Re: [PATCH v2 3/3] arch/*/: remove CONFIG_VIRT_TO_BUS

Christoph Hellwig
2022-06-29T06:22:02Z

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.