ -1929,6 +2086,12 @@ static ssize_t mmc_test_store(struct device *dev,
 	if (!test)
 		return -ENOMEM;
 
+	/*
+	 * Remove all test cases associated with given card. Thus we have only
+	 * actual data of the last run.
+	 */
+	mmc_test_free_result(card);
+
 	test->card = card;
 
 	test->buffer = kzalloc(BUFFER_SIZE, GFP_KERNEL);
@@ -1975,6 +2138,7 @@ static int mmc_test_probe(struct mmc_card *card)
 
 static void mmc_test_remove(struct mmc_card *card)
 {
+	mmc_test_free_result(card);
 	device_remove_file(&card->dev, &dev_attr_test);
 }
 
@@ -1993,6 +2157,9 @@ static int __init mmc_test_init(void)
 
 static void __exit mmc_test_exit(void)
 {
+	/* Clear stalled data if card is still plugged */
+	mmc_test_free_result(NULL);
+
 	mmc_unregister_driver(&mmc_driver);
 }
 
-- 
1.6.3.3

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