On 5/25/2023 6:23 AM, Sergey Senozhatsky wrote:
> On (23/05/24 22:06), Vikash Garodia wrote:
>>> Instead the struct v4l2_m2m_ctx q_lock pointer, if set, will use that
>>> mutex for all vb2 operations.
>>>
>>> I think you can set it to the 'lock' mutex in struct venus_inst.
>>
>> IIUC, the suggestion is to use the 'lock' in struct venus_inst while
>> initializing the queue. This might lead to deadlock as the same lock is used
>> during vb2 operations in driver. Might be introducing a new lock for this
>> purpose in struct venus_inst would do, unless we are trying to serialize at
>> video device (or core) context.
>
> Something like this?
>
> Video device has to provide a lock so that __video_do_ioctl()
> can serialize IOCTL calls. Introduce a dedicated venus_inst
> mutex (which is set a ctx ->q_lock) for the purpose of vb2
> operations synchronization.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> ---
> drivers/media/platform/qcom/venus/core.h | 2 ++
> drivers/media/platform/qcom/venus/vdec.c | 4 ++++
> drivers/media/platform/qcom/venus/venc.c | 3 +++
> 3 files changed, 9 insertions(+)
>
> diff --git a/drivers/media/platform/qcom/venus/core.h b/drivers/media/platform/qcom/venus/core.h
> index 4f81669986ba..6ac5236d6888 100644
> --- a/drivers/media/platform/qcom/venus/core.h
> +++ b/drivers/media/platform/qcom/venus/core.h
> @@ -389,6 +389,7 @@ enum venus_inst_modes {
> * @sequence_out: a sequence counter for output queue
> * @m2m_dev: a reference to m2m device structure
> * @m2m_ctx: a reference to m2m context structure
> + * @ctx_queue_lock: a lock to serialize video device ioctl calls
suggestion: we can keep this as ctx_q_lock.
> * @state: current state of the instance
> * @done: a completion for sync HFI operation
> * @error: an error returned during last HFI sync operation
> @@ -460,6 +461,7 @@ struct venus_inst {
> u32 sequence_out;
> struct v4l2_m2m_dev *m2m_dev;
> struct v4l2_m2m_ctx *m2m_ctx;
> + struct mutex ctx_queue_lock;
> unsigned int state;
> struct completion done;
> unsigned int error;
> diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c
> index 51a53bf82bd3..2caeba5b6378 100644
> --- a/drivers/media/platform/qcom/venus/vdec.c
> +++ b/drivers/media/platform/qcom/venus/vdec.c
> @@ -1641,6 +1641,7 @@ static int vdec_open(struct file *file)
> INIT_LIST_HEAD(&inst->internalbufs);
> INIT_LIST_HEAD(&inst->list);
> mutex_init(&inst->lock);
> + mutex_init(&inst->ctx_queue_lock);
>
> inst->core = core;
> inst->session_type = VIDC_SESSION_TYPE_DEC;
> @@ -1684,8 +1685,10 @@ static int vdec_open(struct file *file)
> goto err_m2m_release;
> }
>
> +
> v4l2_fh_init(&inst->fh, core->vdev_dec);
>
> + inst->m2m_ctx->q_lock = &inst->ctx_queue_lock;
Better to do this in queue_init callback i.e "m2m_queue_init" in vdec.c.
src_vq->lock = &inst->ctx_q_lock;
...
dst_vq->lock = src_vq->lock;
> inst->fh.ctrl_handler = &inst->ctrl_handler;
> v4l2_fh_add(&inst->fh);
> inst->fh.m2m_ctx = inst->m2m_ctx;
> @@ -1716,6 +1719,7 @@ static int vdec_close(struct file *file)
> ida_destroy(&inst->dpb_ids);
> hfi_session_destroy(inst);
> mutex_destroy(&inst->lock);
> + mutex_destroy(&inst->ctx_queue_lock);
> v4l2_fh_del(&inst->fh);
> v4l2_fh_exit(&inst->fh);
>
> diff --git a/drivers/media/platform/qcom/venus/venc.c b/drivers/media/platform/qcom/venus/venc.c
> index 4666f42feea3..4292b299f014 100644
> --- a/drivers/media/platform/qcom/venus/venc.c
> +++ b/drivers/media/platform/qcom/venus/venc.c
> @@ -1443,6 +1443,7 @@ static int venc_open(struct file *file)
> INIT_LIST_HEAD(&inst->internalbufs);
> INIT_LIST_HEAD(&inst->list);
> mutex_init(&inst->lock);
> + mutex_init(&inst->ctx_queue_lock);
>
> inst->core = core;
> inst->session_type = VIDC_SESSION_TYPE_ENC;
> @@ -1483,6 +1484,7 @@ static int venc_open(struct file *file)
>
> v4l2_fh_init(&inst->fh, core->vdev_enc);
>
> + inst->m2m_ctx->q_lock = &inst->ctx_queue_lock;
Same comment applies here. This can be moved to "m2m_queue_init" in venc.c.
> inst->fh.ctrl_handler = &inst->ctrl_handler;
> v4l2_fh_add(&inst->fh);
> inst->fh.m2m_ctx = inst->m2m_ctx;
> @@ -1512,6 +1514,7 @@ static int venc_close(struct file *file)
> venc_ctrl_deinit(inst);
> hfi_session_destroy(inst);
> mutex_destroy(&inst->lock);
> + mutex_destroy(&inst->ctx_queue_lock);
> v4l2_fh_del(&inst->fh);
> v4l2_fh_exit(&inst->fh);
>
