On Mon, 11 Oct 2021 16:33:45 +0200 Cornelia Huck cohuck@redhat.com wrote:
On Mon, Oct 11 2021, Pierre Morel pmorel@linux.ibm.com 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?
Yes, that is what is documented.
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.
I don't think the extra care will hurt us too badly. I prefer to keep the IS_ERR_OR_NULL() check because it needs less domain specific knowledge to be understood, and because it is more robust.
Regards, Halil