Re: [RFC] Bluetooth: Add debugfs option to enable runtime debug statements

[Alain Michaud <alainmichaud@google.com>]

Resending in plain text... Sorry, old dog, new tricks... (or is it the
opposite? :))


On Tue, Jan 28, 2020 at 7:48 PM Alain Michaud <alainmichaud@google.com> wrote:
>
> Hi Marcel,
>
> Just a quick ack from me.
>
> It looks good for me, but I'd like to get feedback from our team which has implemented the earlier proposal.  The team however in Taipei aren't due back in from holiday until next week, so it may take some time before we get back to you.
>
> Thanks,
> Alain
>
> On Mon, Jan 27, 2020 at 11:49 AM Marcel Holtmann <marcel@holtmann.org> wrote:
>>
>> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
>> ---
>>  include/net/bluetooth/bluetooth.h | 10 ++++-
>>  net/bluetooth/Kconfig             |  4 ++
>>  net/bluetooth/af_bluetooth.c      |  2 +
>>  net/bluetooth/lib.c               | 69 +++++++++++++++++++++++++++++++
>>  4 files changed, 84 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
>> index e42bb8e03c09..d32d1f401efb 100644
>> --- a/include/net/bluetooth/bluetooth.h
>> +++ b/include/net/bluetooth/bluetooth.h
>> @@ -129,6 +129,8 @@ void bt_warn(const char *fmt, ...);
>>  __printf(1, 2)
>>  void bt_err(const char *fmt, ...);
>>  __printf(1, 2)
>> +void bt_dbg(const char *fmt, ...);
>> +__printf(1, 2)
>>  void bt_warn_ratelimited(const char *fmt, ...);
>>  __printf(1, 2)
>>  void bt_err_ratelimited(const char *fmt, ...);
>> @@ -136,7 +138,11 @@ void bt_err_ratelimited(const char *fmt, ...);
>>  #define BT_INFO(fmt, ...)      bt_info(fmt "\n", ##__VA_ARGS__)
>>  #define BT_WARN(fmt, ...)      bt_warn(fmt "\n", ##__VA_ARGS__)
>>  #define BT_ERR(fmt, ...)       bt_err(fmt "\n", ##__VA_ARGS__)
>> -#define BT_DBG(fmt, ...)       pr_debug(fmt "\n", ##__VA_ARGS__)
>> +#if IS_ENABLED(CONFIG_BT_DEBUGFS_OPTION)
>> +#define BT_DBG(fmt, ...)       bt_dbg(fmt "\n", ##__VA_ARGS__)
>> +#else
>> +#define BT_DBG(fmt, ...)       pr_debug(mt "\n", ##__VA_ARGS__)
>> +#endif
>>
>>  #define bt_dev_info(hdev, fmt, ...)                            \
>>         BT_INFO("%s: " fmt, (hdev)->name, ##__VA_ARGS__)
>> @@ -393,6 +399,8 @@ void bt_procfs_cleanup(struct net *net, const char *name);
>>
>>  extern struct dentry *bt_debugfs;
>>
>> +void bt_lib_debugfs_init(void);
>> +
>>  int l2cap_init(void);
>>  void l2cap_exit(void);
>>
>> diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig
>> index 165148c7c4ce..64833640bf3d 100644
>> --- a/net/bluetooth/Kconfig
>> +++ b/net/bluetooth/Kconfig
>> @@ -128,4 +128,8 @@ config BT_DEBUGFS
>>           Provide extensive information about internal Bluetooth states
>>           in debugfs.
>>
>> +config BT_DEBUGFS_OPTION
>> +       bool
>> +       default y if BT_DEBUGFS && !DYNAMIC_DEBUG
>> +
>>  source "drivers/bluetooth/Kconfig"
>> diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
>> index 3fd124927d4d..fa0cd665f32a 100644
>> --- a/net/bluetooth/af_bluetooth.c
>> +++ b/net/bluetooth/af_bluetooth.c
>> @@ -731,6 +731,8 @@ static int __init bt_init(void)
>>
>>         bt_debugfs = debugfs_create_dir("bluetooth", NULL);
>>
>> +       bt_lib_debugfs_init();
>> +
>>         bt_leds_init();
>>
>>         err = bt_sysfs_init();
>> diff --git a/net/bluetooth/lib.c b/net/bluetooth/lib.c
>> index c09e0a3a0ed9..28cfc3fd8fbe 100644
>> --- a/net/bluetooth/lib.c
>> +++ b/net/bluetooth/lib.c
>> @@ -27,6 +27,7 @@
>>  #define pr_fmt(fmt) "Bluetooth: " fmt
>>
>>  #include <linux/export.h>
>> +#include <linux/debugfs.h>
>>
>>  #include <net/bluetooth/bluetooth.h>
>>
>> @@ -135,6 +136,55 @@ int bt_to_errno(__u16 code)
>>  }
>>  EXPORT_SYMBOL(bt_to_errno);
>>
>> +#ifdef CONFIG_BT_DEBUGFS_OPTION
>> +static bool debug_enable;
>> +
>> +static ssize_t debug_enable_read(struct file *file, char __user *user_buf,
>> +                                size_t count, loff_t *ppos)
>> +{
>> +       char buf[3];
>> +
>> +       buf[0] = debug_enable ? 'Y': 'N';
>> +       buf[1] = '\n';
>> +       buf[2] = '\0';
>> +       return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
>> +}
>> +
>> +static ssize_t debug_enable_write(struct file *file,
>> +                                 const char __user *user_buf,
>> +                                 size_t count, loff_t *ppos)
>> +{
>> +       bool enable;
>> +       int err;
>> +
>> +       err = kstrtobool_from_user(user_buf, count, &enable);
>> +       if (err)
>> +               return err;
>> +
>> +       if (enable == debug_enable)
>> +               return -EALREADY;
>> +
>> +       debug_enable = enable;
>> +
>> +       return count;
>> +}
>> +
>> +static const struct file_operations debug_enable_fops = {
>> +       .open           = simple_open,
>> +       .read           = debug_enable_read,
>> +       .write          = debug_enable_write,
>> +       .llseek         = default_llseek,
>> +};
>> +
>> +void bt_lib_debugfs_init(void)
>> +{
>> +       debugfs_create_file("debug_enable", 0644, bt_debugfs, NULL,
>> +                           &debug_enable_fops);
>> +}
>> +#else
>> +void bt_lib_debugfs_init(void);
>> +#endif
>> +
>>  void bt_info(const char *format, ...)
>>  {
>>         struct va_format vaf;
>> @@ -183,6 +233,25 @@ void bt_err(const char *format, ...)
>>  }
>>  EXPORT_SYMBOL(bt_err);
>>
>> +void bt_dbg(const char *format, ...)
>> +{
>> +       struct va_format vaf;
>> +       va_list args;
>> +
>> +       if (likely(!debug_enable))
>> +               return;
>> +
>> +       va_start(args, format);
>> +
>> +       vaf.fmt = format;
>> +       vaf.va = &args;
>> +
>> +       printk(KERN_DEBUG pr_fmt("%pV"), &vaf);
>> +
>> +       va_end(args);
>> +}
>> +EXPORT_SYMBOL(bt_dbg);
>> +
>>  void bt_warn_ratelimited(const char *format, ...)
>>  {
>>         struct va_format vaf;
>> --
>> 2.24.1
>>