Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932450Ab3EIWyi (ORCPT ); Thu, 9 May 2013 18:54:38 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46101 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757805Ab3EIWdE (ORCPT ); Thu, 9 May 2013 18:33:04 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Vetter , Dave Airlie Subject: [ 34/73] drm/prime: keep a reference from the handle to exported dma-buf (v6) Date: Thu, 9 May 2013 15:31:57 -0700 Message-Id: <20130509222801.676033398@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130509222757.917088509@linuxfoundation.org> References: <20130509222757.917088509@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9295 Lines: 259 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dave Airlie commit 219b47339ced80ca580bb6ce7d1636166984afa7 upstream. Currently we have a problem with this: 1. i915: create gem object 2. i915: export gem object to prime 3. radeon: import gem object 4. close prime fd 5. radeon: unref object 6. i915: unref object i915 has an imported object reference in its file priv, that isn't cleaned up properly until fd close. The reference gets added at step 2, but at step 6 we don't have enough info to clean it up. The solution is to take a reference on the dma-buf when we export it, and drop the reference when the gem handle goes away. So when we export a dma_buf from a gem object, we keep track of it with the handle, we take a reference to the dma_buf. When we close the handle (i.e. userspace is finished with the buffer), we drop the reference to the dma_buf, and it gets collected. This patch isn't meant to fix any other problem or bikesheds, and it doesn't fix any races with other scenarios. v1.1: move export symbol line back up. v2: okay I had to do a bit more, as the first patch showed a leak on one of my tests, that I found using the dma-buf debugfs support, the problem case is exporting a buffer twice with the same handle, we'd add another export handle for it unnecessarily, however we now fail if we try to export the same object with a different gem handle, however I'm not sure if that is a case I want to support, and I've gotten the code to WARN_ON if we hit something like that. v2.1: rebase this patch, write better commit msg. v3: cleanup error handling, track import vs export in linked list, these two patches were separate previously, but seem to work better like this. v4: danvet is correct, this code is no longer useful, since the buffer better exist, so remove it. v5: always take a reference to the dma buf object, import or export. (Imre Deak contributed this originally) v6: square the circle, remove import vs export tracking now that there is no difference Reviewed-by: Daniel Vetter Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_gem.c | 4 +- drivers/gpu/drm/drm_prime.c | 76 +++++++++++++++++++++++--------------------- include/drm/drmP.h | 5 +- 3 files changed, 44 insertions(+), 41 deletions(-) --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -205,11 +205,11 @@ static void drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp) { if (obj->import_attach) { - drm_prime_remove_imported_buf_handle(&filp->prime, + drm_prime_remove_buf_handle(&filp->prime, obj->import_attach->dmabuf); } if (obj->export_dma_buf) { - drm_prime_remove_imported_buf_handle(&filp->prime, + drm_prime_remove_buf_handle(&filp->prime, obj->export_dma_buf); } } --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -61,6 +61,7 @@ struct drm_prime_member { struct dma_buf *dma_buf; uint32_t handle; }; +static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle); int drm_gem_prime_handle_to_fd(struct drm_device *dev, struct drm_file *file_priv, uint32_t handle, uint32_t flags, @@ -68,7 +69,8 @@ int drm_gem_prime_handle_to_fd(struct dr { struct drm_gem_object *obj; void *buf; - int ret; + int ret = 0; + struct dma_buf *dmabuf; obj = drm_gem_object_lookup(dev, file_priv, handle); if (!obj) @@ -77,43 +79,44 @@ int drm_gem_prime_handle_to_fd(struct dr mutex_lock(&file_priv->prime.lock); /* re-export the original imported object */ if (obj->import_attach) { - get_dma_buf(obj->import_attach->dmabuf); - *prime_fd = dma_buf_fd(obj->import_attach->dmabuf, flags); - drm_gem_object_unreference_unlocked(obj); - mutex_unlock(&file_priv->prime.lock); - return 0; + dmabuf = obj->import_attach->dmabuf; + goto out_have_obj; } if (obj->export_dma_buf) { - get_dma_buf(obj->export_dma_buf); - *prime_fd = dma_buf_fd(obj->export_dma_buf, flags); - drm_gem_object_unreference_unlocked(obj); - } else { - buf = dev->driver->gem_prime_export(dev, obj, flags); - if (IS_ERR(buf)) { - /* normally the created dma-buf takes ownership of the ref, - * but if that fails then drop the ref - */ - drm_gem_object_unreference_unlocked(obj); - mutex_unlock(&file_priv->prime.lock); - return PTR_ERR(buf); - } - obj->export_dma_buf = buf; - *prime_fd = dma_buf_fd(buf, flags); + dmabuf = obj->export_dma_buf; + goto out_have_obj; } + + buf = dev->driver->gem_prime_export(dev, obj, flags); + if (IS_ERR(buf)) { + /* normally the created dma-buf takes ownership of the ref, + * but if that fails then drop the ref + */ + ret = PTR_ERR(buf); + goto out; + } + obj->export_dma_buf = buf; + /* if we've exported this buffer the cheat and add it to the import list * so we get the correct handle back */ - ret = drm_prime_add_imported_buf_handle(&file_priv->prime, - obj->export_dma_buf, handle); - if (ret) { - drm_gem_object_unreference_unlocked(obj); - mutex_unlock(&file_priv->prime.lock); - return ret; - } + ret = drm_prime_add_buf_handle(&file_priv->prime, + obj->export_dma_buf, handle); + if (ret) + goto out; + *prime_fd = dma_buf_fd(buf, flags); mutex_unlock(&file_priv->prime.lock); return 0; + +out_have_obj: + get_dma_buf(dmabuf); + *prime_fd = dma_buf_fd(dmabuf, flags); +out: + drm_gem_object_unreference_unlocked(obj); + mutex_unlock(&file_priv->prime.lock); + return ret; } EXPORT_SYMBOL(drm_gem_prime_handle_to_fd); @@ -130,7 +133,7 @@ int drm_gem_prime_fd_to_handle(struct dr mutex_lock(&file_priv->prime.lock); - ret = drm_prime_lookup_imported_buf_handle(&file_priv->prime, + ret = drm_prime_lookup_buf_handle(&file_priv->prime, dma_buf, handle); if (!ret) { ret = 0; @@ -149,7 +152,7 @@ int drm_gem_prime_fd_to_handle(struct dr if (ret) goto out_put; - ret = drm_prime_add_imported_buf_handle(&file_priv->prime, + ret = drm_prime_add_buf_handle(&file_priv->prime, dma_buf, *handle); if (ret) goto fail; @@ -307,7 +310,7 @@ void drm_prime_destroy_file_private(stru } EXPORT_SYMBOL(drm_prime_destroy_file_private); -int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) +static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) { struct drm_prime_member *member; @@ -315,14 +318,14 @@ int drm_prime_add_imported_buf_handle(st if (!member) return -ENOMEM; + get_dma_buf(dma_buf); member->dma_buf = dma_buf; member->handle = handle; list_add(&member->entry, &prime_fpriv->head); return 0; } -EXPORT_SYMBOL(drm_prime_add_imported_buf_handle); -int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle) +int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle) { struct drm_prime_member *member; @@ -334,19 +337,20 @@ int drm_prime_lookup_imported_buf_handle } return -ENOENT; } -EXPORT_SYMBOL(drm_prime_lookup_imported_buf_handle); +EXPORT_SYMBOL(drm_prime_lookup_buf_handle); -void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) +void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) { struct drm_prime_member *member, *safe; mutex_lock(&prime_fpriv->lock); list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) { if (member->dma_buf == dma_buf) { + dma_buf_put(dma_buf); list_del(&member->entry); kfree(member); } } mutex_unlock(&prime_fpriv->lock); } -EXPORT_SYMBOL(drm_prime_remove_imported_buf_handle); +EXPORT_SYMBOL(drm_prime_remove_buf_handle); --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1559,9 +1559,8 @@ extern void drm_prime_gem_destroy(struct void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv); void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv); -int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle); -int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle); -void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf); +int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle); +void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf); int drm_prime_add_dma_buf(struct drm_device *dev, struct drm_gem_object *obj); int drm_prime_lookup_obj(struct drm_device *dev, struct dma_buf *buf, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/