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: Sumit Semwal <sumit.semwal@linaro.org>

diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index d89102a29f65079028a22ea2d786404ce77d3668..08fe897c0b4cfcdc4c2eed939870cf46ddf57735 100644 (file)
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -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);

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 6f55c0424f120610ac700ad3663743f98eabec42..dfac5ed311205d2469628273b161e4008fcfcbfb 100644 (file)
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -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__ */