mmc_test: move files from sysfs to debugfs

As proposed by Greg K-H it is more logical to keep files for the mmc_test
driver under debugfs.

Additionally this patch brings seq_file API for show() method.  It allows
to write unlimited data to the file.

Example of usage:
  # mount -t debugfs none /sys/kernel/debug
  # modprobe mmc_test
    [  581.395843] mmc_test mmc0:0001: Card claimed for testing.
  # echo 25 > /sys/kernel/debug/mmc0/mmc0\:0001/test
    [  604.568542] mmc0: Starting tests of card mmc0:0001...
    [  604.582733] mmc0: Test case 25. Best-case read performance into scattered pages...
    [  604.923553] mmc0: Transfer of 8192 sectors (4096 KiB) took 0.124664314 seconds (33644 kB/s, 32856 KiB/s)
    [  604.933227] mmc0: Result: OK
    [  604.936248] mmc0: Tests completed.
  # cat /sys/kernel/debug/mmc0/mmc0\:0001/test
    Test 25: 0
    1 8192 0.124664314 33644784

Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Cc: Greg KH <greg@kroah.com>
Cc: Adrian Hunter <adrian.hunter@nokia.com>
Cc: Chris Ball <cjb@laptop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c
index 0c8b568..6580af7 100644 (file)
--- a/drivers/mmc/card/mmc_test.c
+++ b/drivers/mmc/card/mmc_test.c
@@ -19,6 +19,10 @@
 #include <linux/swap.h>                /* For nr_free_buffer_pages() */
 #include <linux/list.h>
 
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+
 #define RESULT_OK              0
 #define RESULT_FAIL            1
 #define RESULT_UNSUP_HOST      2
@@ -109,6 +113,18 @@ struct mmc_test_general_result {
        struct list_head tr_lst;
 };
 
+/**
+ * struct mmc_test_dbgfs_file - debugfs related file.
+ * @link: double-linked list
+ * @card: card under test
+ * @file: file created under debugfs
+ */
+struct mmc_test_dbgfs_file {
+       struct list_head link;
+       struct mmc_card *card;
+       struct dentry *file;
+};
+
 /**
  * struct mmc_test_card - test information.
  * @card: card under test
@@ -2124,14 +2140,12 @@ static void mmc_test_free_result(struct mmc_card *card)
        mutex_unlock(&mmc_test_lock);
 }
 
-static ssize_t mmc_test_show(struct device *dev,
-       struct device_attribute *attr, char *buf)
+static LIST_HEAD(mmc_test_file_test);
+
+static int mtf_test_show(struct seq_file *sf, void *data)
 {
-       struct mmc_card *card = mmc_dev_to_card(dev);
+       struct mmc_card *card = (struct mmc_card *)sf->private;
        struct mmc_test_general_result *gr;
-       char *p = buf;
-       size_t len = PAGE_SIZE;
-       int ret;
 
        mutex_lock(&mmc_test_lock);
 
@@ -2141,49 +2155,44 @@ static ssize_t mmc_test_show(struct device *dev,
                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;
+               seq_printf(sf, "Test %d: %d\n", gr->testcase + 1, gr->result);
 
                list_for_each_entry(tr, &gr->tr_lst, link) {
-                       ret = snprintf(p, len, "%u %d %lu.%09lu %u\n",
+                       seq_printf(sf, "%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 ret;
+       return 0;
 }
 
-static ssize_t mmc_test_store(struct device *dev,
-       struct device_attribute *attr, const char *buf, size_t count)
+static int mtf_test_open(struct inode *inode, struct file *file)
 {
-       struct mmc_card *card = mmc_dev_to_card(dev);
+       return single_open(file, mtf_test_show, inode->i_private);
+}
+
+static ssize_t mtf_test_write(struct file *file, const char __user *buf,
+       size_t count, loff_t *pos)
+{
+       struct seq_file *sf = (struct seq_file *)file->private_data;
+       struct mmc_card *card = (struct mmc_card *)sf->private;
        struct mmc_test_card *test;
+       char lbuf[12];
        long testcase;
 
-       if (strict_strtol(buf, 10, &testcase))
+       if (count >= sizeof(lbuf))
+               return -EINVAL;
+
+       if (copy_from_user(lbuf, buf, count))
+               return -EFAULT;
+       lbuf[count] = '\0';
+
+       if (strict_strtol(lbuf, 10, &testcase))
                return -EINVAL;
 
        test = kzalloc(sizeof(struct mmc_test_card), GFP_KERNEL);
@@ -2222,7 +2231,69 @@ static ssize_t mmc_test_store(struct device *dev,
        return count;
 }
 
-static DEVICE_ATTR(test, S_IWUSR | S_IRUGO, mmc_test_show, mmc_test_store);
+static const struct file_operations mmc_test_fops_test = {
+       .open           = mtf_test_open,
+       .read           = seq_read,
+       .write          = mtf_test_write,
+       .llseek         = seq_lseek,
+       .release        = single_release,
+};
+
+static void mmc_test_free_file_test(struct mmc_card *card)
+{
+       struct mmc_test_dbgfs_file *df, *dfs;
+
+       mutex_lock(&mmc_test_lock);
+
+       list_for_each_entry_safe(df, dfs, &mmc_test_file_test, link) {
+               if (card && df->card != card)
+                       continue;
+               debugfs_remove(df->file);
+               list_del(&df->link);
+               kfree(df);
+       }
+
+       mutex_unlock(&mmc_test_lock);
+}
+
+static int mmc_test_register_file_test(struct mmc_card *card)
+{
+       struct dentry *file = NULL;
+       struct mmc_test_dbgfs_file *df;
+       int ret = 0;
+
+       mutex_lock(&mmc_test_lock);
+
+       if (card->debugfs_root)
+               file = debugfs_create_file("test", S_IWUSR | S_IRUGO,
+                       card->debugfs_root, card, &mmc_test_fops_test);
+
+       if (IS_ERR_OR_NULL(file)) {
+               dev_err(&card->dev,
+                       "Can't create file. Perhaps debugfs is disabled.\n");
+               ret = -ENODEV;
+               goto err;
+       }
+
+       df = kmalloc(sizeof(struct mmc_test_dbgfs_file), GFP_KERNEL);
+       if (!df) {
+               debugfs_remove(file);
+               dev_err(&card->dev,
+                       "Can't allocate memory for internal usage.\n");
+               ret = -ENOMEM;
+               goto err;
+       }
+
+       df->card = card;
+       df->file = file;
+
+       list_add(&df->link, &mmc_test_file_test);
+
+err:
+       mutex_unlock(&mmc_test_lock);
+
+       return ret;
+}
 
 static int mmc_test_probe(struct mmc_card *card)
 {
@@ -2231,7 +2302,7 @@ static int mmc_test_probe(struct mmc_card *card)
        if (!mmc_card_mmc(card) && !mmc_card_sd(card))
                return -ENODEV;
 
-       ret = device_create_file(&card->dev, &dev_attr_test);
+       ret = mmc_test_register_file_test(card);
        if (ret)
                return ret;
 
@@ -2243,7 +2314,7 @@ 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);
+       mmc_test_free_file_test(card);
 }
 
 static struct mmc_driver mmc_driver = {
@@ -2263,6 +2334,7 @@ static void __exit mmc_test_exit(void)
 {
        /* Clear stalled data if card is still plugged */
        mmc_test_free_result(NULL);
+       mmc_test_free_file_test(NULL);
 
        mmc_unregister_driver(&mmc_driver);
 }