On Mon, Oct 11 2021, Pierre Morel <pmorel@xxxxxxxxxxxxx> wrote:
> On 10/11/21 1:59 PM, Halil Pasic wrote:
>> diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
>> index 0fe7b2f2e7f5..c533d1dadc6b 100644
>> --- a/drivers/s390/cio/device_ops.c
>> +++ b/drivers/s390/cio/device_ops.c
>> @@ -825,13 +825,23 @@ EXPORT_SYMBOL_GPL(ccw_device_get_chid);
>> */
>> void *ccw_device_dma_zalloc(struct ccw_device *cdev, size_t size)
>> {
>> - return cio_gp_dma_zalloc(cdev->private->dma_pool, &cdev->dev, size);
>> + void *addr;
>> +
>> + if (!get_device(&cdev->dev))
>> + return NULL;
>> + addr = cio_gp_dma_zalloc(cdev->private->dma_pool, &cdev->dev, size);
>> + if (IS_ERR_OR_NULL(addr))
>
> I can be wrong but it seems that only dma_alloc_coherent() used in
> cio_gp_dma_zalloc() report an error but the error is ignored and used as
> a valid pointer.
Hm, I thought dma_alloc_coherent() returned either NULL or a valid
address?
>
> So shouldn't we modify this function and just test for a NULL address here?
If I read cio_gp_dma_zalloc() correctly, we either get NULL or a valid
address, so yes.
