From patchwork Wed Aug 28 13:36:01 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans Verkuil X-Patchwork-Id: 13781286 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3506618787C for ; Wed, 28 Aug 2024 13:39:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724852388; cv=none; b=kgDBrJMlIp+OjwjHQyWbydSQV3TVBj7TACD6mctF1e200GLGD9Be2cX3EmqcHLIekm47bJu7IZsSFKl3IJwvRWEpKXBuAAtOwzV50AIQT4E6NMWQ87gId9Op3Gh7eeu8R9e0hHS1Gqqlgtcu8xW8X0oviihutD2PgAPdYDXAELo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724852388; c=relaxed/simple; bh=ohHIXhKxXwNXJFI+JOnAESedElO7c/salAEaKQGgO2o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FeIuSCMVOzXC3IS+SOY+l8gpXaAS3cdHZaT2hcfY1JdboPWK63+8ZeJW/dDU4vap4CfC0ZY/snb/COtyv7ydV34fLQJl35U6wCZS7CivNl/5Hho3fx3/BfMCKFcnRhv85yjGql9P5ZzNwZI1Ys4nxyksk7YAza2rA/sKV6bJ8DM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4EDDC58102; Wed, 28 Aug 2024 13:39:46 +0000 (UTC) From: Hans Verkuil To: linux-media@vger.kernel.org Cc: Nicolas Dufresne , Sebastian Fricke , Hans Verkuil Subject: [PATCHv2 1/3] media: mc: add manual request completion Date: Wed, 28 Aug 2024 15:36:01 +0200 Message-ID: <28354a6110564fec87dddd79cafa51ab6773e005.1724852163.git.hverkuil-cisco@xs4all.nl> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 By default when the last request object is completed, the whole request completes as well. But sometimes you want to manually complete a request in a driver, so add a manual complete mode for this. In req_queue the driver marks the request for manual completion by calling media_request_mark_manual_completion, and when the driver wants to manually complete the request it calls media_request_manual_complete(). Signed-off-by: Hans Verkuil --- drivers/media/mc/mc-request.c | 38 +++++++++++++++++++++++++++++++++-- include/media/media-request.h | 36 ++++++++++++++++++++++++++++++++- 2 files changed, 71 insertions(+), 3 deletions(-) diff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c index addb8f2d8939..1ad725522a7d 100644 --- a/drivers/media/mc/mc-request.c +++ b/drivers/media/mc/mc-request.c @@ -54,6 +54,7 @@ static void media_request_clean(struct media_request *req) req->access_count = 0; WARN_ON(req->num_incomplete_objects); req->num_incomplete_objects = 0; + req->manual_completion = false; wake_up_interruptible_all(&req->poll_wait); } @@ -319,6 +320,7 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd) req->mdev = mdev; req->state = MEDIA_REQUEST_STATE_IDLE; req->num_incomplete_objects = 0; + req->manual_completion = false; kref_init(&req->kref); INIT_LIST_HEAD(&req->objects); spin_lock_init(&req->lock); @@ -465,7 +467,7 @@ void media_request_object_unbind(struct media_request_object *obj) req->num_incomplete_objects--; if (req->state == MEDIA_REQUEST_STATE_QUEUED && - !req->num_incomplete_objects) { + !req->num_incomplete_objects && !req->manual_completion) { req->state = MEDIA_REQUEST_STATE_COMPLETE; completed = true; wake_up_interruptible_all(&req->poll_wait); @@ -494,7 +496,7 @@ void media_request_object_complete(struct media_request_object *obj) WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED)) goto unlock; - if (!--req->num_incomplete_objects) { + if (!--req->num_incomplete_objects && !req->manual_completion) { req->state = MEDIA_REQUEST_STATE_COMPLETE; wake_up_interruptible_all(&req->poll_wait); completed = true; @@ -505,3 +507,35 @@ void media_request_object_complete(struct media_request_object *obj) media_request_put(req); } EXPORT_SYMBOL_GPL(media_request_object_complete); + +void media_request_manual_complete(struct media_request *req) +{ + unsigned long flags; + bool completed = false; + + if (WARN_ON(!req)) + return; + if (WARN_ON(!req->manual_completion)) + return; + + spin_lock_irqsave(&req->lock, flags); + if (WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED)) + goto unlock; + + req->manual_completion = false; + /* + * It is expected that all other objects in this request are + * completed when this function is called. WARN if that is + * not the case. + */ + if (!WARN_ON(req->num_incomplete_objects)) { + req->state = MEDIA_REQUEST_STATE_COMPLETE; + wake_up_interruptible_all(&req->poll_wait); + completed = true; + } +unlock: + spin_unlock_irqrestore(&req->lock, flags); + if (completed) + media_request_put(req); +} +EXPORT_SYMBOL_GPL(media_request_manual_complete); diff --git a/include/media/media-request.h b/include/media/media-request.h index 3cd25a2717ce..6434758ab597 100644 --- a/include/media/media-request.h +++ b/include/media/media-request.h @@ -56,6 +56,10 @@ struct media_request_object; * @access_count: count the number of request accesses that are in progress * @objects: List of @struct media_request_object request objects * @num_incomplete_objects: The number of incomplete objects in the request + * @manual_completion: if true, then the request won't be marked as completed + * when @num_incomplete_objects reaches 0. Call media_request_manual_complete() + * to set this field to false and complete the request + * if @num_incomplete_objects == 0. * @poll_wait: Wait queue for poll * @lock: Serializes access to this struct */ @@ -68,6 +72,7 @@ struct media_request { unsigned int access_count; struct list_head objects; unsigned int num_incomplete_objects; + bool manual_completion; wait_queue_head_t poll_wait; spinlock_t lock; }; @@ -218,6 +223,35 @@ media_request_get_by_fd(struct media_device *mdev, int request_fd); int media_request_alloc(struct media_device *mdev, int *alloc_fd); +/** + * media_request_mark_manual_completion - Set manual_completion to true + * + * @req: The request + * + * Mark that the request has to be manually completed by calling + * media_request_manual_complete(). + * + * This function should be called in the req_queue callback. + */ +static inline void +media_request_mark_manual_completion(struct media_request *req) +{ + req->manual_completion = true; +} + +/** + * media_request_manual_complete - Set manual_completion to false + * + * @req: The request + * + * Set @manual_completion to false, and if @num_incomplete_objects + * is 0, then mark the request as completed. + * + * If there are still incomplete objects in the request, then + * WARN for that since that suggests a driver error. + */ +void media_request_manual_complete(struct media_request *req); + #else static inline void media_request_get(struct media_request *req) @@ -336,7 +370,7 @@ void media_request_object_init(struct media_request_object *obj); * @req: The media request * @ops: The object ops for this object * @priv: A driver-specific priv pointer associated with this object - * @is_buffer: Set to true if the object a buffer object. + * @is_buffer: Set to true if the object is a buffer object. * @obj: The object * * Bind this object to the request and set the ops and priv values of From patchwork Wed Aug 28 13:36:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans Verkuil X-Patchwork-Id: 13781287 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BAF42187FF9 for ; Wed, 28 Aug 2024 13:39:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724852389; cv=none; b=Vzi1N7swkLz5qHXzAGqGRJF2bJtWIFj0LGsjIayHQ0baHvi9Qb0qih8TT1BkY267RwN7wttfxvMxiJPYB60HXuPokh+ADrNIN5CXjekULD0t23YO6ccGh3jfuk8K/SA98dWEQQr2Hx7aTYNVYapA8tMzUd/I1bfAzjszuuIOKt8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724852389; c=relaxed/simple; bh=b7hAnTXb6v6EfVyR/DTJvxjBiLhOZDYrDvhSY9GnO6g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Bi9/tOlmPi1GUDTyxs/T9lbXembiNn6bgIpdlmGXQ9Bf1QK5FJiG1PwWxRD0xg64Aov7sY7jHuiOjSgHzSDcqo4EHJA+83p8GCr9osWCt7RugmGcPJ8JoCrJQtNNyrkEu/8/GUA0OU6Syn6H4VRnaL/qL9uYBjlHCI5YxbUiVvc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E020C58101; Wed, 28 Aug 2024 13:39:47 +0000 (UTC) From: Hans Verkuil To: linux-media@vger.kernel.org Cc: Nicolas Dufresne , Sebastian Fricke , Hans Verkuil Subject: [PATCHv2 2/3] media: vicodec: add support for manual completion Date: Wed, 28 Aug 2024 15:36:02 +0200 Message-ID: X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Manually complete the requests: this tests the manual completion code. Signed-off-by: Hans Verkuil --- .../media/test-drivers/vicodec/vicodec-core.c | 21 +++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/drivers/media/test-drivers/vicodec/vicodec-core.c b/drivers/media/test-drivers/vicodec/vicodec-core.c index 846e90c06291..2870fa3b529c 100644 --- a/drivers/media/test-drivers/vicodec/vicodec-core.c +++ b/drivers/media/test-drivers/vicodec/vicodec-core.c @@ -446,8 +446,10 @@ static void device_run(void *priv) ctx->comp_magic_cnt = 0; ctx->comp_has_frame = false; spin_unlock(ctx->lock); - if (ctx->is_stateless && src_req) + if (ctx->is_stateless && src_req) { v4l2_ctrl_request_complete(src_req, &ctx->hdl); + media_request_manual_complete(src_req); + } if (ctx->is_enc) v4l2_m2m_job_finish(dev->stateful_enc.m2m_dev, ctx->fh.m2m_ctx); @@ -1523,8 +1525,12 @@ static void vicodec_return_bufs(struct vb2_queue *q, u32 state) vbuf = v4l2_m2m_dst_buf_remove(ctx->fh.m2m_ctx); if (vbuf == NULL) return; - v4l2_ctrl_request_complete(vbuf->vb2_buf.req_obj.req, - &ctx->hdl); + if (ctx->is_stateless && V4L2_TYPE_IS_OUTPUT(q->type)) { + struct media_request *req = vbuf->vb2_buf.req_obj.req; + + v4l2_ctrl_request_complete(req, &ctx->hdl); + media_request_manual_complete(req); + } spin_lock(ctx->lock); v4l2_m2m_buf_done(vbuf, state); spin_unlock(ctx->lock); @@ -1677,6 +1683,7 @@ static void vicodec_buf_request_complete(struct vb2_buffer *vb) struct vicodec_ctx *ctx = vb2_get_drv_priv(vb->vb2_queue); v4l2_ctrl_request_complete(vb->req_obj.req, &ctx->hdl); + media_request_manual_complete(vb->req_obj.req); } @@ -2001,6 +2008,12 @@ static int vicodec_request_validate(struct media_request *req) return vb2_request_validate(req); } +static void vicodec_request_queue(struct media_request *req) +{ + media_request_mark_manual_completion(req); + v4l2_m2m_request_queue(req); +} + static const struct v4l2_file_operations vicodec_fops = { .owner = THIS_MODULE, .open = vicodec_open, @@ -2021,7 +2034,7 @@ static const struct video_device vicodec_videodev = { static const struct media_device_ops vicodec_m2m_media_ops = { .req_validate = vicodec_request_validate, - .req_queue = v4l2_m2m_request_queue, + .req_queue = vicodec_request_queue, }; static const struct v4l2_m2m_ops m2m_ops = { From patchwork Wed Aug 28 13:36:03 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans Verkuil X-Patchwork-Id: 13781288 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2D50218787C for ; Wed, 28 Aug 2024 13:39:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724852391; cv=none; b=p/Lc7StSNS1X+Kwc9082AOHYeq2uf11vq1shloEqg1SB0aYw3zeLd/XNCLJM2a+Hivs8i5nHiql3wn9+rH1bzSLVt5vek34lZxKvD1N5QFUqpOHiNWHw7SXitRLNZvASsH5rO2ct2aNZwSbMdb2H3/2970ezYpwig80sewT0oMA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724852391; c=relaxed/simple; bh=ocwQH3on8Bipv1OsbdDYOURUtphA8l+O1gyIZbeIC2s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ut4ONEG8c3c+tpgoXwELjxXTI/0CYC2y/00tZZEOA0z1XU+wHhYqjWcQe5jHsX47A7QeJ2NC/Vj57GjCcVhOE1MoXfXjfxUlxX/ynzSYmzsmQTMYVNy9rpWjmJq/Qbmv4WHlm7pl05Q+Z8Nr49OGhg6/wZk2DuxQOd7JTw2WJPM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABB30C58108; Wed, 28 Aug 2024 13:39:49 +0000 (UTC) From: Hans Verkuil To: linux-media@vger.kernel.org Cc: Nicolas Dufresne , Sebastian Fricke , Hans Verkuil Subject: [PATCHv2 3/3] media: mc: add debugfs node to keep track of requests Date: Wed, 28 Aug 2024 15:36:03 +0200 Message-ID: X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Keep track of the number of requests and request objects of a media device. Helps to verify that all request-related memory is freed. Signed-off-by: Hans Verkuil --- drivers/media/mc/mc-device.c | 30 ++++++++++++++++++++++++++++++ drivers/media/mc/mc-devnode.c | 5 +++++ drivers/media/mc/mc-request.c | 5 +++++ include/media/media-device.h | 9 +++++++++ include/media/media-devnode.h | 4 ++++ include/media/media-request.h | 2 ++ 6 files changed, 55 insertions(+) diff --git a/drivers/media/mc/mc-device.c b/drivers/media/mc/mc-device.c index c0dd4ae57227..cf21bd8e8094 100644 --- a/drivers/media/mc/mc-device.c +++ b/drivers/media/mc/mc-device.c @@ -679,6 +679,23 @@ void media_device_unregister_entity(struct media_entity *entity) } EXPORT_SYMBOL_GPL(media_device_unregister_entity); +#ifdef CONFIG_DEBUG_FS +/* + * Log the state of media requests. + * Very useful for debugging. + */ +static int media_device_requests(struct seq_file *file, void *priv) +{ + struct media_device *dev = dev_get_drvdata(file->private); + + seq_printf(file, "number of requests: %d\n", + atomic_read(&dev->num_requests)); + seq_printf(file, "number of request objects: %d\n", + atomic_read(&dev->num_request_objects)); + return 0; +} +#endif + void media_device_init(struct media_device *mdev) { INIT_LIST_HEAD(&mdev->entities); @@ -697,6 +714,9 @@ void media_device_init(struct media_device *mdev) media_set_bus_info(mdev->bus_info, sizeof(mdev->bus_info), mdev->dev); + atomic_set(&mdev->num_requests, 0); + atomic_set(&mdev->num_request_objects, 0); + dev_dbg(mdev->dev, "Media device initialized\n"); } EXPORT_SYMBOL_GPL(media_device_init); @@ -748,6 +768,15 @@ int __must_check __media_device_register(struct media_device *mdev, dev_dbg(mdev->dev, "Media device registered\n"); +#ifdef CONFIG_DEBUG_FS + if (!media_debugfs_root) + media_debugfs_root = debugfs_create_dir("media", NULL); + mdev->media_dir = debugfs_create_dir(dev_name(&devnode->dev), + media_debugfs_root); + debugfs_create_devm_seqfile(&devnode->dev, + "requests", mdev->media_dir, media_device_requests); +#endif + return 0; } EXPORT_SYMBOL_GPL(__media_device_register); @@ -824,6 +853,7 @@ void media_device_unregister(struct media_device *mdev) dev_dbg(mdev->dev, "Media device unregistered\n"); + debugfs_remove_recursive(mdev->media_dir); device_remove_file(&mdev->devnode->dev, &dev_attr_model); media_devnode_unregister(mdev->devnode); /* devnode free is handled in media_devnode_*() */ diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c index 318e267e798e..e01764fc1491 100644 --- a/drivers/media/mc/mc-devnode.c +++ b/drivers/media/mc/mc-devnode.c @@ -45,6 +45,9 @@ static dev_t media_dev_t; static DEFINE_MUTEX(media_devnode_lock); static DECLARE_BITMAP(media_devnode_nums, MEDIA_NUM_DEVICES); +/* debugfs */ +struct dentry *media_debugfs_root; + /* Called when the last user of the media device exits. */ static void media_devnode_release(struct device *cd) { @@ -237,6 +240,7 @@ int __must_check media_devnode_register(struct media_device *mdev, if (devnode->parent) devnode->dev.parent = devnode->parent; dev_set_name(&devnode->dev, "media%d", devnode->minor); + dev_set_drvdata(&devnode->dev, mdev); device_initialize(&devnode->dev); /* Part 2: Initialize the character device */ @@ -314,6 +318,7 @@ static int __init media_devnode_init(void) static void __exit media_devnode_exit(void) { + debugfs_remove_recursive(media_debugfs_root); bus_unregister(&media_bus_type); unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES); } diff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c index 1ad725522a7d..7f3d84e60ef8 100644 --- a/drivers/media/mc/mc-request.c +++ b/drivers/media/mc/mc-request.c @@ -75,6 +75,7 @@ static void media_request_release(struct kref *kref) mdev->ops->req_free(req); else kfree(req); + atomic_dec(&mdev->num_requests); } void media_request_put(struct media_request *req) @@ -332,6 +333,7 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd) snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d", atomic_inc_return(&mdev->request_id), fd); + atomic_inc(&mdev->num_requests); dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str); fd_install(fd, filp); @@ -359,6 +361,7 @@ static void media_request_object_release(struct kref *kref) if (WARN_ON(req)) media_request_object_unbind(obj); obj->ops->release(obj); + atomic_dec(&obj->mdev->num_request_objects); } struct media_request_object * @@ -423,6 +426,7 @@ int media_request_object_bind(struct media_request *req, obj->req = req; obj->ops = ops; obj->priv = priv; + obj->mdev = req->mdev; if (is_buffer) list_add_tail(&obj->list, &req->objects); @@ -430,6 +434,7 @@ int media_request_object_bind(struct media_request *req, list_add(&obj->list, &req->objects); req->num_incomplete_objects++; ret = 0; + atomic_inc(&obj->mdev->num_request_objects); unlock: spin_unlock_irqrestore(&req->lock, flags); diff --git a/include/media/media-device.h b/include/media/media-device.h index 53d2a16a70b0..749c327e3c58 100644 --- a/include/media/media-device.h +++ b/include/media/media-device.h @@ -11,6 +11,7 @@ #ifndef _MEDIA_DEVICE_H #define _MEDIA_DEVICE_H +#include #include #include #include @@ -106,6 +107,9 @@ struct media_device_ops { * @ops: Operation handler callbacks * @req_queue_mutex: Serialise the MEDIA_REQUEST_IOC_QUEUE ioctl w.r.t. * other operations that stop or start streaming. + * @num_requests: number of associated requests + * @num_request_objects: number of associated request objects + * @media_dir: DebugFS media directory * @request_id: Used to generate unique request IDs * * This structure represents an abstract high-level media device. It allows easy @@ -179,6 +183,11 @@ struct media_device { const struct media_device_ops *ops; struct mutex req_queue_mutex; + atomic_t num_requests; + atomic_t num_request_objects; + + /* debugfs */ + struct dentry *media_dir; atomic_t request_id; }; diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h index d27c1c646c28..dbcabeffcb57 100644 --- a/include/media/media-devnode.h +++ b/include/media/media-devnode.h @@ -20,9 +20,13 @@ #include #include #include +#include struct media_device; +/* debugfs top-level media directory */ +extern struct dentry *media_debugfs_root; + /* * Flag to mark the media_devnode struct as registered. Drivers must not touch * this flag directly, it will be set and cleared by media_devnode_register and diff --git a/include/media/media-request.h b/include/media/media-request.h index 6434758ab597..db0d9edfb38f 100644 --- a/include/media/media-request.h +++ b/include/media/media-request.h @@ -290,6 +290,7 @@ struct media_request_object_ops { * struct media_request_object - An opaque object that belongs to a media * request * + * @mdev: Media device this object belongs to * @ops: object's operations * @priv: object's priv pointer * @req: the request this object belongs to (can be NULL) @@ -301,6 +302,7 @@ struct media_request_object_ops { * another struct that contains the actual data for this request object. */ struct media_request_object { + struct media_device *mdev; const struct media_request_object_ops *ops; void *priv; struct media_request *req;