OpenCloudOS-Kernel/tools
Dan Williams a95c90f1e2 mm, devm_memremap_pages: fix shutdown handling
The last step before devm_memremap_pages() returns success is to allocate
a release action, devm_memremap_pages_release(), to tear the entire setup
down.  However, the result from devm_add_action() is not checked.

Checking the error from devm_add_action() is not enough.  The api
currently relies on the fact that the percpu_ref it is using is killed by
the time the devm_memremap_pages_release() is run.  Rather than continue
this awkward situation, offload the responsibility of killing the
percpu_ref to devm_memremap_pages_release() directly.  This allows
devm_memremap_pages() to do the right thing relative to init failures and
shutdown.

Without this change we could fail to register the teardown of
devm_memremap_pages().  The likelihood of hitting this failure is tiny as
small memory allocations almost always succeed.  However, the impact of
the failure is large given any future reconfiguration, or disable/enable,
of an nvdimm namespace will fail forever as subsequent calls to
devm_memremap_pages() will fail to setup the pgmap_radix since there will
be stale entries for the physical address range.

An argument could be made to require that the ->kill() operation be set in
the @pgmap arg rather than passed in separately.  However, it helps code
readability, tracking the lifetime of a given instance, to be able to grep
the kill routine directly at the devm_memremap_pages() call site.

Link: http://lkml.kernel.org/r/154275558526.76910.7535251937849268605.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Fixes: e8d5134833 ("memremap: change devm_memremap_pages interface...")
Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Reported-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
..
accounting delayacct: track delays from thrashing cache pages 2018-10-26 16:26:32 -07:00
arch powerpc updates for 4.21 2018-12-27 10:43:24 -08:00
bpf tools: bpftool: do not force gcc as CC 2018-12-19 21:57:25 +01:00
build perf cs-etm: Support for ARM A32/T32 instruction sets in CoreSight trace 2018-12-17 14:56:18 -03:00
cgroup
crypto crypto: user - rename err_cnt parameter 2018-12-07 14:15:00 +08:00
firewire
gpio
hv tools: hv: fcopy: set 'error' in case an unknown operation was requested 2018-09-30 08:49:55 -07:00
iio iio: Add modifier for DUV light 2018-07-23 19:18:10 +01:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
kvm/kvm_stat tools/kvm_stat: switch to python3 2018-11-27 12:53:44 +01:00
laptop
leds
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
memory-model tools/memory-model: Add more LKMM limitations 2018-10-02 10:28:04 +02:00
nfsd
objtool objtool: Fix segfault in .cold detection with -ffunction-sections 2018-11-20 18:59:00 +01:00
pci tools: PCI: Change pcitest compiling process 2018-10-03 11:19:52 +01:00
pcmcia
perf powerpc updates for 4.21 2018-12-27 10:43:24 -08:00
power ACPI updates for 4.21-rc1 2018-12-25 14:21:18 -08:00
scripts Kbuild: fix # escaping in .cmd files for future Make 2018-04-11 00:03:02 +09:00
spi spi: spidev_test: Improve decoded text part of hex dump 2018-09-04 17:00:37 +01:00
testing mm, devm_memremap_pages: fix shutdown handling 2018-12-28 12:11:47 -08:00
thermal/tmon
time
usb usbip: tools: fix atoi() on non-null terminated string 2018-10-18 19:44:39 +02:00
virtio virtio: fix test build after uio.h change 2018-12-19 18:23:49 -05:00
vm tools/vm/page-types.c: fix "defined but not used" warning 2018-09-04 16:45:02 -07:00
wmi
Makefile tools: PCI: Change pcitest compiling process 2018-10-03 11:19:52 +01:00