Re: [PATCH v3] dma-buf: Add a capabilities directory
On Tue, May 31, 2022 at 07:53:50AM -0500, Jason Ekstrand wrote:
> On Mon, 2022-05-30 at 10:26 +0200, Greg KH wrote:
> > On Mon, May 30, 2022 at 08:15:04AM +, Simon Ser wrote:
> > > On Monday, May 30th, 2022 at 09:20, Greg KH
> > > wrote:
> > >
> > > > > > +static struct attribute *dma_buf_caps_attrs[] = {
> > > > > > + _buf_sync_file_import_export_attr.attr,
> > > > > > + NULL,
> > > > > > +};
> > > > > > +
> > > > > > +static const struct attribute_group dma_buf_caps_attr_group
> > > > > > = {
> > > > > > + .attrs = dma_buf_caps_attrs,
> > > > > > +};
> > > > >
> > > > > Didn't we had macros for those? I think I have seen something
> > > > > for that.
> > > >
> > > > Yes, please use ATTRIBUTE_GROUPS()
> > >
> > > This doesn't allow the user to set a group name, and creates an
> > > unused
> > > "_groups" variable, causing warnings.
> >
> > Then set a group name.
> >
> > But you really want to almost always be using lists of groups, which
> > is
> > why that macro works that way.
>
> I think I see the confusion here. The ATTRIBUTE_GROUPS() macro is
> intended for device drivers and to be used with add_device(). However,
> this is dma-buf so there is no device and no add_device() call to hook.
> Unless there are other magic macros to use in this case, I think we're
> stuck doing it manually.
Have a list of attribute groups and add it to the kobject when you
create it so they all get created at the same time.
Don't do piece-meal "add one, and then another, and then another" as
that just gets messy and complex and impossible to unwind the error
conditions from.
sysfs_create_groups() is what you need to use here. I need to drop
sysfs_create_group() one day...
thanks,
greg k-h
Re: [PATCH v3] dma-buf: Add a capabilities directory
On Mon, 2022-05-30 at 10:26 +0200, Greg KH wrote:
> On Mon, May 30, 2022 at 08:15:04AM +, Simon Ser wrote:
> > On Monday, May 30th, 2022 at 09:20, Greg KH
> > wrote:
> >
> > > > > +static struct attribute *dma_buf_caps_attrs[] = {
> > > > > + _buf_sync_file_import_export_attr.attr,
> > > > > + NULL,
> > > > > +};
> > > > > +
> > > > > +static const struct attribute_group dma_buf_caps_attr_group
> > > > > = {
> > > > > + .attrs = dma_buf_caps_attrs,
> > > > > +};
> > > >
> > > > Didn't we had macros for those? I think I have seen something
> > > > for that.
> > >
> > > Yes, please use ATTRIBUTE_GROUPS()
> >
> > This doesn't allow the user to set a group name, and creates an
> > unused
> > "_groups" variable, causing warnings.
>
> Then set a group name.
>
> But you really want to almost always be using lists of groups, which
> is
> why that macro works that way.
I think I see the confusion here. The ATTRIBUTE_GROUPS() macro is
intended for device drivers and to be used with add_device(). However,
this is dma-buf so there is no device and no add_device() call to hook.
Unless there are other magic macros to use in this case, I think we're
stuck doing it manually.
--Jason
> >
> > > > > +
> > > > > +static struct kobject *dma_buf_caps_kobj;
> > > > > +
> > > > > +int dma_buf_init_sysfs_capabilities(struct kset *kset)
> > > > > +{
> > > > > + int ret;
> > > > > +
> > > > > + dma_buf_caps_kobj = kobject_create_and_add("caps",
> > > > > >kobj);
> > > > > + if (!dma_buf_caps_kobj)
> > > > > + return -ENOMEM;
> > > > > +
> > > > > + ret = sysfs_create_group(dma_buf_caps_kobj,
> > > > > _buf_caps_attr_group);
> > >
> > > Why do we have "raw" kobjects here?
> > >
> > > A group can have a name, which puts it in the subdirectory of the
> > > object
> > > it is attached to. Please do that and do not create a new
> > > kobject.
> >
> > I see, I'll switch to sysfs_create_group with a group name in the
> > next version.
>
> No, do not do that, add it to the list of groups for the original
> kobject.
>
> thanks,
>
> greg k-h
Re: [PATCH v3] dma-buf: Add a capabilities directory
On Mon, May 30, 2022 at 08:15:04AM +, Simon Ser wrote:
> On Monday, May 30th, 2022 at 09:20, Greg KH
> wrote:
>
> > > > +static struct attribute *dma_buf_caps_attrs[] = {
> > > > + _buf_sync_file_import_export_attr.attr,
> > > > + NULL,
> > > > +};
> > > > +
> > > > +static const struct attribute_group dma_buf_caps_attr_group = {
> > > > + .attrs = dma_buf_caps_attrs,
> > > > +};
> > >
> > > Didn't we had macros for those? I think I have seen something for that.
> >
> > Yes, please use ATTRIBUTE_GROUPS()
>
> This doesn't allow the user to set a group name, and creates an unused
> "_groups" variable, causing warnings.
Then set a group name.
But you really want to almost always be using lists of groups, which is
why that macro works that way.
>
> > > > +
> > > > +static struct kobject *dma_buf_caps_kobj;
> > > > +
> > > > +int dma_buf_init_sysfs_capabilities(struct kset *kset)
> > > > +{
> > > > + int ret;
> > > > +
> > > > + dma_buf_caps_kobj = kobject_create_and_add("caps", >kobj);
> > > > + if (!dma_buf_caps_kobj)
> > > > + return -ENOMEM;
> > > > +
> > > > + ret = sysfs_create_group(dma_buf_caps_kobj,
> > > > _buf_caps_attr_group);
> >
> > Why do we have "raw" kobjects here?
> >
> > A group can have a name, which puts it in the subdirectory of the object
> > it is attached to. Please do that and do not create a new kobject.
>
> I see, I'll switch to sysfs_create_group with a group name in the next
> version.
No, do not do that, add it to the list of groups for the original
kobject.
thanks,
greg k-h
Re: [PATCH v3] dma-buf: Add a capabilities directory
On Monday, May 30th, 2022 at 09:20, Greg KH wrote:
> > > +static struct attribute *dma_buf_caps_attrs[] = {
> > > + _buf_sync_file_import_export_attr.attr,
> > > + NULL,
> > > +};
> > > +
> > > +static const struct attribute_group dma_buf_caps_attr_group = {
> > > + .attrs = dma_buf_caps_attrs,
> > > +};
> >
> > Didn't we had macros for those? I think I have seen something for that.
>
> Yes, please use ATTRIBUTE_GROUPS()
This doesn't allow the user to set a group name, and creates an unused
"_groups" variable, causing warnings.
> > > +
> > > +static struct kobject *dma_buf_caps_kobj;
> > > +
> > > +int dma_buf_init_sysfs_capabilities(struct kset *kset)
> > > +{
> > > + int ret;
> > > +
> > > + dma_buf_caps_kobj = kobject_create_and_add("caps", >kobj);
> > > + if (!dma_buf_caps_kobj)
> > > + return -ENOMEM;
> > > +
> > > + ret = sysfs_create_group(dma_buf_caps_kobj, _buf_caps_attr_group);
>
> Why do we have "raw" kobjects here?
>
> A group can have a name, which puts it in the subdirectory of the object
> it is attached to. Please do that and do not create a new kobject.
I see, I'll switch to sysfs_create_group with a group name in the next version.
Thanks for the pointers!
Re: [PATCH v3] dma-buf: Add a capabilities directory
On Monday, May 30th, 2022 at 09:09, Christian König wrote: > I find a separate directory rather unusual, but can't come up with any > better idea either. > > IIRC the security module had a mask file with names for the supported > capabilities. Are you referring to /sys/kernel/security/lsm? This sounds more painful to parse from user-space. Instead of a simple stat(), user-space would need to read the file, split on commas, and compare strings.
Re: [PATCH v3] dma-buf: Add a capabilities directory
On Mon, May 30, 2022 at 09:09:30AM +0200, Christian König wrote:
> Am 27.05.22 um 09:34 schrieb Simon Ser:
> > To discover support for new DMA-BUF IOCTLs, user-space has no
> > choice but to try to perform the IOCTL on an existing DMA-BUF.
> > However, user-space may want to figure out whether or not the
> > IOCTL is available before it has a DMA-BUF at hand, e.g. at
> > initialization time in a Wayland compositor.
> >
> > Add a /sys/kernel/dmabuf/caps directory which allows the DMA-BUF
> > subsystem to advertise supported features. Add a
> > sync_file_import_export entry which indicates that importing and
> > exporting sync_files from/to DMA-BUFs is supported.
>
> I find a separate directory rather unusual, but can't come up with any
> better idea either.
>
> IIRC the security module had a mask file with names for the supported
> capabilities.
>
> >
> > v2: Add missing files lost in a rebase
> >
> > v3:
> > - Create separate file in Documentation/ABI/testing/, add it to
> >MAINTAINERS
> > - Fix kernel version (Daniel)
> > - Remove unnecessary brackets (Jason)
> > - Fix SPDX comment style
> >
> > Signed-off-by: Simon Ser
> > Reviewed-by: Jason Ekstrand
> > Cc: Daniel Vetter
> > Cc: Bas Nieuwenhuizen
> > Cc: Christian König
> > Cc: Greg KH
> > ---
> > .../ABI/testing/sysfs-kernel-dmabuf-caps | 13 +
> > MAINTAINERS | 1 +
> > drivers/dma-buf/Makefile | 2 +-
> > drivers/dma-buf/dma-buf-sysfs-caps.c | 51 +++
> > drivers/dma-buf/dma-buf-sysfs-caps.h | 16 ++
> > drivers/dma-buf/dma-buf-sysfs-stats.c | 16 ++
> > drivers/dma-buf/dma-buf-sysfs-stats.h | 6 ++-
> > drivers/dma-buf/dma-buf.c | 43 ++--
> > include/uapi/linux/dma-buf.h | 6 +++
> > 9 files changed, 134 insertions(+), 20 deletions(-)
> > create mode 100644 Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
> > create mode 100644 drivers/dma-buf/dma-buf-sysfs-caps.c
> > create mode 100644 drivers/dma-buf/dma-buf-sysfs-caps.h
> >
> > diff --git a/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
> > b/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
> > new file mode 100644
> > index ..f83af422fd18
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
> > @@ -0,0 +1,13 @@
> > +What: /sys/kernel/dmabuf/caps
> > +Date: May 2022
> > +KernelVersion: v5.20
> > +Contact: Simon Ser
> > +Description: This directory advertises DMA-BUF capabilities
> > supported by the
> > + kernel.
> > +
> > +What: /sys/kernel/dmabuf/caps/sync_file_import_export
> > +Date: May 2022
> > +KernelVersion: v5.20
> > +Contact: Simon Ser
> > +Description: This file is read-only and advertises support for
> > importing and
> > + exporting sync_files from/to DMA-BUFs.
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 11da16bfa123..8966686f7231 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -5871,6 +5871,7 @@ L:dri-devel@lists.freedesktop.org
> > L:linaro-mm-...@lists.linaro.org (moderated for non-subscribers)
> > S:Maintained
> > T:git git://anongit.freedesktop.org/drm/drm-misc
> > +F: Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
> > F:Documentation/driver-api/dma-buf.rst
> > F:drivers/dma-buf/
> > F:include/linux/*fence.h
> > diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
> > index 4c9eb53ba3f8..afc874272710 100644
> > --- a/drivers/dma-buf/Makefile
> > +++ b/drivers/dma-buf/Makefile
> > @@ -1,6 +1,6 @@
> > # SPDX-License-Identifier: GPL-2.0-only
> > obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
> > -dma-resv.o
> > +dma-resv.o dma-buf-sysfs-caps.o
> > obj-$(CONFIG_DMABUF_HEAPS)+= dma-heap.o
> > obj-$(CONFIG_DMABUF_HEAPS)+= heaps/
> > obj-$(CONFIG_SYNC_FILE) += sync_file.o
> > diff --git a/drivers/dma-buf/dma-buf-sysfs-caps.c
> > b/drivers/dma-buf/dma-buf-sysfs-caps.c
> > new file mode 100644
> > index ..82b91eb874a9
> > --- /dev/null
> > +++ b/drivers/dma-buf/dma-buf-sysfs-caps.c
> > @@ -0,0 +1,51 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * DMA-BUF sysfs capabilities.
> > + *
> > + * Copyright (C) 2022 Simon Ser
> > + */
> > +
> > +#include
> > +#include
> > +
> > +#include "dma-buf-sysfs-caps.h"
> > +
> > +static ssize_t sync_file_import_export_show(struct kobject *kobj,
> > + struct kobj_attribute *attr,
> > + char *buf)
> > +{
> > + return sysfs_emit(buf, "1\n");
> > +}
> > +
> > +static struct kobj_attribute dma_buf_sync_file_import_export_attr =
> > + __ATTR_RO(sync_file_import_export);
> > +
> > +static struct attribute *dma_buf_caps_attrs[] = {
> > +
Re: [PATCH v3] dma-buf: Add a capabilities directory
Am 27.05.22 um 09:34 schrieb Simon Ser:
To discover support for new DMA-BUF IOCTLs, user-space has no
choice but to try to perform the IOCTL on an existing DMA-BUF.
However, user-space may want to figure out whether or not the
IOCTL is available before it has a DMA-BUF at hand, e.g. at
initialization time in a Wayland compositor.
Add a /sys/kernel/dmabuf/caps directory which allows the DMA-BUF
subsystem to advertise supported features. Add a
sync_file_import_export entry which indicates that importing and
exporting sync_files from/to DMA-BUFs is supported.
I find a separate directory rather unusual, but can't come up with any
better idea either.
IIRC the security module had a mask file with names for the supported
capabilities.
v2: Add missing files lost in a rebase
v3:
- Create separate file in Documentation/ABI/testing/, add it to
MAINTAINERS
- Fix kernel version (Daniel)
- Remove unnecessary brackets (Jason)
- Fix SPDX comment style
Signed-off-by: Simon Ser
Reviewed-by: Jason Ekstrand
Cc: Daniel Vetter
Cc: Bas Nieuwenhuizen
Cc: Christian König
Cc: Greg KH
---
.../ABI/testing/sysfs-kernel-dmabuf-caps | 13 +
MAINTAINERS | 1 +
drivers/dma-buf/Makefile | 2 +-
drivers/dma-buf/dma-buf-sysfs-caps.c | 51 +++
drivers/dma-buf/dma-buf-sysfs-caps.h | 16 ++
drivers/dma-buf/dma-buf-sysfs-stats.c | 16 ++
drivers/dma-buf/dma-buf-sysfs-stats.h | 6 ++-
drivers/dma-buf/dma-buf.c | 43 ++--
include/uapi/linux/dma-buf.h | 6 +++
9 files changed, 134 insertions(+), 20 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
create mode 100644 drivers/dma-buf/dma-buf-sysfs-caps.c
create mode 100644 drivers/dma-buf/dma-buf-sysfs-caps.h
diff --git a/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
b/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
new file mode 100644
index ..f83af422fd18
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
@@ -0,0 +1,13 @@
+What: /sys/kernel/dmabuf/caps
+Date: May 2022
+KernelVersion: v5.20
+Contact: Simon Ser
+Description: This directory advertises DMA-BUF capabilities supported by the
+ kernel.
+
+What: /sys/kernel/dmabuf/caps/sync_file_import_export
+Date: May 2022
+KernelVersion: v5.20
+Contact: Simon Ser
+Description: This file is read-only and advertises support for importing and
+ exporting sync_files from/to DMA-BUFs.
diff --git a/MAINTAINERS b/MAINTAINERS
index 11da16bfa123..8966686f7231 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5871,6 +5871,7 @@ L:dri-devel@lists.freedesktop.org
L:linaro-mm-...@lists.linaro.org (moderated for non-subscribers)
S:Maintained
T:git git://anongit.freedesktop.org/drm/drm-misc
+F: Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
F:Documentation/driver-api/dma-buf.rst
F:drivers/dma-buf/
F:include/linux/*fence.h
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index 4c9eb53ba3f8..afc874272710 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
-dma-resv.o
+dma-resv.o dma-buf-sysfs-caps.o
obj-$(CONFIG_DMABUF_HEAPS)+= dma-heap.o
obj-$(CONFIG_DMABUF_HEAPS)+= heaps/
obj-$(CONFIG_SYNC_FILE) += sync_file.o
diff --git a/drivers/dma-buf/dma-buf-sysfs-caps.c
b/drivers/dma-buf/dma-buf-sysfs-caps.c
new file mode 100644
index ..82b91eb874a9
--- /dev/null
+++ b/drivers/dma-buf/dma-buf-sysfs-caps.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DMA-BUF sysfs capabilities.
+ *
+ * Copyright (C) 2022 Simon Ser
+ */
+
+#include
+#include
+
+#include "dma-buf-sysfs-caps.h"
+
+static ssize_t sync_file_import_export_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sysfs_emit(buf, "1\n");
+}
+
+static struct kobj_attribute dma_buf_sync_file_import_export_attr =
+ __ATTR_RO(sync_file_import_export);
+
+static struct attribute *dma_buf_caps_attrs[] = {
+ _buf_sync_file_import_export_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group dma_buf_caps_attr_group = {
+ .attrs = dma_buf_caps_attrs,
+};
Didn't we had macros for those? I think I have seen something for that.
Apart from those two random thoughts looks good to me as well.
Regards,
Christian.
+
+static struct kobject *dma_buf_caps_kobj;
+
+int dma_buf_init_sysfs_capabilities(struct kset *kset)
+{
+ int ret;
+
+ dma_buf_caps_kobj = kobject_create_and_add("caps", >kobj);
+ if (!dma_buf_caps_kobj)
+
[PATCH v3] dma-buf: Add a capabilities directory
To discover support for new DMA-BUF IOCTLs, user-space has no
choice but to try to perform the IOCTL on an existing DMA-BUF.
However, user-space may want to figure out whether or not the
IOCTL is available before it has a DMA-BUF at hand, e.g. at
initialization time in a Wayland compositor.
Add a /sys/kernel/dmabuf/caps directory which allows the DMA-BUF
subsystem to advertise supported features. Add a
sync_file_import_export entry which indicates that importing and
exporting sync_files from/to DMA-BUFs is supported.
v2: Add missing files lost in a rebase
v3:
- Create separate file in Documentation/ABI/testing/, add it to
MAINTAINERS
- Fix kernel version (Daniel)
- Remove unnecessary brackets (Jason)
- Fix SPDX comment style
Signed-off-by: Simon Ser
Reviewed-by: Jason Ekstrand
Cc: Daniel Vetter
Cc: Bas Nieuwenhuizen
Cc: Christian König
Cc: Greg KH
---
.../ABI/testing/sysfs-kernel-dmabuf-caps | 13 +
MAINTAINERS | 1 +
drivers/dma-buf/Makefile | 2 +-
drivers/dma-buf/dma-buf-sysfs-caps.c | 51 +++
drivers/dma-buf/dma-buf-sysfs-caps.h | 16 ++
drivers/dma-buf/dma-buf-sysfs-stats.c | 16 ++
drivers/dma-buf/dma-buf-sysfs-stats.h | 6 ++-
drivers/dma-buf/dma-buf.c | 43 ++--
include/uapi/linux/dma-buf.h | 6 +++
9 files changed, 134 insertions(+), 20 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
create mode 100644 drivers/dma-buf/dma-buf-sysfs-caps.c
create mode 100644 drivers/dma-buf/dma-buf-sysfs-caps.h
diff --git a/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
b/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
new file mode 100644
index ..f83af422fd18
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
@@ -0,0 +1,13 @@
+What: /sys/kernel/dmabuf/caps
+Date: May 2022
+KernelVersion: v5.20
+Contact: Simon Ser
+Description: This directory advertises DMA-BUF capabilities supported by the
+ kernel.
+
+What: /sys/kernel/dmabuf/caps/sync_file_import_export
+Date: May 2022
+KernelVersion: v5.20
+Contact: Simon Ser
+Description: This file is read-only and advertises support for importing and
+ exporting sync_files from/to DMA-BUFs.
diff --git a/MAINTAINERS b/MAINTAINERS
index 11da16bfa123..8966686f7231 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5871,6 +5871,7 @@ L:dri-devel@lists.freedesktop.org
L: linaro-mm-...@lists.linaro.org (moderated for non-subscribers)
S: Maintained
T: git git://anongit.freedesktop.org/drm/drm-misc
+F: Documentation/ABI/testing/sysfs-kernel-dmabuf-caps
F: Documentation/driver-api/dma-buf.rst
F: drivers/dma-buf/
F: include/linux/*fence.h
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index 4c9eb53ba3f8..afc874272710 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-y := dma-buf.o dma-fence.o dma-fence-array.o dma-fence-chain.o \
-dma-resv.o
+dma-resv.o dma-buf-sysfs-caps.o
obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o
obj-$(CONFIG_DMABUF_HEAPS) += heaps/
obj-$(CONFIG_SYNC_FILE)+= sync_file.o
diff --git a/drivers/dma-buf/dma-buf-sysfs-caps.c
b/drivers/dma-buf/dma-buf-sysfs-caps.c
new file mode 100644
index ..82b91eb874a9
--- /dev/null
+++ b/drivers/dma-buf/dma-buf-sysfs-caps.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DMA-BUF sysfs capabilities.
+ *
+ * Copyright (C) 2022 Simon Ser
+ */
+
+#include
+#include
+
+#include "dma-buf-sysfs-caps.h"
+
+static ssize_t sync_file_import_export_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sysfs_emit(buf, "1\n");
+}
+
+static struct kobj_attribute dma_buf_sync_file_import_export_attr =
+ __ATTR_RO(sync_file_import_export);
+
+static struct attribute *dma_buf_caps_attrs[] = {
+ _buf_sync_file_import_export_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group dma_buf_caps_attr_group = {
+ .attrs = dma_buf_caps_attrs,
+};
+
+static struct kobject *dma_buf_caps_kobj;
+
+int dma_buf_init_sysfs_capabilities(struct kset *kset)
+{
+ int ret;
+
+ dma_buf_caps_kobj = kobject_create_and_add("caps", >kobj);
+ if (!dma_buf_caps_kobj)
+ return -ENOMEM;
+
+ ret = sysfs_create_group(dma_buf_caps_kobj, _buf_caps_attr_group);
+ if (ret)
+ kobject_put(dma_buf_caps_kobj);
+ return ret;
+}
+
+void dma_buf_uninit_sysfs_capabilities(void)
+{
+ kobject_put(dma_buf_caps_kobj);
+}
diff --git a/drivers/dma-buf/dma-buf-sysfs-caps.h
b/drivers/dma-buf/dma-buf-sysfs-caps.h
new file mode 100644
