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Filename Latest commit message Latest commit date
Anshuman Khandual 9c9ea7ac18 arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory
[ Upstream commit eeb0753ba27b26f609e61f9950b14f1b934fe429 ]

pfn_valid() validates a pfn but basically it checks for a valid struct page
backing for that pfn. It should always return positive for memory ranges
backed with struct page mapping. But currently pfn_valid() fails for all
ZONE_DEVICE based memory types even though they have struct page mapping.

pfn_valid() asserts that there is a memblock entry for a given pfn without
MEMBLOCK_NOMAP flag being set. The problem with ZONE_DEVICE based memory is
that they do not have memblock entries. Hence memblock_is_map_memory() will
invariably fail via memblock_search() for a ZONE_DEVICE based address. This
eventually fails pfn_valid() which is wrong. memblock_is_map_memory() needs
to be skipped for such memory ranges. As ZONE_DEVICE memory gets hotplugged
into the system via memremap_pages() called from a driver, their respective
memory sections will not have SECTION_IS_EARLY set.

Normal hotplug memory will never have MEMBLOCK_NOMAP set in their memblock
regions. Because the flag MEMBLOCK_NOMAP was specifically designed and set
for firmware reserved memory regions. memblock_is_map_memory() can just be
skipped as its always going to be positive and that will be an optimization
for the normal hotplug memory. Like ZONE_DEVICE based memory, all normal
hotplugged memory too will not have SECTION_IS_EARLY set for their sections

Skipping memblock_is_map_memory() for all non early memory sections would
fix pfn_valid() problem for ZONE_DEVICE based memory and also improve its
performance for normal hotplug memory as well.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Acked-by: David Hildenbrand <david@redhat.com>
Fixes: 73b20c84d4 ("arm64: mm: implement pte_devmap support")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/1614921898-4099-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-17 17:03:56 +01:00
arch arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory 2021-03-17 17:03:56 +01:00
block blk-settings: align max_sectors on "logical_block_size" boundary 2021-03-04 10:26:40 +01:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: tcrypt - avoid signed overflow in byte count 2021-03-07 12:20:46 +01:00
Documentation sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output 2021-03-07 12:20:48 +01:00
drivers sh_eth: fix TRSCER mask for R7S72100 2021-03-17 17:03:55 +01:00
fs udf: fix silent AED tagLocation corruption 2021-03-17 17:03:41 +01:00
include scsi: target: core: Add cmd length set before cmd complete 2021-03-17 17:03:45 +01:00
init fgraph: Initialize tracing_graph_pause at task creation 2021-02-10 09:25:29 +01:00
ipc
kernel sysctl.c: fix underflow value setting risk in vm_table 2021-03-17 17:03:45 +01:00
lib PCI: Fix pci_register_io_range() memory leak 2021-03-17 17:03:44 +01:00
LICENSES
mm Revert "mm, slub: consider rest of partial list if acquire_slab() fails" 2021-03-17 17:03:34 +01:00
net net: qrtr: fix error return code of qrtr_sendmsg() 2021-03-17 17:03:36 +01:00
samples samples, bpf: Add missing munmap in xdpsock 2021-03-17 17:03:33 +01:00
scripts ftrace: Have recordmcount use w8 to read relp->r_info in arm64_is_fake_mcount 2021-03-09 11:09:39 +01:00
security Revert 95ebabde382c ("capabilities: Don't allow writing ambiguous v3 file capabilities") 2021-03-17 17:03:47 +01:00
sound ALSA: usb-audio: Apply the control quirk to Plantronics headsets 2021-03-17 17:03:47 +01:00
tools perf traceevent: Ensure read cmdlines are null terminated. 2021-03-17 17:03:37 +01:00
usr
virt KVM: Use kvm_pfn_t for local PFN variable in hva_to_pfn_remapped() 2021-02-26 10:10:28 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile kbuild: clamp SUBLEVEL to 255 2021-03-17 17:03:44 +01:00
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.