FAILED: patch "[PATCH] [media] vb2: Only requeue buffers immediately once streaming" failed to apply to 4.1-stable tree

FAILED: patch "[PATCH] [media] vb2: Only requeue buffers immediately once streaming" failed to apply to 4.1-stable tree

[gregkh]

The patch below does not apply to the 4.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 6d058c5643e16779ae4c001d2e893c140940e48f Mon Sep 17 00:00:00 2001
From: Sakari Ailus <sakari.ailus@linux.intel.com>
Date: Fri, 3 Jul 2015 04:37:07 -0300
Subject: [PATCH] [media] vb2: Only requeue buffers immediately once streaming
 is started

Buffers can be returned back to videobuf2 in driver's streamon handler. In
this case vb2_buffer_done() with buffer state VB2_BUF_STATE_QUEUED will
cause the driver's buf_queue vb2 operation to be called, queueing the same
buffer again only to be returned to videobuf2 using vb2_buffer_done() and so
on.

Add a new buffer state VB2_BUF_STATE_REQUEUEING which, when used as the
state argument to vb2_buffer_done(), will result in buffers queued to the
driver. Using VB2_BUF_STATE_QUEUED will leave the buffer to videobuf2, as it
was before "[media] vb2: allow requeuing buffers while streaming".

Fixes: ce0eff016f72 ("[media] vb2: allow requeuing buffers while streaming")

[mchehab@osg.samsung.com: fix warning: enumeration value 'VB2_BUF_STATE_REQUEUEING' not handled in switch]

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: stable@vger.kernel.org # for v4.1
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/pci/cobalt/cobalt-irq.c b/drivers/media/pci/cobalt/cobalt-irq.c
index dd4bff9cf339..d1f5898d11ba 100644
--- a/drivers/media/pci/cobalt/cobalt-irq.c
+++ b/drivers/media/pci/cobalt/cobalt-irq.c
@@ -139,7 +139,7 @@ done:
 	   also know about dropped frames. */
 	cb->vb.v4l2_buf.sequence = s->sequence++;
 	vb2_buffer_done(&cb->vb, (skip || s->unstable_frame) ?
-			VB2_BUF_STATE_QUEUED : VB2_BUF_STATE_DONE);
+			VB2_BUF_STATE_REQUEUEING : VB2_BUF_STATE_DONE);
 }
 
 irqreturn_t cobalt_irq_handler(int irq, void *dev_id)
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 93b315459098..0c7b6a7ad2b4 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -715,6 +715,7 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, struct v4l2_buffer *b)
 		break;
 	case VB2_BUF_STATE_PREPARING:
 	case VB2_BUF_STATE_DEQUEUED:
+	case VB2_BUF_STATE_REQUEUEING:
 		/* nothing */
 		break;
 	}
@@ -1182,7 +1183,8 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
 
 	if (WARN_ON(state != VB2_BUF_STATE_DONE &&
 		    state != VB2_BUF_STATE_ERROR &&
-		    state != VB2_BUF_STATE_QUEUED))
+		    state != VB2_BUF_STATE_QUEUED &&
+		    state != VB2_BUF_STATE_REQUEUEING))
 		state = VB2_BUF_STATE_ERROR;
 
 #ifdef CONFIG_VIDEO_ADV_DEBUG
@@ -1199,22 +1201,30 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
 	for (plane = 0; plane < vb->num_planes; ++plane)
 		call_void_memop(vb, finish, vb->planes[plane].mem_priv);
 
-	/* Add the buffer to the done buffers list */
 	spin_lock_irqsave(&q->done_lock, flags);
-	vb->state = state;
-	if (state != VB2_BUF_STATE_QUEUED)
+	if (state == VB2_BUF_STATE_QUEUED ||
+	    state == VB2_BUF_STATE_REQUEUEING) {
+		vb->state = VB2_BUF_STATE_QUEUED;
+	} else {
+		/* Add the buffer to the done buffers list */
 		list_add_tail(&vb->done_entry, &q->done_list);
+		vb->state = state;
+	}
 	atomic_dec(&q->owned_by_drv_count);
 	spin_unlock_irqrestore(&q->done_lock, flags);
 
-	if (state == VB2_BUF_STATE_QUEUED) {
+	switch (state) {
+	case VB2_BUF_STATE_QUEUED:
+		return;
+	case VB2_BUF_STATE_REQUEUEING:
 		if (q->start_streaming_called)
 			__enqueue_in_driver(vb);
 		return;
+	default:
+		/* Inform any processes that may be waiting for buffers */
+		wake_up(&q->done_wq);
+		break;
 	}
-
-	/* Inform any processes that may be waiting for buffers */
-	wake_up(&q->done_wq);
 }
 EXPORT_SYMBOL_GPL(vb2_buffer_done);
 
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 22a44c2f5963..c192e1b46cdc 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -139,6 +139,7 @@ enum vb2_io_modes {
  * @VB2_BUF_STATE_PREPARING:	buffer is being prepared in videobuf
  * @VB2_BUF_STATE_PREPARED:	buffer prepared in videobuf and by the driver
  * @VB2_BUF_STATE_QUEUED:	buffer queued in videobuf, but not in driver
+ * @VB2_BUF_STATE_REQUEUEING:	re-queue a buffer to the driver
  * @VB2_BUF_STATE_ACTIVE:	buffer queued in driver and possibly used
  *				in a hardware operation
  * @VB2_BUF_STATE_DONE:		buffer returned from driver to videobuf, but
@@ -152,6 +153,7 @@ enum vb2_buffer_state {
 	VB2_BUF_STATE_PREPARING,
 	VB2_BUF_STATE_PREPARED,
 	VB2_BUF_STATE_QUEUED,
+	VB2_BUF_STATE_REQUEUEING,
 	VB2_BUF_STATE_ACTIVE,
 	VB2_BUF_STATE_DONE,
 	VB2_BUF_STATE_ERROR,

Re: FAILED: patch "[PATCH] [media] vb2: Only requeue buffers immediately once streaming" failed to apply to 4.1-stable tree

[Sakari Ailus]

Hi Greg,

gregkh@linuxfoundation.org wrote:
>
> The patch below does not apply to the 4.1-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

For some reason I was under the impression the patch was needed for 
v4.1. However, I can now see that e0eff016f72 ("[media] vb2: allow 
requeuing buffers while streaming") which caused the original issue is 
only in v4.2 (with the fix on top).

So this patch can be safely ignored when it comes to stable.

My apologies for the noise.

-- 
Kind regards,

Sakari Ailus
sakari.ailus@linux.intel.com