[media] media: v4l2-mem2mem: extend m2m APIs for more accurate buffer management

this add functions for:
  - remove buffers from src/dst queue by index
  - remove exact buffer from src/dst queue

also extends m2m API to iterate over a list of src/dst buffers
in safely and non-safely manner.
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/v4l2-core/v4l2-mem2mem.c

@@ -126,6 +126,43 @@ void *v4l2_m2m_buf_remove(struct v4l2_m2m_queue_ctx *q_ctx)
 }
 EXPORT_SYMBOL_GPL(v4l2_m2m_buf_remove);
 
+void v4l2_m2m_buf_remove_by_buf(struct v4l2_m2m_queue_ctx *q_ctx,
+				struct vb2_v4l2_buffer *vbuf)
+{
+	struct v4l2_m2m_buffer *b;
+	unsigned long flags;
+
+	spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
+	b = container_of(vbuf, struct v4l2_m2m_buffer, vb);
+	list_del(&b->list);
+	q_ctx->num_rdy--;
+	spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
+}
+EXPORT_SYMBOL_GPL(v4l2_m2m_buf_remove_by_buf);
+
+struct vb2_v4l2_buffer *
+v4l2_m2m_buf_remove_by_idx(struct v4l2_m2m_queue_ctx *q_ctx, unsigned int idx)
+
+{
+	struct v4l2_m2m_buffer *b, *tmp;
+	struct vb2_v4l2_buffer *ret = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
+	list_for_each_entry_safe(b, tmp, &q_ctx->rdy_queue, list) {
+		if (b->vb.vb2_buf.index == idx) {
+			list_del(&b->list);
+			q_ctx->num_rdy--;
+			ret = &b->vb;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_m2m_buf_remove_by_idx);
+
 /*
  * Scheduling handlers
  */

include/media/v4l2-mem2mem.h

@@ -436,6 +436,47 @@ static inline void *v4l2_m2m_next_dst_buf(struct v4l2_m2m_ctx *m2m_ctx)
 	return v4l2_m2m_next_buf(&m2m_ctx->cap_q_ctx);
 }
 
+/**
+ * v4l2_m2m_for_each_dst_buf() - iterate over a list of destination ready
+ * buffers
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @b: current buffer of type struct v4l2_m2m_buffer
+ */
+#define v4l2_m2m_for_each_dst_buf(m2m_ctx, b)	\
+	list_for_each_entry(b, &m2m_ctx->cap_q_ctx.rdy_queue, list)
+
+/**
+ * v4l2_m2m_for_each_src_buf() - iterate over a list of source ready buffers
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @b: current buffer of type struct v4l2_m2m_buffer
+ */
+#define v4l2_m2m_for_each_src_buf(m2m_ctx, b)	\
+	list_for_each_entry(b, &m2m_ctx->out_q_ctx.rdy_queue, list)
+
+/**
+ * v4l2_m2m_for_each_dst_buf_safe() - iterate over a list of destination ready
+ * buffers safely
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @b: current buffer of type struct v4l2_m2m_buffer
+ * @n: used as temporary storage
+ */
+#define v4l2_m2m_for_each_dst_buf_safe(m2m_ctx, b, n)	\
+	list_for_each_entry_safe(b, n, &m2m_ctx->cap_q_ctx.rdy_queue, list)
+
+/**
+ * v4l2_m2m_for_each_src_buf_safe() - iterate over a list of source ready
+ * buffers safely
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @b: current buffer of type struct v4l2_m2m_buffer
+ * @n: used as temporary storage
+ */
+#define v4l2_m2m_for_each_src_buf_safe(m2m_ctx, b, n)	\
+	list_for_each_entry_safe(b, n, &m2m_ctx->out_q_ctx.rdy_queue, list)
+
 /**
  * v4l2_m2m_get_src_vq() - return vb2_queue for source buffers
  *
@@ -488,6 +529,57 @@ static inline void *v4l2_m2m_dst_buf_remove(struct v4l2_m2m_ctx *m2m_ctx)
 	return v4l2_m2m_buf_remove(&m2m_ctx->cap_q_ctx);
 }
 
+/**
+ * v4l2_m2m_buf_remove_by_buf() - take off exact buffer from the list of ready
+ * buffers
+ *
+ * @q_ctx: pointer to struct @v4l2_m2m_queue_ctx
+ * @vbuf: the buffer to be removed
+ */
+void v4l2_m2m_buf_remove_by_buf(struct v4l2_m2m_queue_ctx *q_ctx,
+				struct vb2_v4l2_buffer *vbuf);
+
+/**
+ * v4l2_m2m_src_buf_remove_by_buf() - take off exact source buffer from the list
+ * of ready buffers
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @vbuf: the buffer to be removed
+ */
+static inline void v4l2_m2m_src_buf_remove_by_buf(struct v4l2_m2m_ctx *m2m_ctx,
+						  struct vb2_v4l2_buffer *vbuf)
+{
+	v4l2_m2m_buf_remove_by_buf(&m2m_ctx->out_q_ctx, vbuf);
+}
+
+/**
+ * v4l2_m2m_dst_buf_remove_by_buf() - take off exact destination buffer from the
+ * list of ready buffers
+ *
+ * @m2m_ctx: m2m context assigned to the instance given by struct &v4l2_m2m_ctx
+ * @vbuf: the buffer to be removed
+ */
+static inline void v4l2_m2m_dst_buf_remove_by_buf(struct v4l2_m2m_ctx *m2m_ctx,
+						  struct vb2_v4l2_buffer *vbuf)
+{
+	v4l2_m2m_buf_remove_by_buf(&m2m_ctx->cap_q_ctx, vbuf);
+}
+
+struct vb2_v4l2_buffer *
+v4l2_m2m_buf_remove_by_idx(struct v4l2_m2m_queue_ctx *q_ctx, unsigned int idx);
+
+static inline struct vb2_v4l2_buffer *
+v4l2_m2m_src_buf_remove_by_idx(struct v4l2_m2m_ctx *m2m_ctx, unsigned int idx)
+{
+	return v4l2_m2m_buf_remove_by_idx(&m2m_ctx->out_q_ctx, idx);
+}
+
+static inline struct vb2_v4l2_buffer *
+v4l2_m2m_dst_buf_remove_by_idx(struct v4l2_m2m_ctx *m2m_ctx, unsigned int idx)
+{
+	return v4l2_m2m_buf_remove_by_idx(&m2m_ctx->cap_q_ctx, idx);
+}
+
 /* v4l2 ioctl helpers */
 
 int v4l2_m2m_ioctl_reqbufs(struct file *file, void *priv,