On Wed, Jun 29, 2022 at 11:09:00AM +1200, Michael Schmitz wrote: > And all SCSI buffers are allocated using kmalloc? No way at all for user > space to pass unaligned data? Most that you will see actually comes from the page allocator. But the block layer has a dma_alignment limit, and when userspace sends I/O that is not properly aligned it will be bounce buffered before it it sent to the driver.