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ib_umem_num_pages() should only be used by things working with the SGL in CPU pages directly. Drivers building DMA lists should use the new ib_num_dma_blocks() which returns the number of blocks rdma_umem_for_each_block() will return. To make this general for DMA drivers requires a different implementation. Computing DMA block count based on umem->address only works if the requested page size is < PAGE_SIZE and/or the IOVA == umem->address. Instead the number of DMA pages should be computed in the IOVA address space, not umem->address. Thus the IOVA has to be stored inside the umem so it can be used for these calculations. For now set it to umem->address by default and fix it up if ib_umem_find_best_pgsz() was called. This allows drivers to be converted to ib_umem_num_dma_blocks() safely. Link: https://lore.kernel.org/r/6-v2-270386b7e60b+28f4-umem_1_jgg@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.