On Sat, Feb 10, 2024 at 12:58 PM Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Sat, Feb 10, 2024, at 00:41, Linus Walleij wrote: > > The only difference is where the CPU have to read/write the > > buffers really, before the change those were all guaranteed to > > be in lowmem (bounced there by the block core), now they can > > also be in highmem, but sg_miter will deal with it for sure. > > Yes, that was my point: The sg_miter() code is meant to > handle exactly this case with highmem data, but as far > as I can tell, that code path has never been tested on > 32-bit systems with highmem but without BLK_BOUNCE_HIGH. It's actually possible to enforce testing of highmem scatterlists to an MMC card (one need to be careful as this is destructive testing!) drivers/mmc/core/mmc_test.c ...but the one relevant target I have is a Kirkwood and it only has 128 MB of memory so highmem won't be exercised. I'll put this into the cover letter on the other series (fixing a bunch of drivers to use sg_miter) though. Yours, Linus Walleij
