Re: [PATCH v2 2/2] misc: fastrpc: Move prints outside spinlock in fastrpc_cb_probe

[Bjorn Andersson <andersson@kernel.org>]

On Mon, May 04, 2026 at 10:47:01PM +0530, Mukesh Ojha wrote:
> dev_err() and dev_info() were called while holding a spinlock with
> IRQs disabled, which is incorrect as printk can be slow and should
> not be called in atomic context.
> 
> Move the dev_err() for the FASTRPC_MAX_SESSIONS check to after the
> spinlock is released, and save the return value of of_property_read_u32()
> to print dev_info() after the lock is dropped. Minor variable style
> correction in probe function.
> 

Reviewed-by: Bjorn Andersson <andersson@kernel.org>

Regards,
Bjorn

> Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
> ---
> Changes in v2:
>  - New change.
> 
>  drivers/misc/fastrpc.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index a1a54453bb7e..d169dea961f0 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -2197,19 +2197,22 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	int i, sessions = 0;
>  	unsigned long flags;
> -	int rc;
>  	u32 dma_bits;
> +	u32 sid = 0;
> +	int rc;
>  
>  	cctx = dev_get_drvdata(dev->parent);
>  	if (!cctx)
>  		return -EINVAL;
>  
>  	of_property_read_u32(dev->of_node, "qcom,nsessions", &sessions);
> +	if (of_property_read_u32(dev->of_node, "reg", &sid))
> +		dev_info(dev, "FastRPC Session ID not specified in DT\n");
>  
>  	spin_lock_irqsave(&cctx->lock, flags);
>  	if (cctx->sesscount >= FASTRPC_MAX_SESSIONS) {
> -		dev_err(&pdev->dev, "too many sessions\n");
>  		spin_unlock_irqrestore(&cctx->lock, flags);
> +		dev_err(&pdev->dev, "too many sessions\n");
>  		return -ENOSPC;
>  	}
>  	dma_bits = cctx->soc_data->dma_addr_bits_default;
> @@ -2218,13 +2221,11 @@ static int fastrpc_cb_probe(struct platform_device *pdev)
>  	sess->valid = true;
>  	sess->dev = dev;
>  	dev_set_drvdata(dev, sess);
> +	sess->sid = sid;
>  
>  	if (cctx->domain_id == CDSP_DOMAIN_ID)
>  		dma_bits = cctx->soc_data->dma_addr_bits_cdsp;
>  
> -	if (of_property_read_u32(dev->of_node, "reg", &sess->sid))
> -		dev_info(dev, "FastRPC Session ID not specified in DT\n");
> -
>  	if (sessions > 0) {
>  		struct fastrpc_session_ctx *dup_sess;
>  
> -- 
> 2.53.0
> 
>