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Commit b89e3563 authored by Sumit Semwal's avatar Sumit Semwal
Browse files

dma-buf: Add debugfs support 



Add debugfs support to make it easier to print debug information
about the dma-buf buffers.

Cc: Dave Airlie <airlied@redhat.com>
 [minor fixes on init and warning fix]
Cc: Dan Carpenter <dan.carpenter@oracle.com>
 [remove double unlock in fail case]
Signed-off-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
parent 78df9695

drivers/base/dma-buf.c

+158 −0
Original line number Diff line number Diff line
@@ -27,9 +27,18 @@ 
#include <linux/dma-buf.h>

#include <linux/anon_inodes.h>

#include <linux/export.h>

#include <linux/debugfs.h>

#include <linux/seq_file.h>



static inline int is_dma_buf_file(struct file *);



struct dma_buf_list {

	struct list_head head;

	struct mutex lock;

};



static struct dma_buf_list db_list;



static int dma_buf_release(struct inode *inode, struct file *file)

{

	struct dma_buf *dmabuf;
@@ -42,6 +51,11 @@ static int dma_buf_release(struct inode *inode, struct file *file) 
	BUG_ON(dmabuf->vmapping_counter);



	dmabuf->ops->release(dmabuf);



	mutex_lock(&db_list.lock);

	list_del(&dmabuf->list_node);

	mutex_unlock(&db_list.lock);



	kfree(dmabuf);

	return 0;

}
@@ -125,6 +139,10 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops, 
	mutex_init(&dmabuf->lock);

	INIT_LIST_HEAD(&dmabuf->attachments);



	mutex_lock(&db_list.lock);

	list_add(&dmabuf->list_node, &db_list.head);

	mutex_unlock(&db_list.lock);



	return dmabuf;

}

EXPORT_SYMBOL_GPL(dma_buf_export_named);
@@ -551,3 +569,143 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) 
	mutex_unlock(&dmabuf->lock);

}

EXPORT_SYMBOL_GPL(dma_buf_vunmap);



#ifdef CONFIG_DEBUG_FS

static int dma_buf_describe(struct seq_file *s)

{

	int ret;

	struct dma_buf *buf_obj;

	struct dma_buf_attachment *attach_obj;

	int count = 0, attach_count;

	size_t size = 0;



	ret = mutex_lock_interruptible(&db_list.lock);



	if (ret)

		return ret;



	seq_printf(s, "\nDma-buf Objects:\n");

	seq_printf(s, "\texp_name\tsize\tflags\tmode\tcount\n");



	list_for_each_entry(buf_obj, &db_list.head, list_node) {

		ret = mutex_lock_interruptible(&buf_obj->lock);



		if (ret) {

			seq_printf(s,

				  "\tERROR locking buffer object: skipping\n");

			continue;

		}



		seq_printf(s, "\t");



		seq_printf(s, "\t%s\t%08zu\t%08x\t%08x\t%08ld\n",

				buf_obj->exp_name, buf_obj->size,

				buf_obj->file->f_flags, buf_obj->file->f_mode,

				(long)(buf_obj->file->f_count.counter));



		seq_printf(s, "\t\tAttached Devices:\n");

		attach_count = 0;



		list_for_each_entry(attach_obj, &buf_obj->attachments, node) {

			seq_printf(s, "\t\t");



			seq_printf(s, "%s\n", attach_obj->dev->init_name);

			attach_count++;

		}



		seq_printf(s, "\n\t\tTotal %d devices attached\n",

				attach_count);



		count++;

		size += buf_obj->size;

		mutex_unlock(&buf_obj->lock);

	}



	seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size);



	mutex_unlock(&db_list.lock);

	return 0;

}



static int dma_buf_show(struct seq_file *s, void *unused)

{

	void (*func)(struct seq_file *) = s->private;

	func(s);

	return 0;

}



static int dma_buf_debug_open(struct inode *inode, struct file *file)

{

	return single_open(file, dma_buf_show, inode->i_private);

}



static const struct file_operations dma_buf_debug_fops = {

	.open           = dma_buf_debug_open,

	.read           = seq_read,

	.llseek         = seq_lseek,

	.release        = single_release,

};



static struct dentry *dma_buf_debugfs_dir;



static int dma_buf_init_debugfs(void)

{

	int err = 0;

	dma_buf_debugfs_dir = debugfs_create_dir("dma_buf", NULL);

	if (IS_ERR(dma_buf_debugfs_dir)) {

		err = PTR_ERR(dma_buf_debugfs_dir);

		dma_buf_debugfs_dir = NULL;

		return err;

	}



	err = dma_buf_debugfs_create_file("bufinfo", dma_buf_describe);



	if (err)

		pr_debug("dma_buf: debugfs: failed to create node bufinfo\n");



	return err;

}



static void dma_buf_uninit_debugfs(void)

{

	if (dma_buf_debugfs_dir)

		debugfs_remove_recursive(dma_buf_debugfs_dir);

}



int dma_buf_debugfs_create_file(const char *name,

				int (*write)(struct seq_file *))

{

	struct dentry *d;



	d = debugfs_create_file(name, S_IRUGO, dma_buf_debugfs_dir,

			write, &dma_buf_debug_fops);



	if (IS_ERR(d))

		return PTR_ERR(d);



	return 0;

}

#else

static inline int dma_buf_init_debugfs(void)

{

	return 0;

}

static inline void dma_buf_uninit_debugfs(void)

{

}

#endif



static int __init dma_buf_init(void)

{

	mutex_init(&db_list.lock);

	INIT_LIST_HEAD(&db_list.head);

	dma_buf_init_debugfs();

	return 0;

}

subsys_initcall(dma_buf_init);



static void __exit dma_buf_deinit(void)

{

	dma_buf_uninit_debugfs();

}

__exitcall(dma_buf_deinit);

include/linux/dma-buf.h

+4 −1
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ struct dma_buf_ops { 
 * @attachments: list of dma_buf_attachment that denotes all devices attached.

 * @ops: dma_buf_ops associated with this buffer object.

 * @exp_name: name of the exporter; useful for debugging.

 * @list_node: node for dma_buf accounting and debugging.

 * @priv: exporter specific private data for this buffer object.

 */

struct dma_buf {
@@ -125,6 +126,7 @@ struct dma_buf { 
	unsigned vmapping_counter;

	void *vmap_ptr;

	const char *exp_name;

	struct list_head list_node;

	void *priv;

};
@@ -192,5 +194,6 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, 
		 unsigned long);

void *dma_buf_vmap(struct dma_buf *);

void dma_buf_vunmap(struct dma_buf *, void *vaddr);



int dma_buf_debugfs_create_file(const char *name,

				int (*write)(struct seq_file *));

#endif /* __DMA_BUF_H__ */