7610ab57de
The umem DMA list calculation was locked at 4k pages due to confusion around how this API works and is used when larger pages are present. The conclusion is: - umem's cannot extend past what is mapped into the process, so creating a lage page size and referring to a sub-range is not allowed - umem's must always have a page offset of zero, except for sub PAGE_SIZE umems - The feature of umem_offset to create multiple objects inside a umem is buggy and isn't used anyplace. Thus we can assume all users of the current API have umem_offset == 0 as well Provide a new page size calculator that limits the DMA list to the VA range and enforces umem_offset == 0. Allow user space to specify the page sizes which it can accept, this bitmap must be derived from the intended use of the umem, based on per-usage HW limitations. Link: https://lore.kernel.org/r/20210304130501.1102577-4-leon@kernel.org Signed-off-by: Yishai Hadas <yishaih@nvidia.com> Signed-off-by: Leon Romanovsky <leonro@nvidia.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
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 Restructured Text 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.