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When adding a large scatterlist entry that covers more than the L3 superpage size (1GB) but has an alignment such that we must use L2 superpages (2MB) , we give dma_pte_free_level() a range that causes it to free the L3 pagetable we're about to populate. We fix this by telling dma_pte_free_pagetable() about the pagetable level we're about to populate to prevent freeing it. For example, mapping a scatterlist with entry lengths 854MB and 1194MB at IOVA 0xffff80000000 would, when processing the 2MB-aligned second entry, cause pfn_to_dma_pte() to create a L3 directory to hold L2 superpages for the mapping at IOVA 0xffffc0000000. We would previously call dma_pte_free_pagetable(domain, 0xffffc0000, 0xfffffffff), which would free the L3 directory pfn_to_dma_pte() just created for IO PFN 0xffffc0000. Telling dma_pte_free_pagetable() to retain the L3 directories while using L2 superpages avoids the erroneous free. Signed-off-by: David Dillow <dillow@google.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.