On Sat, May 11, 2024 at 08:40:57AM -0600, Jens Axboe wrote: > By default, this will be 511, as that's the block layer default. But > drivers these days can support memory alignments that aren't tied to > the sector sizes, instead just being limited by what the DMA engine > supports. An example is NVMe, where it's generally set to a 32-bit or > 64-bit boundary. As ublk itself doesn't really care, just set it low > enough that we don't run into issues with NVMe where the required > O_DIRECT memory alignment is now more restrictive on ublk than it is > on the underlying device. > > This was triggered by spurious -EINVAL returns on O_DIRECT IO on a > setup with ublk managing NVMe devices, which previously worked just > fine on the NVMe device itself. With the alignment relaxed, the test > works fine. > > Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> It should be triggered since DIO DMA alignment is relaxed: Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> Thanks, Ming
