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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Ezequiel Garcia <ezequiel@collabora.com>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.18 040/136] media: sta2x11: Add video_device and
 vb2_queue locks
Thread-Topic: [PATCH AUTOSEL 4.18 040/136] media: sta2x11: Add video_device
 and vb2_queue locks
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Date:   Mon, 17 Sep 2018 03:00:37 +0000
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From: Ezequiel Garcia <ezequiel@collabora.com>

[ Upstream commit cd63c0288fd760ce7de247fba618e2bbcfc0c35c ]

Currently, this driver does not serialize its video4linux
ioctls, which is a bug, as race conditions might appear.

In addition, video_device and vb2_queue locks are now both
mandatory. Add them, and implement wait_prepare and
wait_finish.

To stay on the safe side, this commit uses a single mutex
for both locks. Better latency can be obtained by separating
these if needed.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/media/pci/sta2x11/sta2x11_vip.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/media/pci/sta2x11/sta2x11_vip.c b/drivers/media/pci/st=
a2x11/sta2x11_vip.c
index 069c4a853346..da2b2a2292d0 100644
--- a/drivers/media/pci/sta2x11/sta2x11_vip.c
+++ b/drivers/media/pci/sta2x11/sta2x11_vip.c
@@ -145,6 +145,7 @@ struct sta2x11_vip {
 	unsigned int sequence;
 	struct vip_buffer *active; /* current active buffer */
 	spinlock_t lock; /* Used in videobuf2 callback */
+	struct mutex v4l_lock;
=20
 	/* Interrupt counters */
 	int tcount, bcount;
@@ -385,6 +386,8 @@ static const struct vb2_ops vip_video_qops =3D {
 	.buf_queue		=3D buffer_queue,
 	.start_streaming	=3D start_streaming,
 	.stop_streaming		=3D stop_streaming,
+	.wait_prepare		=3D vb2_ops_wait_prepare,
+	.wait_finish		=3D vb2_ops_wait_finish,
 };
=20
=20
@@ -870,6 +873,7 @@ static int sta2x11_vip_init_buffer(struct sta2x11_vip *=
vip)
 	vip->vb_vidq.mem_ops =3D &vb2_dma_contig_memops;
 	vip->vb_vidq.timestamp_flags =3D V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
 	vip->vb_vidq.dev =3D &vip->pdev->dev;
+	vip->vb_vidq.lock =3D &vip->v4l_lock;
 	err =3D vb2_queue_init(&vip->vb_vidq);
 	if (err)
 		return err;
@@ -1034,6 +1038,7 @@ static int sta2x11_vip_init_one(struct pci_dev *pdev,
 	vip->std =3D V4L2_STD_PAL;
 	vip->format =3D formats_50[0];
 	vip->config =3D config;
+	mutex_init(&vip->v4l_lock);
=20
 	ret =3D sta2x11_vip_init_controls(vip);
 	if (ret)
@@ -1080,6 +1085,7 @@ static int sta2x11_vip_init_one(struct pci_dev *pdev,
 	vip->video_dev =3D video_dev_template;
 	vip->video_dev.v4l2_dev =3D &vip->v4l2_dev;
 	vip->video_dev.queue =3D &vip->vb_vidq;
+	vip->video_dev.lock =3D &vip->v4l_lock;
 	video_set_drvdata(&vip->video_dev, vip);
=20
 	ret =3D video_register_device(&vip->video_dev, VFL_TYPE_GRABBER, -1);
--=20
2.17.1