The DRM DP code has macros for the DP power sequencing commands. Use
them in the anx7625 driver instead of raw numbers.
Fixes: 548b512e144f ("drm/bridge: anx7625: send DPCD command to downstream") Fixes: 27f26359de9b ("drm/bridge: anx7625: Set downstream sink into normal status") Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> Signed-off-by: Robert Foss <rfoss@kernel.org> Link: https://patchwork.freedesktop.org/patch/msgid/20230710090929.1873646-1-wenst@chromium.org Signed-off-by: Sasha Levin <sashal@kernel.org>
Visible glitches have been observed when running graphics applications on
Linux under Xen hypervisor. Those observations have been confirmed with
failures from kms_pwrite_crc Intel GPU test that verifies data coherency
of DRM frame buffer objects using hardware CRC checksums calculated by
display controllers, exposed to userspace via debugfs. Affected
processing paths have then been identified with new IGT test variants that
mmap the objects using different methods and caching modes [1].
When running as a Xen PV guest, Linux uses Xen provided PAT configuration
which is different from its native one. In particular, Xen specific PTE
encoding of write-combining caching, likely used by graphics applications,
differs from the Linux default one found among statically defined minimal
set of supported modes. Since Xen defines PTE encoding of the WC mode as
_PAGE_PAT, it no longer belongs to the minimal set, depends on correct
handling of _PAGE_PAT bit, and can be mismatched with write-back caching.
When a user calls mmap() for a DRM buffer object, DRM device specific
.mmap file operation, called from mmap_region(), takes care of setting PTE
encoding bits in a vm_page_prot field of an associated virtual memory area
structure. Unfortunately, _PAGE_PAT bit is not preserved when the vma's
.vm_flags are then applied to .vm_page_prot via vm_set_page_prot(). Bits
to be preserved are determined with _PAGE_CHG_MASK symbol that doesn't
cover _PAGE_PAT. As a consequence, WB caching is requested instead of WC
when running under Xen (also, WP is silently changed to WT, and UC
downgraded to UC_MINUS). When running on bare metal, WC is not affected,
but WP and WT extra modes are unintentionally replaced with WC and UC,
respectively.
WP and WT modes, encoded with _PAGE_PAT bit set, were introduced by commit 281d4078bec3 ("x86: Make page cache mode a real type"). Care was taken
to extend _PAGE_CACHE_MASK symbol with that additional bit, but that
symbol has never been used for identification of bits preserved when
applying page protection flags. Support for all cache modes under Xen,
including the problematic WC mode, was then introduced by commit 47591df50512 ("xen: Support Xen pv-domains using PAT").
The issue needs to be fixed by including _PAGE_PAT bit into a bitmask used
by pgprot_modify() for selecting bits to be preserved. We can do that
either internally to pgprot_modify() (as initially proposed), or by making
_PAGE_PAT a part of _PAGE_CHG_MASK. If we go for the latter then, since
_PAGE_PAT is the same as _PAGE_PSE, we need to note that _HPAGE_CHG_MASK
-- a huge pmds' counterpart of _PAGE_CHG_MASK, introduced by commit c489f1257b8c ("thp: add pmd_modify"), defined as (_PAGE_CHG_MASK |
_PAGE_PSE) -- will no longer differ from _PAGE_CHG_MASK. If such
modification of _PAGE_CHG_MASK was irrelevant to its users then one might
wonder why that new _HPAGE_CHG_MASK symbol was introduced instead of
reusing the existing one with that otherwise irrelevant bit (_PAGE_PSE in
that case) added.
Add _PAGE_PAT to _PAGE_CHG_MASK and _PAGE_PAT_LARGE to _HPAGE_CHG_MASK for
symmetry. Split out common bits from both symbols to a common symbol for
clarity.
[ dhansen: tweak the solution changelog description ]
Currently the write_cache attribute allows enabling the QUEUE_FLAG_WC
flag on devices that never claimed the capability.
Fix that by adding a QUEUE_FLAG_HW_WC flag that is set by
blk_queue_write_cache and guards re-enabling the cache through sysfs.
Note that any rescan that calls blk_queue_write_cache will still
re-enable the write cache as in the current code.
Fixes: 93e9d8e836cb ("block: add ability to flag write back caching on a device") Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230707094239.107968-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
gpu->mmu_context is the MMU context of the last job in the HW queue, which
isn't necessarily the same as the context from the bad job. Dump the MMU
context from the scheduler determined bad submit to make it work as intended.
Fixes: 17e4660ae3d7 ("drm/etnaviv: implement per-process address spaces on MMUv2") Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
After commit 71de0a054d0e ("arm64: tegra: Drop serial clock-names and
reset-names") was applied, the HSUART failed to probe and the following
error is seen:
serial-tegra 70006300.serial: Couldn't get the reset
serial-tegra: probe of 70006300.serial failed with error -2
Commit 71de0a054d0e ("arm64: tegra: Drop serial clock-names and
reset-names") is correct because the "reset-names" property is not
needed for 8250 UARTs. However, the "reset-names" is required for the
HSUART and should have been populated as part of commit a63c0cd83720c
("arm64: dts: tegra: smaug: Add Bluetooth node") that enabled the HSUART
for the Pixel C. Fix this by populating the "reset-names" property for
the HSUART on the Pixel C.
Fixes: a63c0cd83720 ("arm64: dts: tegra: smaug: Add Bluetooth node") Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt> Reviewed-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
After commit 71de0a054d0e ("arm64: tegra: Drop serial clock-names and
reset-names") was applied, the HSUART failed to probe and the following
error is seen:
serial-tegra 3100000.serial: Couldn't get the reset
serial-tegra: probe of 3100000.serial failed with error -2
Commit 71de0a054d0e ("arm64: tegra: Drop serial clock-names and
reset-names") is correct because the "reset-names" property is not
needed for 8250 UARTs. However, the "reset-names" is required for the
HSUART and should have been populated as part of commit ff578db7b693
("arm64: tegra: Enable UART instance on 40-pin header") that
enabled the HSUART for Jetson AGX Orin. Fix this by populating the
"reset-names" property for the HSUART on Jetson AGX Orin.
This fixes:
arch/arm/boot/dts/broadcom/bcm947189acdbmr.dtb: spi: gpio-sck: False schema does not allow [[3, 21, 0]]
From schema: Documentation/devicetree/bindings/spi/spi-gpio.yaml
arch/arm/boot/dts/broadcom/bcm947189acdbmr.dtb: spi: gpio-miso: False schema does not allow [[3, 22, 0]]
From schema: Documentation/devicetree/bindings/spi/spi-gpio.yaml
arch/arm/boot/dts/broadcom/bcm947189acdbmr.dtb: spi: gpio-mosi: False schema does not allow [[3, 23, 0]]
From schema: Documentation/devicetree/bindings/spi/spi-gpio.yaml
arch/arm/boot/dts/broadcom/bcm947189acdbmr.dtb: spi: 'sck-gpios' is a required property
From schema: Documentation/devicetree/bindings/spi/spi-gpio.yaml
arch/arm/boot/dts/broadcom/bcm947189acdbmr.dtb: spi: Unevaluated properties are not allowed ('gpio-miso', 'gpio-mosi', 'gpio-sck' were unexpected)
From schema: Documentation/devicetree/bindings/spi/spi-gpio.yaml
This fixes:
arch/arm/boot/dts/broadcom/bcm47189-luxul-xap-1440.dtb: pcie@2000: '#address-cells' is a required property
From schema: /lib/python3.10/site-packages/dtschema/schemas/pci/pci-bus.yaml
arch/arm/boot/dts/broadcom/bcm47189-luxul-xap-1440.dtb: pcie@2000: '#size-cells' is a required property
From schema: /lib/python3.10/site-packages/dtschema/schemas/pci/pci-bus.yaml
Two properties that need to be added later are "device_type" and
"ranges". Adding "device_type" on its own causes a new warning and the
value of "ranges" needs to be determined yet.
Such property simply doesn't exist (is not documented or used anywhere).
This fixes:
arch/arm/boot/dts/broadcom/bcm47189-luxul-xap-1440.dtb: usb@d000: Unevaluated properties are not allowed ('#usb-cells' was unexpected)
From schema: Documentation/devicetree/bindings/usb/generic-ohci.yaml
There is no such trigger documented or implemented in Linux. It was a
copy & paste mistake.
This fixes:
arch/arm/boot/dts/broadcom/bcm47189-luxul-xap-1440.dtb: leds: led-wlan:linux,default-trigger: 'oneOf' conditional failed, one must be fixed:
'default-off' is not one of ['backlight', 'default-on', 'heartbeat', 'disk-activity', 'disk-read', 'disk-write', 'timer', 'pattern', 'audio-micmute', 'audio-mute', 'bluetooth-power', 'flash', 'kbd-capslock', 'mtd', 'nand-disk', 'none', 'torch', 'usb-gadget', 'usb-host', 'usbport']
'default-off' does not match '^cpu[0-9]*$'
'default-off' does not match '^hci[0-9]+-power$'
'default-off' does not match '^mmc[0-9]+$'
'default-off' does not match '^phy[0-9]+tx$'
From schema: Documentation/devicetree/bindings/leds/leds-gpio.yaml
On 32-bit architectures comparing a resource against a value larger than
U32_MAX can cause a warning:
drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:1344:18: error: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
res->start > 0x100000000ull)
~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
As gcc does not warn about this in dead code, add an IS_ENABLED() check at
the start of the function. This will always return success but not actually resize
the BAR on 32-bit architectures without high memory, which is exactly what
we want here, as the driver can fall back to bank switching the VRAM
access.
Fixes: 31b8adab3247 ("drm/amdgpu: require a root bus window above 4GB for BAR resize") Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Commit b9e8a7d950ff ("firmware: ti_sci: Switch transport to polled
mode during system suspend") aims to resolve issues with tisci
operations during system suspend operation. However, the system may
enter a no_irq stage in various other usage modes, including power-off
and restart. To determine if polling mode is appropriate, use the
system_state instead.
While at this, drop the unused is_suspending state variable and
related helpers.
Fixes: b9e8a7d950ff ("firmware: ti_sci: Switch transport to polled mode during system suspend") Reported-by: Francesco Dolcini <francesco@dolcini.it> Reported-by: Wadim Egorov <w.egorov@phytec.de> Tested-by: Francesco Dolcini <francesco.dolcini@toradex.com> # Toradex Verdin AM62 Link: https://lore.kernel.org/r/20230620130329.4120443-1-nm@ti.com Closes: https://lore.kernel.org/all/ZGeHMjlnob2GFyHF@francesco-nb.int.toradex.com/ Signed-off-by: Nishanth Menon <nm@ti.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Add missing "detach" mailbox to this board to permit the CPU to inform
the remote processor on a detach. This signal allows the remote processor
firmware to stop IPC communication and to reinitialize the resources for
a re-attach.
Without this mailbox, detach is not possible and kernel log contains the
following warning to, so make sure all the STM32MP15xx platform DTs are
in sync regarding the mailboxes to fix the detach issue and the warning:
"
stm32-rproc 10000000.m4: mbox_request_channel_byname() could not locate channel named "detach"
"
Add missing "detach" mailbox to this board to permit the CPU to inform
the remote processor on a detach. This signal allows the remote processor
firmware to stop IPC communication and to reinitialize the resources for
a re-attach.
Without this mailbox, detach is not possible and kernel log contains the
following warning to, so make sure all the STM32MP15xx platform DTs are
in sync regarding the mailboxes to fix the detach issue and the warning:
"
stm32-rproc 10000000.m4: mbox_request_channel_byname() could not locate channel named "detach"
"
The generic ADC channel binding is recommended over legacy one, update the
DT to the modern binding. No functional change. For further details, see
commit which adds the generic binding to STM32 ADC binding document:
'664b9879f56e ("dt-bindings: iio: stm32-adc: add generic channel binding")'
Add missing "detach" mailbox to this board to permit the CPU to inform
the remote processor on a detach. This signal allows the remote processor
firmware to stop IPC communication and to reinitialize the resources for
a re-attach.
Without this mailbox, detach is not possible and kernel log contains the
following warning to, so make sure all the STM32MP15xx platform DTs are
in sync regarding the mailboxes to fix the detach issue and the warning:
"
stm32-rproc 10000000.m4: mbox_request_channel_byname() could not locate channel named "detach"
"
Add missing "detach" mailbox to this board to permit the CPU to inform
the remote processor on a detach. This signal allows the remote processor
firmware to stop IPC communication and to reinitialize the resources for
a re-attach.
Without this mailbox, detach is not possible and kernel log contains the
following warning to, so make sure all the STM32MP15xx platform DTs are
in sync regarding the mailboxes to fix the detach issue and the warning:
"
stm32-rproc 10000000.m4: mbox_request_channel_byname() could not locate channel named "detach"
"
Use STM32 ADC generic bindings instead of legacy bindings on
emtrion GmbH Argon boards.
The STM32 ADC specific binding to declare channels has been deprecated,
hence adopt the generic IIO channels bindings, instead.
The STM32MP151 device tree now exposes internal channels using the
generic binding. This makes the change mandatory here to avoid a mixed
use of legacy and generic binding, which is not supported by the driver.
The commit b2de43136058 ("arm64: dts: qcom: pmk8350: Add peripherals for
pmk8350") for the ADC TM (thermal monitoring device) have used the
compatible string from the vendor kernel ("qcom,adc-tm7"). Use the
proper compatible string that is defined in the upstream kernel
("qcom,spmi-adc-tm5-gen2").
The name of the thermal zone in pmr735b.dtsi (pmr735a-thermal) conflicts
with the thermal zone in pmr735a.dtsi. Rename the thermal zone according
to the chip name.
The name of the thermal zone in pm8350b.dtsi (pm8350c-thermal) conflicts
with the thermal zone in pm8350c.dtsi. Rename the thermal zone according
to the chip name.
The name of the thermal zone in pm8350.dtsi (pm8350c-thermal) conflicts
with the thermal zone in pm8350c.dtsi. Rename the thermal zone according
to the chip name.
Sony ever so graciously provides GPIO line names in their downstream
kernel (though sometimes they are not 100% accurate and you can judge
that by simply looking at them and with what drivers they are used).
Add these to the PDX203&206 DTSIs to better document the hardware.
Diff between 203 and 206:
pm8009_gpios
< "CAM_PWR_LD_EN",
> "NC",
pm8150_gpios
< "NC",
> "G_ASSIST_N",
< "WLC_EN_N", /* GPIO_10 */
> "NC", /* GPIO_10 */
Which is due to 5 II having an additional Google Assistant hardware
button and 1 II having a wireless charger & different camera wiring
to accommodate the additional 3D iToF sensor.
Sony ever so graciously provides GPIO line names in their downstream
kernel (though sometimes they are not 100% accurate and you can judge
that by simply looking at them and with what drivers they are used).
Add these to the PDX203&206 DTSIs to better document the hardware.
sm8250 faces the same problem with its Energy Model as sdm845. The energy
cost of LITTLE cores is reported to be higher than medium or big cores
EM computes the energy with formula:
energy = OPP's cost / maximum cpu capacity * utilization
On v6.4-rc6 we have:
max capacity of CPU0 = 284
capacity of CPU0's OPP(1612800 Hz) = 253
cost of CPU0's OPP(1612800 Hz) = 191704
max capacity of CPU4 = 871
capacity of CPU4's OPP(710400 Hz) = 255
cost of CPU4's OPP(710400 Hz) = 343217
Both OPPs have almost the same compute capacity but the estimated energy
per unit of utilization will be estimated to:
energy CPU0 = 191704 / 284 * 1 = 675
energy CPU4 = 343217 / 871 * 1 = 394
EM estimates that little CPU0 will consume 71% more than medium CPU4 for
the same compute capacity. According to [1], little consumes 25% less than
medium core for Coremark benchmark at those OPPs for the same duration.
Set the dynamic-power-coefficient of CPU0-3 to 105 to fix the energy model
for little CPUs.
The commit 8f680c287445 ("arm64: defconfig: Switch msm8996 clk drivers
to module") switched CONFIG_MSM_MMCC_8996 to module, which also resulted
in CONFIG_MSM_GCC_8996 being switched to module. This breaks useful
bootflow for Qualcomm MSM8996 / APQ8096 platforms, because the serial is
not enabled anymore until the GCC module is loaded.
Reported-by: Rob Clark <robdclark@gmail.com> Fixes: 8f680c287445 ("arm64: defconfig: Switch msm8996 clk drivers to module") Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org> Link: https://lore.kernel.org/r/20230619125404.562137-1-dmitry.baryshkov@linaro.org Signed-off-by: Bjorn Andersson <andersson@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Since we're using these two macros to read a value from a register, we
need to use the FIELD_GET instead of the FIELD_PREP macro, otherwise
we're getting wrong values.
drivers/video/fbdev/hyperv_fb.c: In function 'hvfb_getmem':
>> drivers/video/fbdev/hyperv_fb.c:1033:24: error: 'screen_info' undeclared (first use in this function)
1033 | base = screen_info.lfb_base;
| ^~~~~~~~~~~
drivers/video/fbdev/hyperv_fb.c:1033:24: note: each undeclared identifier is reported only once for each function it appears in
>> drivers/gpu/drm/hyperv/hyperv_drm_drv.c:75:54: error: 'screen_info' undeclared (first use in this function)
75 | drm_aperture_remove_conflicting_framebuffers(screen_info.lfb_base,
| ^~~~~~~~~~~
drivers/gpu/drm/hyperv/hyperv_drm_drv.c:75:54: note: each undeclared identifier is reported only once for each function it appears in
Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202307090823.nxnT8Kk5-lkp@intel.com/ Fixes: 81d2393485f0 ("fbdev/hyperv-fb: Do not set struct fb_info.apertures") Fixes: 8b0d13545b09 ("efi: Do not include <linux/screen_info.h> from EFI header") Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Link: https://patchwork.freedesktop.org/patch/msgid/20230709100514.703759-1-suijingfeng@loongson.cn Signed-off-by: Sasha Levin <sashal@kernel.org>
The dquot_mark_dquot_dirty() using dquot references from the inode
should be protected by dquot_srcu. quota_off code takes care to call
synchronize_srcu(&dquot_srcu) to not drop dquot references while they
are used by other users. But dquot_transfer() breaks this assumption.
We call dquot_transfer() to drop the last reference of dquot and add
it to free_dquots, but there may still be other users using the dquot
at this time, as shown in the function graph below:
cpu1 cpu2
_________________|_________________
wb_do_writeback CHOWN(1)
...
ext4_da_update_reserve_space
dquot_claim_block
...
dquot_mark_dquot_dirty // try to dirty old quota
test_bit(DQ_ACTIVE_B, &dquot->dq_flags) // still ACTIVE
if (test_bit(DQ_MOD_B, &dquot->dq_flags))
// test no dirty, wait dq_list_lock
...
dquot_transfer
__dquot_transfer
dqput_all(transfer_from) // rls old dquot
dqput // last dqput
dquot_release
clear_bit(DQ_ACTIVE_B, &dquot->dq_flags)
atomic_dec(&dquot->dq_count)
put_dquot_last(dquot)
list_add_tail(&dquot->dq_free, &free_dquots)
// add the dquot to free_dquots
if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags))
add dqi_dirty_list // add released dquot to dirty_list
This can cause various issues, such as dquot being destroyed by
dqcache_shrink_scan() after being added to free_dquots, which can trigger
a UAF in dquot_mark_dquot_dirty(); or after dquot is added to free_dquots
and then to dirty_list, it is added to free_dquots again after
dquot_writeback_dquots() is executed, which causes the free_dquots list to
be corrupted and triggers a UAF when dqcache_shrink_scan() is called for
freeing dquot twice.
As Honza said, we need to fix dquot_transfer() to follow the guarantees
dquot_srcu should provide. But calling synchronize_srcu() directly from
dquot_transfer() is too expensive (and mostly unnecessary). So we add
dquot whose last reference should be dropped to the new global dquot
list releasing_dquots, and then queue work item which would call
synchronize_srcu() and after that perform the final cleanup of all the
dquots on releasing_dquots.
Fixes: 4580b30ea887 ("quota: Do not dirty bad dquots") Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-5-libaokun1@huawei.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Add new helper function dquot_active() to make the code more concise.
Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-4-libaokun1@huawei.com>
Stable-dep-of: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Signed-off-by: Sasha Levin <sashal@kernel.org>
Now we have a helper function dquot_dirty() to determine if dquot has
DQ_MOD_B bit. dquot_active() can easily be misunderstood as a helper
function to determine if dquot has DQ_ACTIVE_B bit. So we avoid this by
renaming it to inode_quota_active() and later on we will add the helper
function dquot_active() to determine if dquot has DQ_ACTIVE_B bit.
Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-3-libaokun1@huawei.com>
Stable-dep-of: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Signed-off-by: Sasha Levin <sashal@kernel.org>
Refactor out dquot_write_dquot() to reduce duplicate code.
Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230630110822.3881712-2-libaokun1@huawei.com>
Stable-dep-of: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Signed-off-by: Sasha Levin <sashal@kernel.org>
would result in failures to re-enable the panel. Mode set callback is
called only once during boot in this scenario, while calls to
enable/disable callbacks are balanced afterwards. The driver doesn't
work unless userspace calls modeset before enabling the CRTC/connector.
This patch moves enabling of the DSI host from mode_set into pre_enable
callback, and removes some old hacks where this bridge driver is
directly calling into other bridge driver's callbacks.
pre_enable_prev_first flag is set on the panel's bridge so that panel
drivers will get their prepare function called between DSI host's
pre_enable and enable callbacks, so that they get a chance to
perform panel setup while DSI host is already enabled in command
mode. Otherwise panel's prepare would be called before DSI host
is enabled, and any DSI communication used in prepare callback
would fail.
With all these changes, the enable/disable sequence is now well
balanced, and host's and panel's callbacks are called in proper order
documented in the drm_panel API documentation without needing the old
hacks. (Mainly that panel->prepare is called when DSI host is ready to
allow the panel driver to send DSI commands and vice versa during
disable.)
Tested on Pinephone Pro. Trace of the callbacks follows.
In converting to using the standard u16_fract type, commit [1] made the
obvious mistake and failed to take account of the difference in
numerator and denominator ordering, breaking all uses of the cs43130
codec.
The debug print parameters were swapped in the output and they were
printed as decimal values, both the hardware address and the value.
Update the debug print to print the parameters in correct order, and
use hexadecimal print for both address and value.
Fixes: f38b7cca6d0e ("drm/bridge: tc358764: Add DSI to LVDS bridge driver") Signed-off-by: Marek Vasut <marex@denx.de> Reviewed-by: Robert Foss <rfoss@kernel.org> Signed-off-by: Robert Foss <rfoss@kernel.org> Link: https://patchwork.freedesktop.org/patch/msgid/20230615152817.359420-1-marex@denx.de Signed-off-by: Sasha Levin <sashal@kernel.org>
syzkaller reported null-ptr-deref [0] related to AF_NETROM.
This is another self-accept issue from the strace log. [1]
syz-executor creates an AF_NETROM socket and calls connect(), which
is blocked at that time. Then, sk->sk_state is TCP_SYN_SENT and
sock->state is SS_CONNECTING.
Another thread calls connect() concurrently, which finally fails
with -EINVAL. However, the problem here is the socket state is
reset even while the first connect() is blocked.
As sk->state is TCP_CLOSE and sock->state is SS_UNCONNECTED, the
following listen() succeeds. Then, the first connect() looks up
itself as a listener and puts skb into the queue with skb->sk itself.
As a result, the next accept() gets another FD of itself as 3, and
the first connect() finishes.
Finally, the leader thread close()s all FDs. Since the three FDs
reference the same socket, nr_release() does the cleanup for it
three times, and the remaining accept4() causes the following fault.
Don't rely on the PCI memory for the devcmd opcode because we
read a 0xff value if the PCI bus is broken, which can cause us
to report a bogus dev_cmd opcode later.
Fixes: 523847df1b37 ("pds_core: add devcmd device interfaces") Signed-off-by: Shannon Nelson <shannon.nelson@amd.com> Reviewed-by: Brett Creeley <brett.creeley@amd.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20230824161754.34264-6-shannon.nelson@amd.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Don't access structs that have been cleared when in the fw_down
state and the various structs have been cleaned and are waiting
to recover. This caused a panic on rmmod when already in fw_down
and devlink_param_unregister() tried to check the parameters.
Fixes: 40ced8944536 ("pds_core: devlink params for enabling VIF support") Signed-off-by: Shannon Nelson <shannon.nelson@amd.com> Reviewed-by: Brett Creeley <brett.creeley@amd.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20230824161754.34264-2-shannon.nelson@amd.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
HFSC assumes that inner classes have an fsc curve, but it is currently
possible for classes without an fsc curve to become parents. This leads
to bugs including a use-after-free.
Don't allow non-root classes without HFSC_FSC to become parents.
MAC (CGX or RPM) asserts backpressure at TL3 or TL2 node of the egress
hierarchical scheduler tree depending on link level config done. If
there are multiple PFC priorities enabled at a time and for all such
flows to backoff, each priority will have to assert backpressure at
different TL3/TL2 scheduler nodes and these flows will need to submit
egress pkts to these nodes.
Current PFC configuration has an issue where in only one backpressure
scheduler node is being allocated which is resulting in only one PFC
priority to work. This patch fixes this issue.
Suppose user has enabled pfc with prio 0,1 on a PF netdev(eth0)
dcb pfc set dev eth0 prio-pfc o:on 1:on
later user enabled pfc priorities 2 and 3 on the VF interface(eth1)
dcb pfc set dev eth1 prio-pfc 2:on 3:on
Instead of enabling pfc on all priorities (0..3), the driver only
enables on priorities 2,3. This patch corrects the issue by using
the proper CSR address.
Fixes: b9d0fedc6234 ("octeontx2-af: cn10kb: Add RPM_USX MAC support") Signed-off-by: Hariprasad Kelam <hkelam@marvell.com> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20230824081032.436432-3-sumang@marvell.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
During PFC TX schedulers free, flag TXSCHQ_FREE_ALL was being set
which caused free up all schedulers other than the PFC schedulers.
This patch fixes that to free only the PFC Tx schedulers.
1. Upon txschq free request, the transmit schedular config in hardware
is not getting reset. This patch adds necessary changes to do the same.
2. Current implementation calls txschq alloc during interface
initialization and in response handler updates the default txschq array.
This creates a problem for htb offload where txsch alloc will be called
for every tc class. This patch addresses the issue by reading txschq
response in mbox caller function instead in the response handler.
3. Current otx2_txschq_stop routine tries to free all txschq nodes
allocated to the interface. This creates a problem for htb offload.
This patch introduces the otx2_txschq_free_one to free txschq in a
given level.
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com> Signed-off-by: Naveen Mamindlapalli <naveenm@marvell.com> Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: a9ac2e187795 ("octeontx2-pf: Fix PFC TX scheduler free") Signed-off-by: Sasha Levin <sashal@kernel.org>
Transceiver module temperature sensors are indexed after ASIC and
platform sensors. The current label printing method does not take this
into account and simply prints the index of the transceiver module
sensor.
On new systems that have platform sensors this results in incorrect
(shifted) transceiver module labels being printed:
Maximum size of buffer is obtained from underlying I2C adapter and in
case adapter allows I2C transaction buffer size greater than 100 bytes,
transaction will fail due to firmware limitation.
As a result driver will fail initialization.
Limit the maximum size of transaction buffer by 100 bytes to fit to
firmware.
Remove unnecessary calculation:
max_t(u16, MLXSW_I2C_BLK_DEF, quirk_size).
This condition can not happened.
Fixes: 3029a693beda ("mlxsw: i2c: Allow flexible setting of I2C transactions size") Signed-off-by: Vadim Pasternak <vadimp@nvidia.com> Reviewed-by: Petr Machata <petrm@nvidia.com> Signed-off-by: Petr Machata <petrm@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
The driver reads commands output from the output mailbox. If the size
of the output mailbox is not a multiple of the transaction /
block size, then the driver will not issue enough read transactions
to read the entire output, which can result in driver initialization
errors.
Fix by determining the number of transactions using DIV_ROUND_UP().
Fixes: 3029a693beda ("mlxsw: i2c: Allow flexible setting of I2C transactions size") Signed-off-by: Vadim Pasternak <vadimp@nvidia.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com> Signed-off-by: Petr Machata <petrm@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
It is not allowed to call kfree_skb() from hardware interrupt
context or with hardware interrupts being disabled.
So replace kfree_skb() with dev_kfree_skb_irq() under
local_irq_disable(). Compile tested only.
Fixes: 05fcd31cc472 ("arcnet: add err_skb package for package status feedback") Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
The ice hardware has a synchronization mechanism used to drive the
simultaneous application of commands on both PHY ports and the source timer
in the MAC.
When issuing a sync via ice_ptp_exec_tmr_cmd(), the hardware will
simultaneously apply the commands programmed for the main timer and each
PHY port. Neither the main timer command register, nor the PHY port command
registers auto clear on command execution.
During the execution of a timer command intended for a single port on E822
devices, such as those used to configure a PHY during link up, the driver
is not correctly clearing the previous commands.
This results in unintentionally executing the last programmed command on
the main timer and other PHY ports whenever performing reconfiguration on
E822 ports after link up. This results in unintended side effects on other
timers, depending on what command was previously programmed.
To fix this, the driver must ensure that the main timer and all other PHY
ports are properly initialized to perform no action.
The enumeration for timer commands does not include an enumeration value
for doing nothing. Introduce ICE_PTP_NOP for this purpose. When writing a
timer command to hardware, leave the command bits set to zero which
indicates that no operation should be performed on that port.
Modify ice_ptp_one_port_cmd() to always initialize all ports. For all ports
other than the one being configured, write their timer command register to
ICE_PTP_NOP. This ensures that no side effect happens on the timer command.
To fix this for the PHY ports, modify ice_ptp_one_port_cmd() to always
initialize all other ports to ICE_PTP_NOP. This ensures that no side
effects happen on the other ports.
Call ice_ptp_src_cmd() with a command value if ICE_PTP_NOP in
ice_sync_phy_timer_e822() and ice_start_phy_timer_e822().
With both of these changes, the driver should no longer execute a stale
command on the main timer or another PHY port when reconfiguring one of the
PHY ports after link up.
Fixes: 3a7496234d17 ("ice: implement basic E822 PTP support") Signed-off-by: Siddaraju DH <siddaraju.dh@intel.com> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Sunitha Mekala <sunithax.d.mekala@intel.com> (A Contingent worker at Intel) Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
The debugfs_create_dir() function returns error pointers,
it never returns NULL. Most incorrect error checks were fixed,
but the one in ath9k_htc_init_debug() was forgotten.
Fix the remaining error check.
Fixes: e5facc75fa91 ("ath9k_htc: Cleanup HTC debugfs") Signed-off-by: Wang Ming <machel@vivo.com> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com> Link: https://lore.kernel.org/r/20230713030358.12379-1-machel@vivo.com Signed-off-by: Sasha Levin <sashal@kernel.org>
Use a dynamic calculation to determine the shift value for the internal
timer cyclecounter that will lead to the highest precision frequency
adjustments. Previously used a constant for the shift value assuming all
devices supported by the driver had a nominal frequency of 1GHz. However,
there are devices that operate at different frequencies. The previous shift
value constant would break the PHC functionality for those devices.
Reported-by: Vadim Fedorenko <vadim.fedorenko@linux.dev> Closes: https://lore.kernel.org/netdev/20230815151507.3028503-1-vadfed@meta.com/ Fixes: 6a4010927562 ("net/mlx5: Update cyclecounter shift value to improve ptp free running mode precision") Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com> Tested-by: Vadim Fedorenko <vadim.fedorenko@linux.dev> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Reviewed-by: Simon Horman <horms@kernel.org> Acked-by: Saeed Mahameed <saeedm@nvidia.com> Link: https://lore.kernel.org/r/20230821230554.236210-1-rrameshbabu@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
In clear_flush(), the original pte may be a present entry, so we should
use ptep_clear() to let page_table_check track the pte clearing operation,
otherwise it may cause false positive in subsequent set_pte_at().
It is not allowed to call kfree_skb() from hardware interrupt
context or with hardware interrupts being disabled.
So replace kfree_skb() with dev_kfree_skb_irq() under
spin_lock_irqsave(). Compile tested only.
Fixes: baac6276c0a9 ("Bluetooth: btusb: handle mSBC audio over USB Endpoints") Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Use-after-free can occur in hci_disconnect_all_sync if a connection is
deleted by concurrent processing of a controller event.
To prevent this the code now tries to iterate over the list backwards
to ensure the links are cleanup before its parents, also it no longer
relies on a cursor, instead it always uses the last element since
hci_abort_conn_sync is guaranteed to call hci_conn_del.
UAF crash log:
==================================================================
BUG: KASAN: slab-use-after-free in hci_set_powered_sync
(net/bluetooth/hci_sync.c:5424) [bluetooth]
Read of size 8 at addr ffff888009d9c000 by task kworker/u9:0/124
Fixes: 182ee45da083 ("Bluetooth: hci_sync: Rework hci_suspend_notifier") Signed-off-by: Pauli Virtanen <pav@iki.fi> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Connections may be cleanup while waiting for the commands to complete so
this attempts to check if the connection handle remains valid in case of
errors that would lead to call hci_conn_failed:
BUG: KASAN: slab-use-after-free in hci_conn_failed+0x1f/0x160
Read of size 8 at addr ffff888001376958 by task kworker/u3:0/52
Some use cases require the user to be informed if BIG synchronization
fails. This commit makes it so that even if the BIG sync established
event arrives with error status, a new hconn is added for each BIS,
and the iso layer is notified about the failed connections.
Unsuccesful bis connections will be marked using the
HCI_CONN_BIG_SYNC_FAILED flag. From the iso layer, the POLLERR event
is triggered on the newly allocated bis sockets, before adding them
to the accept list of the parent socket.
From user space, a new fd for each failed bis connection will be
obtained by calling accept. The user should check for the POLLERR
event on the new socket, to determine if the connection was successful
or not.
The HCI_CONN_BIG_SYNC flag has been added to mark whether the BIG sync
has been successfully established. This flag is checked at bis cleanup,
so the HCI LE BIG Terminate Sync command is only issued if needed.
The BT_SK_BIG_SYNC flag indicates if BIG create sync has been called
for a listening socket, to avoid issuing the command everytime a BIGInfo
advertising report is received.
Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Stable-dep-of: 94d9ba9f9888 ("Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync") Signed-off-by: Sasha Levin <sashal@kernel.org>
This consolidates code for aborting connections using
hci_cmd_sync_queue so it is synchronized with other threads, but
because of the fact that some commands may block the cmd_sync_queue
while waiting specific events this attempt to cancel those requests by
using hci_cmd_sync_cancel.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Stable-dep-of: 94d9ba9f9888 ("Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync") Signed-off-by: Sasha Levin <sashal@kernel.org>
In 'mwifiex_handle_uap_rx_forward()', always check the value
returned by 'skb_copy()' to avoid potential NULL pointer
dereference in 'mwifiex_uap_queue_bridged_pkt()', and drop
original skb in case of copying failure.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 838e4f449297 ("mwifiex: improve uAP RX handling") Acked-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> Signed-off-by: Kalle Valo <kvalo@kernel.org> Link: https://lore.kernel.org/r/20230814095041.16416-1-dmantipov@yandex.ru Signed-off-by: Sasha Levin <sashal@kernel.org>
The commit being fixed introduced a hunk into check_func_arg_reg_off
that bypasses reg->off == 0 enforcement when offset points to a graph
node or root. This might possibly be done for treating bpf_rbtree_remove
and others as KF_RELEASE and then later check correct reg->off in helper
argument checks.
But this is not the case, those helpers are already not KF_RELEASE and
permit non-zero reg->off and verify it later to match the subobject in
BTF type.
However, this logic leads to bpf_obj_drop permitting free of register
arguments with non-zero offset when they point to a graph root or node
within them, which is not ok.
For instance:
struct foo {
int i;
int j;
struct bpf_rb_node node;
};
struct foo *f = bpf_obj_new(typeof(*f));
if (!f) ...
bpf_obj_drop(f); // OK
bpf_obj_drop(&f->i); // still ok from verifier PoV
bpf_obj_drop(&f->node); // Not OK, but permitted right now
Fix this by dropping the whole part of code altogether.
While looking at a bug, I got rather confused by the layout of the
'status' field in ieee80211_tx_info. Apparently, the intention is that
status_driver_data[] is used for driver specific data, and fills up the
size of the union to 40 bytes, just like the other ones.
This is indeed what actually happens, but only because of the
combination of two mistakes:
- "void *status_driver_data[18 / sizeof(void *)];" is intended
to be 18 bytes long but is actually two bytes shorter because of
rounding-down in the division, to a multiple of the pointer
size (4 bytes or 8 bytes).
- The other fields combined are intended to be 22 bytes long, but
are actually 24 bytes because of padding in front of the
unaligned tx_time member, and in front of the pointer array.
The two mistakes cancel out. so the size ends up fine, but it seems
more helpful to make this explicit, by having a multiple of 8 bytes
in the size calculation and explicitly describing the padding.
The previous commit dd3e4fc75b4a ("nl80211/cfg80211: add BSS color to
NDP ranging parameters") adds a parameter for NDP ranging by introducing
a new attribute type named NL80211_PMSR_FTM_REQ_ATTR_BSS_COLOR.
However, the author forgot to also describe the nla_policy at
nl80211_pmsr_ftm_req_attr_policy (net/wireless/nl80211.c). Just
complement it to avoid malformed attribute that causes out-of-attribute
access.
Fixes: dd3e4fc75b4a ("nl80211/cfg80211: add BSS color to NDP ranging parameters") Signed-off-by: Lin Ma <linma@zju.edu.cn> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20230809033151.768910-1-linma@zju.edu.cn Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Code inspection reveals that we switch the puncturing bitmap
before the real channel switch, since that happens only in
the second round of the worker after the channel context is
switched by ieee80211_link_use_reserved_context().
When reviewing local percpu kptr support, Alexei discovered a bug
wherea bpf_kptr_xchg() may succeed even if the map value kptr type and
locally allocated obj type do not match ([1]). Missed struct btf_id
comparison is the reason for the bug. This patch added such struct btf_id
comparison and will flag verification failure if types do not match.
If ath9k_wmi_cmd() has exited with a timeout, it is possible that during
next ath9k_wmi_cmd() call the wmi_rsp callback for previous wmi command
writes to new wmi->cmd_rsp_buf and makes a completion. This results in an
invalid ath9k_wmi_cmd() return value.
Move the replacement of WMI command response buffer and length under
wmi_lock. Note that last_seq_id value is updated there, too.
Thus, the buffer cannot be written to by a belated wmi_rsp callback
because that path is properly rejected by the last_seq_id check.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.") Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com> Link: https://lore.kernel.org/r/20230425192607.18015-2-pchelkin@ispras.ru Signed-off-by: Sasha Levin <sashal@kernel.org>
Currently, the synchronization between ath9k_wmi_cmd() and
ath9k_wmi_ctrl_rx() is exposed to a race condition which, although being
rather unlikely, can lead to invalid behaviour of ath9k_wmi_cmd().
Consider the following scenario:
CPU0 CPU1
ath9k_wmi_cmd(...)
mutex_lock(&wmi->op_mutex)
ath9k_wmi_cmd_issue(...)
wait_for_completion_timeout(...)
---
timeout
---
/* the callback is being processed
* before last_seq_id became zero
*/
ath9k_wmi_ctrl_rx(...)
spin_lock_irqsave(...)
/* wmi->last_seq_id check here
* doesn't detect timeout yet
*/
spin_unlock_irqrestore(...)
/* last_seq_id is zeroed to
* indicate there was a timeout
*/
wmi->last_seq_id = 0
mutex_unlock(&wmi->op_mutex)
return -ETIMEDOUT
ath9k_wmi_cmd(...)
mutex_lock(&wmi->op_mutex)
/* the buffer is replaced with
* another one
*/
wmi->cmd_rsp_buf = rsp_buf
wmi->cmd_rsp_len = rsp_len
ath9k_wmi_cmd_issue(...)
spin_lock_irqsave(...)
spin_unlock_irqrestore(...)
wait_for_completion_timeout(...)
/* the continuation of the
* callback left after the first
* ath9k_wmi_cmd call
*/
ath9k_wmi_rsp_callback(...)
/* copying data designated
* to already timeouted
* WMI command into an
* inappropriate wmi_cmd_buf
*/
memcpy(...)
complete(&wmi->cmd_wait)
/* awakened by the bogus callback
* => invalid return result
*/
mutex_unlock(&wmi->op_mutex)
return 0
To fix this, update last_seq_id on timeout path inside ath9k_wmi_cmd()
under the wmi_lock. Move ath9k_wmi_rsp_callback() under wmi_lock inside
ath9k_wmi_ctrl_rx() so that the wmi->cmd_wait can be completed only for
initially designated wmi_cmd call, otherwise the path would be rejected
with last_seq_id check.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.") Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com> Link: https://lore.kernel.org/r/20230425192607.18015-1-pchelkin@ispras.ru Signed-off-by: Sasha Levin <sashal@kernel.org>
In the commit 7c4cd051add3 ("bpf: Fix syscall's stackmap lookup
potential deadlock"), a potential deadlock issue was addressed, which
resulted in *_map_lookup_elem not triggering BPF programs.
(prior to lookup, bpf_disable_instrumentation() is used)
To resolve the broken map lookup probe using "htab_map_lookup_elem",
this commit introduces an alternative approach. Instead, it utilize
"bpf_map_copy_value" and apply a filter specifically for the hash table
with map_type.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Fixes: 7c4cd051add3 ("bpf: Fix syscall's stackmap lookup potential deadlock") Link: https://lore.kernel.org/r/20230818090119.477441-8-danieltimlee@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
Recently, a new tracepoint for the block layer, specifically the
block_io_start/done tracepoints, was introduced in commit 5a80bd075f3b
("block: introduce block_io_start/block_io_done tracepoints").
Previously, the kprobe entry used for this purpose was quite unstable
and inherently broke relevant probes [1]. Now that a stable tracepoint
is available, this commit replaces the bio latency check with it.
One of the changes made during this replacement is the key used for the
hash table. Since 'struct request' cannot be used as a hash key, the
approach taken follows that which was implemented in bcc/biolatency [2].
(uses dev:sector for the key)