Re: [PATCH v2 3/8] s390/cio: add basic protected virtualization support

Sebastian Ott
2019-05-25T09:44:37Z

On Thu, 23 May 2019, Michael Mueller wrote:
> static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
> {
> struct ccw_device *cdev;
> + struct gen_pool *dma_pool;
>
> cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
> - if (cdev) {
> - cdev->private = kzalloc(sizeof(struct ccw_device_private),
> - GFP_KERNEL | GFP_DMA);
> - if (cdev->private)
> - return cdev;
> - }
> + if (!cdev)
> + goto err_cdev;
> + cdev->private = kzalloc(sizeof(struct ccw_device_private),
> + GFP_KERNEL | GFP_DMA);
> + if (!cdev->private)
> + goto err_priv;
> + cdev->dev.coherent_dma_mask = sch->dev.coherent_dma_mask;
> + cdev->dev.dma_mask = &cdev->dev.coherent_dma_mask;
> + dma_pool = cio_gp_dma_create(&cdev->dev, 1);

This can return NULL. gen_pool_alloc will panic in this case.
[...]

> +err_dma_area:
> + kfree(io_priv);

Indentation.

> +err_priv:
> + put_device(&sch->dev);
> + return ERR_PTR(-ENOMEM);
> }
[...]
> void ccw_device_update_sense_data(struct ccw_device *cdev)
> {
> memset(&cdev->id, 0, sizeof(cdev->id));
> - cdev->id.cu_type = cdev->private->senseid.cu_type;
> - cdev->id.cu_model = cdev->private->senseid.cu_model;
> - cdev->id.dev_type = cdev->private->senseid.dev_type;
> - cdev->id.dev_model = cdev->private->senseid.dev_model;
> + cdev->id.cu_type =
> + cdev->private->dma_area->senseid.cu_type;
> + cdev->id.cu_model =
> + cdev->private->dma_area->senseid.cu_model;
> + cdev->id.dev_type =
> + cdev->private->dma_area->senseid.dev_type;
> + cdev->id.dev_model =
> + cdev->private->dma_area->senseid.dev_model;

These fit into one line.

> +/**
> + * Allocate zeroed dma coherent 31 bit addressable memory using
> + * the subchannels dma pool. Maximal size of allocation supported
> + * is PAGE_SIZE.
> + */
drivers/s390/cio/device_ops.c:708: warning: Function parameter or member 'cdev' not described in 'ccw_device_dma_zalloc'
drivers/s390/cio/device_ops.c:708: warning: Function parameter or member 'size' not described in 'ccw_device_dma_zalloc'

Reviewed-by: Sebastian Ott <sebott@linux.ibm.com>