[PATCH 1/2] drm/debugfs: allow driver to provide a custom read callback

[j.glisse at gmail.com]

From: Jerome Glisse <jglisse at redhat.com>

Allow driver to provide a custom read callback for debugfs file.
Usefull if driver try to dump big buffer, avoid double buffering.

Signed-off-by: Jerome Glisse <jglisse at redhat.com>
---
 drivers/gpu/drm/drm_debugfs.c             |   19 ++++++++++++++++---
 drivers/gpu/drm/i915/i915_debugfs.c       |    2 +-
 drivers/gpu/drm/nouveau/nouveau_debugfs.c |    4 ++--
 drivers/gpu/drm/radeon/radeon_device.c    |    4 ++--
 include/drm/drmP.h                        |    8 +++++++-
 5 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index 1c7a1c0..d5194e6 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -63,11 +63,22 @@ static int drm_debugfs_open(struct inode *inode, struct file *file)
 	return single_open(file, node->info_ent->show, node);
 }
 
+static ssize_t drm_debugfs_read(struct file *filp, char __user *ubuf,
+				size_t max, loff_t *ppos)
+{
+	struct seq_file *m = filp->private_data;
+	struct drm_info_node *node = (struct drm_info_node *) m->private;
+
+	if (node->read) {
+		return node->read(filp, ubuf, max, ppos);
+	}
+	return seq_read(filp, ubuf, max, ppos);
+}
 
 static const struct file_operations drm_debugfs_fops = {
 	.owner = THIS_MODULE,
 	.open = drm_debugfs_open,
-	.read = seq_read,
+	.read = drm_debugfs_read,
 	.llseek = seq_lseek,
 	.release = single_release,
 };
@@ -86,7 +97,8 @@ static const struct file_operations drm_debugfs_fops = {
  * gdm_debugfs_lists in the given root directory.
  */
 int drm_debugfs_create_files(struct drm_info_list *files, int count,
-			     struct dentry *root, struct drm_minor *minor)
+			     struct dentry *root, struct drm_minor *minor,
+			     drm_debugfs_read_t read)
 {
 	struct drm_device *dev = minor->dev;
 	struct dentry *ent;
@@ -118,6 +130,7 @@ int drm_debugfs_create_files(struct drm_info_list *files, int count,
 		tmp->minor = minor;
 		tmp->dent = ent;
 		tmp->info_ent = &files[i];
+		tmp->read = read;
 
 		mutex_lock(&minor->debugfs_lock);
 		list_add(&tmp->list, &minor->debugfs_list);
@@ -159,7 +172,7 @@ int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 	}
 
 	ret = drm_debugfs_create_files(drm_debugfs_list, DRM_DEBUGFS_ENTRIES,
-				       minor->debugfs_root, minor);
+				       minor->debugfs_root, minor, NULL);
 	if (ret) {
 		debugfs_remove(minor->debugfs_root);
 		minor->debugfs_root = NULL;
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 950f72a..636c4f4 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2018,7 +2018,7 @@ int i915_debugfs_init(struct drm_minor *minor)
 
 	return drm_debugfs_create_files(i915_debugfs_list,
 					I915_DEBUGFS_ENTRIES,
-					minor->debugfs_root, minor);
+					minor->debugfs_root, minor, NULL);
 }
 
 void i915_debugfs_cleanup(struct drm_minor *minor)
diff --git a/drivers/gpu/drm/nouveau/nouveau_debugfs.c b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
index fa2ec49..12cbc5c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_debugfs.c
+++ b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
@@ -94,7 +94,7 @@ nouveau_debugfs_channel_init(struct nouveau_channel *chan)
 
 	ret = drm_debugfs_create_files(&chan->debugfs.info, 1,
 				       dev_priv->debugfs.channel_root,
-				       chan->dev->primary);
+				       chan->dev->primary, NULL);
 	if (ret == 0)
 		chan->debugfs.active = true;
 	return ret;
@@ -186,7 +186,7 @@ int
 nouveau_debugfs_init(struct drm_minor *minor)
 {
 	drm_debugfs_create_files(nouveau_debugfs_list, NOUVEAU_DEBUGFS_ENTRIES,
-				 minor->debugfs_root, minor);
+				 minor->debugfs_root, minor, NULL);
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 3d41525..944ac11 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1039,10 +1039,10 @@ int radeon_debugfs_add_files(struct radeon_device *rdev,
 #if defined(CONFIG_DEBUG_FS)
 	drm_debugfs_create_files(files, nfiles,
 				 rdev->ddev->control->debugfs_root,
-				 rdev->ddev->control);
+				 rdev->ddev->control, NULL);
 	drm_debugfs_create_files(files, nfiles,
 				 rdev->ddev->primary->debugfs_root,
-				 rdev->ddev->primary);
+				 rdev->ddev->primary, NULL);
 #endif
 	return 0;
 }
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index efd1249..1e41407 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1011,6 +1011,8 @@ struct drm_info_node {
 	struct drm_minor *minor;
 	struct drm_info_list *info_ent;
 	struct dentry *dent;
+	/* read callback */
+	ssize_t (*read)(struct file *filp, char __user *ubuf,size_t max, loff_t *ppos);
 };
 
 /**
@@ -1528,10 +1530,14 @@ extern int drm_proc_cleanup(struct drm_minor *minor, struct proc_dir_entry *root
 
 				/* Debugfs support */
 #if defined(CONFIG_DEBUG_FS)
+typedef ssize_t (drm_debugfs_read_t)(struct file *filp, char __user *ubuf,
+				     size_t max, loff_t *ppos);
+
 extern int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 			    struct dentry *root);
 extern int drm_debugfs_create_files(struct drm_info_list *files, int count,
-				    struct dentry *root, struct drm_minor *minor);
+				    struct dentry *root, struct drm_minor *minor,
+				    drm_debugfs_read_t read);
 extern int drm_debugfs_remove_files(struct drm_info_list *files, int count,
                                     struct drm_minor *minor);
 extern int drm_debugfs_cleanup(struct drm_minor *minor);
-- 
1.7.7.6