This patch adds reference counting on a module that exports dma-buf and
implements its operations. This prevents the module from being unloaded while
DMABUF file is in use.
Signed-off-by: Tomasz Stanislawski <[email protected]>
---
Documentation/dma-buf-sharing.txt | 3 ++-
drivers/base/dma-buf.c | 10 +++++++++-
drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 1 +
drivers/gpu/drm/i915/i915_gem_dmabuf.c | 1 +
drivers/gpu/drm/nouveau/nouveau_prime.c | 1 +
drivers/gpu/drm/radeon/radeon_prime.c | 1 +
drivers/staging/omapdrm/omap_gem_dmabuf.c | 1 +
include/linux/dma-buf.h | 2 ++
8 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt
index ad86fb8..2613057 100644
--- a/Documentation/dma-buf-sharing.txt
+++ b/Documentation/dma-buf-sharing.txt
@@ -49,7 +49,8 @@ The dma_buf buffer sharing API usage contains the following steps:
The buffer exporter announces its wish to export a buffer. In this, it
connects its own private buffer data, provides implementation for operations
that can be performed on the exported dma_buf, and flags for the file
- associated with this buffer.
+ associated with this buffer. The operations structure has owner field.
+ You should initialize this to THIS_MODULE in most cases.
Interface:
struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index c30f3e1..d14b2f5 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -27,6 +27,7 @@
#include <linux/dma-buf.h>
#include <linux/anon_inodes.h>
#include <linux/export.h>
+#include <linux/module.h>
static inline int is_dma_buf_file(struct file *);
@@ -40,6 +41,7 @@ static int dma_buf_release(struct inode *inode, struct file *file)
dmabuf = file->private_data;
dmabuf->ops->release(dmabuf);
+ module_put(dmabuf->ops->owner);
kfree(dmabuf);
return 0;
}
@@ -96,6 +98,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
struct file *file;
if (WARN_ON(!priv || !ops
+ || !ops->owner
|| !ops->map_dma_buf
|| !ops->unmap_dma_buf
|| !ops->release
@@ -105,9 +108,14 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
return ERR_PTR(-EINVAL);
}
+ if (!try_module_get(ops->owner))
+ return ERR_PTR(-ENOENT);
+
dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
- if (dmabuf == NULL)
+ if (dmabuf == NULL) {
+ module_put(ops->owner);
return ERR_PTR(-ENOMEM);
+ }
dmabuf->priv = priv;
dmabuf->ops = ops;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
index 613bf8a..cf3bc6d 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
@@ -164,6 +164,7 @@ static void exynos_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
}
static struct dma_buf_ops exynos_dmabuf_ops = {
+ .owner = THIS_MODULE,
.map_dma_buf = exynos_gem_map_dma_buf,
.unmap_dma_buf = exynos_gem_unmap_dma_buf,
.kmap = exynos_gem_dmabuf_kmap,
diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index aa308e1..07ff03b 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -152,6 +152,7 @@ static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *
}
static const struct dma_buf_ops i915_dmabuf_ops = {
+ .owner = THIS_MODULE,
.map_dma_buf = i915_gem_map_dma_buf,
.unmap_dma_buf = i915_gem_unmap_dma_buf,
.release = i915_gem_dmabuf_release,
diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c b/drivers/gpu/drm/nouveau/nouveau_prime.c
index a25cf2c..8605033 100644
--- a/drivers/gpu/drm/nouveau/nouveau_prime.c
+++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
@@ -127,6 +127,7 @@ static void nouveau_gem_prime_vunmap(struct dma_buf *dma_buf, void *vaddr)
}
static const struct dma_buf_ops nouveau_dmabuf_ops = {
+ .owner = THIS_MODULE,
.map_dma_buf = nouveau_gem_map_dma_buf,
.unmap_dma_buf = nouveau_gem_unmap_dma_buf,
.release = nouveau_gem_dmabuf_release,
diff --git a/drivers/gpu/drm/radeon/radeon_prime.c b/drivers/gpu/drm/radeon/radeon_prime.c
index 6bef46a..4061fd3 100644
--- a/drivers/gpu/drm/radeon/radeon_prime.c
+++ b/drivers/gpu/drm/radeon/radeon_prime.c
@@ -127,6 +127,7 @@ static void radeon_gem_prime_vunmap(struct dma_buf *dma_buf, void *vaddr)
mutex_unlock(&dev->struct_mutex);
}
const static struct dma_buf_ops radeon_dmabuf_ops = {
+ .owner = THIS_MODULE,
.map_dma_buf = radeon_gem_map_dma_buf,
.unmap_dma_buf = radeon_gem_unmap_dma_buf,
.release = radeon_gem_dmabuf_release,
diff --git a/drivers/staging/omapdrm/omap_gem_dmabuf.c b/drivers/staging/omapdrm/omap_gem_dmabuf.c
index 42728e0..6a4dd67 100644
--- a/drivers/staging/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/staging/omapdrm/omap_gem_dmabuf.c
@@ -179,6 +179,7 @@ out_unlock:
}
struct dma_buf_ops omap_dmabuf_ops = {
+ .owner = THIS_MODULE,
.map_dma_buf = omap_gem_map_dma_buf,
.unmap_dma_buf = omap_gem_unmap_dma_buf,
.release = omap_gem_dmabuf_release,
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index eb48f38..22953de 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -37,6 +37,7 @@ struct dma_buf_attachment;
/**
* struct dma_buf_ops - operations possible on struct dma_buf
+ * @owner: the module that implements dma_buf operations
* @attach: [optional] allows different devices to 'attach' themselves to the
* given buffer. It might return -EBUSY to signal that backing storage
* is already allocated and incompatible with the requirements
@@ -70,6 +71,7 @@ struct dma_buf_attachment;
* @vunmap: [optional] unmaps a vmap from the buffer
*/
struct dma_buf_ops {
+ struct module *owner;
int (*attach)(struct dma_buf *, struct device *,
struct dma_buf_attachment *);
--
1.7.9.5
Hi Tomasz,
Thanks for the patch.
On Wednesday 08 August 2012 12:17:41 Tomasz Stanislawski wrote:
> This patch adds reference counting on a module that exports dma-buf and
> implements its operations. This prevents the module from being unloaded
> while DMABUF file is in use.
>
> Signed-off-by: Tomasz Stanislawski <[email protected]>
> ---
> Documentation/dma-buf-sharing.txt | 3 ++-
> drivers/base/dma-buf.c | 10 +++++++++-
> drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 1 +
> drivers/gpu/drm/i915/i915_gem_dmabuf.c | 1 +
> drivers/gpu/drm/nouveau/nouveau_prime.c | 1 +
> drivers/gpu/drm/radeon/radeon_prime.c | 1 +
> drivers/staging/omapdrm/omap_gem_dmabuf.c | 1 +
> include/linux/dma-buf.h | 2 ++
> 8 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/dma-buf-sharing.txt
> b/Documentation/dma-buf-sharing.txt index ad86fb8..2613057 100644
> --- a/Documentation/dma-buf-sharing.txt
> +++ b/Documentation/dma-buf-sharing.txt
> @@ -49,7 +49,8 @@ The dma_buf buffer sharing API usage contains the
> following steps: The buffer exporter announces its wish to export a buffer.
> In this, it connects its own private buffer data, provides implementation
> for operations that can be performed on the exported dma_buf, and flags for
> the file
> - associated with this buffer.
> + associated with this buffer. The operations structure has owner field.
> + You should initialize this to THIS_MODULE in most cases.
>
> Interface:
> struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,
> diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
> index c30f3e1..d14b2f5 100644
> --- a/drivers/base/dma-buf.c
> +++ b/drivers/base/dma-buf.c
> @@ -27,6 +27,7 @@
> #include <linux/dma-buf.h>
> #include <linux/anon_inodes.h>
> #include <linux/export.h>
> +#include <linux/module.h>
>
> static inline int is_dma_buf_file(struct file *);
>
> @@ -40,6 +41,7 @@ static int dma_buf_release(struct inode *inode, struct
> file *file) dmabuf = file->private_data;
>
> dmabuf->ops->release(dmabuf);
> + module_put(dmabuf->ops->owner);
> kfree(dmabuf);
> return 0;
> }
> @@ -96,6 +98,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct
> dma_buf_ops *ops, struct file *file;
>
> if (WARN_ON(!priv || !ops
> + || !ops->owner
THIS_MODULE is defined as ((struct module *)0) when the driver is built-in,
this check should thus be removed.
> || !ops->map_dma_buf
> || !ops->unmap_dma_buf
> || !ops->release
>
> @@ -105,9 +108,14 @@ struct dma_buf *dma_buf_export(void *priv, const struct
> dma_buf_ops *ops, return ERR_PTR(-EINVAL);
> }
>
> + if (!try_module_get(ops->owner))
> + return ERR_PTR(-ENOENT);
> +
> dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL);
> - if (dmabuf == NULL)
> + if (dmabuf == NULL) {
> + module_put(ops->owner);
> return ERR_PTR(-ENOMEM);
> + }
>
> dmabuf->priv = priv;
> dmabuf->ops = ops;
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c index 613bf8a..cf3bc6d 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
> @@ -164,6 +164,7 @@ static void exynos_gem_dmabuf_kunmap(struct dma_buf
> *dma_buf, }
>
> static struct dma_buf_ops exynos_dmabuf_ops = {
> + .owner = THIS_MODULE,
> .map_dma_buf = exynos_gem_map_dma_buf,
> .unmap_dma_buf = exynos_gem_unmap_dma_buf,
> .kmap = exynos_gem_dmabuf_kmap,
> diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> b/drivers/gpu/drm/i915/i915_gem_dmabuf.c index aa308e1..07ff03b 100644
> --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
> @@ -152,6 +152,7 @@ static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf,
> struct vm_area_struct * }
>
> static const struct dma_buf_ops i915_dmabuf_ops = {
> + .owner = THIS_MODULE,
> .map_dma_buf = i915_gem_map_dma_buf,
> .unmap_dma_buf = i915_gem_unmap_dma_buf,
> .release = i915_gem_dmabuf_release,
> diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c
> b/drivers/gpu/drm/nouveau/nouveau_prime.c index a25cf2c..8605033 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_prime.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
> @@ -127,6 +127,7 @@ static void nouveau_gem_prime_vunmap(struct dma_buf
> *dma_buf, void *vaddr) }
>
> static const struct dma_buf_ops nouveau_dmabuf_ops = {
> + .owner = THIS_MODULE,
> .map_dma_buf = nouveau_gem_map_dma_buf,
> .unmap_dma_buf = nouveau_gem_unmap_dma_buf,
> .release = nouveau_gem_dmabuf_release,
> diff --git a/drivers/gpu/drm/radeon/radeon_prime.c
> b/drivers/gpu/drm/radeon/radeon_prime.c index 6bef46a..4061fd3 100644
> --- a/drivers/gpu/drm/radeon/radeon_prime.c
> +++ b/drivers/gpu/drm/radeon/radeon_prime.c
> @@ -127,6 +127,7 @@ static void radeon_gem_prime_vunmap(struct dma_buf
> *dma_buf, void *vaddr) mutex_unlock(&dev->struct_mutex);
> }
> const static struct dma_buf_ops radeon_dmabuf_ops = {
> + .owner = THIS_MODULE,
> .map_dma_buf = radeon_gem_map_dma_buf,
> .unmap_dma_buf = radeon_gem_unmap_dma_buf,
> .release = radeon_gem_dmabuf_release,
> diff --git a/drivers/staging/omapdrm/omap_gem_dmabuf.c
> b/drivers/staging/omapdrm/omap_gem_dmabuf.c index 42728e0..6a4dd67 100644
> --- a/drivers/staging/omapdrm/omap_gem_dmabuf.c
> +++ b/drivers/staging/omapdrm/omap_gem_dmabuf.c
> @@ -179,6 +179,7 @@ out_unlock:
> }
>
> struct dma_buf_ops omap_dmabuf_ops = {
> + .owner = THIS_MODULE,
> .map_dma_buf = omap_gem_map_dma_buf,
> .unmap_dma_buf = omap_gem_unmap_dma_buf,
> .release = omap_gem_dmabuf_release,
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index eb48f38..22953de 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -37,6 +37,7 @@ struct dma_buf_attachment;
>
> /**
> * struct dma_buf_ops - operations possible on struct dma_buf
> + * @owner: the module that implements dma_buf operations
> * @attach: [optional] allows different devices to 'attach' themselves to
> the * given buffer. It might return -EBUSY to signal that backing
> storage * is already allocated and incompatible with the requirements
> @@ -70,6 +71,7 @@ struct dma_buf_attachment;
> * @vunmap: [optional] unmaps a vmap from the buffer
> */
> struct dma_buf_ops {
> + struct module *owner;
> int (*attach)(struct dma_buf *, struct device *,
> struct dma_buf_attachment *);
--
Regards,
Laurent Pinchart
Hi Laurent,
On 08/08/2012 03:35 PM, Laurent Pinchart wrote:
> Hi Tomasz,
>
> Thanks for the patch.
>
> On Wednesday 08 August 2012 12:17:41 Tomasz Stanislawski wrote:
>> This patch adds reference counting on a module that exports dma-buf and
>> implements its operations. This prevents the module from being unloaded
>> while DMABUF file is in use.
>>
>> Signed-off-by: Tomasz Stanislawski <[email protected]>
>> ---
>> Documentation/dma-buf-sharing.txt | 3 ++-
>> drivers/base/dma-buf.c | 10 +++++++++-
>> drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 1 +
>> drivers/gpu/drm/i915/i915_gem_dmabuf.c | 1 +
>> drivers/gpu/drm/nouveau/nouveau_prime.c | 1 +
>> drivers/gpu/drm/radeon/radeon_prime.c | 1 +
>> drivers/staging/omapdrm/omap_gem_dmabuf.c | 1 +
>> include/linux/dma-buf.h | 2 ++
>> 8 files changed, 18 insertions(+), 2 deletions(-)
>>
[snip]
>> @@ -96,6 +98,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct
>> dma_buf_ops *ops, struct file *file;
>>
>> if (WARN_ON(!priv || !ops
>> + || !ops->owner
Thank you for spotting this.
I didn'y know that try_get_module returned true is module was NULL.
BTW. Is it worth to add ".owner = THIS_MODULE," to all dma_buf
exporters in this patch?
Regards,
Tomasz Stanislawski
>
> THIS_MODULE is defined as ((struct module *)0) when the driver is built-in,
> this check should thus be removed.
>
>> || !ops->map_dma_buf
>> || !ops->unmap_dma_buf
>> || !ops->release
>>
On Wed, Aug 08, 2012 at 03:53:10PM +0200, Tomasz Stanislawski wrote:
> Hi Laurent,
>
> On 08/08/2012 03:35 PM, Laurent Pinchart wrote:
> > Hi Tomasz,
> >
> > Thanks for the patch.
> >
> > On Wednesday 08 August 2012 12:17:41 Tomasz Stanislawski wrote:
> >> This patch adds reference counting on a module that exports dma-buf and
> >> implements its operations. This prevents the module from being unloaded
> >> while DMABUF file is in use.
> >>
> >> Signed-off-by: Tomasz Stanislawski <[email protected]>
> >> ---
> >> Documentation/dma-buf-sharing.txt | 3 ++-
> >> drivers/base/dma-buf.c | 10 +++++++++-
> >> drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 1 +
> >> drivers/gpu/drm/i915/i915_gem_dmabuf.c | 1 +
> >> drivers/gpu/drm/nouveau/nouveau_prime.c | 1 +
> >> drivers/gpu/drm/radeon/radeon_prime.c | 1 +
> >> drivers/staging/omapdrm/omap_gem_dmabuf.c | 1 +
> >> include/linux/dma-buf.h | 2 ++
> >> 8 files changed, 18 insertions(+), 2 deletions(-)
> >>
> [snip]
>
> >> @@ -96,6 +98,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct
> >> dma_buf_ops *ops, struct file *file;
> >>
> >> if (WARN_ON(!priv || !ops
> >> + || !ops->owner
>
> Thank you for spotting this.
> I didn'y know that try_get_module returned true is module was NULL.
>
> BTW. Is it worth to add ".owner = THIS_MODULE," to all dma_buf
> exporters in this patch?
Yeah, I think that makes sense. Otherwise it might get lost somewhere,
i.e. you can smash my Ack on this.
-Daniel
--
Daniel Vetter
Mail: [email protected]
Mobile: +41 (0)79 365 57 48
Hi Tomasz,
On 8 August 2012 19:36, Daniel Vetter <[email protected]> wrote:
> On Wed, Aug 08, 2012 at 03:53:10PM +0200, Tomasz Stanislawski wrote:
>> Hi Laurent,
>>
>> On 08/08/2012 03:35 PM, Laurent Pinchart wrote:
>> > Hi Tomasz,
>> >
>> > Thanks for the patch.
Thanks for the patch; may I ask you to split it into 2 patches (1
dma-buf and 1 drm) and submit? That ways, either Dave or I can take
the patches for either pull request.
With that, please feel free to add my Acked-by as well.
>> >
>> > On Wednesday 08 August 2012 12:17:41 Tomasz Stanislawski wrote:
>> >> This patch adds reference counting on a module that exports dma-buf and
>> >> implements its operations. This prevents the module from being unloaded
>> >> while DMABUF file is in use.
>> >>
>> >> Signed-off-by: Tomasz Stanislawski <[email protected]>
>> >> ---
>> >> Documentation/dma-buf-sharing.txt | 3 ++-
>> >> drivers/base/dma-buf.c | 10 +++++++++-
>> >> drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 1 +
>> >> drivers/gpu/drm/i915/i915_gem_dmabuf.c | 1 +
>> >> drivers/gpu/drm/nouveau/nouveau_prime.c | 1 +
>> >> drivers/gpu/drm/radeon/radeon_prime.c | 1 +
>> >> drivers/staging/omapdrm/omap_gem_dmabuf.c | 1 +
>> >> include/linux/dma-buf.h | 2 ++
>> >> 8 files changed, 18 insertions(+), 2 deletions(-)
>> >>
>> [snip]
>>
>> >> @@ -96,6 +98,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct
>> >> dma_buf_ops *ops, struct file *file;
>> >>
>> >> if (WARN_ON(!priv || !ops
>> >> + || !ops->owner
>>
>> Thank you for spotting this.
>> I didn'y know that try_get_module returned true is module was NULL.
>>
>> BTW. Is it worth to add ".owner = THIS_MODULE," to all dma_buf
>> exporters in this patch?
>
> Yeah, I think that makes sense. Otherwise it might get lost somewhere,
> i.e. you can smash my Ack on this.
> -Daniel
> --
> Daniel Vetter
> Mail: [email protected]
> Mobile: +41 (0)79 365 57 48
--
Thanks and regards,
Sumit Semwal.