summaryrefslogtreecommitdiff
AgeCommit message (Collapse)Author
2016-06-13md/raid10: add rcu protection in raid10_status.NeilBrown
mirrors[].rdev can become NULL at any point unless: - a counted reference is held - ->reconfig_mutex is held, or - rcu_read_lock() is held raid10_status holds none of these. So add rcu_read_lock() protection. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-06-13md/raid10: fix refounct imbalance when resyncing an array with a replacement ↵NeilBrown
device. If you have a raid10 with a replacement device that is resyncing - e.g. after a crash before the replacement was complete - the write to the replacement will increment nr_pending on the wrong device, which will lead to strangeness. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-06-13md/raid1, raid10: don't recheck "Faulty" flag in read-balance.NeilBrown
Re-checking the faulty flag here brings no value. The comment about "risk" refers to the risk that the device could be in the process of being removed by ->hot_remove_disk(). However providing that the ->nr_pending count is incremented inside an rcu_read_locked() region, there is no risk of that happening. This is because the rdev pointer (in the personalities array) is set to NULL before synchronize_rcu(), and ->nr_pending is tested afterwards. If the rcu_read_locked region happens before the synchronize_rcu(), the test will see that nr_pending has been incremented. If it happens afterwards, the rdev pointer will be NULL so there is nothing to increment. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-06-13md: disconnect device from personality before trying to remove it.NeilBrown
When the HOT_REMOVE_DISK ioctl is used to remove a device, we call remove_and_add_spares() which will remove it from the personality if possible. This improves the chances that the removal will succeed. When writing "remove" to dev-XX/state, we don't. So that can fail more easily. So add the remove_and_add_spares() into "remove" handling. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-06-13raid1/raid10: slow down resync if there is non-resync activity pendingTomasz Majchrzak
A performance drop of mkfs has been observed on RAID10 during resync since commit 09314799e4f0 ("md: remove 'go_faster' option from ->sync_request()"). Resync sends so many IOs it slows down non-resync IOs significantly (few times). Add a short delay to a resync. The previous long sleep (1s) has proven unnecessary, even very short delay brings performance right. The change also applied to raid1. The problem has not been observed on raid1, however it shares barriers code with raid10 so it might be an issue for some setup too. Suggested-by: NeilBrown <neilb@suse.com> Link: http://lkml.kernel.org/r/20160609134555.GA9104@proton.igk.intel.com Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-06-13MD:Update superblock when err == 0 in size_storeXiao Ni
This is a simple check before updating the superblock. It should update the superblock when update_size return 0. Signed-off-by: Xiao Ni <xni@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-06-09md: use a mutex to protect a global listCong Wang
We saw a list corruption in the list all_detected_devices: WARNING: CPU: 16 PID: 226 at lib/list_debug.c:29 __list_add+0x3c/0xa9() list_add corruption. next->prev should be prev (ffff880859d58320), but was ffff880859ce74c0. (next=ffffffff81abfdb0). Modules linked in: ahci libahci libata sd_mod scsi_mod CPU: 16 PID: 226 Comm: kworker/u241:4 Not tainted 4.1.20 #1 Hardware name: Dell Inc. PowerEdge C6220/04GD66, BIOS 2.2.3 11/07/2013 Workqueue: events_unbound async_run_entry_fn 0000000000000000 ffff880859a5baf8 ffffffff81502872 ffff880859a5bb48 0000000000000009 ffff880859a5bb38 ffffffff810692a5 ffff880859ee8828 ffffffff812ad02c ffff880859d58320 ffffffff81abfdb0 ffff880859eb90c0 Call Trace: [<ffffffff81502872>] dump_stack+0x4d/0x63 [<ffffffff810692a5>] warn_slowpath_common+0xa1/0xbb [<ffffffff812ad02c>] ? __list_add+0x3c/0xa9 [<ffffffff81069305>] warn_slowpath_fmt+0x46/0x48 [<ffffffff812ad02c>] __list_add+0x3c/0xa9 [<ffffffff81406f28>] md_autodetect_dev+0x41/0x62 [<ffffffff81285862>] rescan_partitions+0x25f/0x29d [<ffffffff81506372>] ? mutex_lock+0x13/0x31 [<ffffffff811a090f>] __blkdev_get+0x1aa/0x3cd [<ffffffff811a0b91>] blkdev_get+0x5f/0x294 [<ffffffff81377ceb>] ? put_device+0x17/0x19 [<ffffffff8128227c>] ? disk_put_part+0x12/0x14 [<ffffffff812836f3>] add_disk+0x29d/0x407 [<ffffffff81384345>] ? __pm_runtime_use_autosuspend+0x5c/0x64 [<ffffffffa004a724>] sd_probe_async+0x115/0x1af [sd_mod] [<ffffffff81083177>] async_run_entry_fn+0x72/0x12c [<ffffffff8107c44c>] process_one_work+0x198/0x2ce [<ffffffff8107cac7>] worker_thread+0x1dd/0x2bb [<ffffffff8107c8ea>] ? cancel_delayed_work_sync+0x15/0x15 [<ffffffff8107c8ea>] ? cancel_delayed_work_sync+0x15/0x15 [<ffffffff81080d9c>] kthread+0xae/0xb6 [<ffffffff81080000>] ? param_array_set+0x40/0xfa [<ffffffff81080cee>] ? __kthread_parkme+0x61/0x61 [<ffffffff81508152>] ret_from_fork+0x42/0x70 [<ffffffff81080cee>] ? __kthread_parkme+0x61/0x61 I suspect it is because there is no lock protecting this global list, autostart_arrays() is called in ioctl() path where there is no lock. Cc: Shaohua Li <shli@kernel.org> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-06-03md: simplify the code with md_kick_rdev_from_arrayGuoqing Jiang
Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-06-03md-cluster: fix deadlock issue when add disk to an recoverying arrayGuoqing Jiang
Add a disk to an array which is performing recovery is a little complicated, we need to do both reap the sync thread and perform add disk for the case, then it caused deadlock as follows. linux44:~ # ps aux|grep md|grep D root 1822 0.0 0.0 0 0 ? D 16:50 0:00 [md127_resync] root 1848 0.0 0.0 19860 952 pts/0 D+ 16:50 0:00 mdadm --manage /dev/md127 --re-add /dev/vdb linux44:~ # cat /proc/1848/stack [<ffffffff8107afde>] kthread_stop+0x6e/0x120 [<ffffffffa051ddb0>] md_unregister_thread+0x40/0x80 [md_mod] [<ffffffffa0526e45>] md_reap_sync_thread+0x15/0x150 [md_mod] [<ffffffffa05271e0>] action_store+0x260/0x270 [md_mod] [<ffffffffa05206b4>] md_attr_store+0xb4/0x100 [md_mod] [<ffffffff81214a7e>] sysfs_write_file+0xbe/0x140 [<ffffffff811a6b98>] vfs_write+0xb8/0x1e0 [<ffffffff811a75b8>] SyS_write+0x48/0xa0 [<ffffffff8152a5c9>] system_call_fastpath+0x16/0x1b [<00007f068ea1ed30>] 0x7f068ea1ed30 linux44:~ # cat /proc/1822/stack [<ffffffffa05251a6>] md_do_sync+0x846/0xf40 [md_mod] [<ffffffffa052402d>] md_thread+0x16d/0x180 [md_mod] [<ffffffff8107ad94>] kthread+0xb4/0xc0 [<ffffffff8152a518>] ret_from_fork+0x58/0x90 Task1848 Task1822 md_attr_store (held reconfig_mutex by call mddev_lock()) action_store md_reap_sync_thread md_unregister_thread kthread_stop md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, !test_bit(MD_CHANGE_PENDING)) md_check_recovery is triggered by wakeup mddev->thread, but it can't clear MD_CHANGE_PENDING flag since it can't get lock which was held by md_attr_store already. To solve the deadlock problem, we move "->resync_finish()" from md_do_sync to md_reap_sync_thread (after md_update_sb), also MD_HELD_RESYNC_LOCK is introduced since it is possible that node can't get resync lock in md_do_sync. Then we do not need to wait for MD_CHANGE_PENDING is cleared or not since metadata should be updated after md_update_sb, so just call resync_finish if MD_HELD_RESYNC_LOCK is set. We also unified the code after skip label, since set PENDING for non-clustered case should be harmless. Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-05-26right meaning of PARITY_ENABLE_RMW and PARITY_PREFER_RMWSong Liu
In current handle_stripe_dirtying, the code prefers rmw with PARITY_ENABLE_RMW; while prefers rcw with PARITY_PREFER_RMW. This patch reverses this behavior. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Shaohua Li <shli@fb.com>
2016-05-26Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Ingo Molnar: "Misc fixes: EFI, entry code, pkeys and MPX fixes, TASK_SIZE cleanups and a tsc frequency table fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Switch from TASK_SIZE to TASK_SIZE_MAX in the page fault code x86/fsgsbase/64: Use TASK_SIZE_MAX for FSBASE/GSBASE upper limits x86/mm/mpx: Work around MPX erratum SKD046 x86/entry/64: Fix stack return address retrieval in thunk x86/efi: Fix 7-parameter efi_call()s x86/cpufeature, x86/mm/pkeys: Fix broken compile-time disabling of pkeys x86/tsc: Add missing Cherrytrail frequency to the table
2016-05-26Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "Two fixes: one for a lost wakeup, the other to fix the compiler optimizing out preempt operations on ARM64 (and possibly other non-x86 architectures)" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/core: Fix remote wakeups sched/preempt: Fix preempt_count manipulations
2016-05-26Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates from Ingo Molnar: "Mostly tooling and PMU driver fixes, but also a number of late updates such as the reworking of the call-chain size limiting logic to make call-graph recording more robust, plus tooling side changes for the new 'backwards ring-buffer' extension to the perf ring-buffer" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits) perf record: Read from backward ring buffer perf record: Rename variable to make code clear perf record: Prevent reading invalid data in record__mmap_read perf evlist: Add API to pause/resume perf trace: Use the ptr->name beautifier as default for "filename" args perf trace: Use the fd->name beautifier as default for "fd" args perf report: Add srcline_from/to branch sort keys perf evsel: Record fd into perf_mmap perf evsel: Add overwrite attribute and check write_backward perf tools: Set buildid dir under symfs when --symfs is provided perf trace: Only auto set call-graph to "dwarf" when syscalls are being traced perf annotate: Sort list of recognised instructions perf annotate: Fix identification of ARM blt and bls instructions perf tools: Fix usage of max_stack sysctl perf callchain: Stop validating callchains by the max_stack sysctl perf trace: Fix exit_group() formatting perf top: Use machine->kptr_restrict_warned perf trace: Warn when trying to resolve kernel addresses with kptr_restrict=1 perf machine: Do not bail out if not managing to read ref reloc symbol perf/x86/intel/p4: Trival indentation fix, remove space ...
2016-05-25Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool build fix from Ingo Molnar: "An libtool fix for older libelf versions" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool: Allow building with older libelf
2016-05-25Merge branch 'work.iov_iter' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs iov_iter regression fix from Al Viro: "Fix for braino in 'fold checks into iterate_and_advance()'" * 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: do "fold checks into iterate_and_advance()" right
2016-05-25Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs xattr regression fixes from Al Viro. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: make xattr_resolve_handlers() safe to use with NULL ->s_xattr xattr: Fail with -EINVAL for NULL attribute names
2016-05-25Merge tag 'acpi-4.7-rc1-more' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI fix from Rafael Wysocki: "Additional ACPI update for v4.7-rc1 Just one fix for incorrect async_synchronize_cookie() usage in the ACPI battery driver (Chris Wilson)" * tag 'acpi-4.7-rc1-more' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPI / battery: Correctly serialise with the pending async probe
2016-05-25Merge tag 'pm-4.7-rc1-more' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull more power management updates from Rafael Wysocki: "These are two stable-candidate fixes (PM core, cpuidle) and a bunch of cpufreq cleanups. Specifics: - Stable-candidate cpuidle fix to make it check the right variable when deciding whether or not to enable interrupts on the local CPU so as to avoid enabling iterrupts too early in some cases if the system has both coupled and per-core idle states (Daniel Lezcano). - Stable-candidate PM core fix to make it handle failures at the "late suspend" stage of device suspend consistently for all devices regardless of whether or not async suspend/resume is enabled for them (Rafael Wysocki). - Cleanups in the cpufreq core, the schedutil governor and the intel_pstate driver (Rafael Wysocki, Pankaj Gupta, Viresh Kumar)" * tag 'pm-4.7-rc1-more' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM / sleep: Handle failures in device_suspend_late() consistently cpufreq: schedutil: Improve prints messages with pr_fmt cpuidle: Fix cpuidle_state_is_coupled() argument in cpuidle_enter() cpufreq: simplified goto out in cpufreq_register_driver() cpufreq: governor: CPUFREQ_GOV_STOP never fails cpufreq: governor: CPUFREQ_GOV_POLICY_EXIT never fails intel_pstate: Simplify conditional in intel_pstate_set_policy()
2016-05-25do "fold checks into iterate_and_advance()" rightAl Viro
the only case when we should skip the iterate_and_advance() guts is when nothing's left in the iterator, _not_ just when requested amount is 0. Said guts will do nothing in the latter case anyway; the problem we tried to deal with in the aforementioned commit is that when there's nothing left *and* the amount requested is 0, we might end up deferencing one iovec too many; the value we fetch from there is discarded in that case, but theoretically it might oops if the iovec array ends exactly at the end of page with the next page not mapped. Bailing out on zero size requested had an unexpected side effect - zero-length segment in the beginning of iovec array ended up throwing do_loop_readv_writev() into infinite spin; we do not advance past the empty segment at all. Reproducer is trivial: echo '#include <sys/uio.h>' >a.c echo 'main() {char c; struct iovec v[] = {{&c,0},{&c,1}}; readv(0,v,2);}' >>a.c cc a.c && ./a.out </proc/uptime which should end up with the process not hanging. Probably ought to go into LTP or xfstests... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-25make xattr_resolve_handlers() safe to use with NULL ->s_xattrAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-25xattr: Fail with -EINVAL for NULL attribute namesAndreas Gruenbacher
Commit 98e9cb57 improved the xattr name checks in xattr_resolve_name but didn't update the NULL attribute name check appropriately, so NULL attribute names lead to NULL pointer dereferences. Turn that into -EINVAL results instead. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> fs/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-25Merge branch 'acpi-battery'Rafael J. Wysocki
* acpi-battery: ACPI / battery: Correctly serialise with the pending async probe
2016-05-25Merge branches 'pm-cpufreq', 'pm-cpuidle' and 'pm-core'Rafael J. Wysocki
* pm-cpufreq: cpufreq: schedutil: Improve prints messages with pr_fmt cpufreq: simplified goto out in cpufreq_register_driver() cpufreq: governor: CPUFREQ_GOV_STOP never fails cpufreq: governor: CPUFREQ_GOV_POLICY_EXIT never fails intel_pstate: Simplify conditional in intel_pstate_set_policy() * pm-cpuidle: cpuidle: Fix cpuidle_state_is_coupled() argument in cpuidle_enter() * pm-core: PM / sleep: Handle failures in device_suspend_late() consistently
2016-05-25Merge tag 'pwm/for-4.7-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm Pull pwm updates from Thierry Reding: "This set of changes introduces an atomic API to the PWM subsystem. This is influenced by the DRM atomic API that was introduced a while back, though it is obviously a lot simpler. The fundamental idea remains the same, though: drivers provide a single callback to implement the atomic configuration of a PWM channel. As a side-effect the PWM subsystem gains the ability for initial state retrieval, so that the logical state mirrors that of the hardware. Many use-cases don't care about this, but for others it is essential. These new features require changes in all users, which these patches take care of. The core is transitioned to use the atomic callback if available and provides a fallback mechanism for other drivers. Changes to transition users and drivers to the atomic API are postponed to v4.8" * tag 'pwm/for-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (30 commits) pwm: Add information about polarity, duty cycle and period to debugfs pwm: Switch to the atomic API pwm: Update documentation pwm: Add core infrastructure to allow atomic updates pwm: Add hardware readout infrastructure pwm: Move the enabled/disabled info into pwm_state pwm: Introduce the pwm_state concept pwm: Keep PWM state in sync with hardware state ARM: Explicitly apply PWM config extracted from pwm_args drm: i915: Explicitly apply PWM config extracted from pwm_args input: misc: pwm-beeper: Explicitly apply PWM config extracted from pwm_args input: misc: max8997: Explicitly apply PWM config extracted from pwm_args backlight: lm3630a: explicitly apply PWM config extracted from pwm_args backlight: lp855x: Explicitly apply PWM config extracted from pwm_args backlight: lp8788: Explicitly apply PWM config extracted from pwm_args backlight: pwm_bl: Use pwm_get_args() where appropriate fbdev: ssd1307fb: Use pwm_get_args() where appropriate regulator: pwm: Use pwm_get_args() where appropriate leds: pwm: Use pwm_get_args() where appropriate input: misc: max77693: Use pwm_get_args() where appropriate ...
2016-05-25Merge git://www.linux-watchdog.org/linux-watchdogLinus Torvalds
Pull watchdog updates from Wim Van Sebroeck: - add support for Fintek F81865 Super-IO chip - add support for watchdogs (RWDT and SWDT) found on RCar Gen3 based SoCs from Renesas - octeon: Handle the FROZEN hot plug notifier actions - f71808e_wdt fixes and cleanups - some small improvements in code and documentation * git://www.linux-watchdog.org/linux-watchdog: MAINTAINERS: Add file patterns for watchdog device tree bindings Documentation: Add ebc-c384_wdt watchdog-parameters.txt entry watchdog: shwdt: Use setup_timer() watchdog: cpwd: Use setup_timer() arm64: defconfig: enable Renesas Watchdog Timer watchdog: renesas-wdt: add driver watchdog: remove error message when unable to allocate watchdog device watchdog: f71808e_wdt: Fix WDTMOUT_STS register read watchdog: f71808e_wdt: Fix typo watchdog: f71808e_wdt: Add F81865 support watchdog: sp5100_tco: properly check for new register layouts watchdog: core: Fix circular locking dependency watchdog: core: fix trivial typo in a comment watchdog: hpwdt: Adjust documentation to match latest kernel module parameters. watchdog: imx2_wdt: add external reset support via dt prop watchdog: octeon: Handle the FROZEN hot plug notifier actions. watchdog: qcom: Report reboot reason
2016-05-25Merge tag 'vfio-v4.7-rc1' of git://github.com/awilliam/linux-vfioLinus Torvalds
Pull VFIO updates from Alex Williamson: - Hide INTx on certain known broken devices (Alex Williamson) - Additional backdoor reset detection (Alex Williamson) - Remove unused iommudata reference (Alexey Kardashevskiy) - Use cfg_size to avoid probing extended config space (Alexey Kardashevskiy) * tag 'vfio-v4.7-rc1' of git://github.com/awilliam/linux-vfio: vfio_pci: Test for extended capabilities if config space > 256 bytes vfio_iommu_spapr_tce: Remove unneeded iommu_group_get_iommudata vfio/pci: Add test for BAR restore vfio/pci: Hide broken INTx support from user
2016-05-25Merge tag 'drm-4.7-rc1-headers-fix' of ↵Linus Torvalds
git://people.freedesktop.org/~airlied/linux Pull header warning fix from Dave Airlie: "Here is the C++ guards warning fix from Arnd" [ Background: there are 'extern "C" { }' guards in include/uapi for the GPU headers. They should arguably be wrapped somehow, but as it is they caused checkpatch to warn because it would trigger on the 'extern' and think it's exporting a function or variable from the kernel to user space. This just fixes checkpatch. Whether we wrap the C++ guards some way in the future will be an independent issue. ] * tag 'drm-4.7-rc1-headers-fix' of git://people.freedesktop.org/~airlied/linux: headers_check: don't warn about c++ guards
2016-05-25Merge branch 'parisc-4.7-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Pull parisc updates from Helge Deller: - Add native high-resolution timing code for sched_clock() and other timing functions based on the processor internal cr16 cycle counters - Add syscall tracepoint support - Add regset support - Speed up get_user() and put_user() functions - Updated futex.h to match generic implementation (John David Anglin) - A few smaller ftrace build fixes - Fixed thuge-gen kernel self test to utilize architectured MAP_HUGETLB value - Added parisc architecture to seccomp_bpf kernel self test - Various typo fixes (Andrea Gelmini) * 'parisc-4.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Whitespace cleanups in unistd.h parisc: Use long jump to reach ftrace_return_to_handler() parisc: Fix typo in fpudispatch.c parisc: Fix typos in eisa_eeprom.h parisc: Fix typo in ldcw.h parisc: Fix typo in pdc.h parisc: Update futex.h to match generic implementation parisc: Merge ftrace C-helper and assembler functions into .text.hot section selftests/thuge-gen: Use platform specific MAP_HUGETLB value parisc: Add native high-resolution sched_clock() implementation parisc: Add ARCH_TRACEHOOK and regset support parisc: Add 64bit get_user() and put_user() for 32bit kernel parisc: Simplify and speed up get_user() and put_user() parisc: Add syscall tracepoint support
2016-05-25parisc: Whitespace cleanups in unistd.hHelge Deller
Clean up whitespaces and mark unused syscalls as such. Signed-off-by: Helge Deller <deller@gmx.de>
2016-05-25sched/core: Fix remote wakeupsPeter Zijlstra
Commit: b5179ac70de8 ("sched/fair: Prepare to fix fairness problems on migration") ... introduced a bug: Mike Galbraith found that it introduced a performance regression, while Paul E. McKenney reported lost wakeups and bisected it to this commit. The reason is that I mis-read ttwu_queue() such that I assumed any wakeup that got a remote queue must have had the task migrated. Since this is not so; we need to transfer this information between queueing the wakeup and actually doing the wakeup. Use a new task_struct::sched_flag for this, we already write to sched_contributes_to_load in the wakeup path so this is a hot and modified cacheline. Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com> Tested-by: Mike Galbraith <umgwanakikbuti@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Hunter <ahh@google.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul Turner <pjt@google.com> Cc: Pavan Kondeti <pkondeti@codeaurora.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: byungchul.park@lge.com Fixes: b5179ac70de8 ("sched/fair: Prepare to fix fairness problems on migration") Link: http://lkml.kernel.org/r/20160523091907.GD15728@worktop.ger.corp.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-24Merge tag 'armsoc-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC fixes from Arnd Bergmann: "This is a first set of bug fixes on top of what was merged for 4.7. Two patches for lpc32xx address a harmless build warning that was just introduced, one patch for the mediatek soc driver fixes a warning for arm64, and the pxa changes are minor cleanups that should have been part of the original pull requests but that I forgot to apply to the cleanup-fixes branch earlier" * tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: ARM: lpc32xx: fix NR_IRQS confict ARM: lpc32xx: remove legacy irq controller driver soc: mtk-pmic-wrap: avoid integer overflow warning ARM: pxa: Remove CLK_IS_ROOT ARM: pxa: activate pinctrl for device-tree machines
2016-05-24Merge tag 'armsoc-late' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull ARM SoC late DT updates from Arnd Bergmann: "This is a collection of a few late fixes and other misc stuff that had dependencies on things being merged from other trees. The Renesas R-Car power domain handling, and the Nvidia Tegra USB support both hand notable changes that required changing the DT binding in a way that only provides compatibility with old DT blobs on new kernels but not vice versa. As a consequence, the DT changes are based on top of the driver changes and are now in this branch. For NXP i.MX and Samsung Exynos, the changes in here depend on other changes that got merged through the clk maintainer tree" * tag 'armsoc-late' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (35 commits) ARM: dts: exynos: Add support of Bus frequency using VDD_INT for exynos5422-odroidxu3 ARM: dts: exynos: Add bus nodes using VDD_INT for Exynos542x SoC ARM: dts: exynos: Add NoC Probe dt node for Exynos542x SoC ARM: dts: exynos: Add support of bus frequency for exynos4412-trats/odroidu3 ARM: dts: exynos: Expand the voltage range of buck1/3 regulator for exynos4412-odroidu3 ARM: dts: exynos: Add support of bus frequency using VDD_INT for exynos3250-rinato ARM: dts: exynos: Add exynos4412-ppmu-common dtsi to delete duplicate PPMU nodes ARM: dts: exynos: Add bus nodes using VDD_MIF for Exynos4210 ARM: dts: exynos: Add bus nodes using VDD_INT for Exynos4x12 ARM: dts: exynos: Add bus nodes using VDD_MIF for Exynos4x12 ARM: dts: exynos: Add bus nodes using VDD_INT for Exynos3250 ARM: dts: exynos: Add DMC bus frequency for exynos3250-rinato/monk ARM: dts: exynos: Add DMC bus node for Exynos3250 ARM: tegra: Enable XUSB on Nyan ARM: tegra: Enable XUSB on Jetson TK1 ARM: tegra: Enable XUSB on Venice2 ARM: tegra: Add Tegra124 XUSB controller ARM: tegra: Move Tegra124 to the new XUSB pad controller binding ARM: dts: r8a7794: Use SYSC "always-on" PM Domain ARM: dts: r8a7793: Use SYSC "always-on" PM Domain ...
2016-05-24Merge tag 'asm-generic-4.7' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic Pull asm-generic cleanup from Arnd Bergmann: "I have only one patch for asm-generic in this release, this one is from James Hogan and updates the generic system call table for renameat2 so we don't need to provide both renameat and renameat2 in newly added architectures" * tag 'asm-generic-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: asm-generic: Drop renameat syscall from default list
2016-05-24Merge tag 'nfsd-4.7' of git://linux-nfs.org/~bfields/linuxLinus Torvalds
Pull nfsd updates from Bruce Fields: "A very quiet cycle for nfsd, mainly just an RDMA update from Chuck Lever" * tag 'nfsd-4.7' of git://linux-nfs.org/~bfields/linux: sunrpc: fix stripping of padded MIC tokens svcrpc: autoload rdma module svcrdma: Generalize svc_rdma_xdr_decode_req() svcrdma: Eliminate code duplication in svc_rdma_recvfrom() svcrdma: Drain QP before freeing svcrdma_xprt svcrdma: Post Receives only for forward channel requests svcrdma: Remove superfluous line from rdma_read_chunks() svcrdma: svc_rdma_put_context() is invoked twice in Send error path svcrdma: Do not add XDR padding to xdr_buf page vector svcrdma: Support IPv6 with NFS/RDMA nfsd: handle seqid wraparound in nfsd4_preprocess_layout_stateid Remove unnecessary allocation
2016-05-24Merge tag 'ext4_for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 updates from Ted Ts'o: "Fix a number of bugs, most notably a potential stale data exposure after a crash and a potential BUG_ON crash if a file has the data journalling flag enabled while it has dirty delayed allocation blocks that haven't been written yet. Also fix a potential crash in the new project quota code and a maliciously corrupted file system. In addition, fix some DAX-specific bugs, including when there is a transient ENOSPC situation and races between writes via direct I/O and an mmap'ed segment that could lead to lost I/O. Finally the usual set of miscellaneous cleanups" * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (23 commits) ext4: pre-zero allocated blocks for DAX IO ext4: refactor direct IO code ext4: fix race in transient ENOSPC detection ext4: handle transient ENOSPC properly for DAX dax: call get_blocks() with create == 1 for write faults to unwritten extents ext4: remove unmeetable inconsisteny check from ext4_find_extent() jbd2: remove excess descriptions for handle_s ext4: remove unnecessary bio get/put ext4: silence UBSAN in ext4_mb_init() ext4: address UBSAN warning in mb_find_order_for_block() ext4: fix oops on corrupted filesystem ext4: fix check of dqget() return value in ext4_ioctl_setproject() ext4: clean up error handling when orphan list is corrupted ext4: fix hang when processing corrupted orphaned inode list ext4: remove trailing \n from ext4_warning/ext4_error calls ext4: fix races between changing inode journal mode and ext4_writepages ext4: handle unwritten or delalloc buffers before enabling data journaling ext4: fix jbd2 handle extension in ext4_ext_truncate_extend_restart() ext4: do not ask jbd2 to write data for delalloc buffers jbd2: add support for avoiding data writes during transaction commits ...
2016-05-24ARM: lpc32xx: fix NR_IRQS confictArnd Bergmann
With the change to sparse IRQs, the lpc32xx platform gets a warning about conflicting macros: In file included from arch/arm/mach-lpc32xx/irq.c:31:0: arch/arm/mach-lpc32xx/include/mach/irqs.h:115:0: warning: "NR_IRQS" redefined #define NR_IRQS 96 arch/arm/include/asm/irq.h:9:0: note: this is the location of the previous definition #define NR_IRQS NR_IRQS_LEGACY One such instance was in the old irq driver that is now removed by the previous patch, but any other file including mach/irqs.h still has the issue. Since none of them use this constant, we can just remove the old definition. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Fixes: 8cb17b5ed017 ("irqchip: Add LPC32xx interrupt controller driver")
2016-05-24ARM: lpc32xx: remove legacy irq controller driverVladimir Zapolskiy
New NXP LPC32xx irq chip driver is used instead of a legacy one. [this also fixes a harmless build warning about the NR_IRQS redefinition] Signed-off-by: Vladimir Zapolskiy <vz@mleia.com> Acked-by: Sylvain Lemieux <slemieux.tyco@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2016-05-24Merge tag 'spi-v4.7' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi Pull spi updates from Mark Brown: "Another quiet release for SPI, almost entirely driver specific changes with the diffstat dominated by two new drivers which are about two thirds of it in terms of lines of code: - new drivers for PIC32 standard and SQI controllers - the Cadence driver has had runtime PM support added and quite a few fixes and cleanups - flash-specific accelerated path support now has a feature query interface - the pxa2xx driver has been moved to use the core DMA mapping support" * tag 'spi-v4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (48 commits) spi: pic32-sqi: Fix linker error, undefined reference to `bad_dma_ops' spi: dw-pci: Spelling s/paltforms/platforms/g spi: pic32-sqi: Remove pic32_sqi_setup and pic32_sqi_cleanup spi: Fix simple typo s/impelment/implement spi: rockchip: potential NULL dereference on error spi: zynqmp: disable clocks in error paths spi: Drop unnecessary dependencies on relaxed I/O accessors spi: qup: Add spi_master_put in remove function spi: qup: Handle clocks in pm_runtime suspend and resume spi: st-ssc4: Fix missing spi_master_put in spi_st_probe error paths spi: st-ssc4: Allow compile test build spi: omap2-mcspi: Use dma_request_chan() for requesting DMA channel spi: davinci: Use dma_request_chan() for requesting DMA channel spi: pic32: Fix checking return value of devm_ioremap_resource spi: spi-fsl-dspi: Update DT binding documentation spi: Drop duplicate code to set master->dev.parent spi: pic32: Set proper bits_per_word_mask spi: return error if kmap'd buffers passed to spi_map_buf() spi: core: add hook flash_read_supported to spi_master spi: pic32-sqi: silence array overflow warning ...
2016-05-24Merge tag 'for-linus-20160523' of git://git.infradead.org/linux-mtdLinus Torvalds
Pull MTD updates from Brian Norris: "First cycle with Boris as NAND maintainer! Many (most) bullets stolen from him. Generic: - Migrated NAND LED trigger to be a generic MTD trigger NAND: - Introduction of the "ECC algorithm" concept, to avoid overloading the ECC mode field too much more - Replaced the nand_ecclayout infrastructure with something a little more flexible (finally!) and future proof - Rework of the OMAP GPMC and NAND drivers; the TI folks pulled some of this into their own tree as well - Prepare the sunxi NAND driver to receive DMA support - Handle bitflips in erased pages on GPMI revisions that do not support this in hardware. SPI NOR: - Start using the spi_flash_read() API for SPI drivers that support it (i.e., SPI drivers with special memory-mapped flash modes) And other small scattered improvments" * tag 'for-linus-20160523' of git://git.infradead.org/linux-mtd: (155 commits) mtd: spi-nor: support GigaDevice gd25lq64c mtd: nand_bch: fix spelling of "probably" mtd: brcmnand: respect ECC algorithm set by NAND subsystem gpmi-nand: Handle ECC Errors in erased pages Documentation: devicetree: deprecate "soft_bch" nand-ecc-mode value mtd: nand: add support for "nand-ecc-algo" DT property mtd: mtd: drop NAND_ECC_SOFT_BCH enum value mtd: drop support for NAND_ECC_SOFT_BCH as "soft_bch" mapping mtd: nand: read ECC algorithm from the new field mtd: nand: fsmc: validate ECC setup by checking algorithm directly mtd: nand: set ECC algorithm to Hamming on fallback staging: mt29f_spinand: set ECC algorithm explicitly CRIS v32: nand: set ECC algorithm explicitly mtd: nand: atmel: set ECC algorithm explicitly mtd: nand: davinci: set ECC algorithm explicitly mtd: nand: bf5xx: set ECC algorithm explicitly mtd: nand: omap2: Fix high memory dma prefetch transfer mtd: nand: omap2: Start dma request before enabling prefetch mtd: nandsim: add __init attribute mtd: nand: move of_get_nand_xxx() helpers into nand_base.c ...
2016-05-24Merge tag 'for-linus-4.7-rc0-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen bug fixes from David Vrabel. * tag 'for-linus-4.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: use same main loop for counting and remapping pages xen/events: Don't move disabled irqs xen/x86: actually allocate legacy interrupts on PV guests Xen: don't warn about 2-byte wchar_t in efi xen/gntdev: reduce copy batch size to 16 xen/x86: don't lose event interrupts
2016-05-24Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds
Pull virtio updates from Michael Tsirkin: "Looks like a quiet cycle for virtio. There's a new inorder option for the ringtest tool, and a bugfix for balloon for ppc platforms when using virtio 1 mode" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: ringtest: pass buf != NULL virtio_balloon: fix PFN format for virtio-1 virtio: add inorder option
2016-05-24Merge tag 'nios2-v4.7' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2 Pull nios2 update from Ley Foon Tan: - add order-only DTC dependency to %.dtb target - fix libgcc location detection * tag 'nios2-v4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/lftan/nios2: nios2: Add order-only DTC dependency to %.dtb target nios2: Fix libgcc location detection
2016-05-24Merge tag 'microblaze-4.7-rc1' of git://git.monstr.eu/linux-2.6-microblazeLinus Torvalds
Pull Microblaze updates from Michal Simek: - Wire-up new syscalls - Fix link error * tag 'microblaze-4.7-rc1' of git://git.monstr.eu/linux-2.6-microblaze: microblaze: pci: export isa_io_base to fix link errors microblaze: Wire up userfaultfd, membarrier, mlock2 syscalls
2016-05-24xen: use same main loop for counting and remapping pagesJuergen Gross
Instead of having two functions for cycling through the E820 map in order to count to be remapped pages and remap them later, just use one function with a caller supplied sub-function called for each region to be processed. This eliminates the possibility of a mismatch between both loops which showed up in certain configurations. Suggested-by: Ed Swierk <eswierk@skyportsystems.com> Signed-off-by: Juergen Gross <jgross@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-05-24xen/events: Don't move disabled irqsRoss Lagerwall
Commit ff1e22e7a638 ("xen/events: Mask a moving irq") open-coded irq_move_irq() but left out checking if the IRQ is disabled. This broke resuming from suspend since it tries to move a (disabled) irq without holding the IRQ's desc->lock. Fix it by adding in a check for disabled IRQs. The resulting stacktrace was: kernel BUG at /build/linux-UbQGH5/linux-4.4.0/kernel/irq/migration.c:31! invalid opcode: 0000 [#1] SMP Modules linked in: xenfs xen_privcmd ... CPU: 0 PID: 9 Comm: migration/0 Not tainted 4.4.0-22-generic #39-Ubuntu Hardware name: Xen HVM domU, BIOS 4.6.1-xs125180 05/04/2016 task: ffff88003d75ee00 ti: ffff88003d7bc000 task.ti: ffff88003d7bc000 RIP: 0010:[<ffffffff810e26e2>] [<ffffffff810e26e2>] irq_move_masked_irq+0xd2/0xe0 RSP: 0018:ffff88003d7bfc50 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff88003d40ba00 RCX: 0000000000000001 RDX: 0000000000000001 RSI: 0000000000000100 RDI: ffff88003d40bad8 RBP: ffff88003d7bfc68 R08: 0000000000000000 R09: ffff88003d000000 R10: 0000000000000000 R11: 000000000000023c R12: ffff88003d40bad0 R13: ffffffff81f3a4a0 R14: 0000000000000010 R15: 00000000ffffffff FS: 0000000000000000(0000) GS:ffff88003da00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd4264de624 CR3: 0000000037922000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffff88003d40ba38 0000000000000024 0000000000000000 ffff88003d7bfca0 ffffffff814c8d92 00000010813ef89d 00000000805ea732 0000000000000009 0000000000000024 ffff88003cc39b80 ffff88003d7bfce0 ffffffff814c8f66 Call Trace: [<ffffffff814c8d92>] eoi_pirq+0xb2/0xf0 [<ffffffff814c8f66>] __startup_pirq+0xe6/0x150 [<ffffffff814ca659>] xen_irq_resume+0x319/0x360 [<ffffffff814c7e75>] xen_suspend+0xb5/0x180 [<ffffffff81120155>] multi_cpu_stop+0xb5/0xe0 [<ffffffff811200a0>] ? cpu_stop_queue_work+0x80/0x80 [<ffffffff811203d0>] cpu_stopper_thread+0xb0/0x140 [<ffffffff810a94e6>] ? finish_task_switch+0x76/0x220 [<ffffffff810ca731>] ? __raw_callee_save___pv_queued_spin_unlock+0x11/0x20 [<ffffffff810a3935>] smpboot_thread_fn+0x105/0x160 [<ffffffff810a3830>] ? sort_range+0x30/0x30 [<ffffffff810a0588>] kthread+0xd8/0xf0 [<ffffffff810a04b0>] ? kthread_create_on_node+0x1e0/0x1e0 [<ffffffff8182568f>] ret_from_fork+0x3f/0x70 [<ffffffff810a04b0>] ? kthread_create_on_node+0x1e0/0x1e0 Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-05-24xen/x86: actually allocate legacy interrupts on PV guestsStefano Stabellini
b4ff8389ed14 is incomplete: relies on nr_legacy_irqs() to get the number of legacy interrupts when actually nr_legacy_irqs() returns 0 after probe_8259A(). Use NR_IRQS_LEGACY instead. Signed-off-by: Stefano Stabellini <sstabellini@kernel.org> CC: stable@vger.kernel.org
2016-05-24Xen: don't warn about 2-byte wchar_t in efiArnd Bergmann
The XEN UEFI code has become available on the ARM architecture recently, but now causes a link-time warning: ld: warning: drivers/xen/efi.o uses 2-byte wchar_t yet the output is to use 4-byte wchar_t; use of wchar_t values across objects may fail This seems harmless, because the efi code only uses 2-byte characters when interacting with EFI, so we don't pass on those strings to elsewhere in the system, and we just need to silence the warning. It is not clear to me whether we actually need to build the file with the -fshort-wchar flag, but if we do, then we should also pass --no-wchar-size-warning to the linker, to avoid the warning. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Fixes: 37060935dc04 ("ARM64: XEN: Add a function to initialize Xen specific UEFI runtime services")
2016-05-24xen/gntdev: reduce copy batch size to 16David Vrabel
IOCTL_GNTDEV_GRANT_COPY batches copy operations to reduce the number of hypercalls. The stack is used to avoid a memory allocation in a hot path. However, a batch size of 24 requires more than 1024 bytes of stack which in some configurations causes a compiler warning. xen/gntdev.c: In function ‘gntdev_ioctl_grant_copy’: xen/gntdev.c:949:1: warning: the frame size of 1248 bytes is larger than 1024 bytes [-Wframe-larger-than=] This is a harmless warning as there is still plenty of stack spare, but people keep trying to "fix" it. Reduce the batch size to 16 to reduce stack usage to less than 1024 bytes. This should have minimal impact on performance. Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2016-05-24xen/x86: don't lose event interruptsStefano Stabellini
On slow platforms with unreliable TSC, such as QEMU emulated machines, it is possible for the kernel to request the next event in the past. In that case, in the current implementation of xen_vcpuop_clockevent, we simply return -ETIME. To be precise the Xen returns -ETIME and we pass it on. However the result of this is a missed event, which simply causes the kernel to hang. Instead it is better to always ask the hypervisor for a timer event, even if the timeout is in the past. That way there are no lost interrupts and the kernel survives. To do that, remove the VCPU_SSHOTTMR_future flag. Signed-off-by: Stefano Stabellini <sstabellini@kernel.org> Acked-by: Juergen Gross <jgross@suse.com>
2016-05-24Merge tag 'perf-core-for-mingo-20160523' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent Pull perf/core improvements from Arnaldo Carvalho de Melo: User visible changes: - Add "srcline_from" and "srcline_to" branch sort keys to 'perf top' and 'perf report' (Andi Kleen) Infrastructure changes: - Make 'perf trace' auto-attach fd->name and ptr->name beautifiers based on the name of syscall arguments, this way new syscalls that have 'const char * (path,pathname,filename)' will use the fd->name beautifier (vfs_getname perf probe, if in place) and the 'fd->name' (vfs_getname or via /proc/PID/fd/) (Arnaldo Carvalho de Melo) - Infrastructure to read from a ring buffer in backward write mode (Wang Nan) Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>