febb82c208
Refactor iommu_iotlb_gather_add_page() and factor out the logic that detects whether IOTLB gather range and a new range are disjoint. To be used by the next patch that implements different gathering logic for AMD. Note that updating gather->pgsize unconditionally does not affect correctness as the function had (and has) an invariant, in which gather->pgsize always represents the flushing granularity of its range. Arguably, “size" should never be zero, but lets assume for the matter of discussion that it might. If "size" equals to "gather->pgsize", then the assignment in question has no impact. Otherwise, if "size" is non-zero, then iommu_iotlb_sync() would initialize the size and range (see iommu_iotlb_gather_init()), and the invariant is kept. Otherwise, "size" is zero, and "gather" already holds a range, so gather->pgsize is non-zero and (gather->pgsize && gather->pgsize != size) is true. Therefore, again, iommu_iotlb_sync() would be called and initialize the size. Cc: Joerg Roedel <joro@8bytes.org> Cc: Jiajun Cao <caojiajun@vmware.com> Cc: Lu Baolu <baolu.lu@linux.intel.com> Cc: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Nadav Amit <namit@vmware.com> Link: https://lore.kernel.org/r/20210723093209.714328-5-namit@vmware.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
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.