include/media/media-request.h

Source file repositories/reference/linux-study-clean/include/media/media-request.h

File Facts

System
Linux kernel
Corpus path
include/media/media-request.h
Extension
.h
Size
13581 bytes
Lines
481
Domain
Repository Root And Misc
Bucket
include
Inferred role
Repository Root And Misc: implementation source
Status
source implementation candidate

Why This File Exists

Top-level or miscellaneous repository surface. Use this as map coverage unless a later manual pass promotes the file into a deeper subsystem dossier.

Dependency Surface

Detected Declarations

Annotated Snippet

struct media_request {
	struct media_device *mdev;
	struct kref kref;
	char debug_str[TASK_COMM_LEN + 11];
	enum media_request_state state;
	unsigned int updating_count;
	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;
};

#ifdef CONFIG_MEDIA_CONTROLLER

/**
 * media_request_lock_for_access - Lock the request to access its objects
 *
 * @req: The media request
 *
 * Use before accessing a completed request. A reference to the request must
 * be held during the access. This usually takes place automatically through
 * a file handle. Use @media_request_unlock_for_access when done.
 */
static inline int __must_check
media_request_lock_for_access(struct media_request *req)
{
	unsigned long flags;
	int ret = -EBUSY;

	spin_lock_irqsave(&req->lock, flags);
	if (req->state == MEDIA_REQUEST_STATE_COMPLETE) {
		req->access_count++;
		ret = 0;
	}
	spin_unlock_irqrestore(&req->lock, flags);

	return ret;
}

/**
 * media_request_unlock_for_access - Unlock a request previously locked for
 *				     access
 *
 * @req: The media request
 *
 * Unlock a request that has previously been locked using
 * @media_request_lock_for_access.
 */
static inline void media_request_unlock_for_access(struct media_request *req)
{
	unsigned long flags;

	spin_lock_irqsave(&req->lock, flags);
	if (!WARN_ON(!req->access_count))
		req->access_count--;
	spin_unlock_irqrestore(&req->lock, flags);
}

/**
 * media_request_lock_for_update - Lock the request for updating its objects
 *
 * @req: The media request
 *
 * Use before updating a request, i.e. adding, modifying or removing a request
 * object in it. A reference to the request must be held during the update. This
 * usually takes place automatically through a file handle. Use
 * @media_request_unlock_for_update when done.
 */
static inline int __must_check
media_request_lock_for_update(struct media_request *req)
{
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&req->lock, flags);
	if (req->state == MEDIA_REQUEST_STATE_IDLE ||
	    req->state == MEDIA_REQUEST_STATE_UPDATING) {
		req->state = MEDIA_REQUEST_STATE_UPDATING;
		req->updating_count++;
	} else {
		ret = -EBUSY;
	}
	spin_unlock_irqrestore(&req->lock, flags);

	return ret;
}

/**

Annotation

Implementation Notes