This is a note to let you know that I've just added the patch titled media: v4l2-mem2mem: Apply DST_QUEUE_OFF_BASE on MMAP buffers across ioctls to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: media-v4l2-mem2mem-apply-dst_queue_off_base-on-mmap-buffers-across-ioctls.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 8310ca94075e784bbb06593cd6c068ee6b6e4ca6 Mon Sep 17 00:00:00 2001 From: Chen-Yu Tsai <wenst@xxxxxxxxxxxx> Date: Thu, 9 Dec 2021 17:38:03 +0100 Subject: media: v4l2-mem2mem: Apply DST_QUEUE_OFF_BASE on MMAP buffers across ioctls From: Chen-Yu Tsai <wenst@xxxxxxxxxxxx> commit 8310ca94075e784bbb06593cd6c068ee6b6e4ca6 upstream. DST_QUEUE_OFF_BASE is applied to offset/mem_offset on MMAP capture buffers only for the VIDIOC_QUERYBUF ioctl, while the userspace fields (including offset/mem_offset) are filled in for VIDIOC_{QUERY,PREPARE,Q,DQ}BUF ioctls. This leads to differences in the values presented to userspace. If userspace attempts to mmap the capture buffer directly using values from DQBUF, it will fail. Move the code that applies the magic offset into a helper, and call that helper from all four ioctl entry points. [hverkuil: drop unnecessary '= 0' in v4l2_m2m_querybuf() for ret] Fixes: 7f98639def42 ("V4L/DVB: add memory-to-memory device helper framework for videobuf") Fixes: 908a0d7c588e ("[media] v4l: mem2mem: port to videobuf2") Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> [OP: backport to 5.4: adjusted return logic in v4l2_m2m_qbuf() to match the logic in the original commit: call v4l2_m2m_adjust_mem_offset() only if !ret and before the v4l2_m2m_try_schedule() call] Signed-off-by: Ovidiu Panait <ovidiu.panait@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/media/v4l2-core/v4l2-mem2mem.c | 60 +++++++++++++++++++++++++-------- 1 file changed, 46 insertions(+), 14 deletions(-) --- a/drivers/media/v4l2-core/v4l2-mem2mem.c +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c @@ -460,19 +460,14 @@ int v4l2_m2m_reqbufs(struct file *file, } EXPORT_SYMBOL_GPL(v4l2_m2m_reqbufs); -int v4l2_m2m_querybuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx, - struct v4l2_buffer *buf) +static void v4l2_m2m_adjust_mem_offset(struct vb2_queue *vq, + struct v4l2_buffer *buf) { - struct vb2_queue *vq; - int ret = 0; - unsigned int i; - - vq = v4l2_m2m_get_vq(m2m_ctx, buf->type); - ret = vb2_querybuf(vq, buf); - /* Adjust MMAP memory offsets for the CAPTURE queue */ if (buf->memory == V4L2_MEMORY_MMAP && !V4L2_TYPE_IS_OUTPUT(vq->type)) { if (V4L2_TYPE_IS_MULTIPLANAR(vq->type)) { + unsigned int i; + for (i = 0; i < buf->length; ++i) buf->m.planes[i].m.mem_offset += DST_QUEUE_OFF_BASE; @@ -480,8 +475,23 @@ int v4l2_m2m_querybuf(struct file *file, buf->m.offset += DST_QUEUE_OFF_BASE; } } +} + +int v4l2_m2m_querybuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx, + struct v4l2_buffer *buf) +{ + struct vb2_queue *vq; + int ret; - return ret; + vq = v4l2_m2m_get_vq(m2m_ctx, buf->type); + ret = vb2_querybuf(vq, buf); + if (ret) + return ret; + + /* Adjust MMAP memory offsets for the CAPTURE queue */ + v4l2_m2m_adjust_mem_offset(vq, buf); + + return 0; } EXPORT_SYMBOL_GPL(v4l2_m2m_querybuf); @@ -500,10 +510,16 @@ int v4l2_m2m_qbuf(struct file *file, str return -EPERM; } ret = vb2_qbuf(vq, vdev->v4l2_dev->mdev, buf); - if (!ret && !(buf->flags & V4L2_BUF_FLAG_IN_REQUEST)) + if (ret) + return ret; + + /* Adjust MMAP memory offsets for the CAPTURE queue */ + v4l2_m2m_adjust_mem_offset(vq, buf); + + if (!(buf->flags & V4L2_BUF_FLAG_IN_REQUEST)) v4l2_m2m_try_schedule(m2m_ctx); - return ret; + return 0; } EXPORT_SYMBOL_GPL(v4l2_m2m_qbuf); @@ -511,9 +527,17 @@ int v4l2_m2m_dqbuf(struct file *file, st struct v4l2_buffer *buf) { struct vb2_queue *vq; + int ret; vq = v4l2_m2m_get_vq(m2m_ctx, buf->type); - return vb2_dqbuf(vq, buf, file->f_flags & O_NONBLOCK); + ret = vb2_dqbuf(vq, buf, file->f_flags & O_NONBLOCK); + if (ret) + return ret; + + /* Adjust MMAP memory offsets for the CAPTURE queue */ + v4l2_m2m_adjust_mem_offset(vq, buf); + + return 0; } EXPORT_SYMBOL_GPL(v4l2_m2m_dqbuf); @@ -522,9 +546,17 @@ int v4l2_m2m_prepare_buf(struct file *fi { struct video_device *vdev = video_devdata(file); struct vb2_queue *vq; + int ret; vq = v4l2_m2m_get_vq(m2m_ctx, buf->type); - return vb2_prepare_buf(vq, vdev->v4l2_dev->mdev, buf); + ret = vb2_prepare_buf(vq, vdev->v4l2_dev->mdev, buf); + if (ret) + return ret; + + /* Adjust MMAP memory offsets for the CAPTURE queue */ + v4l2_m2m_adjust_mem_offset(vq, buf); + + return 0; } EXPORT_SYMBOL_GPL(v4l2_m2m_prepare_buf); Patches currently in stable-queue which might be from wenst@xxxxxxxxxxxx are queue-5.4/media-v4l2-mem2mem-apply-dst_queue_off_base-on-mmap-buffers-across-ioctls.patch