[PATCH v2] ASoC: use seq_file to dump the contents of dai_list,platform_list and codec_list

From: Donglin Peng
Date: Thu Jan 18 2018 - 00:32:04 EST


Now the debugfs files dais/platforms/codecs have a size limit PAGE_SIZE and
the user can not see the whole contents of dai_list/platform_list/codec_list
when they are larger than this limit.

This patch uses seq_file instead to make sure dais/platforms/codecs show the
full contents of dai_list/platform_list/codec_list.

Signed-off-by: Donglin Peng <dolinux.peng@xxxxxxxxx>
---
Changelog
v2
-fix commit log error

sound/soc/soc-core.c | 111 +++++++++++++++++----------------------------------
1 file changed, 37 insertions(+), 74 deletions(-)

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index c0edac80df34..7b582112e3fc 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -349,120 +349,84 @@ static void soc_init_codec_debugfs(struct snd_soc_component *component)
"ASoC: Failed to create codec register debugfs file\n");
}

-static ssize_t codec_list_read_file(struct file *file, char __user *user_buf,
- size_t count, loff_t *ppos)
+static int codec_list_seq_show(struct seq_file *m, void *v)
{
- char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
- ssize_t len, ret = 0;
struct snd_soc_codec *codec;

- if (!buf)
- return -ENOMEM;
-
mutex_lock(&client_mutex);

- list_for_each_entry(codec, &codec_list, list) {
- len = snprintf(buf + ret, PAGE_SIZE - ret, "%s\n",
- codec->component.name);
- if (len >= 0)
- ret += len;
- if (ret > PAGE_SIZE) {
- ret = PAGE_SIZE;
- break;
- }
- }
+ list_for_each_entry(codec, &codec_list, list)
+ seq_printf(m, "%s\n", codec->component.name);

mutex_unlock(&client_mutex);

- if (ret >= 0)
- ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
-
- kfree(buf);
+ return 0;
+}

- return ret;
+static int codec_list_seq_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, codec_list_seq_show, NULL);
}

static const struct file_operations codec_list_fops = {
- .read = codec_list_read_file,
- .llseek = default_llseek,/* read accesses f_pos */
+ .open = codec_list_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
};

-static ssize_t dai_list_read_file(struct file *file, char __user *user_buf,
- size_t count, loff_t *ppos)
+static int dai_list_seq_show(struct seq_file *m, void *v)
{
- char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
- ssize_t len, ret = 0;
struct snd_soc_component *component;
struct snd_soc_dai *dai;

- if (!buf)
- return -ENOMEM;
-
mutex_lock(&client_mutex);

- list_for_each_entry(component, &component_list, list) {
- list_for_each_entry(dai, &component->dai_list, list) {
- len = snprintf(buf + ret, PAGE_SIZE - ret, "%s\n",
- dai->name);
- if (len >= 0)
- ret += len;
- if (ret > PAGE_SIZE) {
- ret = PAGE_SIZE;
- break;
- }
- }
- }
+ list_for_each_entry(component, &component_list, list)
+ list_for_each_entry(dai, &component->dai_list, list)
+ seq_printf(m, "%s\n", dai->name);

mutex_unlock(&client_mutex);

- ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
-
- kfree(buf);
+ return 0;
+}

- return ret;
+static int dai_list_seq_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, dai_list_seq_show, NULL);
}

static const struct file_operations dai_list_fops = {
- .read = dai_list_read_file,
- .llseek = default_llseek,/* read accesses f_pos */
+ .open = dai_list_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
};

-static ssize_t platform_list_read_file(struct file *file,
- char __user *user_buf,
- size_t count, loff_t *ppos)
+static int platform_list_seq_show(struct seq_file *m, void *v)
{
- char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
- ssize_t len, ret = 0;
struct snd_soc_platform *platform;

- if (!buf)
- return -ENOMEM;
-
mutex_lock(&client_mutex);

- list_for_each_entry(platform, &platform_list, list) {
- len = snprintf(buf + ret, PAGE_SIZE - ret, "%s\n",
- platform->component.name);
- if (len >= 0)
- ret += len;
- if (ret > PAGE_SIZE) {
- ret = PAGE_SIZE;
- break;
- }
- }
+ list_for_each_entry(platform, &platform_list, list)
+ seq_printf(m, "%s\n", platform->component.name);

mutex_unlock(&client_mutex);

- ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
-
- kfree(buf);
+ return 0;
+}

- return ret;
+static int platform_list_seq_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, platform_list_seq_show, NULL);
}

static const struct file_operations platform_list_fops = {
- .read = platform_list_read_file,
- .llseek = default_llseek,/* read accesses f_pos */
+ .open = platform_list_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
};

static void soc_init_card_debugfs(struct snd_soc_card *card)
@@ -491,7 +455,6 @@ static void soc_cleanup_card_debugfs(struct snd_soc_card *card)
debugfs_remove_recursive(card->debugfs_card_root);
}

-
static void snd_soc_debugfs_init(void)
{
snd_soc_debugfs_root = debugfs_create_dir("asoc", NULL);
--
2.15.1