From: Robin Murphy > Sent: 14 June 2019 16:06 ... > Well, apart from the bit in DMA-API-HOWTO which has said this since > forever (well, before Git history, at least): > > "The CPU virtual address and the DMA address are both > guaranteed to be aligned to the smallest PAGE_SIZE order which > is greater than or equal to the requested size. This invariant > exists (for example) to guarantee that if you allocate a chunk > which is smaller than or equal to 64 kilobytes, the extent of the > buffer you receive will not cross a 64K boundary." I knew it was somewhere :-) Interestingly that also implies that the address returned for a size of (say) 128 will also be page aligned. In that case 128 byte alignment should probably be ok - but it is still an API change that could have horrid consequences. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
