The DRM-managed function to register an encoder is
drmm_encoder_alloc() and its variants, which will allocate the underlying
structure and initialisation the encoder.
However, we might want to separate the structure creation and the encoder
initialisation, for example if the structure is shared across multiple DRM
entities, for example an encoder and a connector.
Let's create an helper to only initialise an encoder that would be passed
as an argument.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220711173939.1132294-4-maxime@cerno.tech
The DRM-managed function to register a CRTC is
drmm_crtc_alloc_with_planes(), which will allocate the underlying
structure and initialisation the CRTC.
However, we might want to separate the structure creation and the CRTC
initialisation, for example if the structure is shared across multiple
DRM entities, for example an encoder and a connector.
Let's create an helper to only initialise a CRTC that would be passed as
an argument.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220711173939.1132294-3-maxime@cerno.tech
Next for v5.20
GPU:
- a619 support
- Fix for unclocked GMU register access
- Devcore dump enhancements
Core:
- client utilization via fdinfo support
- fix fence rollover issue
- gem: Lockdep false-positive warning fix
- gem: Switch to pfn mappings
DPU:
- constification of HW catalog
- support for using encoder as CRC source
- WB support on sc7180
- WB resolution fixes
DP:
- dropped custom bulk clock implementation
- made dp_bridge_mode_valid() return MODE_CLOCK_HIGH where applicable
- fix link retraining on resolution change
MDP5:
- MSM8953 perf data
HDMI:
- YAML'ification of schema
- dropped obsolete GPIO support
- misc cleanups
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/CAF6AEGtuqswBGPw-kCYzJvckK2RR1XTeUEgaXwVG_mvpbv3gPA@mail.gmail.com
drm/tegra: Changes for v5.20-rc1
The bulk of these changes adds support for context isolation for the
various supported host1x engines, as well as support for the hardware
found on the new Tegra234 SoC generation.
There's also a couple of fixes and cleanups. To round things off, the
device tree bindings are converted to the new json-schema format that
allows DTBs to be validated.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thierry Reding <thierry.reding@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220708181136.673789-1-thierry.reding@gmail.com
drm-misc-next for $kernel-version:
UAPI Changes:
Cross-subsystem Changes:
Core Changes:
* crtc: Remove unnessary include statements from drm_crtc.h, plus
fallout in drivers
* edid: More use of struct drm_edid; implement HF-EEODB extension
Driver Changes:
* bridge:
* anx7625: Implement HDP timeout via callback; Cleanups
* fsl-ldb: Drop DE flip; Modesetting fixes
* imx: Depend on ARCH_MXC
* sil8620: Fix off-by-one
* ti-sn65dsi86: Convert to atomic modesetting
* ingenic: Fix display at maximum resolution
* panel:
* simple: Add support for HannStar HSD101PWW2, plus DT bindings; Add
support for ETML0700Y5DHA, plus DT bindings
* rockchip: Fixes
* vc4: Cleanups
* vmwgfx: Cleanups
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YsaHq1pvE699NtOM@linux-uq9g
Pull char/misc driver fixes from Greg KH:
"Here are four small char/misc driver fixes for 5.19-rc6 to resolve
some reported issues. They only affect two drivers:
- rtsx_usb: fix for of-reported DMA warning error, the driver was
handling memory buffers in odd ways, it has now been fixed up to be
much simpler and correct by Shuah.
- at25 eeprom driver bugfix for reported problem
All of these have been in linux-next for a week with no reported
problems"
* tag 'char-misc-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
misc: rtsx_usb: set return value in rsp_buf alloc err path
misc: rtsx_usb: use separate command and response buffers
misc: rtsx_usb: fix use of dma mapped buffer for usb bulk transfer
eeprom: at25: Rework buggy read splitting
As Rn covers single-channel formats with a direct relationship between
channel value and brightness, and Cn can be any colors, there are
currently no fourcc codes to describe single-channel formats with an
inverse relationship between channel value and brightness.
Introduce fourcc codes for a single-channel frame buffer format with
two, four, sixteen, or 256 brightness ("darkness") levels, where there
is an inverse relationship between channel value and brightness.
As the number of bits per pixel may be less than eight, some of these
formats rely on proper block handling for the calculation of bits per
pixel and pitch.
The fill order (the order in which multiple pixels are packed in a byte)
is the same order as used for grayscale (2, 4, and 16 levels) images in
the PNG specification, Version 1.2.
This order is also the recommended and default order (FillOrder = 1) for
bilevel and grayscale (16 levels) images in the TIFF 6.0 Specification,
and is also used for monochrome images in the PBM file format,
monochrome Linux frame buffer logos, and BDF and PSF (Linux kernel) font
files.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/6119f3abeda9baaa88652843960adc032da276b4.1657294931.git.geert@linux-m68k.org
Introduce fourcc codes for single-channel frame buffer formats with two,
four, and sixteen brightness levels, where there is a direct
relationship between channel value and brightness.
As the number of bits per pixel is less than eight, these rely on proper
block handling for the calculation of bits per pixel and pitch.
The fill order (the order in which multiple pixels are packed in a byte)
is the same order as used for grayscale (2, 4, and 16 levels) images in
the PNG specification, Version 1.2.
This order is also the recommended and default order (FillOrder = 1) for
bilevel and grayscale (16 levels) images in the TIFF 6.0 Specification,
and is also used for monochrome images in the PBM file format,
monochrome Linux frame buffer logos, and BDF and PSF (Linux kernel) font
files.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/96561a88e53c59cac72e66642bf4c097aacefd18.1657294931.git.geert@linux-m68k.org
Introduce fourcc codes for color-indexed frame buffer formats with two,
four, and sixteen colors, and provide a mapping from bits per pixel and
depth to fourcc codes.
As the number of bits per pixel is less than eight, these rely on proper
block handling for the calculation of bits per pixel and pitch.
The fill order (the order in which multiple pixels are packed in a byte)
is the same order as used for indexed-color (2, 4, and 16 colors) images
in the PNG specification, Version 1.2.
This order is also the recommended and default order (FillOrder = 1) for
palette-color (16 colors) images in the TIFF 6.0 Specification, and is
also used for 16-color Linux frame buffer logos.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/3d88ca7ad32ff3ff3469c10f0b36c312ea233a33.1657294931.git.geert@linux-m68k.org
Pull fscache fixes from David Howells:
- Fix a check in fscache_wait_on_volume_collision() in which the
polarity is reversed. It should complain if a volume is still marked
acquisition-pending after 20s, but instead complains if the mark has
been cleared (ie. the condition has cleared).
Also switch an open-coded test of the ACQUIRE_PENDING volume flag to
use the helper function for consistency.
- Not a fix per se, but neaten the code by using a helper to check for
the DROPPED state.
- Fix cachefiles's support for erofs to only flush requests associated
with a released control file, not all requests.
- Fix a race between one process invalidating an object in the cache
and another process trying to look it up.
* tag 'fscache-fixes-20220708' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
fscache: Fix invalidation/lookup race
cachefiles: narrow the scope of flushed requests when releasing fd
fscache: Introduce fscache_cookie_is_dropped()
fscache: Fix if condition in fscache_wait_on_volume_collision()
Pull ACPI fixes from Rafael Wysocki:
"These fix two recent regressions related to CPPC support.
Specifics:
- Prevent _CPC from being used if the platform firmware does not
confirm CPPC v2 support via _OSC (Mario Limonciello)
- Allow systems with X86_FEATURE_CPPC set to use _CPC even if CPPC
support cannot be agreed on via _OSC (Mario Limonciello)"
* tag 'acpi-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported
ACPI: CPPC: Only probe for _CPC if CPPC v2 is acked
Pull power management fixes from Rafael Wysocki:
"These fix a NULL pointer dereference in a devfreq driver and a runtime
PM framework issue that may cause a supplier device to be suspended
before its consumer.
Specifics:
- Fix NULL pointer dereference related to printing a diagnostic
message in the exynos-bus devfreq driver (Christian Marangi)
- Fix race condition in the runtime PM framework which in some cases
may cause a supplier device to be suspended when its consumer is
still active (Rafael Wysocki)"
* tag 'pm-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM / devfreq: exynos-bus: Fix NULL pointer dereference
PM: runtime: Fix supplier device management during consumer probe
PM: runtime: Redefine pm_runtime_release_supplier()
Pull iommu fixes from Joerg Roedel:
- fix device setup failures in the Intel VT-d driver when the PASID
table is shared
- fix Intel VT-d device hot-add failure due to wrong device notifier
order
- remove the old IOMMU mailing list from the MAINTAINERS file now that
it has been retired
* tag 'iommu-fixes-v5.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
MAINTAINERS: Remove iommu@lists.linux-foundation.org
iommu/vt-d: Fix RID2PASID setup/teardown failure
iommu/vt-d: Fix PCI bus rescan device hot add
Pull block fixes from Jens Axboe:
"NVMe pull request with another id quirk addition, and a tracing fix"
* tag 'block-5.19-2022-07-08' of git://git.kernel.dk/linux-block:
nvme: use struct group for generic command dwords
nvme-pci: phison e16 has bogus namespace ids
Pull io_uring tweak from Jens Axboe:
"Just a minor tweak to an addition made in this release cycle: padding
a 32-bit value that's in a 64-bit union to avoid any potential
funkiness from that"
* tag 'io_uring-5.19-2022-07-08' of git://git.kernel.dk/linux-block:
io_uring: explicit sqe padding for ioctl commands
Pull fbdev fixes from Helge Deller:
- fbcon now prevents switching to screen resolutions which are smaller
than the font size, and prevents enabling a font which is bigger than
the current screen resolution. This fixes vmalloc-out-of-bounds
accesses found by KASAN.
- Guiling Deng fixed a bug where the centered fbdev logo wasn't
displayed correctly if the screen size matched the logo size.
- Hsin-Yi Wang provided a patch to include errno.h to fix build when
CONFIG_OF isn't enabled.
* tag 'for-5.19/fbdev-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
fbcon: Use fbcon_info_from_console() in fbcon_modechange_possible()
fbmem: Check virtual screen sizes in fb_set_var()
fbcon: Prevent that screen size is smaller than font size
fbcon: Disallow setting font bigger than screen size
video: of_display_timing.h: include errno.h
fbdev: fbmem: Fix logo center image dx issue
Add code to do stream ID switching at the beginning of a job. The
stream ID is switched to the stream ID specified by the context
passed in the job structure.
Before switching the stream ID, an OP_DONE wait is done on the
channel's engine to ensure that there is no residual ongoing
work that might do DMA using the new stream ID.
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Add code to register context devices from device tree, allocate them
out and manage their refcounts.
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Pull networking fixes from Paolo Abeni:
"Including fixes from bpf, netfilter, can, and bluetooth.
Current release - regressions:
- bluetooth: fix deadlock on hci_power_on_sync
Previous releases - regressions:
- sched: act_police: allow 'continue' action offload
- eth: usbnet: fix memory leak in error case
- eth: ibmvnic: properly dispose of all skbs during a failover
Previous releases - always broken:
- bpf:
- fix insufficient bounds propagation from
adjust_scalar_min_max_vals
- clear page contiguity bit when unmapping pool
- netfilter: nft_set_pipapo: release elements in clone from
abort path
- mptcp: netlink: issue MP_PRIO signals from userspace PMs
- can:
- rcar_canfd: fix data transmission failed on R-Car V3U
- gs_usb: gs_usb_open/close(): fix memory leak
Misc:
- add Wenjia as SMC maintainer"
* tag 'net-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (57 commits)
wireguard: Kconfig: select CRYPTO_CHACHA_S390
crypto: s390 - do not depend on CRYPTO_HW for SIMD implementations
wireguard: selftests: use microvm on x86
wireguard: selftests: always call kernel makefile
wireguard: selftests: use virt machine on m68k
wireguard: selftests: set fake real time in init
r8169: fix accessing unset transport header
net: rose: fix UAF bug caused by rose_t0timer_expiry
usbnet: fix memory leak in error case
Revert "tls: rx: move counting TlsDecryptErrors for sync"
mptcp: update MIB_RMSUBFLOW in cmd_sf_destroy
mptcp: fix local endpoint accounting
selftests: mptcp: userspace PM support for MP_PRIO signals
mptcp: netlink: issue MP_PRIO signals from userspace PMs
mptcp: Acquire the subflow socket lock before modifying MP_PRIO flags
mptcp: Avoid acquiring PM lock for subflow priority changes
mptcp: fix locking in mptcp_nl_cmd_sf_destroy()
net/mlx5e: Fix matchall police parameters validation
net/sched: act_police: allow 'continue' action offload
net: lan966x: hardcode the number of external ports
...
We need to prevent that users configure a screen size which is smaller than the
currently selected font size. Otherwise rendering chars on the screen will
access memory outside the graphics memory region.
This patch adds a new function fbcon_modechange_possible() which
implements this check and which later may be extended with other checks
if necessary. The new function is called from the FBIOPUT_VSCREENINFO
ioctl handler in fbmem.c, which will return -EINVAL if userspace asked
for a too small screen size.
Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org # v5.4+
This will allow the trace event to know the full size of the data
intended to be copied and silence read overflow checks.
Reported-by: John Garry <john.garry@huawei.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Pull sound fixes from Takashi Iwai:
"This became largish as it includes the pending ASoC fixes.
Almost all changes are device-specific small fixes, while many of them
are coverage for mixer issues that were detected by selftest. In
addition, usual suspects for HD/USB-audio are there"
* tag 'sound-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (43 commits)
ALSA: cs46xx: Fix missing snd_card_free() call at probe error
ALSA: usb-audio: Add quirk for Fiero SC-01 (fw v1.0.0)
ALSA: usb-audio: Add quirk for Fiero SC-01
ALSA: hda/realtek: Add quirk for Clevo L140PU
ALSA: usb-audio: Add quirks for MacroSilicon MS2100/MS2106 devices
ASoC: madera: Fix event generation for rate controls
ASoC: madera: Fix event generation for OUT1 demux
ASoC: cs47l15: Fix event generation for low power mux control
ASoC: cs35l41: Add ASP TX3/4 source to register patch
ASoC: dapm: Initialise kcontrol data for mux/demux controls
ASoC: rt711-sdca: fix kernel NULL pointer dereference when IO error
ASoC: cs35l41: Correct some control names
ASoC: wm5110: Fix DRE control
ASoC: wm_adsp: Fix event for preloader
MAINTAINERS: update ASoC Qualcomm maintainer email-id
ASoC: rockchip: i2s: switch BCLK to GPIO
ASoC: SOF: Intel: disable IMR boot when resuming from ACPI S4 and S5 states
ASoC: SOF: pm: add definitions for S4 and S5 states
ASoC: SOF: pm: add explicit behavior for ACPI S1 and S2
ASoC: SOF: Intel: hda: Fix compressed stream position tracking
...
If CONFIG_OF is not enabled, default of_get_display_timing() returns an
errno, so include the header.
Fixes: 422b67e0b3 ("videomode: provide dummy inline functions for !CONFIG_OF")
Suggested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Offloading police with action TC_ACT_UNSPEC was erroneously disabled even
though it was supported by mlx5 matchall offload implementation, which
didn't verify the action type but instead assumed that any single police
action attached to matchall classifier is a 'continue' action. Lack of
action type check made it non-obvious what mlx5 matchall implementation
actually supports and caused implementers and reviewers of referenced
commits to disallow it as a part of improved validation code.
Fixes: b8cd5831c6 ("net: flow_offload: add tc police action parameters")
Fixes: b50e462bc2 ("net/sched: act_police: Add extack messages for offload failure")
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Tested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The IOMMU driver shares the pasid table for PCI alias devices. When the
RID2PASID entry of the shared pasid table has been filled by the first
device, the subsequent device will encounter the "DMAR: Setup RID2PASID
failed" failure as the pasid entry has already been marked as present.
As the result, the IOMMU probing process will be aborted.
On the contrary, when any alias device is hot-removed from the system,
for example, by writing to /sys/bus/pci/devices/.../remove, the shared
RID2PASID will be cleared without any notifications to other devices.
As the result, any DMAs from those rest devices are blocked.
Sharing pasid table among PCI alias devices could save two memory pages
for devices underneath the PCIe-to-PCI bridges. Anyway, considering that
those devices are rare on modern platforms that support VT-d in scalable
mode and the saved memory is negligible, it's reasonable to remove this
part of immature code to make the driver feasible and stable.
Fixes: ef848b7e5a ("iommu/vt-d: Setup pasid entry for RID2PASID support")
Reported-by: Chenyi Qiang <chenyi.qiang@intel.com>
Reported-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220623065720.727849-1-baolu.lu@linux.intel.com
Link: https://lore.kernel.org/r/20220625133430.2200315-2-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
commit 72f2ecb7ec ("ACPI: bus: Set CPPC _OSC bits for all and
when CPPC_LIB is supported") added support for claiming to
support CPPC in _OSC on non-Intel platforms.
This unfortunately caused a regression on a vartiety of AMD
platforms in the field because a number of AMD platforms don't set
the `_OSC` bit 5 or 6 to indicate CPPC or CPPC v2 support.
As these AMD platforms already claim CPPC support via a dedicated
MSR from `X86_FEATURE_CPPC`, use this enable this feature rather
than requiring the `_OSC` on platforms with a dedicated MSR.
If there is additional breakage on the shared memory designs also
missing this _OSC, additional follow up changes may be needed.
Fixes: 72f2ecb7ec ("Set CPPC _OSC bits for all and when CPPC_LIB is supported")
Reported-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Previously the kernel used to ignore whether the firmware masked CPPC
or CPPCv2 and would just pretend that it worked.
When support for the USB4 bit in _OSC was introduced from commit
9e1f561afb ("ACPI: Execute platform _OSC also with query bit clear")
the kernel began to look at the return when the query bit was clear.
This caused regressions that were misdiagnosed and attempted to be solved
as part of commit 2ca8e62852 ("Revert "ACPI: Pass the same capabilities
to the _OSC regardless of the query flag""). This caused a different
regression where non-Intel systems weren't able to negotiate _OSC
properly.
This was reverted in commit 2ca8e62852 ("Revert "ACPI: Pass the same
capabilities to the _OSC regardless of the query flag"") and attempted to
be fixed by commit c42fa24b44 ("ACPI: bus: Avoid using CPPC if not
supported by firmware") but the regression still returned.
These systems with the regression only load support for CPPC from an SSDT
dynamically when _OSC reports CPPC v2. Avoid the problem by not letting
CPPC satisfy the requirement in `acpi_cppc_processor_probe`.
Reported-by: CUI Hao <cuihao.leo@gmail.com>
Reported-by: maxim.novozhilov@gmail.com
Reported-by: lethe.tree@protonmail.com
Reported-by: garystephenwright@gmail.com
Reported-by: galaxyking0419@gmail.com
Fixes: c42fa24b44 ("ACPI: bus: Avoid using CPPC if not supported by firmware")
Fixes: 2ca8e62852 ("Revert "ACPI Pass the same capabilities to the _OSC regardless of the query flag"")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=213023
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2075387
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: CUI Hao <cuihao.leo@gmail.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If an NFS file is opened for writing and closed, fscache_invalidate() will
be asked to invalidate the file - however, if the cookie is in the
LOOKING_UP state (or the CREATING state), then request to invalidate
doesn't get recorded for fscache_cookie_state_machine() to do something
with.
Fix this by making __fscache_invalidate() set a flag if it sees the cookie
is in the LOOKING_UP state to indicate that we need to go to invalidation.
Note that this requires a count on the n_accesses counter for the state
machine, which that will release when it's done.
fscache_cookie_state_machine() then shifts to the INVALIDATING state if it
sees the flag.
Without this, an nfs file can get corrupted if it gets modified locally and
then read locally as the cache contents may not get updated.
Fixes: d24af13e2e ("fscache: Implement cookie invalidation")
Reported-by: Max Kellermann <mk@cm4all.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Max Kellermann <mk@cm4all.com>
Link: https://lore.kernel.org/r/YlWWbpW5Foynjllo@rabbit.intern.cm-ag [1]
Looking at the conditional lock acquire functions in the kernel due to
the new sparse support (see commit 4a557a5d1a "sparse: introduce
conditional lock acquire function attribute"), it became obvious that
the lockref code has a couple of them, but they don't match the usual
naming convention for the other ones, and their return value logic is
also reversed.
In the other very similar places, the naming pattern is '*_and_lock()'
(eg 'atomic_put_and_lock()' and 'refcount_dec_and_lock()'), and the
function returns true when the lock is taken.
The lockref code is superficially very similar to the refcount code,
only with the special "atomic wrt the embedded lock" semantics. But
instead of the '*_and_lock()' naming it uses '*_or_lock()'.
And instead of returning true in case it took the lock, it returns true
if it *didn't* take the lock.
Now, arguably the reflock code is quite logical: it really is a "either
decrement _or_ lock" kind of situation - and the return value is about
whether the operation succeeded without any special care needed.
So despite the similarities, the differences do make some sense, and
maybe it's not worth trying to unify the different conditional locking
primitives in this area.
But while looking at this all, it did become obvious that the
'lockref_get_or_lock()' function hasn't actually had any users for
almost a decade.
The only user it ever had was the shortlived 'd_rcu_to_refcount()'
function, and it got removed and replaced with 'lockref_get_not_dead()'
back in 2013 in commits 0d98439ea3 ("vfs: use lockred 'dead' flag to
mark unrecoverably dead dentries") and e5c832d555 ("vfs: fix dentry
RCU to refcounting possibly sleeping dput()")
In fact, that single use was removed less than a week after the whole
function was introduced in commit b3abd80250 ("lockref: add
'lockref_get_or_lock() helper") so this function has been around for a
decade, but only had a user for six days.
Let's just put this mis-designed and unused function out of its misery.
We can think about the naming and semantic oddities of the remaining
'lockref_put_or_lock()' later, but at least that function has users.
And while the naming is different and the return value doesn't match,
that function matches the whole '{atomic,refcount}_dec_and_test()'
pattern much better (ie the magic happens when the count goes down to
zero, not when it is incremented from zero).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
