928b607d1a
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. Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.