On 2023-08-21 14:19, Laurent Pinchart wrote:
[...]
+ viif_dev->tables =
+ dma_alloc_wc(dev, sizeof(struct viif_table_area), &tables_dma, GFP_KERNEL);
+ if (!viif_dev->tables) {
+ dev_err(dev, "dma_alloc_wc failed\n");
Are you sure DMA memory allocation errors shall be printed?
Printing this error is useless for users in general?
If so, I'll drop this debug output.
Failures to allocate memory in the kernel generally result in warning
messages being printed by the allocation function, so there's no need to
do so manually in drivers. This being said, I check dma_alloc_wc()
(which is a wrapper around dma_alloc_attrs()), and unless I'm missing
something, it can return NULL without printing any error. I don't know
if this is an oversight in some code paths taken by dma_alloc_attrs() or
if it's on purpose. Maybe Christoph, Marek or Roben will known.
Yeah, there might be a few edge cases, but in most cases
dma_alloc_attrs() will end up falling back to the page allocator as a
last resort if all the more preferred allocation options fail, and thus
complete failure should eventually cause that to scream unless
DMA_ATTR_NO_WARN was specified.
Thanks,
Robin.
