14 May
2020
14 May
'20
2:39 p.m.
On Thu, May 14, 2020 at 02:09:44PM +0200, Greg Kroah-Hartman wrote:
if (dma_mmap_coherent(hcd->self.sysdev, vma, mem, dma_handle,size)) {dec_usb_memory_use_count(usbm, &usbm->vma_use_count);return -EAGAIN;}What about a goto label to share the error handling path?
I thought about that, but that's a bit messier than the duplicated lines here :)
Actually the error handling looks weird, we can just use normal unwinding here with an extra call to usb_free_coherent. Also -EAGAIN is a strange error to return in this case, as it is simply incorrect. I think passing through the errors from dma_mmap_coherent and remap_pfn_range would make a lot more sense.
Last but not least I wonder if this is the right place to open code the localmem and has_dma checks - from a layering POV it should be a usb_mmap_coherent helper at the same level as usb_alloc_coherent.