Re: [RFC PATCH 1/3] drm/debugfs: create debugfs files during drm_dev_register().

Hi

Am 13.05.20 um 13:41 schrieb Wambui Karuga:

Introduce the ability to track requests for the addition of drm debugfs files at any time and have them added all at once during drm_dev_register().

Drivers can add drm debugfs file requests to a new list tied to drm_device. During drm_dev_register(), the new function drm_debugfs_create_file() will iterate over the list of added files on a given minor to create them.

Two new structs are introduced in this change: struct drm_simple_info which represents a drm debugfs file entry and struct drm_simple_info_entry which is used to track file requests and is the main parameter of choice passed by functions. Each drm_simple_info_entry is added to the new struct drm_device->debugfs_list for file requests.

Signed-off-by: Wambui Karuga wambui.karugax@gmail.com

drivers/gpu/drm/drm_debugfs.c | 59 ++++++++++++++++++++++++++++++++--- drivers/gpu/drm/drm_drv.c | 2 ++ include/drm/drm_debugfs.h | 38 ++++++++++++++++++++++ include/drm/drm_device.h | 12 +++++++ 4 files changed, 107 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c index 2bea22130703..03b0588ede68 100644 --- a/drivers/gpu/drm/drm_debugfs.c +++ b/drivers/gpu/drm/drm_debugfs.c @@ -145,9 +145,10 @@ static const struct drm_info_list drm_debugfs_list[] = {

static int drm_debugfs_open(struct inode *inode, struct file *file) {

• struct drm_info_node *node = inode->i_private;

• struct drm_simple_info_entry *entry = inode->i_private;
• struct drm_simple_info *node = &entry->file;

• return single_open(file, node->info_ent->show, node);

• return single_open(file, node->show_fn, entry);

}

@@ -159,6 +160,25 @@ static const struct file_operations drm_debugfs_fops = { .release = single_release, };

+/**

• • drm_debugfs_create_file - create DRM debugfs file.
• • @dev: drm_device that the file belongs to
• • Create a DRM debugfs file from the list of files to be created
• • from dev->debugfs_list.
• */

+static void drm_debugfs_create_file(struct drm_minor *minor)

This function creates several files. I'd rather call it drm_debugfs_create_added_files().

+{

• struct drm_device *dev = minor->dev;
• struct drm_simple_info_entry *entry;
• list_for_each_entry(entry, &dev->debugfs_list, list) {

• debugfs_create_file(entry->file.name,
  

• 		    S_IFREG | S_IRUGO, minor->debugfs_root,
  

• 		    entry,
  

• 		    &drm_debugfs_fops);
  

• }

I think the created items should be removed from the list. That way, drivers can call the function multiple times without recreating the same files again.

+}

/**

• drm_debugfs_create_files - Initialize a given set of debugfs files for DRM

@@ -213,8 +233,7 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id, sprintf(name, "%d", minor_id); minor->debugfs_root = debugfs_create_dir(name, root);

• drm_debugfs_create_files(drm_debugfs_list, DRM_DEBUGFS_ENTRIES,

• 		 minor->debugfs_root, minor);
  

By removing these two lines, aren't you losing the files listed in DRM_DEBUGFS_ENTRIES?

• drm_debugfs_create_file(minor);

  if (drm_drv_uses_atomic_modeset(dev)) { drm_atomic_debugfs_init(minor);

@@ -449,4 +468,36 @@ void drm_debugfs_crtc_remove(struct drm_crtc *crtc) crtc->debugfs_entry = NULL; }

+void drm_debugfs_add_file(struct drm_device *dev, const char *name,

• 	  drm_simple_show_t show_fn, void *data)
  

+{

• struct drm_simple_info_entry *entry =

• kzalloc(sizeof(*entry), GFP_KERNEL);
  

• if (!entry)

• return;
  

• entry->file.name = name;
• entry->file.show_fn = show_fn;
• entry->file.data = data;
• entry->dev = dev;
• mutex_lock(&dev->debugfs_mutex);
• list_add(&entry->list, &dev->debugfs_list);
• mutex_unlock(&dev->debugfs_mutex);

+} +EXPORT_SYMBOL(drm_debugfs_add_file);

+void drm_debugfs_add_files(struct drm_device *dev,

• 	   const struct drm_simple_info *files, int count)
  

+{

• int i;
• for (i = 0; i < count; i++) {

• drm_debugfs_add_file(dev, files[i].name, files[i].show_fn,
  

• 		     files[i].data);
  

• }

+} +EXPORT_SYMBOL(drm_debugfs_add_files);

#endif /* CONFIG_DEBUG_FS */ diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index bc38322f306e..c68df4e31aa0 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -646,12 +646,14 @@ int drm_dev_init(struct drm_device *dev, INIT_LIST_HEAD(&dev->filelist_internal); INIT_LIST_HEAD(&dev->clientlist); INIT_LIST_HEAD(&dev->vblank_event_list);

• INIT_LIST_HEAD(&dev->debugfs_list);

  spin_lock_init(&dev->event_lock); mutex_init(&dev->struct_mutex); mutex_init(&dev->filelist_mutex); mutex_init(&dev->clientlist_mutex); mutex_init(&dev->master_mutex);

• mutex_init(&dev->debugfs_mutex);

  ret = drmm_add_action(dev, drm_dev_init_release, NULL); if (ret)

diff --git a/include/drm/drm_debugfs.h b/include/drm/drm_debugfs.h index 2188dc83957f..bbce580c3b38 100644 --- a/include/drm/drm_debugfs.h +++ b/include/drm/drm_debugfs.h @@ -34,6 +34,44 @@

#include <linux/types.h> #include <linux/seq_file.h>

+struct drm_device;

+typedef int (*drm_simple_show_t)(struct seq_file *, void *);

+/**

• • struct drm_simple_info - debugfs file entry
• • This struct represents a debugfs file to be created.
• */

+struct drm_simple_info {

drm_simple_info and drm_simple_info_entry seem to be misnomers. They should probably have some reference to debugfs in their name.

Best regards Thomas

• const char *name;
• drm_simple_show_t show_fn;
• u32 driver_features;
• void *data;

+};

+/**

• • struct drm_simple_info_entry - debugfs list entry
• • This struct is used in tracking requests for new debugfs files
• • to be created.
• */

+struct drm_simple_info_entry {

• struct drm_device *dev;
• struct drm_simple_info file;
• struct list_head list;

+};

+void drm_debugfs_add_file(struct drm_device *dev,

• 	  const char *name,
  

• 	  drm_simple_show_t show_fn,
  

• 	  void *data);
  

+void drm_debugfs_add_files(struct drm_device *dev,

• 	   const struct drm_simple_info *files,
  

• 	   int count);
  

/**

• struct drm_info_list - debugfs info list entry

diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h index a55874db9dd4..b84dfdac27b7 100644 --- a/include/drm/drm_device.h +++ b/include/drm/drm_device.h @@ -326,6 +326,18 @@ struct drm_device { */ struct drm_fb_helper *fb_helper;

• /**

• * @debugfs_mutex:
  

• * Protects debugfs_list access.
  

• */
  

• struct mutex debugfs_mutex;
• /** @debugfs_list:

• * List of debugfs files to add.
  

• * Files are added during drm_dev_register().
  

• */
  

• struct list_head debugfs_list;
• /* Everything below here is for legacy driver, never use! */ /* private: */

#if IS_ENABLED(CONFIG_DRM_LEGACY)