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2020-07-31init: add an init_eaccess helperChristoph Hellwig
Add a simple helper to check if a file exists based on kernel space file name and switch the early init code over to it. Note that this theoretically changes behavior as it always is based on the effective permissions. But during early init that doesn't make a difference. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chmod helperChristoph Hellwig
Add a simple helper to chmod with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chown helperChristoph Hellwig
Add a simple helper to chown with a kernel space file name and switch the early init code over to it. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chroot helperChristoph Hellwig
Add a simple helper to chroot with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_chroot. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_chdir helperChristoph Hellwig
Add a simple helper to chdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_chdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_rmdir helperChristoph Hellwig
Add a simple helper to rmdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_rmdir. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_unlink helperChristoph Hellwig
Add a simple helper to unlink with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_unlink. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_umount helperChristoph Hellwig
Like ksys_umount, but takes a kernel pointer for the destination path. Switch over the umount in the init code, which just happen to work due to the implicit set_fs(KERNEL_DS) during early init right now. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31init: add an init_mount helperChristoph Hellwig
Like do_mount, but takes a kernel pointer for the destination path. Switch over the mounts in the init code and devtmpfs to it, which just happen to work due to the implicit set_fs(KERNEL_DS) during early init right now. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31fs: push the getname from do_rmdir into the callersChristoph Hellwig
This mirrors do_unlinkat and will make life a little easier for the init code to reuse the whole function with a kernel filename. Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-07-31fs: expose utimes_commonChristoph Hellwig
Rename utimes_common to vfs_utimes and make it available outside of utimes.c. This will be used by the initramfs unpacking code. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31fs: remove ksys_ioctlChristoph Hellwig
Fold it into the only remaining caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31fs: remove ksys_fchmodChristoph Hellwig
Fold it into the only remaining caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31fs: remove ksys_dupChristoph Hellwig
Fold it into the only remaining caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31fs: remove ksys_openChristoph Hellwig
Just open code it in the two callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-31fs: remove ksys_getdents64Christoph Hellwig
Just open code it in the only caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30Merge remote-tracking branch 'regulator/for-5.9' into regulator-nextMark Brown
2020-07-31Merge branch 'for-mingo' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull the v5.9 RCU bits from Paul E. McKenney: - Documentation updates - Miscellaneous fixes - kfree_rcu updates - RCU tasks updates - Read-side scalability tests - SRCU updates - Torture-test updates Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-30mm: pgtable: Make generic pgprot_* macros available for no-MMUPekka Enberg
The <linux/pgtable.h> header defines some generic pgprot_* implementations, but they are only available when CONFIG_MMU is enabled. The RISC-V architecture, for example, therefore defines some of these pgprot_* macros for !NOMMU. Let's make the pgprot_* generic available even for !NOMMU so we can remove the RISC-V specific definitions. Compile-tested with x86 defconfig, and riscv defconfig and !MMU defconfig. Suggested-by: Palmer Dabbelt <palmerdabbelt@google.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-07-30tasklet: Introduce new initialization APIRomain Perier
Nowadays, modern kernel subsystems that use callbacks pass the data structure associated with a given callback as argument to the callback. The tasklet subsystem remains one which passes an arbitrary unsigned long to the callback function. This has several problems: - This keeps an extra field for storing the argument in each tasklet data structure, it bloats the tasklet_struct structure with a redundant .data field - No type checking can be performed on this argument. Instead of using container_of() like other callback subsystems, it forces callbacks to do explicit type cast of the unsigned long argument into the required object type. - Buffer overflows can overwrite the .func and the .data field, so an attacker can easily overwrite the function and its first argument to whatever it wants. Add a new tasklet initialization API, via DECLARE_TASKLET() and tasklet_setup(), which will replace the existing ones. This work is greatly inspired by the timer_struct conversion series, see commit e99e88a9d2b0 ("treewide: setup_timer() -> timer_setup()") To avoid problems with both -Wcast-function-type (which is enabled in the kernel via -Wextra is several subsystems), and with mismatched function prototypes when build with Control Flow Integrity enabled, this adds the "use_callback" member to let the tasklet caller choose which union member to call through. Once all old API uses are removed, this and the .data member will be removed as well. (On 64-bit this does not grow the struct size as the new member fills the hole after atomic_t, which is also "int" sized.) Signed-off-by: Romain Perier <romain.perier@gmail.com> Co-developed-by: Allen Pais <allen.lkml@gmail.com> Signed-off-by: Allen Pais <allen.lkml@gmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-30treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD()Kees Cook
This converts all the existing DECLARE_TASKLET() (and ...DISABLED) macros with DECLARE_TASKLET_OLD() in preparation for refactoring the tasklet callback type. All existing DECLARE_TASKLET() users had a "0" data argument, it has been removed here as well. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-30thermal: Update power allocator and devfreq cooling to SPDX licensingLukasz Luba
Update the license to the SPDX licensing format. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20200730165117.13998-1-lukasz.luba@arm.com
2020-07-30random: fix circular include dependency on arm64 after addition of percpu.hWilly Tarreau
Daniel Díaz and Kees Cook independently reported that commit f227e3ec3b5c ("random32: update the net random state on interrupt and activity") broke arm64 due to a circular dependency on include files since the addition of percpu.h in random.h. The correct fix would definitely be to move all the prandom32 stuff out of random.h but for backporting, a smaller solution is preferred. This one replaces linux/percpu.h with asm/percpu.h, and this fixes the problem on x86_64, arm64, arm, and mips. Note that moving percpu.h around didn't change anything and that removing it entirely broke differently. When backporting, such options might still be considered if this patch fails to help. [ It turns out that an alternate fix seems to be to just remove the troublesome <asm/pointer_auth.h> remove from the arm64 <asm/smp.h> that causes the circular dependency. But we might as well do the whole belt-and-suspenders thing, and minimize inclusion in <linux/random.h> too. Either will fix the problem, and both are good changes. - Linus ] Reported-by: Daniel Díaz <daniel.diaz@linaro.org> Reported-by: Kees Cook <keescook@chromium.org> Tested-by: Marc Zyngier <maz@kernel.org> Fixes: f227e3ec3b5c Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30PM / devfreq: Add support delayed timer for polling modeChanwoo Choi
Until now, the devfreq driver using polling mode like simple_ondemand governor have used only deferrable timer for reducing the redundant power consumption. It reduces the CPU wake-up from idle due to polling mode which check the status of Non-CPU device. But, it has a problem for Non-CPU device like DMC device with DMA operation. Some Non-CPU device need to do monitor continuously regardless of CPU state in order to decide the proper next status of Non-CPU device. So, add support the delayed timer for polling mode to support the repetitive monitoring. The devfreq driver and user can select the kind of timer on either deferrable and delayed timer. For example, change the timer type of DMC device based on Exynos5422-based Odroid-XU3 as following: - If want to use deferrable timer as following: echo deferrable > /sys/class/devfreq/10c20000.memory-controller/timer - If want to use delayed timer as following: echo delayed > /sys/class/devfreq/10c20000.memory-controller/timer Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
2020-07-30driver core: add device probe log helperAndrzej Hajda
During probe every time driver gets resource it should usually check for error printk some message if it is not -EPROBE_DEFER and return the error. This pattern is simple but requires adding few lines after any resource acquisition code, as a result it is often omitted or implemented only partially. dev_err_probe helps to replace such code sequences with simple call, so code: if (err != -EPROBE_DEFER) dev_err(dev, ...); return err; becomes: return dev_err_probe(dev, err, ...); Signed-off-by: Andrzej Hajda <a.hajda@samsung.com> Reviewed-by: Rafael J. Wysocki <rafael@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20200713144324.23654-2-a.hajda@samsung.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-30initrd: switch initrd loading to struct file based APIsChristoph Hellwig
There is no good reason to mess with file descriptors from in-kernel code, switch the initrd loading to struct file based read and writes instead. Also Pass an explicit offset instead of ->f_pos, and to make that easier, use file scope file structs and offsets everywhere except for identify_ramdisk_image instead of the current strange mix. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30initrd: remove support for multiple floppiesChristoph Hellwig
Remove the special handling for multiple floppies in the initrd code. No one should be using floppies for booting these days. (famous last words..) Includes a spelling fix from Colin Ian King <colin.king@canonical.com>. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-30cpufreq: cached_resolved_idx can not be negativeViresh Kumar
It is not possible for cached_resolved_idx to be invalid here as the cpufreq core always sets index to a positive value. Change its type to unsigned int and fix qcom usage a bit. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-07-30OPP: Add and export helper to set bandwidthSibi Sankar
Add and export 'dev_pm_opp_set_bw' to set the bandwidth levels associated with an OPP. Signed-off-by: Sibi Sankar <sibis@codeaurora.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-07-29random32: remove net_rand_state from the latent entropy gcc pluginLinus Torvalds
It turns out that the plugin right now ends up being really unhappy about the change from 'static' to 'extern' storage that happened in commit f227e3ec3b5c ("random32: update the net random state on interrupt and activity"). This is probably a trivial fix for the latent_entropy plugin, but for now, just remove net_rand_state from the list of things the plugin worries about. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Emese Revfy <re.emese@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-29power: supply: bq27xxx_battery: Add the BQ28z610 Battery monitorDan Murphy
Add the Texas Instruments BQ28z610 battery monitor. The register address map is laid out the same as compared to other devices within the file. The battery status register bits are similar to the bq27z561 but they are different compared to other fuel gauge devices within this file. Signed-off-by: Dan Murphy <dmurphy@ti.com> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2020-07-29power: supply: bq27xxx_battery: Add the BQ27Z561 Battery monitorDan Murphy
Add the Texas Instruments BQ27Z561 battery monitor. The register address map is laid out the same as compared to other devices within the file. The battery status register has differing bits to determine if the battery is full, discharging or dead. Signed-off-by: Dan Murphy <dmurphy@ti.com> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
2020-07-29PCI: Remove unused pci_lost_interrupt()Heiner Kallweit
388c8c16abaf ("PCI: add routines for debugging and handling lost interrupts") added pci_lost_interrupt() that apparently never has had a single user. Remove it. Link: https://lore.kernel.org/r/e328d059-3068-6a40-28df-f81f616d15a0@gmail.com Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2020-07-29random32: update the net random state on interrupt and activityWilly Tarreau
This modifies the first 32 bits out of the 128 bits of a random CPU's net_rand_state on interrupt or CPU activity to complicate remote observations that could lead to guessing the network RNG's internal state. Note that depending on some network devices' interrupt rate moderation or binding, this re-seeding might happen on every packet or even almost never. In addition, with NOHZ some CPUs might not even get timer interrupts, leaving their local state rarely updated, while they are running networked processes making use of the random state. For this reason, we also perform this update in update_process_times() in order to at least update the state when there is user or system activity, since it's the only case we care about. Reported-by: Amit Klein <aksecurity@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Eric Dumazet <edumazet@google.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-07-29cpuidle: change enter_s2idle() prototypeNeal Liu
Control Flow Integrity(CFI) is a security mechanism that disallows changes to the original control flow graph of a compiled binary, making it significantly harder to perform such attacks. init_state_node() assign same function callback to different function pointer declarations. static int init_state_node(struct cpuidle_state *idle_state, const struct of_device_id *matches, struct device_node *state_node) { ... idle_state->enter = match_id->data; ... idle_state->enter_s2idle = match_id->data; } Function declarations: struct cpuidle_state { ... int (*enter) (struct cpuidle_device *dev, struct cpuidle_driver *drv, int index); void (*enter_s2idle) (struct cpuidle_device *dev, struct cpuidle_driver *drv, int index); }; In this case, either enter() or enter_s2idle() would cause CFI check failed since they use same callee. Align function prototype of enter() since it needs return value for some use cases. The return value of enter_s2idle() is no need currently. Signed-off-by: Neal Liu <neal.liu@mediatek.com> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-07-29serial: 8250: Add 8250 port clock update methodSerge Semin
Some platforms can be designed in a way so the UART port reference clock might be asynchronously changed at some point. In Baikal-T1 SoC this may happen due to the reference clock being shared between two UART ports, on the Allwinner SoC the reference clock is derived from the CPU clock, so any CPU frequency change should get to be known/reflected by/in the UART controller as well. But it's not enough to just update the uart_port->uartclk field of the corresponding UART port, the 8250 controller reference clock divisor should be altered so to preserve current baud rate setting. All of these things is done in a coherent way by calling the serial8250_update_uartclk() method provided in this patch. Though note that it isn't supposed to be called from within the UART port callbacks because the locks using to the protect the UART port data are already taken in there. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Link: https://lore.kernel.org/r/20200723003357.26897-2-Sergey.Semin@baikalelectronics.ru Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29nvmem: core: add support to auto devidSrinivas Kandagatla
For nvmem providers which have multiple instances, it is required to suffix the provider name with proper id, so that they do not confict for the same name. Currently the core does not handle this case properly eventhough core already has logic to generate the id. This patch add new devid type NVMEM_DEVID_AUTO for providers to be able to allow core to assign id and append it to provier name. Reported-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Tested-by: Shawn Guo <shawn.guo@linaro.org> Link: https://lore.kernel.org/r/20200722100705.7772-8-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
2020-07-29seqcount: More consistent seqprop namesPeter Zijlstra
Attempt uniformity and brevity. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-07-29seqcount: Compress SEQCNT_LOCKNAME_ZERO()Peter Zijlstra
Less is more. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-07-29seqlock: Fold seqcount_LOCKNAME_init() definitionPeter Zijlstra
Manual repetition is boring and error prone. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-07-29seqlock: Fold seqcount_LOCKNAME_t definitionPeter Zijlstra
Manual repetition is boring and error prone. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-07-29seqlock: s/__SEQ_LOCKDEP/__SEQ_LOCK/gPeter Zijlstra
__SEQ_LOCKDEP() is an expression gate for the seqcount_LOCKNAME_t::lock member. Rename it to be about the member, not the gate condition. Later (PREEMPT_RT) patches will make the member available for !LOCKDEP configs. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-07-29hrtimer: Use sequence counter with associated raw spinlockAhmed S. Darwish
A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_raw_spinlock_t data type, which allows to associate a raw spinlock with the sequence counter. This enables lockdep to verify that the raw spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. 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/20200720155530.1173732-25-a.darwish@linutronix.de
2020-07-29kvm/eventfd: Use sequence counter with associated spinlockAhmed S. Darwish
A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Link: https://lkml.kernel.org/r/20200720155530.1173732-24-a.darwish@linutronix.de
2020-07-29vfs: Use sequence counter with associated spinlockAhmed S. Darwish
A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. 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/20200720155530.1173732-19-a.darwish@linutronix.de
2020-07-29sched: tasks: Use sequence counter with associated spinlockAhmed S. Darwish
A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_spinlock_t data type, which allows to associate a spinlock with the sequence counter. This enables lockdep to verify that the spinlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. 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/20200720155530.1173732-14-a.darwish@linutronix.de
2020-07-29dma-buf: Use sequence counter with associated wound/wait mutexAhmed S. Darwish
A sequence counter write side critical section must be protected by some form of locking to serialize writers. If the serialization primitive is not disabling preemption implicitly, preemption has to be explicitly disabled before entering the sequence counter write side critical section. The dma-buf reservation subsystem uses plain sequence counters to manage updates to reservations. Writer serialization is accomplished through a wound/wait mutex. Acquiring a wound/wait mutex does not disable preemption, so this needs to be done manually before and after the write side critical section. Use the newly-added seqcount_ww_mutex_t instead: - It associates the ww_mutex with the sequence count, which enables lockdep to validate that the write side critical section is properly serialized. - It removes the need to explicitly add preempt_disable/enable() around the write side critical section because the write_begin/end() functions for this new data type automatically do this. If lockdep is disabled this ww_mutex lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://lkml.kernel.org/r/20200720155530.1173732-13-a.darwish@linutronix.de
2020-07-29dma-buf: Remove custom seqcount lockdep class keyAhmed S. Darwish
Commit 3c3b177a9369 ("reservation: add support for read-only access using rcu") introduced a sequence counter to manage updates to reservations. Back then, the reservation object initializer reservation_object_init() was always inlined. Having the sequence counter initialization inlined meant that each of the call sites would have a different lockdep class key, which would've broken lockdep's deadlock detection. The aforementioned commit thus introduced, and exported, a custom seqcount lockdep class key and name. The commit 8735f16803f00 ("dma-buf: cleanup reservation_object_init...") transformed the reservation object initializer to a normal non-inlined C function. seqcount_init(), which automatically defines the seqcount lockdep class key and must be called non-inlined, can now be safely used. Remove the seqcount custom lockdep class key, name, and export. Use seqcount_init() inside the dma reservation object initializer. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://lkml.kernel.org/r/20200720155530.1173732-12-a.darwish@linutronix.de
2020-07-29seqlock: Align multi-line macros newline escapes at 72 columnsAhmed S. Darwish
Parent commit, "seqlock: Extend seqcount API with associated locks", introduced a big number of multi-line macros that are newline-escaped at 72 columns. For overall cohesion, align the earlier-existing macros similarly. 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/20200720155530.1173732-11-a.darwish@linutronix.de