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Niklas Schnelle 4e32c4c701 s390/pci: improve zpci_dev reference counting
[ Upstream commit c122383d22 ]

Currently zpci_dev uses kref based reference counting but only accounts
for one original reference plus one reference from an added pci_dev to
its underlying zpci_dev. Counting just the original reference worked
until the pci_dev reference was added in commit 2a671f77ee ("s390/pci:
fix use after free of zpci_dev") because once a zpci_dev goes away, i.e.
enters the reserved state, it would immediately get released. However
with the pci_dev reference this is no longer the case and the zpci_dev
may still appear in multiple availability events indicating that it was
reserved. This was solved by detecting when the zpci_dev is already on
its way out but still hanging around. This has however shown some light
on how unusual our zpci_dev reference counting is.

Improve upon this by modelling zpci_dev reference counting on pci_dev.
Analogous to pci_get_slot() increment the reference count in
get_zdev_by_fid(). Thus all users of get_zdev_by_fid() must drop the
reference once they are done with the zpci_dev.

Similar to pci_scan_single_device(), zpci_create_device() returns the
device with an initial count of 1 and the device added to the zpci_list
(analogous to the PCI bus' device_list). In turn users of
zpci_create_device() must only drop the reference once the device is
gone from the point of view of the zPCI subsystem, it might still be
referenced by the common PCI subsystem though.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-05-25 09:57:25 +02:00
arch s390/pci: improve zpci_dev reference counting 2022-05-25 09:57:25 +02:00
block iocost: don't reset the inuse weight of under-weighted debtors 2022-05-09 09:14:31 +02:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto crypto: xts - Add softdep on ecb 2022-04-08 14:23:55 +02:00
Documentation ext4, doc: fix incorrect h_reserved size 2022-04-27 14:39:01 +02:00
drivers crypto: stm32 - fix reference leak in stm32_crc_remove 2022-05-25 09:57:24 +02:00
fs gfs2: Disable page faults during lockless buffered reads 2022-05-25 09:57:24 +02:00
include kernel/resource: Introduce request_mem_region_muxed() 2022-05-25 09:57:22 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-13 20:59:10 +02:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-08 18:34:03 +01:00
kernel cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp() 2022-05-18 10:26:56 +02:00
lib dim: initialize all struct fields 2022-05-18 10:26:49 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/kfence: reset PG_slab and memcg_data before freeing __kfence_pool 2022-05-25 09:57:23 +02:00
net ping: fix address binding wrt vrf 2022-05-18 10:26:57 +02:00
samples x86: Prepare inline-asm for straight-line-speculation 2022-05-15 20:18:50 +02:00
scripts x86: Add straight-line-speculation mitigation 2022-05-15 20:18:51 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-08 14:23:55 +02:00
sound ALSA: hda/realtek: Enable headset mic on Lenovo P360 2022-05-25 09:57:25 +02:00
tools selftests: vm: Makefile: rename TARGETS to VMTARGETS 2022-05-18 10:26:50 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: avoid NULL pointer dereference in kvm_dirty_ring_push 2022-04-13 20:59:26 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: adjust file entry for of_net.c after movement 2022-03-08 19:12:53 +01:00
Makefile Linux 5.15.41 2022-05-18 10:26:57 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.