| Message ID | 20230529223935.2672495-7-dmitry.osipenko@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Move dma-buf mmap() reservation locking down to exporters | expand |
Hi Dmitry, On Tue, 30 May 2023 01:39:35 +0300 Dmitry Osipenko <dmitry.osipenko@collabora.com> wrote: > Replace all drm-shmem locks with a GEM reservation lock. This makes locks > consistent with dma-buf locking convention where importers are responsible > for holding reservation lock for all operations performed over dma-bufs, > preventing deadlock between dma-buf importers and exporters. I've rebased some of my work on drm-misc-next this morning and noticed that the drm_gem_shmem_get_pages() I was using to pin pages no longer exists, so I ended looking at this patch to check what I should use instead, and I have a few questions/comments. > > Suggested-by: Daniel Vetter <daniel@ffwll.ch> > Acked-by: Thomas Zimmermann <tzimmermann@suse.de> > Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> > Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 210 ++++++++---------- > drivers/gpu/drm/lima/lima_gem.c | 8 +- > drivers/gpu/drm/panfrost/panfrost_drv.c | 7 +- > .../gpu/drm/panfrost/panfrost_gem_shrinker.c | 6 +- > drivers/gpu/drm/panfrost/panfrost_mmu.c | 19 +- > include/drm/drm_gem_shmem_helper.h | 14 +- > 6 files changed, 116 insertions(+), 148 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 4ea6507a77e5..a783d2245599 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -88,8 +88,6 @@ __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private) > if (ret) > goto err_release; > > - mutex_init(&shmem->pages_lock); > - mutex_init(&shmem->vmap_lock); > INIT_LIST_HEAD(&shmem->madv_list); > > if (!private) { > @@ -141,11 +139,13 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) > { > struct drm_gem_object *obj = &shmem->base; > > - drm_WARN_ON(obj->dev, shmem->vmap_use_count); > - > if (obj->import_attach) { > drm_prime_gem_destroy(obj, shmem->sgt); > } else { > + dma_resv_lock(shmem->base.resv, NULL); > + > + drm_WARN_ON(obj->dev, shmem->vmap_use_count); > + > if (shmem->sgt) { > dma_unmap_sgtable(obj->dev->dev, shmem->sgt, > DMA_BIDIRECTIONAL, 0); > @@ -154,22 +154,24 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) > } > if (shmem->pages) > drm_gem_shmem_put_pages(shmem); > - } > > - drm_WARN_ON(obj->dev, shmem->pages_use_count); > + drm_WARN_ON(obj->dev, shmem->pages_use_count); > + > + dma_resv_unlock(shmem->base.resv); > + } > > drm_gem_object_release(obj); > - mutex_destroy(&shmem->pages_lock); > - mutex_destroy(&shmem->vmap_lock); > kfree(shmem); > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_free); > > -static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) > +static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem) I find this name change confusing, because the function requires the GEM resv lock to be held, and the _locked suffix was making it pretty clear. > { > struct drm_gem_object *obj = &shmem->base; > struct page **pages; > > + dma_resv_assert_held(shmem->base.resv); > + > if (shmem->pages_use_count++ > 0) > return 0; > > @@ -197,35 +199,16 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) > } > > /* > - * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object > + * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object > * @shmem: shmem GEM object > * > - * This function makes sure that backing pages exists for the shmem GEM object > - * and increases the use count. > - * > - * Returns: > - * 0 on success or a negative error code on failure. > + * This function decreases the use count and puts the backing pages when use drops to zero. > */ > -int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem) > +void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem) Same comment about the name change. That's even more confusing since this function was previously taking care of the locking. Also not sure why you'd want to expose this _put() helper when the _get() helper is private. > { > struct drm_gem_object *obj = &shmem->base; > - int ret; > > - drm_WARN_ON(obj->dev, obj->import_attach); > - > - ret = mutex_lock_interruptible(&shmem->pages_lock); > - if (ret) > - return ret; > - ret = drm_gem_shmem_get_pages_locked(shmem); > - mutex_unlock(&shmem->pages_lock); > - > - return ret; > -} > -EXPORT_SYMBOL(drm_gem_shmem_get_pages); > - > -static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) > -{ > - struct drm_gem_object *obj = &shmem->base; > + dma_resv_assert_held(shmem->base.resv); > > if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count)) > return; > @@ -243,20 +226,25 @@ static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) > shmem->pages_mark_accessed_on_put); > shmem->pages = NULL; > } > +EXPORT_SYMBOL(drm_gem_shmem_put_pages); > > -/* > - * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object > - * @shmem: shmem GEM object > - * > - * This function decreases the use count and puts the backing pages when use drops to zero. > - */ > -void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem) > +static int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem) > { > - mutex_lock(&shmem->pages_lock); > - drm_gem_shmem_put_pages_locked(shmem); > - mutex_unlock(&shmem->pages_lock); > + int ret; > + > + dma_resv_assert_held(shmem->base.resv); > + > + ret = drm_gem_shmem_get_pages(shmem); > + > + return ret; > +} > + > +static void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem) > +{ > + dma_resv_assert_held(shmem->base.resv); > + > + drm_gem_shmem_put_pages(shmem); > } > -EXPORT_SYMBOL(drm_gem_shmem_put_pages); > > /** > * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object > @@ -271,10 +259,17 @@ EXPORT_SYMBOL(drm_gem_shmem_put_pages); > int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem) > { > struct drm_gem_object *obj = &shmem->base; > + int ret; > > drm_WARN_ON(obj->dev, obj->import_attach); > > - return drm_gem_shmem_get_pages(shmem); > + ret = dma_resv_lock_interruptible(shmem->base.resv, NULL); > + if (ret) > + return ret; I think here is the major problem I have with this patch: you've made drm_gem_shmem_{get_pages,pin}() private, which forces me to call drm_gem_shmem_pin() in a path where I already acquired the resv lock (using the drm_exec infra proposed by Christian). That would probably work if you were letting ret == -EALREADY go through, but I'm wondering if it wouldn't be preferable to expose drm_gem_shmem_pin_locked(). > + ret = drm_gem_shmem_pin_locked(shmem); > + dma_resv_unlock(shmem->base.resv); > + > + return ret; > } > EXPORT_SYMBOL(drm_gem_shmem_pin); > > @@ -291,12 +286,29 @@ void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem) > > drm_WARN_ON(obj->dev, obj->import_attach); > > - drm_gem_shmem_put_pages(shmem); > + dma_resv_lock(shmem->base.resv, NULL); > + drm_gem_shmem_unpin_locked(shmem); > + dma_resv_unlock(shmem->base.resv); > } > EXPORT_SYMBOL(drm_gem_shmem_unpin); If we want to be consistent, let's just expose drm_gem_shmem_unpin() and drm_gem_shmem_pin() and keep drm_gem_shmem_{get,put}_pages() private, or even better, rename them drm_gem_shmem_{pin,unpin}_locked() insert of having drm_gem_shmem_{pin,unpin}_locked() wrappers that just forward the call to drm_gem_shmem_{get,put}_pages(). > > -static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, > - struct iosys_map *map) > +/* > + * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object > + * @shmem: shmem GEM object > + * @map: Returns the kernel virtual address of the SHMEM GEM object's backing > + * store. > + * > + * This function makes sure that a contiguous kernel virtual address mapping > + * exists for the buffer backing the shmem GEM object. It hides the differences > + * between dma-buf imported and natively allocated objects. > + * > + * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap(). > + * > + * Returns: > + * 0 on success or a negative error code on failure. > + */ > +int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, > + struct iosys_map *map) Same problem with this renaming: it's confusing because this function was previously taking care of the locking, and it's no longer the case. That's actually true for other public functions your patching, but I won't go over all of them. I know this patch has been under discussion for quite some time, and has been validated by other devs/maintainers, but I'd like to understand the reasoning behind these decisions. Not the decision to replace all locks by dma_resv, which I kinda understand, but the decision to change the behavior of functions without making the name reflect the new behavior (_locked prefix), or the fact we now prohibit some functions to succeed when the dma_resv lock is taken by the driver beforehand (which, unless I'm mistaken, will happen in the VM_BIND logic, and can happen in the SUBMIT ioctl too depending on the driver). Regards, Boris
On Mon, 26 Jun 2023 11:40:14 +0200 Boris Brezillon <boris.brezillon@collabora.com> wrote: > Hi Dmitry, > > On Tue, 30 May 2023 01:39:35 +0300 > Dmitry Osipenko <dmitry.osipenko@collabora.com> wrote: > > > Replace all drm-shmem locks with a GEM reservation lock. This makes locks > > consistent with dma-buf locking convention where importers are responsible > > for holding reservation lock for all operations performed over dma-bufs, > > preventing deadlock between dma-buf importers and exporters. > > I've rebased some of my work on drm-misc-next this morning and noticed > that the drm_gem_shmem_get_pages() I was using to pin pages no longer > exists, so I ended looking at this patch to check what I should use > instead, and I have a few questions/comments. > > > > > Suggested-by: Daniel Vetter <daniel@ffwll.ch> > > Acked-by: Thomas Zimmermann <tzimmermann@suse.de> > > Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> > > Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> > > --- > > drivers/gpu/drm/drm_gem_shmem_helper.c | 210 ++++++++---------- > > drivers/gpu/drm/lima/lima_gem.c | 8 +- > > drivers/gpu/drm/panfrost/panfrost_drv.c | 7 +- > > .../gpu/drm/panfrost/panfrost_gem_shrinker.c | 6 +- > > drivers/gpu/drm/panfrost/panfrost_mmu.c | 19 +- > > include/drm/drm_gem_shmem_helper.h | 14 +- > > 6 files changed, 116 insertions(+), 148 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > > index 4ea6507a77e5..a783d2245599 100644 > > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > > @@ -88,8 +88,6 @@ __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private) > > if (ret) > > goto err_release; > > > > - mutex_init(&shmem->pages_lock); > > - mutex_init(&shmem->vmap_lock); > > INIT_LIST_HEAD(&shmem->madv_list); > > > > if (!private) { > > @@ -141,11 +139,13 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) > > { > > struct drm_gem_object *obj = &shmem->base; > > > > - drm_WARN_ON(obj->dev, shmem->vmap_use_count); > > - > > if (obj->import_attach) { > > drm_prime_gem_destroy(obj, shmem->sgt); > > } else { > > + dma_resv_lock(shmem->base.resv, NULL); > > + > > + drm_WARN_ON(obj->dev, shmem->vmap_use_count); > > + > > if (shmem->sgt) { > > dma_unmap_sgtable(obj->dev->dev, shmem->sgt, > > DMA_BIDIRECTIONAL, 0); > > @@ -154,22 +154,24 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) > > } > > if (shmem->pages) > > drm_gem_shmem_put_pages(shmem); > > - } > > > > - drm_WARN_ON(obj->dev, shmem->pages_use_count); > > + drm_WARN_ON(obj->dev, shmem->pages_use_count); > > + > > + dma_resv_unlock(shmem->base.resv); > > + } > > > > drm_gem_object_release(obj); > > - mutex_destroy(&shmem->pages_lock); > > - mutex_destroy(&shmem->vmap_lock); > > kfree(shmem); > > } > > EXPORT_SYMBOL_GPL(drm_gem_shmem_free); > > > > -static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) > > +static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem) > > I find this name change confusing, because the function requires the > GEM resv lock to be held, and the _locked suffix was making it pretty > clear. > > > { > > struct drm_gem_object *obj = &shmem->base; > > struct page **pages; > > > > + dma_resv_assert_held(shmem->base.resv); > > + > > if (shmem->pages_use_count++ > 0) > > return 0; > > > > @@ -197,35 +199,16 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) > > } > > > > /* > > - * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object > > + * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object > > * @shmem: shmem GEM object > > * > > - * This function makes sure that backing pages exists for the shmem GEM object > > - * and increases the use count. > > - * > > - * Returns: > > - * 0 on success or a negative error code on failure. > > + * This function decreases the use count and puts the backing pages when use drops to zero. > > */ > > -int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem) > > +void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem) > > Same comment about the name change. That's even more confusing since > this function was previously taking care of the locking. Also not sure > why you'd want to expose this _put() helper when the _get() helper is > private. > > > { > > struct drm_gem_object *obj = &shmem->base; > > - int ret; > > > > - drm_WARN_ON(obj->dev, obj->import_attach); > > - > > - ret = mutex_lock_interruptible(&shmem->pages_lock); > > - if (ret) > > - return ret; > > - ret = drm_gem_shmem_get_pages_locked(shmem); > > - mutex_unlock(&shmem->pages_lock); > > - > > - return ret; > > -} > > -EXPORT_SYMBOL(drm_gem_shmem_get_pages); > > - > > -static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) > > -{ > > - struct drm_gem_object *obj = &shmem->base; > > + dma_resv_assert_held(shmem->base.resv); > > > > if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count)) > > return; > > @@ -243,20 +226,25 @@ static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) > > shmem->pages_mark_accessed_on_put); > > shmem->pages = NULL; > > } > > +EXPORT_SYMBOL(drm_gem_shmem_put_pages); > > > > -/* > > - * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object > > - * @shmem: shmem GEM object > > - * > > - * This function decreases the use count and puts the backing pages when use drops to zero. > > - */ > > -void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem) > > +static int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem) > > { > > - mutex_lock(&shmem->pages_lock); > > - drm_gem_shmem_put_pages_locked(shmem); > > - mutex_unlock(&shmem->pages_lock); > > + int ret; > > + > > + dma_resv_assert_held(shmem->base.resv); > > + > > + ret = drm_gem_shmem_get_pages(shmem); > > + > > + return ret; > > +} > > + > > +static void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem) > > +{ > > + dma_resv_assert_held(shmem->base.resv); > > + > > + drm_gem_shmem_put_pages(shmem); > > } > > -EXPORT_SYMBOL(drm_gem_shmem_put_pages); > > > > /** > > * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object > > @@ -271,10 +259,17 @@ EXPORT_SYMBOL(drm_gem_shmem_put_pages); > > int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem) > > { > > struct drm_gem_object *obj = &shmem->base; > > + int ret; > > > > drm_WARN_ON(obj->dev, obj->import_attach); > > > > - return drm_gem_shmem_get_pages(shmem); > > + ret = dma_resv_lock_interruptible(shmem->base.resv, NULL); > > + if (ret) > > + return ret; > > I think here is the major problem I have with this patch: you've made > drm_gem_shmem_{get_pages,pin}() private, which forces me to call > drm_gem_shmem_pin() in a path where I already acquired the resv lock > (using the drm_exec infra proposed by Christian). That would > probably work if you were letting ret == -EALREADY go through, but I'm > wondering if it wouldn't be preferable to expose > drm_gem_shmem_pin_locked(). > > > + ret = drm_gem_shmem_pin_locked(shmem); > > + dma_resv_unlock(shmem->base.resv); > > + > > + return ret; > > } > > EXPORT_SYMBOL(drm_gem_shmem_pin); > > > > @@ -291,12 +286,29 @@ void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem) > > > > drm_WARN_ON(obj->dev, obj->import_attach); > > > > - drm_gem_shmem_put_pages(shmem); > > + dma_resv_lock(shmem->base.resv, NULL); > > + drm_gem_shmem_unpin_locked(shmem); > > + dma_resv_unlock(shmem->base.resv); > > } > > EXPORT_SYMBOL(drm_gem_shmem_unpin); > > If we want to be consistent, let's just expose drm_gem_shmem_unpin() > and drm_gem_shmem_pin() and keep drm_gem_shmem_{get,put}_pages() > private, or even better, rename them drm_gem_shmem_{pin,unpin}_locked() > insert of having drm_gem_shmem_{pin,unpin}_locked() wrappers that just > forward the call to drm_gem_shmem_{get,put}_pages(). > > > > > -static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, > > - struct iosys_map *map) > > +/* > > + * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object > > + * @shmem: shmem GEM object > > + * @map: Returns the kernel virtual address of the SHMEM GEM object's backing > > + * store. > > + * > > + * This function makes sure that a contiguous kernel virtual address mapping > > + * exists for the buffer backing the shmem GEM object. It hides the differences > > + * between dma-buf imported and natively allocated objects. > > + * > > + * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap(). > > + * > > + * Returns: > > + * 0 on success or a negative error code on failure. > > + */ > > +int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, > > + struct iosys_map *map) > > Same problem with this renaming: it's confusing because this function > was previously taking care of the locking, and it's no longer the case. > That's actually true for other public functions your patching, but I > won't go over all of them. vmap() is less of a problem, because we're not supposed to call drm_gem_shmem_vmap() directly, but rather go through drm_gem_vmap(). This should probably be clarified in the doc though, with this sort of disclaimer: "don't use this function to map stuff, only use it to implement drm_gem_object_funcs::vmap()." Also noticed that the drm_gem API has the _locked pattern reversed, with a few drm_gem_xxx_unlocked() helper that take the lock and call the drm_gem_xxx() function. Don't have a strong opinion on whether this is better than the xxx_locked() and xxx() pattern or not, but the fact things are inconsistent across the API (drm_gem_pin() is letting the backend take the lock before pinning pages, when drm_gem_vmap() is not) is super confusing.
On 6/26/23 12:40, Boris Brezillon wrote: > Same problem with this renaming: it's confusing because this function > was previously taking care of the locking, and it's no longer the case. > That's actually true for other public functions your patching, but I > won't go over all of them. > > I know this patch has been under discussion for quite some time, and has > been validated by other devs/maintainers, but I'd like to understand the > reasoning behind these decisions. Not the decision to replace all locks > by dma_resv, which I kinda understand, but the decision to change the > behavior of functions without making the name reflect the new behavior > (_locked prefix), or the fact we now prohibit some functions to > succeed when the dma_resv lock is taken by the driver beforehand (which, > unless I'm mistaken, will happen in the VM_BIND logic, and can happen > in the SUBMIT ioctl too depending on the driver). Adding explicit _locked/unlocked postfix to all function names indeed won't hurt to do. There was no decision made about the function names, the old functions kept the old name where possible to minimize code changes during transition to the resv lock. Improving the names could be the next step. Thanks for the feedback!
On 6/26/23 12:40, Boris Brezillon wrote: > I think here is the major problem I have with this patch: you've made > drm_gem_shmem_{get_pages,pin}() private, which forces me to call > drm_gem_shmem_pin() in a path where I already acquired the resv lock > (using the drm_exec infra proposed by Christian). That would > probably work if you were letting ret == -EALREADY go through, but I'm > wondering if it wouldn't be preferable to expose > drm_gem_shmem_pin_locked(). You should be free to expose the necessary functions. They are private because nobody need them so far and we don't want to export unused functions.
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 4ea6507a77e5..a783d2245599 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -88,8 +88,6 @@ __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private) if (ret) goto err_release; - mutex_init(&shmem->pages_lock); - mutex_init(&shmem->vmap_lock); INIT_LIST_HEAD(&shmem->madv_list); if (!private) { @@ -141,11 +139,13 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; - drm_WARN_ON(obj->dev, shmem->vmap_use_count); - if (obj->import_attach) { drm_prime_gem_destroy(obj, shmem->sgt); } else { + dma_resv_lock(shmem->base.resv, NULL); + + drm_WARN_ON(obj->dev, shmem->vmap_use_count); + if (shmem->sgt) { dma_unmap_sgtable(obj->dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0); @@ -154,22 +154,24 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem) } if (shmem->pages) drm_gem_shmem_put_pages(shmem); - } - drm_WARN_ON(obj->dev, shmem->pages_use_count); + drm_WARN_ON(obj->dev, shmem->pages_use_count); + + dma_resv_unlock(shmem->base.resv); + } drm_gem_object_release(obj); - mutex_destroy(&shmem->pages_lock); - mutex_destroy(&shmem->vmap_lock); kfree(shmem); } EXPORT_SYMBOL_GPL(drm_gem_shmem_free); -static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) +static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; struct page **pages; + dma_resv_assert_held(shmem->base.resv); + if (shmem->pages_use_count++ > 0) return 0; @@ -197,35 +199,16 @@ static int drm_gem_shmem_get_pages_locked(struct drm_gem_shmem_object *shmem) } /* - * drm_gem_shmem_get_pages - Allocate backing pages for a shmem GEM object + * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object * @shmem: shmem GEM object * - * This function makes sure that backing pages exists for the shmem GEM object - * and increases the use count. - * - * Returns: - * 0 on success or a negative error code on failure. + * This function decreases the use count and puts the backing pages when use drops to zero. */ -int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem) +void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; - int ret; - drm_WARN_ON(obj->dev, obj->import_attach); - - ret = mutex_lock_interruptible(&shmem->pages_lock); - if (ret) - return ret; - ret = drm_gem_shmem_get_pages_locked(shmem); - mutex_unlock(&shmem->pages_lock); - - return ret; -} -EXPORT_SYMBOL(drm_gem_shmem_get_pages); - -static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) -{ - struct drm_gem_object *obj = &shmem->base; + dma_resv_assert_held(shmem->base.resv); if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count)) return; @@ -243,20 +226,25 @@ static void drm_gem_shmem_put_pages_locked(struct drm_gem_shmem_object *shmem) shmem->pages_mark_accessed_on_put); shmem->pages = NULL; } +EXPORT_SYMBOL(drm_gem_shmem_put_pages); -/* - * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object - * @shmem: shmem GEM object - * - * This function decreases the use count and puts the backing pages when use drops to zero. - */ -void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem) +static int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem) { - mutex_lock(&shmem->pages_lock); - drm_gem_shmem_put_pages_locked(shmem); - mutex_unlock(&shmem->pages_lock); + int ret; + + dma_resv_assert_held(shmem->base.resv); + + ret = drm_gem_shmem_get_pages(shmem); + + return ret; +} + +static void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem) +{ + dma_resv_assert_held(shmem->base.resv); + + drm_gem_shmem_put_pages(shmem); } -EXPORT_SYMBOL(drm_gem_shmem_put_pages); /** * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object @@ -271,10 +259,17 @@ EXPORT_SYMBOL(drm_gem_shmem_put_pages); int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; + int ret; drm_WARN_ON(obj->dev, obj->import_attach); - return drm_gem_shmem_get_pages(shmem); + ret = dma_resv_lock_interruptible(shmem->base.resv, NULL); + if (ret) + return ret; + ret = drm_gem_shmem_pin_locked(shmem); + dma_resv_unlock(shmem->base.resv); + + return ret; } EXPORT_SYMBOL(drm_gem_shmem_pin); @@ -291,12 +286,29 @@ void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem) drm_WARN_ON(obj->dev, obj->import_attach); - drm_gem_shmem_put_pages(shmem); + dma_resv_lock(shmem->base.resv, NULL); + drm_gem_shmem_unpin_locked(shmem); + dma_resv_unlock(shmem->base.resv); } EXPORT_SYMBOL(drm_gem_shmem_unpin); -static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, - struct iosys_map *map) +/* + * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object + * @shmem: shmem GEM object + * @map: Returns the kernel virtual address of the SHMEM GEM object's backing + * store. + * + * This function makes sure that a contiguous kernel virtual address mapping + * exists for the buffer backing the shmem GEM object. It hides the differences + * between dma-buf imported and natively allocated objects. + * + * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap(). + * + * Returns: + * 0 on success or a negative error code on failure. + */ +int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, + struct iosys_map *map) { struct drm_gem_object *obj = &shmem->base; int ret = 0; @@ -312,6 +324,8 @@ static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, } else { pgprot_t prot = PAGE_KERNEL; + dma_resv_assert_held(shmem->base.resv); + if (shmem->vmap_use_count++ > 0) { iosys_map_set_vaddr(map, shmem->vaddr); return 0; @@ -346,45 +360,30 @@ static int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, return ret; } +EXPORT_SYMBOL(drm_gem_shmem_vmap); /* - * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object + * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object * @shmem: shmem GEM object - * @map: Returns the kernel virtual address of the SHMEM GEM object's backing - * store. - * - * This function makes sure that a contiguous kernel virtual address mapping - * exists for the buffer backing the shmem GEM object. It hides the differences - * between dma-buf imported and natively allocated objects. + * @map: Kernel virtual address where the SHMEM GEM object was mapped * - * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap(). + * This function cleans up a kernel virtual address mapping acquired by + * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to + * zero. * - * Returns: - * 0 on success or a negative error code on failure. + * This function hides the differences between dma-buf imported and natively + * allocated objects. */ -int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem, - struct iosys_map *map) -{ - int ret; - - ret = mutex_lock_interruptible(&shmem->vmap_lock); - if (ret) - return ret; - ret = drm_gem_shmem_vmap_locked(shmem, map); - mutex_unlock(&shmem->vmap_lock); - - return ret; -} -EXPORT_SYMBOL(drm_gem_shmem_vmap); - -static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, - struct iosys_map *map) +void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem, + struct iosys_map *map) { struct drm_gem_object *obj = &shmem->base; if (obj->import_attach) { dma_buf_vunmap(obj->import_attach->dmabuf, map); } else { + dma_resv_assert_held(shmem->base.resv); + if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count)) return; @@ -397,26 +396,6 @@ static void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, shmem->vaddr = NULL; } - -/* - * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object - * @shmem: shmem GEM object - * @map: Kernel virtual address where the SHMEM GEM object was mapped - * - * This function cleans up a kernel virtual address mapping acquired by - * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to - * zero. - * - * This function hides the differences between dma-buf imported and natively - * allocated objects. - */ -void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem, - struct iosys_map *map) -{ - mutex_lock(&shmem->vmap_lock); - drm_gem_shmem_vunmap_locked(shmem, map); - mutex_unlock(&shmem->vmap_lock); -} EXPORT_SYMBOL(drm_gem_shmem_vunmap); static int @@ -447,24 +426,24 @@ drm_gem_shmem_create_with_handle(struct drm_file *file_priv, */ int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv) { - mutex_lock(&shmem->pages_lock); + dma_resv_assert_held(shmem->base.resv); if (shmem->madv >= 0) shmem->madv = madv; madv = shmem->madv; - mutex_unlock(&shmem->pages_lock); - return (madv >= 0); } EXPORT_SYMBOL(drm_gem_shmem_madvise); -void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem) +void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem) { struct drm_gem_object *obj = &shmem->base; struct drm_device *dev = obj->dev; + dma_resv_assert_held(shmem->base.resv); + drm_WARN_ON(obj->dev, !drm_gem_shmem_is_purgeable(shmem)); dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0); @@ -472,7 +451,7 @@ void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem) kfree(shmem->sgt); shmem->sgt = NULL; - drm_gem_shmem_put_pages_locked(shmem); + drm_gem_shmem_put_pages(shmem); shmem->madv = -1; @@ -488,17 +467,6 @@ void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem) invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1); } -EXPORT_SYMBOL(drm_gem_shmem_purge_locked); - -bool drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem) -{ - if (!mutex_trylock(&shmem->pages_lock)) - return false; - drm_gem_shmem_purge_locked(shmem); - mutex_unlock(&shmem->pages_lock); - - return true; -} EXPORT_SYMBOL(drm_gem_shmem_purge); /** @@ -551,7 +519,7 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) /* We don't use vmf->pgoff since that has the fake offset */ page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT; - mutex_lock(&shmem->pages_lock); + dma_resv_lock(shmem->base.resv, NULL); if (page_offset >= num_pages || drm_WARN_ON_ONCE(obj->dev, !shmem->pages) || @@ -563,7 +531,7 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page)); } - mutex_unlock(&shmem->pages_lock); + dma_resv_unlock(shmem->base.resv); return ret; } @@ -575,7 +543,7 @@ static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) drm_WARN_ON(obj->dev, obj->import_attach); - mutex_lock(&shmem->pages_lock); + dma_resv_lock(shmem->base.resv, NULL); /* * We should have already pinned the pages when the buffer was first @@ -585,7 +553,7 @@ static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) if (!drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count)) shmem->pages_use_count++; - mutex_unlock(&shmem->pages_lock); + dma_resv_unlock(shmem->base.resv); drm_gem_vm_open(vma); } @@ -595,7 +563,10 @@ static void drm_gem_shmem_vm_close(struct vm_area_struct *vma) struct drm_gem_object *obj = vma->vm_private_data; struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); + dma_resv_lock(shmem->base.resv, NULL); drm_gem_shmem_put_pages(shmem); + dma_resv_unlock(shmem->base.resv); + drm_gem_vm_close(vma); } @@ -633,7 +604,10 @@ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct return ret; } + dma_resv_lock(shmem->base.resv, NULL); ret = drm_gem_shmem_get_pages(shmem); + dma_resv_unlock(shmem->base.resv); + if (ret) return ret; @@ -699,7 +673,7 @@ static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_ drm_WARN_ON(obj->dev, obj->import_attach); - ret = drm_gem_shmem_get_pages_locked(shmem); + ret = drm_gem_shmem_get_pages(shmem); if (ret) return ERR_PTR(ret); @@ -721,7 +695,7 @@ static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_ sg_free_table(sgt); kfree(sgt); err_put_pages: - drm_gem_shmem_put_pages_locked(shmem); + drm_gem_shmem_put_pages(shmem); return ERR_PTR(ret); } @@ -746,11 +720,11 @@ struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem) int ret; struct sg_table *sgt; - ret = mutex_lock_interruptible(&shmem->pages_lock); + ret = dma_resv_lock_interruptible(shmem->base.resv, NULL); if (ret) return ERR_PTR(ret); sgt = drm_gem_shmem_get_pages_sgt_locked(shmem); - mutex_unlock(&shmem->pages_lock); + dma_resv_unlock(shmem->base.resv); return sgt; } diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c index 10252dc11a22..4f9736e5f929 100644 --- a/drivers/gpu/drm/lima/lima_gem.c +++ b/drivers/gpu/drm/lima/lima_gem.c @@ -34,7 +34,7 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm) new_size = min(new_size, bo->base.base.size); - mutex_lock(&bo->base.pages_lock); + dma_resv_lock(bo->base.base.resv, NULL); if (bo->base.pages) { pages = bo->base.pages; @@ -42,7 +42,7 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm) pages = kvmalloc_array(bo->base.base.size >> PAGE_SHIFT, sizeof(*pages), GFP_KERNEL | __GFP_ZERO); if (!pages) { - mutex_unlock(&bo->base.pages_lock); + dma_resv_unlock(bo->base.base.resv); return -ENOMEM; } @@ -56,13 +56,13 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm) struct page *page = shmem_read_mapping_page(mapping, i); if (IS_ERR(page)) { - mutex_unlock(&bo->base.pages_lock); + dma_resv_unlock(bo->base.base.resv); return PTR_ERR(page); } pages[i] = page; } - mutex_unlock(&bo->base.pages_lock); + dma_resv_unlock(bo->base.base.resv); ret = sg_alloc_table_from_pages(&sgt, pages, i, 0, new_size, GFP_KERNEL); diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c index bbada731bbbd..d9dda6acdfac 100644 --- a/drivers/gpu/drm/panfrost/panfrost_drv.c +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c @@ -407,6 +407,10 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data, bo = to_panfrost_bo(gem_obj); + ret = dma_resv_lock_interruptible(bo->base.base.resv, NULL); + if (ret) + goto out_put_object; + mutex_lock(&pfdev->shrinker_lock); mutex_lock(&bo->mappings.lock); if (args->madv == PANFROST_MADV_DONTNEED) { @@ -444,7 +448,8 @@ static int panfrost_ioctl_madvise(struct drm_device *dev, void *data, out_unlock_mappings: mutex_unlock(&bo->mappings.lock); mutex_unlock(&pfdev->shrinker_lock); - + dma_resv_unlock(bo->base.base.resv); +out_put_object: drm_gem_object_put(gem_obj); return ret; } diff --git a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c index bf0170782f25..6a71a2555f85 100644 --- a/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c +++ b/drivers/gpu/drm/panfrost/panfrost_gem_shrinker.c @@ -48,14 +48,14 @@ static bool panfrost_gem_purge(struct drm_gem_object *obj) if (!mutex_trylock(&bo->mappings.lock)) return false; - if (!mutex_trylock(&shmem->pages_lock)) + if (!dma_resv_trylock(shmem->base.resv)) goto unlock_mappings; panfrost_gem_teardown_mappings_locked(bo); - drm_gem_shmem_purge_locked(&bo->base); + drm_gem_shmem_purge(&bo->base); ret = true; - mutex_unlock(&shmem->pages_lock); + dma_resv_unlock(shmem->base.resv); unlock_mappings: mutex_unlock(&bo->mappings.lock); diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c index 666a5e53fe19..0679df57f394 100644 --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c @@ -443,6 +443,7 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, struct panfrost_gem_mapping *bomapping; struct panfrost_gem_object *bo; struct address_space *mapping; + struct drm_gem_object *obj; pgoff_t page_offset; struct sg_table *sgt; struct page **pages; @@ -465,15 +466,16 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, page_offset = addr >> PAGE_SHIFT; page_offset -= bomapping->mmnode.start; - mutex_lock(&bo->base.pages_lock); + obj = &bo->base.base; + + dma_resv_lock(obj->resv, NULL); if (!bo->base.pages) { bo->sgts = kvmalloc_array(bo->base.base.size / SZ_2M, sizeof(struct sg_table), GFP_KERNEL | __GFP_ZERO); if (!bo->sgts) { - mutex_unlock(&bo->base.pages_lock); ret = -ENOMEM; - goto err_bo; + goto err_unlock; } pages = kvmalloc_array(bo->base.base.size >> PAGE_SHIFT, @@ -481,9 +483,8 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, if (!pages) { kvfree(bo->sgts); bo->sgts = NULL; - mutex_unlock(&bo->base.pages_lock); ret = -ENOMEM; - goto err_bo; + goto err_unlock; } bo->base.pages = pages; bo->base.pages_use_count = 1; @@ -491,7 +492,6 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, pages = bo->base.pages; if (pages[page_offset]) { /* Pages are already mapped, bail out. */ - mutex_unlock(&bo->base.pages_lock); goto out; } } @@ -502,14 +502,11 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, for (i = page_offset; i < page_offset + NUM_FAULT_PAGES; i++) { pages[i] = shmem_read_mapping_page(mapping, i); if (IS_ERR(pages[i])) { - mutex_unlock(&bo->base.pages_lock); ret = PTR_ERR(pages[i]); goto err_pages; } } - mutex_unlock(&bo->base.pages_lock); - sgt = &bo->sgts[page_offset / (SZ_2M / PAGE_SIZE)]; ret = sg_alloc_table_from_pages(sgt, pages + page_offset, NUM_FAULT_PAGES, 0, SZ_2M, GFP_KERNEL); @@ -528,6 +525,8 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, dev_dbg(pfdev->dev, "mapped page fault @ AS%d %llx", as, addr); out: + dma_resv_unlock(obj->resv); + panfrost_gem_mapping_put(bomapping); return 0; @@ -536,6 +535,8 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as, sg_free_table(sgt); err_pages: drm_gem_shmem_put_pages(&bo->base); +err_unlock: + dma_resv_unlock(obj->resv); err_bo: panfrost_gem_mapping_put(bomapping); return ret; diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h index 5994fed5e327..20ddcd799df9 100644 --- a/include/drm/drm_gem_shmem_helper.h +++ b/include/drm/drm_gem_shmem_helper.h @@ -26,11 +26,6 @@ struct drm_gem_shmem_object { */ struct drm_gem_object base; - /** - * @pages_lock: Protects the page table and use count - */ - struct mutex pages_lock; - /** * @pages: Page table */ @@ -65,11 +60,6 @@ struct drm_gem_shmem_object { */ struct sg_table *sgt; - /** - * @vmap_lock: Protects the vmap address and use count - */ - struct mutex vmap_lock; - /** * @vaddr: Kernel virtual address of the backing memory */ @@ -109,7 +99,6 @@ struct drm_gem_shmem_object { struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size); void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem); -int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem); void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem); int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem); void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem); @@ -128,8 +117,7 @@ static inline bool drm_gem_shmem_is_purgeable(struct drm_gem_shmem_object *shmem !shmem->base.dma_buf && !shmem->base.import_attach; } -void drm_gem_shmem_purge_locked(struct drm_gem_shmem_object *shmem); -bool drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem); +void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem); struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem); struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem);