mainlining shenanigans
c13704f568
Previously, the kernel sometimes assigned more MMIO or MMIO_PREF space than desired. For example, if the user requested 128M of space with "pci=realloc,hpmemsize=128M", we sometimes assigned 256M: pci 0000:06:01.0: BAR 14: assigned [mem 0x90100000-0xa00fffff] = 256M pci 0000:06:04.0: BAR 14: assigned [mem 0xa0200000-0xb01fffff] = 256M With this patch applied: pci 0000:06:01.0: BAR 14: assigned [mem 0x90100000-0x980fffff] = 128M pci 0000:06:04.0: BAR 14: assigned [mem 0x98200000-0xa01fffff] = 128M This happened when in the first pass, the MMIO_PREF succeeded but the MMIO failed. In the next pass, because MMIO_PREF was already assigned, the attempt to assign MMIO_PREF returned an error code instead of success (nothing more to do, already allocated). Hence, the size which was actually allocated, but thought to have failed, was placed in the MMIO window. The bug resulted in the MMIO_PREF being added to the MMIO window, which meant doubling if MMIO_PREF size = MMIO size. With a large MMIO_PREF, the MMIO window would likely fail to be assigned altogether due to lack of 32-bit address space. Change find_free_bus_resource() to do the following: - Return first unassigned resource of the correct type. - If there is none, return first assigned resource of the correct type. - If none of the above, return NULL. Returning an assigned resource of the correct type allows the caller to distinguish between already assigned and no resource of the correct type. Add checks in pbus_size_io() and pbus_size_mem() to return success if resource returned from find_free_bus_resource() is already allocated. This avoids pbus_size_io() and pbus_size_mem() returning error code to __pci_bus_size_bridges() when a resource has been successfully assigned in a previous pass. This fixes the existing behaviour where space for a resource could be reserved multiple times in different parent bridge windows. Link: https://lore.kernel.org/lkml/20190531171216.20532-2-logang@deltatee.com/T/#u Link: https://bugzilla.kernel.org/show_bug.cgi?id=203243 Link: https://lore.kernel.org/r/PS2P216MB075563AA6AD242AA666EDC6A80760@PS2P216MB0755.KORP216.PROD.OUTLOOK.COM Reported-by: Kit Chow <kchow@gigaio.com> Reported-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au> Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.