The patch series adds a much-missed support for debugfs to dma-buf framework.
Based on the feedback received on v1 of this patch series, support is also added to allow exporters to provide name-strings that will prove useful while debugging.
Some more magic can be added for more advanced debugging, but we'll leave that for the time being.
Best regards, ~Sumit.
--- changes since v2: (based on review comments from Laurent Pinchart) - reordered functions to avoid forward declaration - added __exitcall for dma_buf_deinit()
changes since v1: - added patch to replace dma_buf_export() with dma_buf_export_named(), per suggestion from Daniel Vetter. - fixes on init and warnings as reported and corrected by Dave Airlie. - added locking while walking attachment list - reported by Daniel Vetter.
Sumit Semwal (2): dma-buf: replace dma_buf_export() with dma_buf_export_named() dma-buf: Add debugfs support
Documentation/dma-buf-sharing.txt | 13 ++- drivers/base/dma-buf.c | 170 ++++++++++++++++++++++++++++++++++++- include/linux/dma-buf.h | 16 +++- 3 files changed, 190 insertions(+), 9 deletions(-)
For debugging purposes, it is useful to have a name-string added while exporting buffers. Hence, dma_buf_export() is replaced with dma_buf_export_named(), which additionally takes 'exp_name' as a parameter.
For backward compatibility, and for lazy exporters who don't wish to name themselves, a #define dma_buf_export() is also made available, which adds a __FILE__ instead of 'exp_name'.
Cc: Daniel Vetter daniel.vetter@ffwll.ch [Thanks for the idea!] Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch Signed-off-by: Sumit Semwal sumit.semwal@linaro.org --- Documentation/dma-buf-sharing.txt | 13 +++++++++++-- drivers/base/dma-buf.c | 11 +++++++---- include/linux/dma-buf.h | 11 +++++++++-- 3 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt index 4966b1b..0b23261 100644 --- a/Documentation/dma-buf-sharing.txt +++ b/Documentation/dma-buf-sharing.txt @@ -52,14 +52,23 @@ The dma_buf buffer sharing API usage contains the following steps: associated with this buffer.
Interface: - struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops, - size_t size, int flags) + struct dma_buf *dma_buf_export_named(void *priv, struct dma_buf_ops *ops, + size_t size, int flags, + const char *exp_name)
If this succeeds, dma_buf_export allocates a dma_buf structure, and returns a pointer to the same. It also associates an anonymous file with this buffer, so it can be exported. On failure to allocate the dma_buf object, it returns NULL.
+ 'exp_name' is the name of exporter - to facilitate information while + debugging. + + Exporting modules which do not wish to provide any specific name may use the + helper define 'dma_buf_export()', with the same arguments as above, but + without the last argument; a __FILE__ pre-processor directive will be + inserted in place of 'exp_name' instead. + 2. Userspace gets a handle to pass around to potential buffer-users
Userspace entity requests for a file-descriptor (fd) which is a handle to the diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index 2a7cb0d..d89102a 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -77,22 +77,24 @@ static inline int is_dma_buf_file(struct file *file) }
/** - * dma_buf_export - Creates a new dma_buf, and associates an anon file + * dma_buf_export_named - Creates a new dma_buf, and associates an anon file * with this buffer, so it can be exported. * Also connect the allocator specific data and ops to the buffer. + * Additionally, provide a name string for exporter; useful in debugging. * * @priv: [in] Attach private data of allocator to this buffer * @ops: [in] Attach allocator-defined dma buf ops to the new buffer. * @size: [in] Size of the buffer * @flags: [in] mode flags for the file. + * @exp_name: [in] name of the exporting module - useful for debugging. * * Returns, on success, a newly created dma_buf object, which wraps the * supplied private data and operations for dma_buf_ops. On either missing * ops, or error in allocating struct dma_buf, will return negative error. * */ -struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, - size_t size, int flags) +struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops, + size_t size, int flags, const char *exp_name) { struct dma_buf *dmabuf; struct file *file; @@ -114,6 +116,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, dmabuf->priv = priv; dmabuf->ops = ops; dmabuf->size = size; + dmabuf->exp_name = exp_name;
file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
@@ -124,7 +127,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
return dmabuf; } -EXPORT_SYMBOL_GPL(dma_buf_export); +EXPORT_SYMBOL_GPL(dma_buf_export_named);
/** diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 9978b61..6f55c04 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -112,6 +112,7 @@ struct dma_buf_ops { * @file: file pointer used for sharing buffers across, and for refcounting. * @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. * @priv: exporter specific private data for this buffer object. */ struct dma_buf { @@ -123,6 +124,7 @@ struct dma_buf { struct mutex lock; unsigned vmapping_counter; void *vmap_ptr; + const char *exp_name; void *priv; };
@@ -162,8 +164,13 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, struct device *dev); void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *dmabuf_attach); -struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, - size_t size, int flags); + +struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops, + size_t size, int flags, const char *); + +#define dma_buf_export(priv, ops, size, flags) \ + dma_buf_export_named(priv, ops, size, flags, __FILE__) + int dma_buf_fd(struct dma_buf *dmabuf, int flags); struct dma_buf *dma_buf_get(int fd); void dma_buf_put(struct dma_buf *dmabuf);
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] Signed-off-by: Sumit Semwal sumit.semwal@linaro.org --- changes since v2: (based on review comments from Laurent Pinchart) - reordered functions to avoid forward declaration - added __exitcall for dma_buf_deinit()
changes since v1: - fixes on init and warnings as reported and corrected by Dave Airlie. - add locking while walking attachment list - reported by Daniel Vetter. --- drivers/base/dma-buf.c | 159 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 5 +- 2 files changed, 163 insertions(+), 1 deletion(-)
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index d89102a..466476f 100644 --- 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 +569,144 @@ 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"); + goto skip_buffer; + } + + seq_printf(s, "\t"); + + seq_printf(s, "\t%s\t%08zu\t%08x\t%08x\t%08d\n", + buf_obj->exp_name, buf_obj->size, + buf_obj->file->f_flags, buf_obj->file->f_mode, + 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; +skip_buffer: + 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 6f55c04..dfac5ed 100644 --- 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__ */
Hi All,
On 4 April 2013 11:58, Sumit Semwal sumit.semwal@linaro.org wrote:
The patch series adds a much-missed support for debugfs to dma-buf framework.
Based on the feedback received on v1 of this patch series, support is also added to allow exporters to provide name-strings that will prove useful while debugging.
Since there're no more comments, I'll add this to my for-next, to queue it up for 3.10.
Best regards, ~Sumit.
Some more magic can be added for more advanced debugging, but we'll leave that for the time being.
Best regards, ~Sumit.
changes since v2: (based on review comments from Laurent Pinchart)
- reordered functions to avoid forward declaration
- added __exitcall for dma_buf_deinit()
changes since v1:
- added patch to replace dma_buf_export() with dma_buf_export_named(), per suggestion from Daniel Vetter.
- fixes on init and warnings as reported and corrected by Dave Airlie.
- added locking while walking attachment list - reported by Daniel Vetter.
Sumit Semwal (2): dma-buf: replace dma_buf_export() with dma_buf_export_named() dma-buf: Add debugfs support
Documentation/dma-buf-sharing.txt | 13 ++- drivers/base/dma-buf.c | 170 ++++++++++++++++++++++++++++++++++++- include/linux/dma-buf.h | 16 +++- 3 files changed, 190 insertions(+), 9 deletions(-)
-- 1.7.10.4
-- Thanks and regards,
Sumit Semwal
Linaro Kernel Engineer - Graphics working group
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
linaro-kernel@lists.linaro.org
-
Sumit Semwal