diff options
Diffstat (limited to 'Documentation')
25 files changed, 821 insertions, 426 deletions
diff --git a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst index 11cdab037bff..eeb351296df1 100644 --- a/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst +++ b/Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst @@ -112,6 +112,35 @@ on PowerPC. The ``smp_mb__after_unlock_lock()`` invocations prevent this ``WARN_ON()`` from triggering. ++-----------------------------------------------------------------------+ +| **Quick Quiz**: | ++-----------------------------------------------------------------------+ +| But the chain of rcu_node-structure lock acquisitions guarantees | +| that new readers will see all of the updater's pre-grace-period | +| accesses and also guarantees that the updater's post-grace-period | +| accesses will see all of the old reader's accesses. So why do we | +| need all of those calls to smp_mb__after_unlock_lock()? | ++-----------------------------------------------------------------------+ +| **Answer**: | ++-----------------------------------------------------------------------+ +| Because we must provide ordering for RCU's polling grace-period | +| primitives, for example, get_state_synchronize_rcu() and | +| poll_state_synchronize_rcu(). Consider this code:: | +| | +| CPU 0 CPU 1 | +| ---- ---- | +| WRITE_ONCE(X, 1) WRITE_ONCE(Y, 1) | +| g = get_state_synchronize_rcu() smp_mb() | +| while (!poll_state_synchronize_rcu(g)) r1 = READ_ONCE(X) | +| continue; | +| r0 = READ_ONCE(Y) | +| | +| RCU guarantees that the outcome r0 == 0 && r1 == 0 will not | +| happen, even if CPU 1 is in an RCU extended quiescent state | +| (idle or offline) and thus won't interact directly with the RCU | +| core processing at all. | ++-----------------------------------------------------------------------+ + This approach must be extended to include idle CPUs, which need RCU's grace-period memory ordering guarantee to extend to any RCU read-side critical sections preceding and following the current diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst index 38a39476fc24..45278e2974c0 100644 --- a/Documentation/RCU/Design/Requirements/Requirements.rst +++ b/Documentation/RCU/Design/Requirements/Requirements.rst @@ -362,9 +362,8 @@ do_something_gp() uses rcu_dereference() to fetch from ``gp``: 12 } The rcu_dereference() uses volatile casts and (for DEC Alpha) memory -barriers in the Linux kernel. Should a `high-quality implementation of -C11 ``memory_order_consume`` -[PDF] <http://www.rdrop.com/users/paulmck/RCU/consume.2015.07.13a.pdf>`__ +barriers in the Linux kernel. Should a |high-quality implementation of +C11 memory_order_consume [PDF]|_ ever appear, then rcu_dereference() could be implemented as a ``memory_order_consume`` load. Regardless of the exact implementation, a pointer fetched by rcu_dereference() may not be used outside of the @@ -374,6 +373,9 @@ element has been passed from RCU to some other synchronization mechanism, most commonly locking or `reference counting <https://www.kernel.org/doc/Documentation/RCU/rcuref.txt>`__. +.. |high-quality implementation of C11 memory_order_consume [PDF]| replace:: high-quality implementation of C11 ``memory_order_consume`` [PDF] +.. _high-quality implementation of C11 memory_order_consume [PDF]: http://www.rdrop.com/users/paulmck/RCU/consume.2015.07.13a.pdf + In short, updaters use rcu_assign_pointer() and readers use rcu_dereference(), and these two RCU API elements work together to ensure that readers have a consistent view of newly added data elements. diff --git a/Documentation/RCU/checklist.rst b/Documentation/RCU/checklist.rst index 01cc21f17f7b..f4545b7c9a63 100644 --- a/Documentation/RCU/checklist.rst +++ b/Documentation/RCU/checklist.rst @@ -37,7 +37,7 @@ over a rather long period of time, but improvements are always welcome! 1. Does the update code have proper mutual exclusion? - RCU does allow -readers- to run (almost) naked, but -writers- must + RCU does allow *readers* to run (almost) naked, but *writers* must still use some sort of mutual exclusion, such as: a. locking, @@ -73,7 +73,7 @@ over a rather long period of time, but improvements are always welcome! critical section is every bit as bad as letting them leak out from under a lock. Unless, of course, you have arranged some other means of protection, such as a lock or a reference count - -before- letting them out of the RCU read-side critical section. + *before* letting them out of the RCU read-side critical section. 3. Does the update code tolerate concurrent accesses? @@ -101,7 +101,7 @@ over a rather long period of time, but improvements are always welcome! c. Make updates appear atomic to readers. For example, pointer updates to properly aligned fields will appear atomic, as will individual atomic primitives. - Sequences of operations performed under a lock will -not- + Sequences of operations performed under a lock will *not* appear to be atomic to RCU readers, nor will sequences of multiple atomic primitives. @@ -333,7 +333,7 @@ over a rather long period of time, but improvements are always welcome! for example) may be omitted. 10. Conversely, if you are in an RCU read-side critical section, - and you don't hold the appropriate update-side lock, you -must- + and you don't hold the appropriate update-side lock, you *must* use the "_rcu()" variants of the list macros. Failing to do so will break Alpha, cause aggressive compilers to generate bad code, and confuse people trying to read your code. @@ -359,12 +359,12 @@ over a rather long period of time, but improvements are always welcome! callback pending, then that RCU callback will execute on some surviving CPU. (If this was not the case, a self-spawning RCU callback would prevent the victim CPU from ever going offline.) - Furthermore, CPUs designated by rcu_nocbs= might well -always- + Furthermore, CPUs designated by rcu_nocbs= might well *always* have their RCU callbacks executed on some other CPUs, in fact, for some real-time workloads, this is the whole point of using the rcu_nocbs= kernel boot parameter. -13. Unlike other forms of RCU, it -is- permissible to block in an +13. Unlike other forms of RCU, it *is* permissible to block in an SRCU read-side critical section (demarked by srcu_read_lock() and srcu_read_unlock()), hence the "SRCU": "sleepable RCU". Please note that if you don't need to sleep in read-side critical @@ -411,16 +411,16 @@ over a rather long period of time, but improvements are always welcome! 14. The whole point of call_rcu(), synchronize_rcu(), and friends is to wait until all pre-existing readers have finished before carrying out some otherwise-destructive operation. It is - therefore critically important to -first- remove any path + therefore critically important to *first* remove any path that readers can follow that could be affected by the - destructive operation, and -only- -then- invoke call_rcu(), + destructive operation, and *only then* invoke call_rcu(), synchronize_rcu(), or friends. Because these primitives only wait for pre-existing readers, it is the caller's responsibility to guarantee that any subsequent readers will execute safely. -15. The various RCU read-side primitives do -not- necessarily contain +15. The various RCU read-side primitives do *not* necessarily contain memory barriers. You should therefore plan for the CPU and the compiler to freely reorder code into and out of RCU read-side critical sections. It is the responsibility of the @@ -459,8 +459,8 @@ over a rather long period of time, but improvements are always welcome! pass in a function defined within a loadable module, then it in necessary to wait for all pending callbacks to be invoked after the last invocation and before unloading that module. Note that - it is absolutely -not- sufficient to wait for a grace period! - The current (say) synchronize_rcu() implementation is -not- + it is absolutely *not* sufficient to wait for a grace period! + The current (say) synchronize_rcu() implementation is *not* guaranteed to wait for callbacks registered on other CPUs. Or even on the current CPU if that CPU recently went offline and came back online. @@ -470,7 +470,7 @@ over a rather long period of time, but improvements are always welcome! - call_rcu() -> rcu_barrier() - call_srcu() -> srcu_barrier() - However, these barrier functions are absolutely -not- guaranteed + However, these barrier functions are absolutely *not* guaranteed to wait for a grace period. In fact, if there are no call_rcu() callbacks waiting anywhere in the system, rcu_barrier() is within its rights to return immediately. diff --git a/Documentation/RCU/rcu_dereference.rst b/Documentation/RCU/rcu_dereference.rst index f3e587acb4de..0b418a5b243c 100644 --- a/Documentation/RCU/rcu_dereference.rst +++ b/Documentation/RCU/rcu_dereference.rst @@ -43,7 +43,7 @@ Follow these rules to keep your RCU code working properly: - Set bits and clear bits down in the must-be-zero low-order bits of that pointer. This clearly means that the pointer must have alignment constraints, for example, this does - -not- work in general for char* pointers. + *not* work in general for char* pointers. - XOR bits to translate pointers, as is done in some classic buddy-allocator algorithms. @@ -174,7 +174,7 @@ Follow these rules to keep your RCU code working properly: Please see the "CONTROL DEPENDENCIES" section of Documentation/memory-barriers.txt for more details. - - The pointers are not equal -and- the compiler does + - The pointers are not equal *and* the compiler does not have enough information to deduce the value of the pointer. Note that the volatile cast in rcu_dereference() will normally prevent the compiler from knowing too much. @@ -360,7 +360,7 @@ in turn destroying the ordering between this load and the loads of the return values. This can result in "p->b" returning pre-initialization garbage values. -In short, rcu_dereference() is -not- optional when you are going to +In short, rcu_dereference() is *not* optional when you are going to dereference the resulting pointer. diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst index 7148e9be08c3..5036df24ae61 100644 --- a/Documentation/RCU/stallwarn.rst +++ b/Documentation/RCU/stallwarn.rst @@ -32,7 +32,7 @@ warnings: - Booting Linux using a console connection that is too slow to keep up with the boot-time console-message rate. For example, - a 115Kbaud serial console can be -way- too slow to keep up + a 115Kbaud serial console can be *way* too slow to keep up with boot-time message rates, and will frequently result in RCU CPU stall warning messages. Especially if you have added debug printk()s. @@ -105,7 +105,7 @@ warnings: leading the realization that the CPU had failed. The RCU, RCU-sched, and RCU-tasks implementations have CPU stall warning. -Note that SRCU does -not- have CPU stall warnings. Please note that +Note that SRCU does *not* have CPU stall warnings. Please note that RCU only detects CPU stalls when there is a grace period in progress. No grace period, no CPU stall warnings. @@ -145,7 +145,7 @@ CONFIG_RCU_CPU_STALL_TIMEOUT this parameter is checked only at the beginning of a cycle. So if you are 10 seconds into a 40-second stall, setting this sysfs parameter to (say) five will shorten the timeout for the - -next- stall, or the following warning for the current stall + *next* stall, or the following warning for the current stall (assuming the stall lasts long enough). It will not affect the timing of the next warning for the current stall. @@ -189,8 +189,8 @@ rcupdate.rcu_task_stall_timeout Interpreting RCU's CPU Stall-Detector "Splats" ============================================== -For non-RCU-tasks flavors of RCU, when a CPU detects that it is stalling, -it will print a message similar to the following:: +For non-RCU-tasks flavors of RCU, when a CPU detects that some other +CPU is stalling, it will print a message similar to the following:: INFO: rcu_sched detected stalls on CPUs/tasks: 2-...: (3 GPs behind) idle=06c/0/0 softirq=1453/1455 fqs=0 @@ -202,8 +202,10 @@ causing stalls, and that the stall was affecting RCU-sched. This message will normally be followed by stack dumps for each CPU. Please note that PREEMPT_RCU builds can be stalled by tasks as well as by CPUs, and that the tasks will be indicated by PID, for example, "P3421". It is even -possible for an rcu_state stall to be caused by both CPUs -and- tasks, +possible for an rcu_state stall to be caused by both CPUs *and* tasks, in which case the offending CPUs and tasks will all be called out in the list. +In some cases, CPUs will detect themselves stalling, which will result +in a self-detected stall. CPU 2's "(3 GPs behind)" indicates that this CPU has not interacted with the RCU core for the past three grace periods. In contrast, CPU 16's "(0 @@ -224,7 +226,7 @@ is the number that had executed since boot at the time that this CPU last noted the beginning of a grace period, which might be the current (stalled) grace period, or it might be some earlier grace period (for example, if the CPU might have been in dyntick-idle mode for an extended -time period. The number after the "/" is the number that have executed +time period). The number after the "/" is the number that have executed since boot until the current time. If this latter number stays constant across repeated stall-warning messages, it is possible that RCU's softirq handlers are no longer able to execute on this CPU. This can happen if @@ -283,7 +285,8 @@ If the relevant grace-period kthread has been unable to run prior to the stall warning, as was the case in the "All QSes seen" line above, the following additional line is printed:: - kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x1 ->cpu=5 + rcu_sched kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x1 ->cpu=5 + Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. Starving the grace-period kthreads of CPU time can of course result in RCU CPU stall warnings even when all CPUs and tasks have passed @@ -313,15 +316,21 @@ is the current ``TIMER_SOFTIRQ`` count on cpu 4. If this value does not change on successive RCU CPU stall warnings, there is further reason to suspect a timer problem. +These messages are usually followed by stack dumps of the CPUs and tasks +involved in the stall. These stack traces can help you locate the cause +of the stall, keeping in mind that the CPU detecting the stall will have +an interrupt frame that is mainly devoted to detecting the stall. + Multiple Warnings From One Stall ================================ -If a stall lasts long enough, multiple stall-warning messages will be -printed for it. The second and subsequent messages are printed at +If a stall lasts long enough, multiple stall-warning messages will +be printed for it. The second and subsequent messages are printed at longer intervals, so that the time between (say) the first and second message will be about three times the interval between the beginning -of the stall and the first message. +of the stall and the first message. It can be helpful to compare the +stack dumps for the different messages for the same stalled grace period. Stall Warnings for Expedited Grace Periods diff --git a/Documentation/devicetree/bindings/fsi/ibm,fsi2spi.yaml b/Documentation/devicetree/bindings/fsi/ibm,fsi2spi.yaml index e425278653f5..e2ca0b000471 100644 --- a/Documentation/devicetree/bindings/fsi/ibm,fsi2spi.yaml +++ b/Documentation/devicetree/bindings/fsi/ibm,fsi2spi.yaml @@ -19,7 +19,6 @@ properties: compatible: enum: - ibm,fsi2spi - - ibm,fsi2spi-restricted reg: items: diff --git a/Documentation/devicetree/bindings/power/supply/battery.yaml b/Documentation/devicetree/bindings/power/supply/battery.yaml index c3b4b7543591..d56ac484fec5 100644 --- a/Documentation/devicetree/bindings/power/supply/battery.yaml +++ b/Documentation/devicetree/bindings/power/supply/battery.yaml @@ -31,6 +31,20 @@ properties: compatible: const: simple-battery + device-chemistry: + description: This describes the chemical technology of the battery. + oneOf: + - const: nickel-cadmium + - const: nickel-metal-hydride + - const: lithium-ion + description: This is a blanket type for all lithium-ion batteries, + including those below. If possible, a precise compatible string + from below should be used, but sometimes it is unknown which specific + lithium ion battery is employed and this wide compatible can be used. + - const: lithium-ion-polymer + - const: lithium-ion-iron-phosphate + - const: lithium-ion-manganese-oxide + over-voltage-threshold-microvolt: description: battery over-voltage limit diff --git a/Documentation/devicetree/bindings/power/supply/maxim,max17042.yaml b/Documentation/devicetree/bindings/power/supply/maxim,max17042.yaml index c70f05ea6d27..971b53c58cc6 100644 --- a/Documentation/devicetree/bindings/power/supply/maxim,max17042.yaml +++ b/Documentation/devicetree/bindings/power/supply/maxim,max17042.yaml @@ -19,12 +19,15 @@ properties: - maxim,max17047 - maxim,max17050 - maxim,max17055 + - maxim,max77849-battery reg: maxItems: 1 interrupts: maxItems: 1 + description: | + The ALRT pin, an open-drain interrupt. maxim,rsns-microohm: $ref: /schemas/types.yaml#/definitions/uint32 diff --git a/Documentation/devicetree/bindings/power/supply/mt6360_charger.yaml b/Documentation/devicetree/bindings/power/supply/mt6360_charger.yaml new file mode 100644 index 000000000000..b89b15a5bfa4 --- /dev/null +++ b/Documentation/devicetree/bindings/power/supply/mt6360_charger.yaml @@ -0,0 +1,48 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/power/supply/mt6360_charger.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Battery charger driver for MT6360 PMIC from MediaTek Integrated. + +maintainers: + - Gene Chen <gene_chen@richtek.com> + +description: | + This module is part of the MT6360 MFD device. + Provides Battery Charger, Boost for OTG devices and BC1.2 detection. + +properties: + compatible: + const: mediatek,mt6360-chg + + richtek,vinovp-microvolt: + description: Maximum CHGIN regulation voltage in uV. + enum: [ 5500000, 6500000, 11000000, 14500000 ] + + + usb-otg-vbus-regulator: + type: object + description: OTG boost regulator. + $ref: /schemas/regulator/regulator.yaml# + +required: + - compatible + +additionalProperties: false + +examples: + - | + mt6360_charger: charger { + compatible = "mediatek,mt6360-chg"; + richtek,vinovp-microvolt = <14500000>; + + otg_vbus_regulator: usb-otg-vbus-regulator { + regulator-compatible = "usb-otg-vbus"; + regulator-name = "usb-otg-vbus"; + regulator-min-microvolt = <4425000>; + regulator-max-microvolt = <5825000>; + }; + }; +... diff --git a/Documentation/devicetree/bindings/power/supply/summit,smb347-charger.yaml b/Documentation/devicetree/bindings/power/supply/summit,smb347-charger.yaml index 983fc215c1e5..20862cdfc116 100644 --- a/Documentation/devicetree/bindings/power/supply/summit,smb347-charger.yaml +++ b/Documentation/devicetree/bindings/power/supply/summit,smb347-charger.yaml @@ -73,6 +73,26 @@ properties: - 1 # SMB3XX_SOFT_TEMP_COMPENSATE_CURRENT Current compensation - 2 # SMB3XX_SOFT_TEMP_COMPENSATE_VOLTAGE Voltage compensation + summit,inok-polarity: + description: | + Polarity of INOK signal indicating presence of external power supply. + $ref: /schemas/types.yaml#/definitions/uint32 + enum: + - 0 # SMB3XX_SYSOK_INOK_ACTIVE_LOW + - 1 # SMB3XX_SYSOK_INOK_ACTIVE_HIGH + + usb-vbus: + $ref: "../../regulator/regulator.yaml#" + type: object + + properties: + summit,needs-inok-toggle: + type: boolean + description: INOK signal is fixed and polarity needs to be toggled + in order to enable/disable output mode. + + unevaluatedProperties: false + allOf: - if: properties: @@ -134,6 +154,7 @@ examples: reg = <0x7f>; summit,enable-charge-control = <SMB3XX_CHG_ENABLE_PIN_ACTIVE_HIGH>; + summit,inok-polarity = <SMB3XX_SYSOK_INOK_ACTIVE_LOW>; summit,chip-temperature-threshold-celsius = <110>; summit,mains-current-limit-microamp = <2000000>; summit,usb-current-limit-microamp = <500000>; @@ -141,6 +162,15 @@ examples: summit,enable-mains-charging; monitored-battery = <&battery>; + + usb-vbus { + regulator-name = "usb_vbus"; + regulator-min-microvolt = <5000000>; + regulator-max-microvolt = <5000000>; + regulator-min-microamp = <750000>; + regulator-max-microamp = <750000>; + summit,needs-inok-toggle; + }; }; }; diff --git a/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-ac-power-supply.yaml b/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-ac-power-supply.yaml index dcda6660b8ed..de6a23aee977 100644 --- a/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-ac-power-supply.yaml +++ b/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-ac-power-supply.yaml @@ -21,10 +21,13 @@ allOf: properties: compatible: - enum: - - x-powers,axp202-ac-power-supply - - x-powers,axp221-ac-power-supply - - x-powers,axp813-ac-power-supply + oneOf: + - const: x-powers,axp202-ac-power-supply + - const: x-powers,axp221-ac-power-supply + - items: + - const: x-powers,axp803-ac-power-supply + - const: x-powers,axp813-ac-power-supply + - const: x-powers,axp813-ac-power-supply required: - compatible diff --git a/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-battery-power-supply.yaml b/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-battery-power-supply.yaml index 86e8a713d4e2..d055428ae39f 100644 --- a/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-battery-power-supply.yaml +++ b/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-battery-power-supply.yaml @@ -19,10 +19,14 @@ allOf: properties: compatible: - enum: - - x-powers,axp209-battery-power-supply - - x-powers,axp221-battery-power-supply - - x-powers,axp813-battery-power-supply + oneOf: + - const: x-powers,axp202-battery-power-supply + - const: x-powers,axp209-battery-power-supply + - const: x-powers,axp221-battery-power-supply + - items: + - const: x-powers,axp803-battery-power-supply + - const: x-powers,axp813-battery-power-supply + - const: x-powers,axp813-battery-power-supply required: - compatible diff --git a/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-usb-power-supply.yaml b/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-usb-power-supply.yaml index 61f1b320c157..0c371b55c9e1 100644 --- a/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-usb-power-supply.yaml +++ b/Documentation/devicetree/bindings/power/supply/x-powers,axp20x-usb-power-supply.yaml @@ -20,11 +20,15 @@ allOf: properties: compatible: - enum: - - x-powers,axp202-usb-power-supply - - x-powers,axp221-usb-power-supply - - x-powers,axp223-usb-power-supply - - x-powers,axp813-usb-power-supply + oneOf: + - enum: + - x-powers,axp202-usb-power-supply + - x-powers,axp221-usb-power-supply + - x-powers,axp223-usb-power-supply + - x-powers,axp813-usb-power-supply + - items: + - const: x-powers,axp803-usb-power-supply + - const: x-powers,axp813-usb-power-supply required: diff --git a/Documentation/devicetree/bindings/regulator/richtek,rtq2134-regulator.yaml b/Documentation/devicetree/bindings/regulator/richtek,rtq2134-regulator.yaml new file mode 100644 index 000000000000..3f47e8e6c4fd --- /dev/null +++ b/Documentation/devicetree/bindings/regulator/richtek,rtq2134-regulator.yaml @@ -0,0 +1,106 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/regulator/richtek,rtq2134-regulator.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Richtek RTQ2134 SubPMIC Regulator + +maintainers: + - ChiYuan Huang <cy_huang@richtek.com> + +description: | + The RTQ2134 is a multi-phase, programmable power management IC that + integrates with four high efficient, synchronous step-down converter cores. + + Datasheet is available at + https://www.richtek.com/assets/product_file/RTQ2134-QA/DSQ2134-QA-01.pdf + +properties: + compatible: + enum: + - richtek,rtq2134 + + reg: + maxItems: 1 + + regulators: + type: object + + patternProperties: + "^buck[1-3]$": + type: object + $ref: regulator.yaml# + description: | + regulator description for buck[1-3]. + + properties: + richtek,use-vsel-dvs: + type: boolean + description: | + If specified, buck will listen to 'vsel' pin for dvs config. + Else, use dvs0 voltage by default. + + richtek,uv-shutdown: + type: boolean + description: | + If specified, use shutdown as UV action. Else, hiccup by default. + + unevaluatedProperties: false + + additionalProperties: false + +required: + - compatible + - reg + - regulators + +additionalProperties: false + +examples: + - | + i2c { + #address-cells = <1>; + #size-cells = <0>; + + rtq2134@18 { + compatible = "richtek,rtq2134"; + reg = <0x18>; + + regulators { + buck1 { + regulator-name = "rtq2134-buck1"; + regulator-min-microvolt = <300000>; + regulator-max-microvolt = <1850000>; + regulator-always-on; + richtek,use-vsel-dvs; + regulator-state-mem { + regulator-suspend-min-microvolt = <550000>; + regulator-suspend-max-microvolt = <550000>; + }; + }; + buck2 { + regulator-name = "rtq2134-buck2"; + regulator-min-microvolt = <1120000>; + regulator-max-microvolt = <1120000>; + regulator-always-on; + richtek,use-vsel-dvs; + regulator-state-mem { + regulator-suspend-min-microvolt = <1120000>; + regulator-suspend-max-microvolt = <1120000>; + }; + }; + buck3 { + regulator-name = "rtq2134-buck3"; + regulator-min-microvolt = <600000>; + regulator-max-microvolt = <600000>; + regulator-always-on; + richtek,use-vsel-dvs; + regulator-state-mem { + regulator-suspend-min-microvolt = <600000>; + regulator-suspend-max-microvolt = <600000>; + }; + }; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/regulator/richtek,rtq6752-regulator.yaml b/Documentation/devicetree/bindings/regulator/richtek,rtq6752-regulator.yaml new file mode 100644 index 000000000000..e6e5a9a7d940 --- /dev/null +++ b/Documentation/devicetree/bindings/regulator/richtek,rtq6752-regulator.yaml @@ -0,0 +1,76 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/regulator/richtek,rtq6752-regulator.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Richtek RTQ6752 TFT LCD Voltage Regulator + +maintainers: + - ChiYuan Huang <cy_huang@richtek.com> + +description: | + The RTQ6752 is an I2C interface pgorammable power management IC. It includes + two synchronous boost converter for PAVDD, and one synchronous NAVDD + buck-boost. The device is suitable for automotive TFT-LCD panel. + +properties: + compatible: + enum: + - richtek,rtq6752 + + reg: + maxItems: 1 + + enable-gpios: + description: | + A connection of the chip 'enable' gpio line. If not provided, treat it as + external pull up. + maxItems: 1 + + regulators: + type: object + + patternProperties: + "^(p|n)avdd$": + type: object + $ref: regulator.yaml# + description: | + regulator description for pavdd and navdd. + + additionalProperties: false + +required: + - compatible + - reg + - regulators + +additionalProperties: false + +examples: + - | + i2c { + #address-cells = <1>; + #size-cells = <0>; + + rtq6752@6b { + compatible = "richtek,rtq6752"; + reg = <0x6b>; + enable-gpios = <&gpio26 2 0>; + + regulators { + pavdd { + regulator-name = "rtq6752-pavdd"; + regulator-min-microvolt = <5000000>; + regulator-max-microvolt = <7300000>; + regulator-boot-on; + }; + navdd { + regulator-name = "rtq6752-navdd"; + regulator-min-microvolt = <5000000>; + regulator-max-microvolt = <7300000>; + regulator-boot-on; + }; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/regulator/socionext,uniphier-regulator.yaml b/Documentation/devicetree/bindings/regulator/socionext,uniphier-regulator.yaml new file mode 100644 index 000000000000..861d5f3c79e8 --- /dev/null +++ b/Documentation/devicetree/bindings/regulator/socionext,uniphier-regulator.yaml @@ -0,0 +1,85 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/regulator/socionext,uniphier-regulator.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Socionext UniPhier regulator controller + +description: | + This regulator controls VBUS and belongs to USB3 glue layer. Before using + the regulator, it is necessary to control the clocks and resets to enable + this layer. These clocks and resets should be described in each property. + +maintainers: + - Kunihiko Hayashi <hayashi.kunihiko@socionext.com> + +allOf: + - $ref: "regulator.yaml#" + +# USB3 Controller + +properties: + compatible: + enum: + - socionext,uniphier-pro4-usb3-regulator + - socionext,uniphier-pro5-usb3-regulator + - socionext,uniphier-pxs2-usb3-regulator + - socionext,uniphier-ld20-usb3-regulator + - socionext,uniphier-pxs3-usb3-regulator + + reg: + maxItems: 1 + + clocks: + minItems: 1 + maxItems: 2 + + clock-names: + oneOf: + - items: # for Pro4, Pro5 + - const: gio + - const: link + - items: # for others + - const: link + + resets: + minItems: 1 + maxItems: 2 + + reset-names: + oneOf: + - items: # for Pro4, Pro5 + - const: gio + - const: link + - items: + - const: link + +additionalProperties: false + +required: + - compatible + - reg + - clocks + - clock-names + - resets + - reset-names + +examples: + - | + usb-glue@65b00000 { + compatible = "simple-mfd"; + #address-cells = <1>; + #size-cells = <1>; + ranges = <0 0x65b00000 0x400>; + + usb_vbus0: regulators@100 { + compatible = "socionext,uniphier-ld20-usb3-regulator"; + reg = <0x100 0x10>; + clock-names = "link"; + clocks = <&sys_clk 14>; + reset-names = "link"; + resets = <&sys_rst 14>; + }; + }; + diff --git a/Documentation/devicetree/bindings/regulator/uniphier-regulator.txt b/Documentation/devicetree/bindings/regulator/uniphier-regulator.txt deleted file mode 100644 index 94fd38b0d163..000000000000 --- a/Documentation/devicetree/bindings/regulator/uniphier-regulator.txt +++ /dev/null @@ -1,58 +0,0 @@ -Socionext UniPhier Regulator Controller - -This describes the devicetree bindings for regulator controller implemented -on Socionext UniPhier SoCs. - -USB3 Controller ---------------- - -This regulator controls VBUS and belongs to USB3 glue layer. Before using -the regulator, it is necessary to control the clocks and resets to enable -this layer. These clocks and resets should be described in each property. - -Required properties: -- compatible: Should be - "socionext,uniphier-pro4-usb3-regulator" - for Pro4 SoC - "socionext,uniphier-pro5-usb3-regulator" - for Pro5 SoC - "socionext,uniphier-pxs2-usb3-regulator" - for PXs2 SoC - "socionext,uniphier-ld20-usb3-regulator" - for LD20 SoC - "socionext,uniphier-pxs3-usb3-regulator" - for PXs3 SoC -- reg: Specifies offset and length of the register set for the device. -- clocks: A list of phandles to the clock gate for USB3 glue layer. - According to the clock-names, appropriate clocks are required. -- clock-names: Should contain - "gio", "link" - for Pro4 and Pro5 SoCs - "link" - for others -- resets: A list of phandles to the reset control for USB3 glue layer. - According to the reset-names, appropriate resets are required. -- reset-names: Should contain - "gio", "link" - for Pro4 and Pro5 SoCs - "link" - for others - -See Documentation/devicetree/bindings/regulator/regulator.txt -for more details about the regulator properties. - -Example: - - usb-glue@65b00000 { - compatible = "socionext,uniphier-ld20-dwc3-glue", - "simple-mfd"; - #address-cells = <1>; - #size-cells = <1>; - ranges = <0 0x65b00000 0x400>; - - usb_vbus0: regulators@100 { - compatible = "socionext,uniphier-ld20-usb3-regulator"; - reg = <0x100 0x10>; - clock-names = "link"; - clocks = <&sys_clk 14>; - reset-names = "link"; - resets = <&sys_rst 14>; - }; - - phy { - ... - phy-supply = <&usb_vbus0>; - }; - ... - }; diff --git a/Documentation/devicetree/bindings/spi/omap-spi.txt b/Documentation/devicetree/bindings/spi/omap-spi.txt deleted file mode 100644 index 487208c256c0..000000000000 --- a/Documentation/devicetree/bindings/spi/omap-spi.txt +++ /dev/null @@ -1,48 +0,0 @@ -OMAP2+ McSPI device - -Required properties: -- compatible : - - "ti,am654-mcspi" for AM654. - - "ti,omap2-mcspi" for OMAP2 & OMAP3. - - "ti,omap4-mcspi" for OMAP4+. -- ti,spi-num-cs : Number of chipselect supported by the instance. -- ti,hwmods: Name of the hwmod associated to the McSPI -- ti,pindir-d0-out-d1-in: Select the D0 pin as output and D1 as - input. The default is D0 as input and - D1 as output. - -Optional properties: -- dmas: List of DMA specifiers with the controller specific format - as described in the generic DMA client binding. A tx and rx - specifier is required for each chip select. -- dma-names: List of DMA request names. These strings correspond - 1:1 with the DMA specifiers listed in dmas. The string naming - is to be "rxN" and "txN" for RX and TX requests, - respectively, where N equals the chip select number. - -Examples: - -[hwmod populated DMA resources] - -mcspi1: mcspi@1 { - #address-cells = <1>; - #size-cells = <0>; - compatible = "ti,omap4-mcspi"; - ti,hwmods = "mcspi1"; - ti,spi-num-cs = <4>; -}; - -[generic DMA request binding] - -mcspi1: mcspi@1 { - #address-cells = <1>; - #size-cells = <0>; - compatible = "ti,omap4-mcspi"; - ti,hwmods = "mcspi1"; - ti,spi-num-cs = <2>; - dmas = <&edma 42 - &edma 43 - &edma 44 - &edma 45>; - dma-names = "tx0", "rx0", "tx1", "rx1"; -}; diff --git a/Documentation/devicetree/bindings/spi/omap-spi.yaml b/Documentation/devicetree/bindings/spi/omap-spi.yaml new file mode 100644 index 000000000000..e55538186cf6 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/omap-spi.yaml @@ -0,0 +1,117 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/spi/omap-spi.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: SPI controller bindings for OMAP and K3 SoCs + +maintainers: + - Aswath Govindraju <a-govindraju@ti.com> + +allOf: + - $ref: spi-controller.yaml# + +properties: + compatible: + oneOf: + - items: + - enum: + - ti,am654-mcspi + - ti,am4372-mcspi + - const: ti,omap4-mcspi + - items: + - enum: + - ti,omap2-mcspi + - ti,omap4-mcspi + + reg: + maxItems: 1 + + interrupts: + maxItems: 1 + + clocks: + maxItems: 1 + + power-domains: + maxItems: 1 + + ti,spi-num-cs: + $ref: /schemas/types.yaml#/definitions/uint32 + description: Number of chipselect supported by the instance. + minimum: 1 + maximum: 4 + + ti,hwmods: + $ref: /schemas/types.yaml#/definitions/string + description: + Must be "mcspi<n>", n being the instance number (1-based). + This property is applicable only on legacy platforms mainly omap2/3 + and ti81xx and should not be used on other platforms. + deprecated: true + + ti,pindir-d0-out-d1-in: + description: + Select the D0 pin as output and D1 as input. The default is D0 + as input and D1 as output. + type: boolean + + dmas: + description: + List of DMA specifiers with the controller specific format as + described in the generic DMA client binding. A tx and rx + specifier is required for each chip select. + minItems: 1 + maxItems: 8 + + dma-names: + description: + List of DMA request names. These strings correspond 1:1 with + the DMA sepecifiers listed in dmas. The string names is to be + "rxN" and "txN" for RX and TX requests, respectively. Where N + is the chip select number. + minItems: 1 + maxItems: 8 + +required: + - compatible + - reg + - interrupts + +unevaluatedProperties: false + +if: + properties: + compatible: + oneOf: + - const: ti,omap2-mcspi + - const: ti,omap4-mcspi + +then: + properties: + ti,hwmods: + items: + - pattern: "^mcspi([1-9])$" + +else: + properties: + ti,hwmods: false + +examples: + - | + #include <dt-bindings/interrupt-controller/irq.h> + #include <dt-bindings/interrupt-controller/arm-gic.h> + #include <dt-bindings/soc/ti,sci_pm_domain.h> + + spi@2100000 { + compatible = "ti,am654-mcspi","ti,omap4-mcspi"; + reg = <0x2100000 0x400>; + interrupts = <GIC_SPI 184 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&k3_clks 137 1>; + power-domains = <&k3_pds 137 TI_SCI_PD_EXCLUSIVE>; + #address-cells = <1>; + #size-cells = <0>; + dmas = <&main_udmap 0xc500>, <&main_udmap 0x4500>; + dma-names = "tx0", "rx0"; + }; diff --git a/Documentation/devicetree/bindings/spi/rockchip-sfc.yaml b/Documentation/devicetree/bindings/spi/rockchip-sfc.yaml new file mode 100644 index 000000000000..339fb39529f3 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/rockchip-sfc.yaml @@ -0,0 +1,91 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/spi/rockchip-sfc.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Rockchip Serial Flash Controller (SFC) + +maintainers: + - Heiko Stuebner <heiko@sntech.de> + - Chris Morgan <macromorgan@hotmail.com> + +allOf: + - $ref: spi-controller.yaml# + +properties: + compatible: + const: rockchip,sfc + description: + The rockchip sfc controller is a standalone IP with version register, + and the driver can handle all the feature difference inside the IP + depending on the version register. + + reg: + maxItems: 1 + + interrupts: + maxItems: 1 + + clocks: + items: + - description: Bus Clock + - description: Module Clock + + clock-names: + items: + - const: clk_sfc + - const: hclk_sfc + + power-domains: + maxItems: 1 + + rockchip,sfc-no-dma: + description: Disable DMA and utilize FIFO mode only + type: boolean + +patternProperties: + "^flash@[0-3]$": + type: object + properties: + reg: + minimum: 0 + maximum: 3 + +required: + - compatible + - reg + - interrupts + - clocks + - clock-names + +unevaluatedProperties: false + +examples: + - | + #include <dt-bindings/clock/px30-cru.h> + #include <dt-bindings/interrupt-controller/arm-gic.h> + #include <dt-bindings/power/px30-power.h> + + sfc: spi@ff3a0000 { + compatible = "rockchip,sfc"; + reg = <0xff3a0000 0x4000>; + interrupts = <GIC_SPI 56 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&cru SCLK_SFC>, <&cru HCLK_SFC>; + clock-names = "clk_sfc", "hclk_sfc"; + pinctrl-0 = <&sfc_clk &sfc_cs &sfc_bus2>; + pinctrl-names = "default"; + power-domains = <&power PX30_PD_MMC_NAND>; + #address-cells = <1>; + #size-cells = <0>; + + flash@0 { + compatible = "jedec,spi-nor"; + reg = <0>; + spi-max-frequency = <108000000>; + spi-rx-bus-width = <2>; + spi-tx-bus-width = <2>; + }; + }; + +... diff --git a/Documentation/devicetree/bindings/spi/spi-mt65xx.txt b/Documentation/devicetree/bindings/spi/spi-mt65xx.txt index 4d0e4c15c4ea..2a24969159cc 100644 --- a/Documentation/devicetree/bindings/spi/spi-mt65xx.txt +++ b/Documentation/devicetree/bindings/spi/spi-mt65xx.txt @@ -11,6 +11,7 @@ Required properties: - mediatek,mt8135-spi: for mt8135 platforms - mediatek,mt8173-spi: for mt8173 platforms - mediatek,mt8183-spi: for mt8183 platforms + - mediatek,mt6893-spi: for mt6893 platforms - "mediatek,mt8192-spi", "mediatek,mt6765-spi": for mt8192 platforms - "mediatek,mt8195-spi", "mediatek,mt6765-spi": for mt8195 platforms - "mediatek,mt8516-spi", "mediatek,mt2712-spi": for mt8516 platforms diff --git a/Documentation/devicetree/bindings/spi/spi-sprd-adi.txt b/Documentation/devicetree/bindings/spi/spi-sprd-adi.txt deleted file mode 100644 index 2567c829e2dc..000000000000 --- a/Documentation/devicetree/bindings/spi/spi-sprd-adi.txt +++ /dev/null @@ -1,63 +0,0 @@ -Spreadtrum ADI controller - -ADI is the abbreviation of Anolog-Digital interface, which is used to access -analog chip (such as PMIC) from digital chip. ADI controller follows the SPI -framework for its hardware implementation is alike to SPI bus and its timing -is compatile to SPI timing. - -ADI controller has 50 channels including 2 software read/write channels and -48 hardware channels to access analog chip. For 2 software read/write channels, -users should set ADI registers to access analog chip. For hardware channels, -we can configure them to allow other hardware components to use it independently, -which means we can just link one analog chip address to one hardware channel, -then users can access the mapped analog chip address by this hardware channel -triggered by hardware components instead of ADI software channels. - -Thus we introduce one property named "sprd,hw-channels" to configure hardware -channels, the first value specifies the hardware channel id which is used to -transfer data triggered by hardware automatically, and the second value specifies -the analog chip address where user want to access by hardware components. - -Since we have multi-subsystems will use unique ADI to access analog chip, when -one system is reading/writing data by ADI software channels, that should be under -one hardware spinlock protection to prevent other systems from reading/writing -data by ADI software channels at the same time, or two parallel routine of setting -ADI registers will make ADI controller registers chaos to lead incorrect results. -Then we need one hardware spinlock to synchronize between the multiple subsystems. - -The new version ADI controller supplies multiple master channels for different -subsystem accessing, that means no need to add hardware spinlock to synchronize, -thus change the hardware spinlock support to be optional to keep backward -compatibility. - -Required properties: -- compatible: Should be "sprd,sc9860-adi". -- reg: Offset and length of ADI-SPI controller register space. -- #address-cells: Number of cells required to define a chip select address - on the ADI-SPI bus. Should be set to 1. -- #size-cells: Size of cells required to define a chip select address size - on the ADI-SPI bus. Should be set to 0. - -Optional properties: -- hwlocks: Reference to a phandle of a hwlock provider node. -- hwlock-names: Reference to hwlock name strings defined in the same order - as the hwlocks, should be "adi". -- sprd,hw-channels: This is an array of channel values up to 49 channels. - The first value specifies the hardware channel id which is used to - transfer data triggered by hardware automatically, and the second - value specifies the analog chip address where user want to access - by hardware components. - -SPI slave nodes must be children of the SPI controller node and can contain -properties described in Documentation/devicetree/bindings/spi/spi-bus.txt. - -Example: - adi_bus: spi@40030000 { - compatible = "sprd,sc9860-adi"; - reg = <0 0x40030000 0 0x10000>; - hwlocks = <&hwlock1 0>; - hwlock-names = "adi"; - #address-cells = <1>; - #size-cells = <0>; - sprd,hw-channels = <30 0x8c20>; - }; diff --git a/Documentation/devicetree/bindings/spi/sprd,spi-adi.yaml b/Documentation/devicetree/bindings/spi/sprd,spi-adi.yaml new file mode 100644 index 000000000000..fe014020da69 --- /dev/null +++ b/Documentation/devicetree/bindings/spi/sprd,spi-adi.yaml @@ -0,0 +1,104 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) + +%YAML 1.2 +--- +$id: "http://devicetree.org/schemas/spi/sprd,spi-adi.yaml#" +$schema: "http://devicetree.org/meta-schemas/core.yaml#" + +title: Spreadtrum ADI controller + +maintainers: + - Orson Zhai <orsonzhai@gmail.com> + - Baolin Wang <baolin.wang7@gmail.com> + - Chunyan Zhang <zhang.lyra@gmail.com> + +description: | + ADI is the abbreviation of Anolog-Digital interface, which is used to access + analog chip (such as PMIC) from digital chip. ADI controller follows the SPI + framework for its hardware implementation is alike to SPI bus and its timing + is compatile to SPI timing. + + ADI controller has 50 channels including 2 software read/write channels and + 48 hardware channels to access analog chip. For 2 software read/write channels, + users should set ADI registers to access analog chip. For hardware channels, + we can configure them to allow other hardware components to use it independently, + which means we can just link one analog chip address to one hardware channel, + then users can access the mapped analog chip address by this hardware channel + triggered by hardware components instead of ADI software channels. + + Thus we introduce one property named "sprd,hw-channels" to configure hardware + channels, the first value specifies the hardware channel id which is used to + transfer data triggered by hardware automatically, and the second value specifies + the analog chip address where user want to access by hardware components. + + Since we have multi-subsystems will use unique ADI to access analog chip, when + one system is reading/writing data by ADI software channels, that should be under + one hardware spinlock protection to prevent other systems from reading/writing + data by ADI software channels at the same time, or two parallel routine of setting + ADI registers will make ADI controller registers chaos to lead incorrect results. + Then we need one hardware spinlock to synchronize between the multiple subsystems. + + The new version ADI controller supplies multiple master channels for different + subsystem accessing, that means no need to add hardware spinlock to synchronize, + thus change the hardware spinlock support to be optional to keep backward + compatibility. + +allOf: + - $ref: /spi/spi-controller.yaml# + +properties: + compatible: + enum: + - sprd,sc9860-adi + - sprd,sc9863-adi + - sprd,ums512-adi + + reg: + maxItems: 1 + + hwlocks: + maxItems: 1 + + hwlock-names: + const: adi + + sprd,hw-channels: + $ref: /schemas/types.yaml#/definitions/uint32-matrix + description: A list of hardware channels + minItems: 1 + maxItems: 48 + items: + items: + - description: The hardware channel id which is used to transfer data + triggered by hardware automatically, channel id 0-1 are for software + use, 2-49 are hardware channels. + minimum: 2 + maximum: 49 + - description: The analog chip address where user want to access by + hardware components. + +required: + - compatible + - reg + - '#address-cells' + - '#size-cells' + +unevaluatedProperties: false + +examples: + - | + aon { + #address-cells = <2>; + #size-cells = <2>; + + adi_bus: spi@40030000 { + compatible = "sprd,sc9860-adi"; + reg = <0 0x40030000 0 0x10000>; + hwlocks = <&hwlock1 0>; + hwlock-names = "adi"; + #address-cells = <1>; + #size-cells = <0>; + sprd,hw-channels = <30 0x8c20>; + }; + }; +... diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst index 2183fd8cc350..2a75dd5da7b5 100644 --- a/Documentation/filesystems/locking.rst +++ b/Documentation/filesystems/locking.rst @@ -271,19 +271,19 @@ prototypes:: locking rules: All except set_page_dirty and freepage may block -====================== ======================== ========= -ops PageLocked(page) i_rwsem -====================== ======================== ========= +====================== ======================== ========= =============== +ops PageLocked(page) i_rwsem invalidate_lock +====================== ======================== ========= =============== writepage: yes, unlocks (see below) -readpage: yes, unlocks +readpage: yes, unlocks shared writepages: set_page_dirty no -readahead: yes, unlocks -readpages: no +readahead: yes, unlocks shared +readpages: no shared write_begin: locks the page exclusive write_end: yes, unlocks exclusive bmap: -invalidatepage: yes +invalidatepage: yes exclusive releasepage: yes freepage: yes direct_IO: @@ -295,7 +295,7 @@ is_partially_uptodate: yes error_remove_page: yes swap_activate: no swap_deactivate: no -====================== ======================== ========= +====================== ======================== ========= =============== ->write_begin(), ->write_end() and ->readpage() may be called from the request handler (/dev/loop). @@ -378,7 +378,10 @@ keep it that way and don't breed new callers. ->invalidatepage() is called when the filesystem must attempt to drop some or all of the buffers from the page when it is being truncated. It returns zero on success. If ->invalidatepage is zero, the kernel uses -block_invalidatepage() instead. +block_invalidatepage() instead. The filesystem must exclusively acquire +invalidate_lock before invalidating page cache in truncate / hole punch path +(and thus calling into ->invalidatepage) to block races between page cache +invalidation and page cache filling functions (fault, read, ...). ->releasepage() is called when the kernel is about to try to drop the buffers from the page in preparation for freeing it. It returns zero to @@ -506,6 +509,7 @@ prototypes:: ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); ssize_t (*read_iter) (struct kiocb *, struct iov_iter *); ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); + int (*iopoll) (struct kiocb *kiocb, bool spin); int (*iterate) (struct file *, struct dir_context *); int (*iterate_shared) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); @@ -518,12 +522,6 @@ prototypes:: int (*fsync) (struct file *, loff_t start, loff_t end, int datasync); int (*fasync) (int, struct file *, int); int (*lock) (struct file *, int, struct file_lock *); - ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, - loff_t *); - ssize_t (*writev) (struct file *, const struct iovec *, unsigned long, - loff_t *); - ssize_t (*sendfile) (struct file *, loff_t *, size_t, read_actor_t, - void __user *); ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int); unsigned long (*get_unmapped_area)(struct file *, unsigned long, @@ -536,6 +534,14 @@ prototypes:: size_t, unsigned int); int (*setlease)(struct file *, long, struct file_lock **, void **); long (*fallocate)(struct file *, int, loff_t, loff_t); + void (*show_fdinfo)(struct seq_file *m, struct file *f); + unsigned (*mmap_capabilities)(struct file *); + ssize_t (*copy_file_range)(struct file *, loff_t, struct file *, + loff_t, size_t, unsigned int); + loff_t (*remap_file_range)(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + loff_t len, unsigned int remap_flags); + int (*fadvise)(struct file *, loff_t, loff_t, int); locking rules: All may block. @@ -570,6 +576,25 @@ in sys_read() and friends. the lease within the individual filesystem to record the result of the operation +->fallocate implementation must be really careful to maintain page cache +consistency when punching holes or performing other operations that invalidate +page cache contents. Usually the filesystem needs to call +truncate_inode_pages_range() to invalidate relevant range of the page cache. +However the filesystem usually also needs to update its internal (and on disk) +view of file offset -> disk block mapping. Until this update is finished, the +filesystem needs to block page faults and reads from reloading now-stale page +cache contents from the disk. Since VFS acquires mapping->invalidate_lock in +shared mode when loading pages from disk (filemap_fault(), filemap_read(), +readahead paths), the fallocate implementation must take the invalidate_lock to +prevent reloading. + +->copy_file_range and ->remap_file_range implementations need to serialize +against modifications of file data while the operation is running. For +blocking changes through write(2) and similar operations inode->i_rwsem can be +used. To block changes to file contents via a memory mapping during the +operation, the filesystem must take mapping->invalidate_lock to coordinate +with ->page_mkwrite. + dquot_operations ================ @@ -627,11 +652,11 @@ pfn_mkwrite: yes access: yes ============= ========= =========================== -->fault() is called when a previously not present pte is about -to be faulted in. The filesystem must find and return the page associated -with the passed in "pgoff" in the vm_fault structure. If it is possible that -the page may be truncated and/or invalidated, then the filesystem must lock -the page, then ensure it is not already truncated (the page lock will block +->fault() is called when a previously not present pte is about to be faulted +in. The filesystem must find and return the page associated with the passed in +"pgoff" in the vm_fault structure. If it is possible that the page may be +truncated and/or invalidated, then the filesystem must lock invalidate_lock, +then ensure the page is not already truncated (invalidate_lock will block subsequent truncate), and then return with VM_FAULT_LOCKED, and the page locked. The VM will unlock the page. @@ -644,12 +669,14 @@ page table entry. Pointer to entry associated with the page is passed in "pte" field in vm_fault structure. Pointers to entries for other offsets should be calculated relative to "pte". -->page_mkwrite() is called when a previously read-only pte is -about to become writeable. The filesystem again must ensure that there are -no truncate/invalidate races, and then return with the page locked. If -the page has been truncated, the filesystem should not look up a new page -like the ->fault() handler, but simply return with VM_FAULT_NOPAGE, which -will cause the VM to retry the fault. +->page_mkwrite() is called when a previously read-only pte is about to become +writeable. The filesystem again must ensure that there are no +truncate/invalidate races or races with operations such as ->remap_file_range +or ->copy_file_range, and then return with the page locked. Usually +mapping->invalidate_lock is suitable for proper serialization. If the page has +been truncated, the filesystem should not look up a new page like the ->fault() +handler, but simply return with VM_FAULT_NOPAGE, which will cause the VM to +retry the fault. ->pfn_mkwrite() is the same as page_mkwrite but when the pte is VM_PFNMAP or VM_MIXEDMAP with a page-less entry. Expected return is diff --git a/Documentation/filesystems/mandatory-locking.rst b/Documentation/filesystems/mandatory-locking.rst deleted file mode 100644 index 9ce73544a8f0..000000000000 --- a/Documentation/filesystems/mandatory-locking.rst +++ /dev/null @@ -1,188 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -===================================================== -Mandatory File Locking For The Linux Operating System -===================================================== - - Andy Walker <andy@lysaker.kvaerner.no> - - 15 April 1996 - - (Updated September 2007) - -0. Why you should avoid mandatory locking ------------------------------------------ - -The Linux implementation is prey to a number of difficult-to-fix race -conditions which in practice make it not dependable: - - - The write system call checks for a mandatory lock only once - at its start. It is therefore possible for a lock request to - be granted after this check but before the data is modified. - A process may then see file data change even while a mandatory - lock was held. - - Similarly, an exclusive lock may be granted on a file after - the kernel has decided to proceed with a read, but before the - read has actually completed, and the reading process may see - the file data in a state which should not have been visible - to it. - - Similar races make the claimed mutual exclusion between lock - and mmap similarly unreliable. - -1. What is mandatory locking? ------------------------------- - -Mandatory locking is kernel enforced file locking, as opposed to the more usual -cooperative file locking used to guarantee sequential access to files among -processes. File locks are applied using the flock() and fcntl() system calls -(and the lockf() library routine which is a wrapper around fcntl().) It is -normally a process' responsibility to check for locks on a file it wishes to -update, before applying its own lock, updating the file and unlocking it again. -The most commonly used example of this (and in the case of sendmail, the most -troublesome) is access to a user's mailbox. The mail user agent and the mail -transfer agent must guard against updating the mailbox at the same time, and -prevent reading the mailbox while it is being updated. - -In a perfect world all processes would use and honour a cooperative, or -"advisory" locking scheme. However, the world isn't perfect, and there's -a lot of poorly written code out there. - -In trying to address this problem, the designers of System V UNIX came up -with a "mandatory" locking scheme, whereby the operating system kernel would -block attempts by a process to write to a file that another process holds a -"read" -or- "shared" lock on, and block attempts to both read and write to a -file that a process holds a "write " -or- "exclusive" lock on. - -The System V mandatory locking scheme was intended to have as little impact as -possible on existing user code. The scheme is based on marking individual files -as candidates for mandatory locking, and using the existing fcntl()/lockf() -interface for applying locks just as if they were normal, advisory locks. - -.. Note:: - - 1. In saying "file" in the paragraphs above I am actually not telling - the whole truth. System V locking is based on fcntl(). The granularity of - fcntl() is such that it allows the locking of byte ranges in files, in - addition to entire files, so the mandatory locking rules also have byte - level granularity. - - 2. POSIX.1 does not specify any scheme for mandatory locking, despite - borrowing the fcntl() locking scheme from System V. The mandatory locking - scheme is defined by the System V Interface Definition (SVID) Version 3. - -2. Marking a file for mandatory locking ---------------------------------------- - -A file is marked as a candidate for mandatory locking by setting the group-id -bit in its file mode but removing the group-execute bit. This is an otherwise -meaningless combination, and was chosen by the System V implementors so as not -to break existing user programs. - -Note that the group-id bit is usually automatically cleared by the kernel when -a setgid file is written to. This is a security measure. The kernel has been -modified to recognize the special case of a mandatory lock candidate and to -refrain from clearing this bit. Similarly the kernel has been modified not -to run mandatory lock candidates with setgid privileges. - -3. Available implementations ----------------------------- - -I have considered the implementations of mandatory locking available with -SunOS 4.1.x, Solaris 2.x and HP-UX 9.x. - -Generally I have tried to make the most sense out of the behaviour exhibited -by these three reference systems. There are many anomalies. - -All the reference systems reject all calls to open() for a file on which -another process has outstanding mandatory locks. This is in direct -contravention of SVID 3, which states that only calls to open() with the -O_TRUNC flag set should be rejected. The Linux implementation follows the SVID -definition, which is the "Right Thing", since only calls with O_TRUNC can -modify the contents of the file. - -HP-UX even disallows open() with O_TRUNC for a file with advisory locks, not -just mandatory locks. That would appear to contravene POSIX.1. - -mmap() is another interesting case. All the operating systems mentioned -prevent mandatory locks from being applied to an mmap()'ed file, but HP-UX -also disallows advisory locks for such a file. SVID actually specifies the -paranoid HP-UX behaviour. - -In my opinion only MAP_SHARED mappings should be immune from locking, and then -only from mandatory locks - that is what is currently implemented. - -SunOS is so hopeless that it doesn't even honour the O_NONBLOCK flag for -mandatory locks, so reads and writes to locked files always block when they -should return EAGAIN. - -I'm afraid that this is such an esoteric area that the semantics described -below are just as valid as any others, so long as the main points seem to -agree. - -4. Semantics ------------- - -1. Mandatory locks can only be applied via the fcntl()/lockf() locking - interface - in other words the System V/POSIX interface. BSD style - locks using flock() never result in a mandatory lock. - -2. If a process has locked a region of a file with a mandatory read lock, then - other processes are permitted to read from that region. If any of these - processes attempts to write to the region it will block until the lock is - released, unless the process has opened the file with the O_NONBLOCK - flag in which case the system call will return immediately with the error - status EAGAIN. - -3. If a process has locked a region of a file with a mandatory write lock, all - attempts to read or write to that region block until the lock is released, - unless a process has opened the file with the O_NONBLOCK flag in which case - the system call will return immediately with the error status EAGAIN. - -4. Calls to open() with O_TRUNC, or to creat(), on a existing file that has - any mandatory locks owned by other processes will be rejected with the - error status EAGAIN. - -5. Attempts to apply a mandatory lock to a file that is memory mapped and - shared (via mmap() with MAP_SHARED) will be rejected with the error status - EAGAIN. - -6. Attempts to create a shared memory map of a file (via mmap() with MAP_SHARED) - that has any mandatory locks in effect will be rejected with the error status - EAGAIN. - -5. Which system calls are affected? ------------------------------------ - -Those which modify a file's contents, not just the inode. That gives read(), -write(), readv(), writev(), open(), creat(), mmap(), truncate() and -ftruncate(). truncate() and ftruncate() are considered to be "write" actions -for the purposes of mandatory locking. - -The affected region is usually defined as stretching from the current position -for the total number of bytes read or written. For the truncate calls it is -defined as the bytes of a file removed or added (we must also consider bytes -added, as a lock can specify just "the whole file", rather than a specific -range of bytes.) - -Note 3: I may have overlooked some system calls that need mandatory lock -checking in my eagerness to get this code out the door. Please let me know, or -better still fix the system calls yourself and submit a patch to me or Linus. - -6. Warning! ------------ - -Not even root can override a mandatory lock, so runaway processes can wreak -havoc if they lock crucial files. The way around it is to change the file -permissions (remove the setgid bit) before trying to read or write to it. -Of course, that might be a bit tricky if the system is hung :-( - -7. The "mand" mount option --------------------------- -Mandatory locking is disabled on all filesystems by default, and must be -administratively enabled by mounting with "-o mand". That mount option -is only allowed if the mounting task has the CAP_SYS_ADMIN capability. - -Since kernel v4.5, it is possible to disable mandatory locking -altogether by setting CONFIG_MANDATORY_FILE_LOCKING to "n". A kernel -with this disabled will reject attempts to mount filesystems with the -"mand" mount option with the error status EPERM. |