regulator: core: Fix size limit of supply_map

Now the debugfs file supply_map has a size limit PAGE_SIZE and the user
can not see the whole content of regulator_map_list when it is larger
than this limit.

This patch uses seq_file instead to make sure supply_map shows the full
information of regulator_map_list.

Signed-off-by: Haishan Zhou <zhssmail@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 13 insertions, 23 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index a0362a63902e..f8e76f73da35 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -4311,41 +4311,31 @@ void *regulator_get_init_drvdata(struct regulator_init_data *reg_init_data)
 EXPORT_SYMBOL_GPL(regulator_get_init_drvdata);
 
 #ifdef CONFIG_DEBUG_FS
-static ssize_t supply_map_read_file(struct file *file, char __user *user_buf,
-                                    size_t count, loff_t *ppos)
+static int supply_map_show(struct seq_file *sf, void *data)
 {
-        char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-        ssize_t len, ret = 0;
         struct regulator_map *map;
 
-        if (!buf)
-                return -ENOMEM;
-
         list_for_each_entry(map, &regulator_map_list, list) {
-                len = snprintf(buf + ret, PAGE_SIZE - ret,
-                               "%s -> %s.%s\n",
-                               rdev_get_name(map->regulator), map->dev_name,
-                               map->supply);
-                if (len >= 0)
-                        ret += len;
-                if (ret > PAGE_SIZE) {
-                        ret = PAGE_SIZE;
-                        break;
-                }
+                seq_printf(sf, "%s -> %s.%s\n",
+                                rdev_get_name(map->regulator), map->dev_name,
+                                map->supply);
         }
 
-        ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
-
-        kfree(buf);
+        return 0;
+}
 
-        return ret;
+static int supply_map_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, supply_map_show, inode->i_private);
 }
 #endif
 
 static const struct file_operations supply_map_fops = {
 #ifdef CONFIG_DEBUG_FS
-        .read = supply_map_read_file,
-        .llseek = default_llseek,
+        .open = supply_map_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = single_release,
 #endif
 };