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2020-07-29nvmem: core: Add nvmem_cell_read_u8()Andreas Färber
Complement the u16, u32 and u64 helpers with a u8 variant to ease accessing byte-sized values. This helper will be useful for Realtek Digital Home Center platforms, which store some byte and sub-byte sized values in non-volatile memory. Signed-off-by: Andreas Färber <afaerber@suse.de> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20200722100705.7772-7-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29nvmem: core: Grammar fixes for help textAndreas Färber
It's "an unsigned" but "a U". Similarly, "an entry" but "a binary entry". While at it, also drop superfluous articles for negative and zero. Signed-off-by: Andreas Färber <afaerber@suse.de> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20200722100705.7772-6-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29nvmem: sc27xx: add sc2730 efuse supportFreeman Liu
Add support to the new efuse IP which is integrated in the SC2730 which includes multiple blocks in a single chip. Signed-off-by: Freeman Liu <freeman.liu@unisoc.com> Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com> Reviewed-by: Baolin Wang <baolin.wang7@gmail.com> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20200722100705.7772-5-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29nvmem: Enforce nvmem stride in the sysfs interfaceDouglas Anderson
The 'struct nvmem_config' has a stride attribute that specifies the needed alignment for accesses into the nvmem. This is used in nvmem_cell_info_to_nvmem_cell() but not in the sysfs read/write functions. If the alignment is important in one place it's important everywhere, so let's add enforcement. For now we'll consider it totally invalid to access with the wrong alignment. We could relax this in the read case where we could just read some extra bytes and throw them away. Relaxing it in the write case seems harder (and less safe?) since we'd have to read some data first and then write it back. To keep it symmetric we'll just disallow it in both cases. Reported-by: Ravi Kumar Bokka <rbokka@codeaurora.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Ravi Kumar Bokka <rbokka@codeaurora.org> Tested-by: Ravi Kumar Bokka <rbokka@codeaurora.org> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20200722100705.7772-4-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29MAINTAINERS: Add git tree for NVMEM FRAMEWORKTiezhu Yang
There is no git tree for NVMEM FRAMEWORK in MAINTAINERS, it is not convinent to rebase, add it. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20200722100705.7772-3-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29nvmem: sprd: Fix return value of sprd_efuse_probe()Tiezhu Yang
When call function devm_platform_ioremap_resource(), we should use IS_ERR() to check the return value and return PTR_ERR() if failed. Fixes: 096030e7f449 ("nvmem: sprd: Add Spreadtrum SoCs eFuse support") Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20200722100705.7772-2-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29drivers: android: Fix the SPDX comment styleMrinal Pandey
C source files should have `//` as SPDX comment and not `/**/`. Fix this by running checkpatch on the file. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131449.zvjutbemg3vqhrzh@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29drivers: android: Fix a variable declaration coding style issueMrinal Pandey
Add a blank line after variable declarations as suggested by checkpatch. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131433.stf3ycooogawyzb3@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29drivers: android: Remove braces for a single statement if-else blockMrinal Pandey
Remove braces for both if and else block as suggested by checkpatch. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131403.dahfhdwa3wirzkxj@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29drivers: android: Remove the use of else after returnMrinal Pandey
Remove the unnecessary else branch after return statement as suggested by checkpatch. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131348.haz4ocxcferdcsgn@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29drivers: android: Fix a variable declaration coding style issueMrinal Pandey
Add a blank line after variable declarations as suggested by checkpatch. Signed-off-by: Mrinal Pandey <mrinalmni@gmail.com> Link: https://lore.kernel.org/r/20200724131254.qxbvderrws36dzzq@mrinalpandey Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29binder: Prevent context manager from incrementing ref 0Jann Horn
Binder is designed such that a binder_proc never has references to itself. If this rule is violated, memory corruption can occur when a process sends a transaction to itself; see e.g. <https://syzkaller.appspot.com/bug?extid=09e05aba06723a94d43d>. There is a remaining edgecase through which such a transaction-to-self can still occur from the context of a task with BINDER_SET_CONTEXT_MGR access: - task A opens /dev/binder twice, creating binder_proc instances P1 and P2 - P1 becomes context manager - P2 calls ACQUIRE on the magic handle 0, allocating index 0 in its handle table - P1 dies (by closing the /dev/binder fd and waiting a bit) - P2 becomes context manager - P2 calls ACQUIRE on the magic handle 0, allocating index 1 in its handle table [this triggers a warning: "binder: 1974:1974 tried to acquire reference to desc 0, got 1 instead"] - task B opens /dev/binder once, creating binder_proc instance P3 - P3 calls P2 (via magic handle 0) with (void*)1 as argument (two-way transaction) - P2 receives the handle and uses it to call P3 (two-way transaction) - P3 calls P2 (via magic handle 0) (two-way transaction) - P2 calls P2 (via handle 1) (two-way transaction) And then, if P2 does *NOT* accept the incoming transaction work, but instead closes the binder fd, we get a crash. Solve it by preventing the context manager from using ACQUIRE on ref 0. There shouldn't be any legitimate reason for the context manager to do that. Additionally, print a warning if someone manages to find another way to trigger a transaction-to-self bug in the future. Cc: stable@vger.kernel.org Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Acked-by: Todd Kjos <tkjos@google.com> Signed-off-by: Jann Horn <jannh@google.com> Reviewed-by: Martijn Coenen <maco@android.com> Link: https://lore.kernel.org/r/20200727120424.1627555-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29greybus: Use fallthrough pseudo-keywordGustavo A. R. Silva
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://lore.kernel.org/r/20200727183258.GA28571@embeddedor Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: simplify mtu3_req_complete()Chunfeng Yun
Use argument req directly instead of mreq->request, they are the same usb request. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-11-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: clear dual mode of u3port when disable deviceChunfeng Yun
If not clear u3port's dual mode when disable device, the IP will fail to enter sleep mode when suspend. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-10-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: use MTU3_EP_WEDGE flagChunfeng Yun
Use MTU3_EP_WEDGE flag instead of the member @wedged in mtu3_ep struct, then @wedged can be removed. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-9-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: remove useless member @busy in mtu3_ep structChunfeng Yun
The member @busy in mtu3_ep struct is unnecessary, so remove it. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-8-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: remove repeated error logChunfeng Yun
The caller already print error log. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-7-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: add ->udc_set_speed()Chunfeng Yun
Make use of the method to make sure connect on speeds supported by the gadget driver. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-6-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: introduce a funtion to check maximum speedChunfeng Yun
The max_speed got from DTS may be not supported by the hardware, so need check it, and assign a proper default value. And make it clear by introducing a funtion. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-5-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: clear interrupts status when disable interruptsChunfeng Yun
When disable interrupts, will also want to clear their status, ensure it by calling mtu3_intr_status_clear() in mtu3_intr_disable(). Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-4-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: reinitialize CSR registersChunfeng Yun
The CSR registers will be reset as default value if the ports are disabled, so reinitialize them when the ports are enabled again. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-3-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: fix macro for maximum number of packetsChunfeng Yun
The bits field for maximum number of packets is 8 bits. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-2-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: remove unnecessary pointer checksChunfeng Yun
The class driver will ensure the parameters are valid pointers before call the hook function of usb_ep_ops, so no need check them again. Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595834101-13094-1-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: xhci: Fix ASMedia ASM1142 DMA addressingForest Crossman
I've confirmed that the ASMedia ASM1142 has the same problem as the ASM2142/ASM3142, in that it too reports that it supports 64-bit DMA addresses when in fact it does not. As with the ASM2142/ASM3142, this can cause problems on systems where the upper bits matter, and adding the XHCI_NO_64BIT_SUPPORT quirk completely fixes the issue. Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Forest Crossman <cyrozap@gmail.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200728042408.180529-3-cyrozap@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: xhci: define IDs for various ASMedia host controllersForest Crossman
Not all ASMedia host controllers have a device ID that matches its part number. #define some of these IDs to make it clearer at a glance which chips require what quirks. Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Forest Crossman <cyrozap@gmail.com> Link: https://lore.kernel.org/r/20200728042408.180529-2-cyrozap@gmail.com Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: musb: convert to devm_platform_ioremap_resource_bynameChunfeng Yun
Use devm_platform_ioremap_resource_byname() to simplify code Cc: Bin Liu <b-liu@ti.com> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595404275-8449-7-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: gadget: tegra-xudc: convert to devm_platform_ioremap_resource_bynameChunfeng Yun
Use devm_platform_ioremap_resource_byname() to simplify code Cc: Nagarjuna Kristam <nkristam@nvidia.com> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595404275-8449-6-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: gadget: r8a66597: convert to devm_platform_ioremap_resource_bynameChunfeng Yun
Use devm_platform_ioremap_resource_byname() to simplify code Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595404275-8449-5-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: dwc3: convert to devm_platform_ioremap_resource_bynameChunfeng Yun
Use devm_platform_ioremap_resource_byname() to simplify code Cc: Patrice Chotard <patrice.chotard@st.com> Reviewed-by: Patrice Chotard <patrice.chotard@st.com> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595404275-8449-4-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: cdns3: convert to devm_platform_ioremap_resource_bynameChunfeng Yun
Use devm_platform_ioremap_resource_byname() to simplify code Cc: Peter Chen <peter.chen@nxp.com> Reviewed-by: Peter Chen <peter.chen@nxp.com> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595404275-8449-3-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: phy: am335x: convert to devm_platform_ioremap_resource_bynameChunfeng Yun
Use devm_platform_ioremap_resource_byname() to simplify code Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595404275-8449-2-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29usb: mtu3: convert to devm_platform_ioremap_resource_bynameChunfeng Yun
Use devm_platform_ioremap_resource_byname() to simplify code Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Link: https://lore.kernel.org/r/1595404275-8449-1-git-send-email-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29USB: Simplify USB ID table matchBastien Nocera
usb_device_match_id() supports being passed NULL tables, so no need to check for it. Signed-off-by: Bastien Nocera <hadess@hadess.net> Link: https://lore.kernel.org/r/20200727104644.149873-1-hadess@hadess.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29x86/i8259: Use printk_deferred() to prevent deadlockThomas Gleixner
0day reported a possible circular locking dependency: Chain exists of: &irq_desc_lock_class --> console_owner --> &port_lock_key Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port_lock_key); lock(console_owner); lock(&port_lock_key); lock(&irq_desc_lock_class); The reason for this is a printk() in the i8259 interrupt chip driver which is invoked with the irq descriptor lock held, which reverses the lock operations vs. printk() from arbitrary contexts. Switch the printk() to printk_deferred() to avoid that. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/87365abt2v.fsf@nanos.tec.linutronix.de
2020-07-29Merge tag 'amlogic-dt64-3' of ↵Arnd Bergmann
git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-amlogic into arm/dt arm64: dts: amlogic updates for v5.9 (round3) - minor fixes * tag 'amlogic-dt64-3' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-amlogic: arm64: dts: meson: fix mmc0 tuning error on Khadas VIM3 arm64: dts: meson: misc fixups for w400 dtsi Link: https://lore.kernel.org/r/7h5za746al.fsf@baylibre.com Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2020-07-29mei: add device kind to sysfsAlexander Usyskin
Some of the mei device heads are not generic and have a specific purpose, we need to announce it to the user space so it is possible to detect the correct device node via matching attributes. Generic heads are marked as 'mei' while special purpose heads have their own names. Currently we are adding 'itouch' string for Intel IPTS 1.0, 2.0 devices. This is done via new sysfs attribute 'kind'. Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> Link: https://lore.kernel.org/r/20200728192242.3117779-1-tomas.winkler@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29MAINTAINERS: Fix maintainer entry for mei driverTomas Winkler
mei driver has sub modules, those are not listed via scripts/get_maintainer.pl when using asterisk: drivers/misc/mei/* The correct notation is: drivers/misc/mei/ Cc: Joe Perches <joe@perches.com> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://lore.kernel.org/r/20200729110540.3205585-1-tomas.winkler@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29seqlock: lockdep assert non-preemptibility on seqcount_t writeAhmed S. Darwish
Preemption must be disabled before entering a sequence count write side critical section. Failing to do so, the seqcount read side can preempt the write side section and spin for the entire scheduler tick. If that reader belongs to a real-time scheduling class, it can spin forever and the kernel will livelock. Assert through lockdep that preemption is disabled for seqcount writers. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-9-a.darwish@linutronix.de
2020-07-29lockdep: Add preemption enabled/disabled assertion APIsAhmed S. Darwish
Asserting that preemption is enabled or disabled is a critical sanity check. Developers are usually reluctant to add such a check in a fastpath as reading the preemption count can be costly. Extend the lockdep API with macros asserting that preemption is disabled or enabled. If lockdep is disabled, or if the underlying architecture does not support kernel preemption, this assert has no runtime overhead. References: f54bb2ec02c8 ("locking/lockdep: Add IRQs disabled/enabled assertion APIs: ...") Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-8-a.darwish@linutronix.de
2020-07-29seqlock: Implement raw_seqcount_begin() in terms of raw_read_seqcount()Ahmed S. Darwish
raw_seqcount_begin() has the same code as raw_read_seqcount(), with the exception of masking the sequence counter's LSB before returning it to the caller. Note, raw_seqcount_begin() masks the counter's LSB before returning it to the caller so that read_seqcount_retry() can fail if the counter is odd -- without the overhead of an extra branching instruction. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-7-a.darwish@linutronix.de
2020-07-29seqlock: Add kernel-doc for seqcount_t and seqlock_t APIsAhmed S. Darwish
seqlock.h is now included by kernel's RST documentation, but a small number of the the exported seqlock.h functions are kernel-doc annotated. Add kernel-doc for all seqlock.h exported APIs. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-6-a.darwish@linutronix.de
2020-07-29seqlock: Reorder seqcount_t and seqlock_t API definitionsAhmed S. Darwish
The seqlock.h seqcount_t and seqlock_t API definitions are presented in the chronological order of their development rather than the order that makes most sense to readers. This makes it hard to follow and understand the header file code. Group and reorder all of the exported seqlock.h functions according to their function. First, group together the seqcount_t standard read path functions: - __read_seqcount_begin() - raw_read_seqcount_begin() - read_seqcount_begin() since each function is implemented exactly in terms of the one above it. Then, group the special-case seqcount_t readers on their own as: - raw_read_seqcount() - raw_seqcount_begin() since the only difference between the two functions is that the second one masks the sequence counter LSB while the first one does not. Note that raw_seqcount_begin() can actually be implemented in terms of raw_read_seqcount(), which will be done in a follow-up commit. Then, group the seqcount_t write path functions, instead of injecting unrelated seqcount_t latch functions between them, and order them as: - raw_write_seqcount_begin() - raw_write_seqcount_end() - write_seqcount_begin_nested() - write_seqcount_begin() - write_seqcount_end() - raw_write_seqcount_barrier() - write_seqcount_invalidate() which is the expected natural order. This also isolates the seqcount_t latch functions into their own area, at the end of the sequence counters section, and before jumping to the next one: sequential locks (seqlock_t). Do a similar grouping and reordering for seqlock_t "locking" readers vs. the "conditionally locking or lockless" ones. No implementation code was changed in any of the reordering above. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-5-a.darwish@linutronix.de
2020-07-29seqlock: seqcount_t latch: End read sections with read_seqcount_retry()Ahmed S. Darwish
The seqcount_t latch reader example at the raw_write_seqcount_latch() kernel-doc comment ends the latch read section with a manual smp memory barrier and sequence counter comparison. This is technically correct, but it is suboptimal: read_seqcount_retry() already contains the same logic of an smp memory barrier and sequence counter comparison. End the latch read critical section example with read_seqcount_retry(). Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-4-a.darwish@linutronix.de
2020-07-29seqlock: Properly format kernel-doc code samplesAhmed S. Darwish
Align the code samples and note sections inside kernel-doc comments with tabs. This way they can be properly parsed and rendered by Sphinx. It also makes the code samples easier to read from text editors. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-3-a.darwish@linutronix.de
2020-07-29Documentation: locking: Describe seqlock design and usageAhmed S. Darwish
Proper documentation for the design and usage of sequence counters and sequential locks does not exist. Complete the seqlock.h documentation as follows: - Divide all documentation on a seqcount_t vs. seqlock_t basis. The description for both mechanisms was intermingled, which is incorrect since the usage constrains for each type are vastly different. - Add an introductory paragraph describing the internal design of, and rationale for, sequence counters. - Document seqcount_t writer non-preemptibility requirement, which was not previously documented anywhere, and provide a clear rationale. - Provide template code for seqcount_t and seqlock_t initialization and reader/writer critical sections. - Recommend using seqlock_t by default. It implicitly handles the serialization and non-preemptibility requirements of writers. At seqlock.h: - Remove references to brlocks as they've long been removed from the kernel. - Remove references to gcc-3.x since the kernel's minimum supported gcc version is 4.9. References: 0f6ed63b1707 ("no need to keep brlock macros anymore...") References: 6ec4476ac825 ("Raise gcc version requirement to 4.9") Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200720155530.1173732-2-a.darwish@linutronix.de
2020-07-29Merge branch 'locking/header'Peter Zijlstra
2020-07-29locking/qspinlock: Do not include atomic.h from qspinlock_types.hHerbert Xu
This patch breaks a header loop involving qspinlock_types.h. The issue is that qspinlock_types.h includes atomic.h, which then eventually includes kernel.h which could lead back to the original file via spinlock_types.h. As ATOMIC_INIT is now defined by linux/types.h, there is no longer any need to include atomic.h from qspinlock_types.h. This also allows the CONFIG_PARAVIRT hack to be removed since it was trying to prevent exactly this loop. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Link: https://lkml.kernel.org/r/20200729123316.GC7047@gondor.apana.org.au
2020-07-29locking/atomic: Move ATOMIC_INIT into linux/types.hHerbert Xu
This patch moves ATOMIC_INIT from asm/atomic.h into linux/types.h. This allows users of atomic_t to use ATOMIC_INIT without having to include atomic.h as that way may lead to header loops. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <longman@redhat.com> Link: https://lkml.kernel.org/r/20200729123105.GB7047@gondor.apana.org.au
2020-07-29arm, arm64: Fix selection of CONFIG_SCHED_THERMAL_PRESSUREValentin Schneider
Qian reported that the current setup forgoes the Kconfig dependencies and results in warnings such as: WARNING: unmet direct dependencies detected for SCHED_THERMAL_PRESSURE Depends on [n]: SMP [=y] && CPU_FREQ_THERMAL [=n] Selected by [y]: - ARM64 [=y] Revert commit e17ae7fea871 ("arm, arm64: Select CONFIG_SCHED_THERMAL_PRESSURE") and re-implement it by making the option default to 'y' for arm64 and arm, which respects Kconfig dependencies (i.e. will remain 'n' if CPU_FREQ_THERMAL=n). Fixes: e17ae7fea871 ("arm, arm64: Select CONFIG_SCHED_THERMAL_PRESSURE") Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200729135718.1871-1-valentin.schneider@arm.com
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