Re: [PATCH] usb: gadget: pch_udc: add checks for dma mapping errors

From: Felipe Balbi
Date: Wed Sep 20 2017 - 07:54:10 EST



Hi,

Alexey Khoroshilov <khoroshilov@xxxxxxxxx> writes:
>>> diff --git a/drivers/usb/gadget/udc/pch_udc.c b/drivers/usb/gadget/udc/pch_udc.c
>>> index 84dcbcd756f0..a305f8392082 100644
>>> --- a/drivers/usb/gadget/udc/pch_udc.c
>>> +++ b/drivers/usb/gadget/udc/pch_udc.c
>>> @@ -1767,7 +1767,7 @@ static struct usb_request *pch_udc_alloc_request(struct usb_ep *usbep,
>>> req->req.dma = DMA_ADDR_INVALID;
>>> req->dma = DMA_ADDR_INVALID;
>>> INIT_LIST_HEAD(&req->queue);
>>> - if (!ep->dev->dma_addr)
>>> + if (ep->dev->dma_addr != DMA_ADDR_INVALID)
>>> return &req->req;
>>> /* ep0 in requests are allocated from data pool here */
>>> dma_desc = dma_pool_alloc(ep->dev->data_requests, gfp,
>>> @@ -1879,6 +1879,13 @@ static int pch_udc_pcd_queue(struct usb_ep *usbep, struct usb_request *usbreq,
>>> usbreq->length,
>>> DMA_FROM_DEVICE);
>>> }
>>> + if (dma_mapping_error(&dev->pdev->dev, req->dma)) {
>>> + req->dma = DMA_ADDR_INVALID;
>>> + retval = -ENOMEM;
>>> + if ((unsigned long)(usbreq->buf) & 0x03)
>>> + kfree(req->buf);
>>> + goto probe_end;
>>> + }
>>> req->dma_mapped = 1;
>>> }
>>> if (usbreq->length > 0) {
>>> @@ -2961,6 +2968,10 @@ static int init_dma_pools(struct pch_udc_dev *dev)
>>> dev->dma_addr = dma_map_single(&dev->pdev->dev, ep0out_buf,
>>> UDC_EP0OUT_BUFF_SIZE * 4,
>>> DMA_FROM_DEVICE);
>>> + if (dma_mapping_error(&dev->pdev->dev, dev->dma_addr)) {
>>> + dev->dma_addr = DMA_ADDR_INVALID;
>>> + return -ENOMEM;
>>> + }
>>
>> Wouldn't this driver be better off using the
>> usb_gadget_{map,unmap}_request() functions provided by UDC core.c?
>> dma_mapping_error() is provided for free that way.
>>
>
> I think so, but it requires quite significant rework of the driver.
> I would not do that without access to hardware.

I'd prefer to see a conversion to the generic helpers.

--
balbi

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