On 05/05/18 09:22, Hans de Goede wrote: > The recent "x86 ZONE_DMA love" discussion at LSF/MM pointed out that some > gspca sub-drivvers are using GFP_DMA to allocate buffers which are used > for USB bulk transfers, there is absolutely no need for this, drop it. > The documentation for kmalloc() says GFP_DMA - Allocation suitable for DMA. end at least in sq905.c the allocation is passed to the USB stack that then uses it for DMA. Looking a bit closer the "suitable for DMA" label that GFP_DMA promises is not really a sensible thing for kmalloc() to determine as it is dependent on the DMA controller in question. The USB stack now ensures that everything works correctly as long as the memory is allocated with kmalloc() so acked by me for sq905.c but, is anyone taking care of fixing the kmalloc() documentation? Adam Baker
