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* x86/paravirt: Set up the virt_spin_lock_key after static keys get initializedDou Liyang2017-10-302-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit: 9043442b43b1 ("locking/paravirt: Use new static key for controlling call of virt_spin_lock()") sets the static virt_spin_lock_key to a value before jump_label_init() has been called, which will result in a WARN(). Reorder the initialization sequence: - Move the native_pv_lock_init() into native_smp_prepare_cpus() - set the value in xen_init_lock_cpu() to avoid calling into the not yet initialized static keys subsystem. Suggested-by: Juergen Gross <jgross@suse.com> Reported-by: Juergen Gross <jgross@suse.com> Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: boris.ostrovsky@oracle.com Cc: bp@suse.de Cc: luto@kernel.org Cc: vkuznets@redhat.com Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1509170804-3813-1-git-send-email-douly.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* block, locking/lockdep: Assign a lock_class per gendisk used for ↵Byungchul Park2017-10-263-11/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wait_for_completion() Darrick posted the following warning and Dave Chinner analyzed it: > ====================================================== > WARNING: possible circular locking dependency detected > 4.14.0-rc1-fixes #1 Tainted: G W > ------------------------------------------------------ > loop0/31693 is trying to acquire lock: > (&(&ip->i_mmaplock)->mr_lock){++++}, at: [<ffffffffa00f1b0c>] xfs_ilock+0x23c/0x330 [xfs] > > but now in release context of a crosslock acquired at the following: > ((complete)&ret.event){+.+.}, at: [<ffffffff81326c1f>] submit_bio_wait+0x7f/0xb0 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #2 ((complete)&ret.event){+.+.}: > lock_acquire+0xab/0x200 > wait_for_completion_io+0x4e/0x1a0 > submit_bio_wait+0x7f/0xb0 > blkdev_issue_zeroout+0x71/0xa0 > xfs_bmapi_convert_unwritten+0x11f/0x1d0 [xfs] > xfs_bmapi_write+0x374/0x11f0 [xfs] > xfs_iomap_write_direct+0x2ac/0x430 [xfs] > xfs_file_iomap_begin+0x20d/0xd50 [xfs] > iomap_apply+0x43/0xe0 > dax_iomap_rw+0x89/0xf0 > xfs_file_dax_write+0xcc/0x220 [xfs] > xfs_file_write_iter+0xf0/0x130 [xfs] > __vfs_write+0xd9/0x150 > vfs_write+0xc8/0x1c0 > SyS_write+0x45/0xa0 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > -> #1 (&xfs_nondir_ilock_class){++++}: > lock_acquire+0xab/0x200 > down_write_nested+0x4a/0xb0 > xfs_ilock+0x263/0x330 [xfs] > xfs_setattr_size+0x152/0x370 [xfs] > xfs_vn_setattr+0x6b/0x90 [xfs] > notify_change+0x27d/0x3f0 > do_truncate+0x5b/0x90 > path_openat+0x237/0xa90 > do_filp_open+0x8a/0xf0 > do_sys_open+0x11c/0x1f0 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > -> #0 (&(&ip->i_mmaplock)->mr_lock){++++}: > up_write+0x1c/0x40 > xfs_iunlock+0x1d0/0x310 [xfs] > xfs_file_fallocate+0x8a/0x310 [xfs] > loop_queue_work+0xb7/0x8d0 > kthread_worker_fn+0xb9/0x1f0 > > Chain exists of: > &(&ip->i_mmaplock)->mr_lock --> &xfs_nondir_ilock_class --> (complete)&ret.event > > Possible unsafe locking scenario by crosslock: > > CPU0 CPU1 > ---- ---- > lock(&xfs_nondir_ilock_class); > lock((complete)&ret.event); > lock(&(&ip->i_mmaplock)->mr_lock); > unlock((complete)&ret.event); > > *** DEADLOCK *** The warning is a false positive, caused by the fact that all wait_for_completion()s in submit_bio_wait() are waiting with the same lock class. However, some bios have nothing to do with others, for example in the case of loop devices, there's no direct connection between the bios of an upper device and the bios of a lower device(=loop device). The safest way to assign different lock classes to different devices is to do it for each gendisk. In other words, this patch assigns a lockdep_map per gendisk and uses it when initializing completion in submit_bio_wait(). Analyzed-by: Dave Chinner <david@fromorbit.com> Reported-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Byungchul Park <byungchul.park@lge.com> Reviewed-by: Jens Axboe <axboe@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-10-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* workqueue: Remove now redundant lock acquisitions wrt. workqueue flushesByungchul Park2017-10-252-18/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The workqueue code added manual lock acquisition annotations to catch deadlocks. After lockdepcrossrelease was introduced, some of those became redundant, since wait_for_completion() already does the acquisition and tracking. Remove the duplicate annotations. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: darrick.wong@oracle.com Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-9-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/completions: Add support for initializing completions with lockdep_mapByungchul Park2017-10-251-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sometimes we want to initialize completions with sparate lockdep maps to assign lock classes as desired. For example, the workqueue code needs to directly manage lockdep maps, since only the code is aware of how to classify lockdep maps properly. Provide additional macros initializing completions in that way. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: darrick.wong@oracle.com Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-8-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep: Introduce CONFIG_BOOTPARAM_LOCKDEP_CROSSRELEASE_FULLSTACK=yByungchul Park2017-10-252-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | Add a Kconfig knob that enables the lockdep "crossrelease_fullstack" boot parameter. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: darrick.wong@oracle.com Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-7-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep: Remove the BROKEN flag from CONFIG_LOCKDEP_CROSSRELEASE and ↵Byungchul Park2017-10-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | CONFIG_LOCKDEP_COMPLETIONS Now that the performance regression is fixed, re-enable CONFIG_LOCKDEP_CROSSRELEASE=y and CONFIG_LOCKDEP_COMPLETIONS=y. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: darrick.wong@oracle.com Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-6-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep: Add a boot parameter allowing unwind in cross-release and ↵Byungchul Park2017-10-252-2/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | disable it by default Johan Hovold reported a heavy performance regression caused by lockdep cross-release: > Boot time (from "Linux version" to login prompt) had in fact doubled > since 4.13 where it took 17 seconds (with my current config) compared to > the 35 seconds I now see with 4.14-rc4. > > I quick bisect pointed to lockdep and specifically the following commit: > > 28a903f63ec0 ("locking/lockdep: Handle non(or multi)-acquisition > of a crosslock") > > which I've verified is the commit which doubled the boot time (compared > to 28a903f63ec0^) (added by lockdep crossrelease series [1]). Currently cross-release performs unwind on every acquisition, but that is very expensive. This patch makes unwind optional and disables it by default and only records acquire_ip. Full stack traces are sometimes required for full analysis, in which case a boot paramter, crossrelease_fullstack, can be specified. On my qemu Ubuntu machine (x86_64, 4 cores, 512M), the regression was fixed. We measure boot times with 'perf stat --null --repeat 10 $QEMU', where $QEMU launches a kernel with init=/bin/true: 1. No lockdep enabled: Performance counter stats for 'qemu_booting_time.sh bzImage' (10 runs): 2.756558155 seconds time elapsed ( +- 0.09% ) 2. Lockdep enabled: Performance counter stats for 'qemu_booting_time.sh bzImage' (10 runs): 2.968710420 seconds time elapsed ( +- 0.12% ) 3. Lockdep enabled + cross-release enabled: Performance counter stats for 'qemu_booting_time.sh bzImage' (10 runs): 3.153839636 seconds time elapsed ( +- 0.31% ) 4. Lockdep enabled + cross-release enabled + this patch applied: Performance counter stats for 'qemu_booting_time.sh bzImage' (10 runs): 2.963669551 seconds time elapsed ( +- 0.11% ) I.e. lockdep cross-release performance is now indistinguishable from vanilla lockdep. Bisected-by: Johan Hovold <johan@kernel.org> Analyzed-by: Thomas Gleixner <tglx@linutronix.de> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: Johan Hovold <johan@kernel.org> Signed-off-by: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: darrick.wong@oracle.com Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-5-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep, sched/completions: Change the prefix of lock name for ↵Byungchul Park2017-10-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | completion variables CONFIG_LOCKDEP_COMPLETIONS uses "(complete)" as a prefix of lock name for completion variable. However, what we should use here is a noun - so use "(completion)" instead. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: darrick.wong@oracle.com Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-4-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/lockdep: Provide empty lockdep_map structure for !CONFIG_LOCKDEPByungchul Park2017-10-251-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | After this patch the lockdep_map structure takes no space if lockdep is disabled, reducing the number of #ifdefs in unrelated kernel code. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: darrick.wong@oracle.com Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-3-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* block: Use DECLARE_COMPLETION_ONSTACK() in submit_bio_wait()Christoph Hellwig2017-10-251-14/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Simplify the code by getting rid of the submit_bio_ret structure. (This also helps address a lockdep false positive.) Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: darrick.wong@oracle.com Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-2-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns ↵Mark Rutland2017-10-25180-385/+383
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, mm: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()Paul E. McKenney2017-10-251-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the mm code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Link: http://lkml.kernel.org/r/1508792849-3115-15-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, doc/filesystems: Convert ACCESS_ONCE() referencesPaul E. McKenney2017-10-251-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle documentation, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the filesystems documentation to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Link: http://lkml.kernel.org/r/1508792849-3115-14-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, rcutorture/formal: Prepare for ACCESS_ONCE() removalMark Rutland2017-10-251-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. The bulk of the kernel code can be transformed via Coccinelle to use {READ,WRITE}_ONCE(), though this only modifies users of ACCESS_ONCE(), and not the implementation itself. As such, it has the potential to break homebrew ACCESS_ONCE() macros seen in some user code in the kernel tree (e.g. the virtio code, as fixed in commit ea9156fb3b71d9f7). To avoid fragility if/when that transformation occurs, this patch reworks the definitions of {READ,WRITE}_ONCE() in the rcutorture formal tests, and removes the unused ACCESS_ONCE() helper. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-13-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, workqueue: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()Mark Rutland2017-10-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the workqueue code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-12-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, selftests/powerpc: Convert ACCESS_ONCE() to ↵Mark Rutland2017-10-252-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | READ_ONCE()/WRITE_ONCE() For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. The bulk of the kernel code can be transformed via Coccinelle to use {READ,WRITE}_ONCE(), though this only modifies users of ACCESS_ONCE(), and not the implementation itself. As such, it has the potential to break homebrew ACCESS_ONCE() macros seen in some user code in the kernel tree (e.g. the virtio code, as fixed in commit ea9156fb3b71d9f7). To avoid fragility if/when that transformation occurs, and to align with the preferred usage of {READ,WRITE}_ONCE(), this patch updates the DSCR selftest code to use READ_ONCE() rather than ACCESS_ONCE(). There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-11-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, samples/mic/mpssd/mpssd.c: Convert ACCESS_ONCE() to ↵Mark Rutland2017-10-251-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | READ_ONCE()/WRITE_ONCE() For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. The bulk of the kernel code can be transformed via Coccinelle to use {READ,WRITE}_ONCE(), though this only modifies users of ACCESS_ONCE(), and not the implementation itself. As such, it has the potential to break homebrew ACCESS_ONCE() macros seen in some user code in the kernel tree (e.g. the virtio code, as fixed in commit ea9156fb3b71d9f7). To avoid fragility if/when that transformation occurs, and to align with the preferred usage of {READ,WRITE}_ONCE(), this patch updates the MPSSD sample code to use READ_ONCE() rather than ACCESS_ONCE(). There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-10-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, net/average: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()Mark Rutland2017-10-251-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't pick up some uses, including those in <linux/average.h>. As a preparatory step, this patch converts the file to use {READ,WRITE}_ONCE() consistently. At the same time, this patch addds missing includes necessary for {READ,WRITE}_ONCE(), *BUG_ON*(), and ilog2(). ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Johannes Berg <johannes@sipsolutions.net> Cc: David S. Miller <davem@davemloft.net> Cc: Johannes Berg <johannes.berg@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-9-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, net/ipv4/tcp_input.c: Convert ACCESS_ONCE() to ↵Mark Rutland2017-10-251-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | READ_ONCE()/WRITE_ONCE() For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the IPv4 TCP input code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-8-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, net/netlink/netfilter: Convert ACCESS_ONCE() to ↵Mark Rutland2017-10-256-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | READ_ONCE()/WRITE_ONCE() For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts netlink and netfilter code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Florian Westphal <fw@strlen.de> Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-7-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, media/dvb_ringbuffer: Convert ACCESS_ONCE() to ↵Mark Rutland2017-10-251-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | READ_ONCE()/WRITE_ONCE() For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the DVB ringbuffer code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-6-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, fs/ncpfs: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()Mark Rutland2017-10-251-9/+0
| | | | | | | | | | | | | | | | | | | | | | | | | The NCPFS code has some stale comments regarding ACCESS_ONCE() uses which were removed a long time ago. Let's remove the stale comments. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Vandrovec <petr@vandrovec.name> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-5-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, fs/dcache: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()Mark Rutland2017-10-252-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the dcache code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-4-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, firmware/ivc: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()Mark Rutland2017-10-251-12/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | workqueue: kill off ACCESS_ONCE() For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the Tegra IVC code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Jonathan Hunter <jonathanh@nvidia.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-3-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, EDAC/altera: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()Mark Rutland2017-10-251-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't handle comments, leaving references to ACCESS_ONCE() instances which have been removed. As a preparatory step, this patch converts the Altera EDAC code and comments to use {READ,WRITE}_ONCE() consistently. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Thor Thayer <thor.thayer@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-2-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics, dm-integrity: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()Mark Rutland2017-10-251-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't pick up some uses, including those in dm-integrity.c. As a preparatory step, this patch converts the driver to use {READ,WRITE}_ONCE() consistently. At the same time, this patch adds the missing include of <linux/compiler.h> necessary for the {READ,WRITE}_ONCE() definitions. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-1-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/qrwlock: Prevent slowpath writers getting held up by fastpathWill Deacon2017-10-253-37/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a prospective writer takes the qrwlock locking slowpath due to the lock being held, it attempts to cmpxchg the wmode field from 0 to _QW_WAITING so that concurrent lockers also take the slowpath and queue on the spinlock accordingly, allowing the lockers to drain. Unfortunately, this isn't fair, because a fastpath writer that comes in after the lock is made available but before the _QW_WAITING flag is set can effectively jump the queue. If there is a steady stream of prospective writers, then the waiter will be held off indefinitely. This patch restores fairness by separating _QW_WAITING and _QW_LOCKED into two distinct fields: _QW_LOCKED continues to occupy the bottom byte of the lockword so that it can be cleared unconditionally when unlocking, but _QW_WAITING now occupies what used to be the bottom bit of the reader count. This then forces the slow-path for concurrent lockers. Tested-by: Waiman Long <longman@redhat.com> Tested-by: Jeremy Linton <jeremy.linton@arm.com> Tested-by: Adam Wallis <awallis@codeaurora.org> Tested-by: Jan Glauber <jglauber@cavium.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Jeremy.Linton@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1507810851-306-6-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/qrwlock, arm64: Move rwlock implementation over to qrwlocksWill Deacon2017-10-254-168/+20
| | | | | | | | | | | | | | | | | | | | Now that the qrwlock can make use of WFE, remove our homebrewed rwlock code in favour of the generic queued implementation. Tested-by: Waiman Long <longman@redhat.com> Tested-by: Jeremy Linton <jeremy.linton@arm.com> Tested-by: Adam Wallis <awallis@codeaurora.org> Tested-by: Jan Glauber <jglauber@cavium.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Jeremy.Linton@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: boqun.feng@gmail.com Cc: linux-arm-kernel@lists.infradead.org Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1507810851-306-5-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/qrwlock: Use atomic_cond_read_acquire() when spinning in qrwlockWill Deacon2017-10-252-40/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The qrwlock slowpaths involve spinning when either a prospective reader is waiting for a concurrent writer to drain, or a prospective writer is waiting for concurrent readers to drain. In both of these situations, atomic_cond_read_acquire() can be used to avoid busy-waiting and make use of any backoff functionality provided by the architecture. This patch replaces the open-code loops and rspin_until_writer_unlock() implementation with atomic_cond_read_acquire(). The write mode transition zero to _QW_WAITING is left alone, since (a) this doesn't need acquire semantics and (b) should be fast. Tested-by: Waiman Long <longman@redhat.com> Tested-by: Jeremy Linton <jeremy.linton@arm.com> Tested-by: Adam Wallis <awallis@codeaurora.org> Tested-by: Jan Glauber <jglauber@cavium.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Jeremy.Linton@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1507810851-306-4-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomic: Add atomic_cond_read_acquire()Will Deacon2017-10-252-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | smp_cond_load_acquire() provides a way to spin on a variable with acquire semantics until some conditional expression involving the variable is satisfied. Architectures such as arm64 can potentially enter a low-power state, waking up only when the value of the variable changes, which reduces the system impact of tight polling loops. This patch makes the same interface available to users of atomic_t, atomic64_t and atomic_long_t, rather than require messy accesses to the structure internals. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Jeremy.Linton@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1507810851-306-3-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/qrwlock: Use 'struct qrwlock' instead of 'struct __qrwlock'Will Deacon2017-10-253-37/+16
| | | | | | | | | | | | | | | | | | | | | | | There's no good reason to keep the internal structure of struct qrwlock hidden from qrwlock.h, particularly as it's actually needed for unlock and ends up being abstracted independently behind the __qrwlock_write_byte() function. Stop pretending we can hide this stuff, and move the __qrwlock definition into qrwlock, removing the __qrwlock_write_byte() nastiness and using the same struct definition everywhere instead. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Jeremy.Linton@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1507810851-306-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/atomics/alpha: Add smp_read_barrier_depends() to ↵Will Deacon2017-10-241-0/+13
| | | | | | | | | | | | | | | | | | | | _release()/_relaxed() atomics As part of the fight against smp_read_barrier_depends(), we require dependency ordering to be preserved when a dependency is headed by a load performed using an atomic operation. This patch adds smp_read_barrier_depends() to the _release() and _relaxed() atomics on alpha, which otherwise lack anything to enforce dependency ordering. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-6-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/barriers: Kill lockless_dereference()Will Deacon2017-10-243-44/+0
| | | | | | | | | | | | | | | | | | | | lockless_dereference() is a nice idea, but it gained little traction in kernel code since its introduction three years ago. This is partly because it's a pain to type, but also because using READ_ONCE() instead has worked correctly on all architectures apart from Alpha, which is a fully supported but somewhat niche architecture these days. Now that READ_ONCE() has been upgraded to contain an implicit smp_read_barrier_depends() and the few callers of lockless_dereference() have been converted, we can remove lockless_dereference() altogether. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-5-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/barriers: Convert users of lockless_dereference() to READ_ONCE()Will Deacon2017-10-2413-27/+27
| | | | | | | | | | | | | | READ_ONCE() now has an implicit smp_read_barrier_depends() call, so it can be used instead of lockless_dereference() without any change in semantics. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-4-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()Will Deacon2017-10-241-0/+1
| | | | | | | | | | | | | | | In preparation for the removal of lockless_dereference(), which is the same as READ_ONCE() on all architectures other than Alpha, add an implicit smp_read_barrier_depends() to READ_ONCE() so that it can be used to head dependency chains on all architectures. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-3-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* linux/compiler.h: Split into compiler.h and compiler_types.hWill Deacon2017-10-2411-271/+286
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | linux/compiler.h is included indirectly by linux/types.h via uapi/linux/types.h -> uapi/linux/posix_types.h -> linux/stddef.h -> uapi/linux/stddef.h and is needed to provide a proper definition of offsetof. Unfortunately, compiler.h requires a definition of smp_read_barrier_depends() for defining lockless_dereference() and soon for defining READ_ONCE(), which means that all users of READ_ONCE() will need to include asm/barrier.h to avoid splats such as: In file included from include/uapi/linux/stddef.h:1:0, from include/linux/stddef.h:4, from arch/h8300/kernel/asm-offsets.c:11: include/linux/list.h: In function 'list_empty': >> include/linux/compiler.h:343:2: error: implicit declaration of function 'smp_read_barrier_depends' [-Werror=implicit-function-declaration] smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ ^ A better alternative is to include asm/barrier.h in linux/compiler.h, but this requires a type definition for "bool" on some architectures (e.g. x86), which is defined later by linux/types.h. Type "bool" is also used directly in linux/compiler.h, so the whole thing is pretty fragile. This patch splits compiler.h in two: compiler_types.h contains type annotations, definitions and the compiler-specific parts, whereas compiler.h #includes compiler-types.h and additionally defines macros such as {READ,WRITE.ACCESS}_ONCE(). uapi/linux/stddef.h and linux/linkage.h are then moved over to include linux/compiler_types.h, which fixes the build for h8 and blackfin. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1508840570-22169-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'v4.14-rc6' into locking/core, to pick up fixesIngo Molnar2017-10-24479-2345/+5183
|\ | | | | | | Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * Linux 4.14-rc6v4.14-rc6Linus Torvalds2017-10-231-1/+1
| |
| * Merge tag 'staging-4.14-rc6' of ↵Linus Torvalds2017-10-239-39/+96
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging Pull staging and IIO fixes from Greg KH: "Here are a small number of patches to resolve some reported IIO and a staging driver problem. Nothing major here, full details are in the shortlog below. All have been in linux-next with no reported issues" * tag 'staging-4.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: staging: bcm2835-audio: Fix memory corruption iio: adc: at91-sama5d2_adc: fix probe error on missing trigger property iio: adc: dln2-adc: fix build error iio: dummy: events: Add missing break staging: iio: ade7759: fix signed extension bug on shift of a u8 iio: pressure: zpa2326: Remove always-true check which confuses gcc iio: proximity: as3935: noise detection + threshold changes
| | * staging: bcm2835-audio: Fix memory corruptionPhil Elwell2017-10-181-12/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous commit (0adbfd46) fixed a memory leak but also freed a block in the success case, causing a stale pointer to be used with potentially fatal results. Only free the vchi_instance block in the case that vchi_connect fails; once connected, the instance is retained for subsequent connections. Simplifying the code by removing a bunch of gotos and returning errors directly. Signed-off-by: Phil Elwell <phil@raspberrypi.org> Fixes: 0adbfd4694c2 ("staging: bcm2835-audio: fix memory leak in bcm2835_audio_open_connection()") Cc: stable <stable@vger.kernel.org> # 4.12+ Tested-by: Stefan Wahren <stefan.wahren@i2se.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| | * Merge tag 'iio-fixes-for-4.14b' of ↵Greg Kroah-Hartman2017-10-158-27/+89
| | |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-linus Jonathan writes: Second set of IIO fixes for the 4.14 cycle. * ade7759 - Fix a signed extension bug. * as3935 - The default noise and watch dog settings were such that the device was unusuable in most applications. Add device tree parameters to allow it to be configured to something that will actually work. * at91-sama5d2 adc - Fix handling of legacy device trees that don't provide the new trigger edge property. * dln2-adc - Fix a missing Kconfig dependency on IIO_TRIGGERED_BUFFER. * dummy driver - Add a missing break so that writing in_voltage0_thresh_rising_en doesn't always result in an error. * zpa2326 - Drop a test for an always true condition so that gcc won't spit out and unused variable warning.
| | | * iio: adc: at91-sama5d2_adc: fix probe error on missing trigger propertyEugen Hristev2017-10-141-16/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fix allows platforms to probe correctly even if the trigger edge property is missing. The hardware trigger will no longer be registered in the sybsystem Preserves backwards compatibility with the support that was in the driver before the hardware trigger. https://storage.kernelci.org/mainline/master/v4.14-rc2-255-g74d83ec2b734/arm/sama5_defconfig/lab-free-electrons/boot-at91-sama5d2_xplained.txt Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> Fixes: 5e1a1da0f ("iio: adc: at91-sama5d2_adc: add hw trigger and buffer support") Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
| | | * iio: adc: dln2-adc: fix build errorRandy Dunlap2017-10-081-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dln2-adc driver uses interface(s) that are controlled by the IIO_TRIGGERED_BUFFER Kconfig symbol, so the driver needs to select that symbol to prevent the build error. drivers/iio/adc/dln2-adc.o: In function `dln2_adc_probe': dln2-adc.c:(.text+0x528): undefined reference to `devm_iio_triggered_buffer_setup' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: kbuild test robot <fengguang.wu@intel.com> Cc: Jonathan Cameron <jic23@kernel.org> Cc: linux-iio@vger.kernel.org Cc: Jack Andersen <jackoalan@gmail.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
| | | * iio: dummy: events: Add missing breakLars-Peter Clausen2017-10-011-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add missing break in iio_simple_dummy_write_event_config() for the voltage threshold event enable attribute. Without this writing to the in_voltage0_thresh_rising_en always returns -EINVAL even though the change was correctly applied. Fixes: 3e34e650db197 ("iio: dummy: Demonstrate the usage of new channel types") Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
| | | * staging: iio: ade7759: fix signed extension bug on shift of a u8Colin Ian King2017-09-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current shift of st->rx[2] left shifts a u8 24 bits left, promotes the integer to a an int and then to a unsigned u64. If the top bit of st->rx[2] is set then we end up with all the upper bits being set to 1. Fix this by casting st->rx[2] to a u64 before the 24 bit left shift. Detected by CoverityScan CID#144940 ("Unintended sign extension") Fixes: 2919fa54ef64 ("staging: iio: meter: new driver for ADE7759 devices") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
| | | * iio: pressure: zpa2326: Remove always-true check which confuses gccGeert Uytterhoeven2017-09-251-7/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With gcc 4.1.2: drivers/iio/pressure/zpa2326.c: In function ‘zpa2326_wait_oneshot_completion’: drivers/iio/pressure/zpa2326.c:868: warning: ‘ret’ may be used uninitialized in this function When testing for "timeout < 0", timeout is already guaranteed to be strict negative, so the branch is always taken, and ret is thus always initialized. But (some version of) gcc is not smart enough to notice. Remove the check to fix this. As there is no other code in between assigning the error codes and returning them, the error codes can be returned immediately, and the intermediate variable can be dropped. Drop the "else" to please checkpatch. Fixes: e7215fe4d51e69c9 ("iio: pressure: zpa2326: report interrupted case as failure") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
| | | * iio: proximity: as3935: noise detection + threshold changesMatt Ranostay2017-09-253-3/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most applications are too noisy to allow the default noise and watchdog settings, and thus need to be configurable via DT properties. Also default settings to POR defaults on a reset, and register distuber interrupts as noise since it prevents proper usage. Cc: devicetree@vger.kernel.org Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
| * | | Merge tag 'char-misc-4.14-rc6' of ↵Linus Torvalds2017-10-234-26/+15
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc driver fixes from Greg KH: "Here are four small fixes for 4.14-rc6. Three of them are binder driver fixes for reported issues, and the last one is a hyperv driver bugfix. Nothing major, but good fixes to get into 4.14-final. All of these have been in linux-next with no reported issues" * tag 'char-misc-4.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: android: binder: Fix null ptr dereference in debug msg android: binder: Don't get mm from task vmbus: hvsock: add proper sync for vmbus_hvsock_device_unregister() binder: call poll_wait() unconditionally.
| | * | | android: binder: Fix null ptr dereference in debug msgSherry Yang2017-10-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't access next->data in kernel debug message when the next buffer is null. Acked-by: Arve Hjønnevåg <arve@android.com> Signed-off-by: Sherry Yang <sherryy@android.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| | * | | android: binder: Don't get mm from taskSherry Yang2017-10-212-14/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use binder_alloc struct's mm_struct rather than getting a reference to the mm struct through get_task_mm to avoid a potential deadlock between lru lock, task lock and dentry lock, since a thread can be holding the task lock and the dentry lock while trying to acquire the lru lock. Acked-by: Arve Hjønnevåg <arve@android.com> Signed-off-by: Sherry Yang <sherryy@android.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-04 21:06:55 +0100