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Mercier" , =?utf-8?q?Christian_K=C3=B6nig?= , Marek Szyprowski , Robin Murphy , Rob Herring , Saravana Kannan Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, iommu@lists.linux.dev, devicetree@vger.kernel.org, Albert Esteve , echanude@redhat.com, mripard@redhat.com X-Developer-Signature: v=1; a=ed25519-sha256; t=1772541243; l=6736; i=aesteve@redhat.com; s=20260303; h=from:subject:message-id; bh=rT4eCrjoQu7EvTeC9Zi2EQ7EHm1V9wN2D3i4WLgOBL8=; b=WyYJMMZjafvKEln5EMzK35BIFWIKyBwZjgKRJeKr/K5sa3XEXqCBPwD2HOUyxnOKeDhqy32W0 LDiUoTUFgtwD0jNccSayx+CrlCFk5prI74Zg2anYbmnK0Ya+AYBc6Ry X-Developer-Key: i=aesteve@redhat.com; a=ed25519; pk=YSFz6sOHd2L45+Fr8DIvHTi6lSIjhLZ5T+rkxspJt1s= X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Mimecast-MFC-PROC-ID: y7ZLRdHb6pbqb7RjrxD1wDBAyKPOODWR9Dm5dt1rexM_1772541264 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Split dma_heap_add() into creation and registration phases while preserving the ordering between cdev_add() and device_add(), and ensuring all device fields are initialised. This will allow to access the heap_dev before it is registered and becomes available to userspace, making error handling easier. Signed-off-by: Albert Esteve --- drivers/dma-buf/dma-heap.c | 126 +++++++++++++++++++++++++++++++++++---------- include/linux/dma-heap.h | 3 ++ 2 files changed, 103 insertions(+), 26 deletions(-) diff --git a/drivers/dma-buf/dma-heap.c b/drivers/dma-buf/dma-heap.c index 1124d63eb1398..88189d4e48561 100644 --- a/drivers/dma-buf/dma-heap.c +++ b/drivers/dma-buf/dma-heap.c @@ -238,15 +238,30 @@ struct device *dma_heap_get_dev(struct dma_heap *heap) } EXPORT_SYMBOL_NS_GPL(dma_heap_get_dev, "DMA_BUF_HEAP"); +static void dma_heap_dev_release(struct device *dev) +{ + struct dma_heap *heap; + + pr_debug("heap device: '%s': %s\n", dev_name(dev), __func__); + heap = dev_get_drvdata(dev); + kfree(heap->name); + kfree(heap); + kfree(dev); +} + /** - * dma_heap_add - adds a heap to dmabuf heaps - * @exp_info: information needed to register this heap + * dma_heap_create() - allocate and initialize a heap object + * @exp_info: information needed to create a heap + * + * Creates a heap instance but does not register it or create device nodes. + * Use dma_heap_register() to make it visible to userspace, or + * dma_heap_destroy() to release it. + * + * Returns a heap on success or ERR_PTR(-errno) on failure. */ -struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) +struct dma_heap *dma_heap_create(const struct dma_heap_export_info *exp_info) { - struct dma_heap *heap, *h, *err_ret; - unsigned int minor; - int ret; + struct dma_heap *heap; if (!exp_info->name || !strcmp(exp_info->name, "")) { pr_err("dma_heap: Cannot add heap without a name\n"); @@ -265,13 +280,41 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) heap->name = exp_info->name; heap->ops = exp_info->ops; heap->priv = exp_info->priv; + heap->heap_dev = kzalloc_obj(*heap->heap_dev); + if (!heap->heap_dev) { + kfree(heap); + return ERR_PTR(-ENOMEM); + } + + device_initialize(heap->heap_dev); + dev_set_drvdata(heap->heap_dev, heap); + + dev_set_name(heap->heap_dev, heap->name); + heap->heap_dev->class = dma_heap_class; + heap->heap_dev->release = dma_heap_dev_release; + + return heap; +} +EXPORT_SYMBOL_NS_GPL(dma_heap_create, "DMA_BUF_HEAP"); + +/** + * dma_heap_register() - register a heap with the dma-heap framework + * @heap: heap instance created with dma_heap_create() + * + * Registers the heap, creating its device node and adding it to the heap + * list. Returns 0 on success or a negative error code on failure. + */ +int dma_heap_register(struct dma_heap *heap) +{ + struct dma_heap *h; + unsigned int minor; + int ret; /* Find unused minor number */ ret = xa_alloc(&dma_heap_minors, &minor, heap, XA_LIMIT(0, NUM_HEAP_MINORS - 1), GFP_KERNEL); if (ret < 0) { pr_err("dma_heap: Unable to get minor number for heap\n"); - err_ret = ERR_PTR(ret); goto err0; } @@ -282,42 +325,34 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) ret = cdev_add(&heap->heap_cdev, heap->heap_devt, 1); if (ret < 0) { pr_err("dma_heap: Unable to add char device\n"); - err_ret = ERR_PTR(ret); goto err1; } - heap->heap_dev = device_create(dma_heap_class, - NULL, - heap->heap_devt, - NULL, - heap->name); - if (IS_ERR(heap->heap_dev)) { - pr_err("dma_heap: Unable to create device\n"); - err_ret = ERR_CAST(heap->heap_dev); + heap->heap_dev->devt = heap->heap_devt; + + ret = device_add(heap->heap_dev); + if (ret) { + pr_err("dma_heap: Unable to add device\n"); goto err2; } mutex_lock(&heap_list_lock); /* check the name is unique */ list_for_each_entry(h, &heap_list, list) { - if (!strcmp(h->name, exp_info->name)) { + if (!strcmp(h->name, heap->name)) { mutex_unlock(&heap_list_lock); pr_err("dma_heap: Already registered heap named %s\n", - exp_info->name); - err_ret = ERR_PTR(-EINVAL); + heap->name); + ret = -EINVAL; goto err3; } } - /* Make sure it doesn't disappear on us */ - heap->heap_dev = get_device(heap->heap_dev); - - /* Add heap to the list */ list_add(&heap->list, &heap_list); mutex_unlock(&heap_list_lock); - return heap; + return 0; err3: device_destroy(dma_heap_class, heap->heap_devt); @@ -326,8 +361,47 @@ struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) err1: xa_erase(&dma_heap_minors, minor); err0: - kfree(heap); - return err_ret; + dma_heap_destroy(heap); + return ret; +} +EXPORT_SYMBOL_NS_GPL(dma_heap_register, "DMA_BUF_HEAP"); + +/** + * dma_heap_destroy() - release a heap created by dma_heap_create() + * @heap: heap instance to release + * + * Drops the heap device reference; the heap and its device are freed in the + * device release path when the last reference is gone. + */ +void dma_heap_destroy(struct dma_heap *heap) +{ + put_device(heap->heap_dev); +} +EXPORT_SYMBOL_NS_GPL(dma_heap_destroy, "DMA_BUF_HEAP"); + +/** + * dma_heap_add - adds a heap to dmabuf heaps + * @exp_info: information needed to register this heap + */ +struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info) +{ + struct dma_heap *heap; + int ret; + + heap = dma_heap_create(exp_info); + if (IS_ERR(heap)) { + pr_err("dma_heap: failed to create heap (%d)\n", PTR_ERR(heap)); + return PTR_ERR(heap); + } + + ret = dma_heap_register(heap); + if (ret) { + pr_err("dma_heap: failed to register heap (%d)\n", ret); + dma_heap_destroy(heap); + return ERR_PTR(ret); + } + + return heap; } EXPORT_SYMBOL_NS_GPL(dma_heap_add, "DMA_BUF_HEAP"); diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index 493085e69b70e..1b0ea43ba66c3 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -46,6 +46,9 @@ void *dma_heap_get_drvdata(struct dma_heap *heap); const char *dma_heap_get_name(struct dma_heap *heap); struct device *dma_heap_get_dev(struct dma_heap *heap); +struct dma_heap *dma_heap_create(const struct dma_heap_export_info *exp_info); +int dma_heap_register(struct dma_heap *heap); +void dma_heap_destroy(struct dma_heap *heap); struct dma_heap *dma_heap_add(const struct dma_heap_export_info *exp_info); extern bool mem_accounting; -- 2.52.0