Re: [PATCH v3 2/7] dmaengine: add a bus for DMA channel devices

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] dmaengine: unmap pool leak on error return in dma_bus_init()
--

commit 3da3c262ba473326c89ad5f74821c3da53e57669
Author: Peng Fan <peng.fan@nxp.com>

dmaengine: add a bus for DMA channel devices

This commit adds a dedicated dma_chan_bus_type bus for DMA channel devices
and registers it in dma_bus_init() so that per-channel IOMMU configuration
can work properly.

> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 34be53487a21d..6fea67f088b35 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -1643,17 +1643,35 @@ void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
>  }
>  EXPORT_SYMBOL_GPL(dma_run_dependencies);
>  
> +static int dma_chan_bus_match(struct device *dev,
> +			      const struct device_driver *drv)
> +{
> +	return 0;
> +}
> +
> +const struct bus_type dma_chan_bus_type = {
> +	.name  = "dma",
> +	.match = dma_chan_bus_match,
> +};
> +
>  static int __init dma_bus_init(void)
>  {
>  	int err = dmaengine_init_unmap_pool();
>  
> +	if (err)
> +		return err;
> +
> +	err = bus_register(&dma_chan_bus_type);
>  	if (err)
>  		return err;
>  
>  	err = class_register(&dma_devclass);
> -	if (!err)
> -		dmaengine_debugfs_init();
> +	if (err) {
> +		bus_unregister(&dma_chan_bus_type);
> +		return err;
> +	}

[Severity: Medium]
If bus_register(&dma_chan_bus_type) or class_register(&dma_devclass) fails in
dma_bus_init(), does this leak the slab caches and mempools allocated in
unmap_pool[] by dmaengine_init_unmap_pool()?

Previously, class_register(&dma_devclass) failure also missed calling
dmaengine_destroy_unmap_pool(), and the new bus_register() error path and
updated class_register() rollback path both return without calling
dmaengine_destroy_unmap_pool() to clean up unmap_pool[].

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261102-edma-iommu-v3-v3-0-9d0e62a954eb@Example.Com?part=2