| Message ID | 50223CC5.9060007@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <t.stanislaws@samsung.com> > --- > 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 *);
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 <t.stanislaws@samsung.com> >> --- >> 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 <t.stanislaws@samsung.com> > >> --- > >> 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
Hi Tomasz, On 8 August 2012 19:36, Daniel Vetter <daniel@ffwll.ch> 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 <t.stanislaws@samsung.com> >> >> --- >> >> 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: daniel@ffwll.ch > Mobile: +41 (0)79 365 57 48
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 *);
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 <t.stanislaws@samsung.com> --- 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(-)