commit 1e38da300e1e395a15048b0af1e5305bd91402f6 upstream.
The handling of the might_cancel queueing is not properly protected, so
parallel operations on the file descriptor can race with each other and
lead to list corruptions or use after free.
Protect the context for these operations with a seperate lock.
The wait queue lock cannot be reused for this because that would create a
lock inversion scenario vs. the cancel lock. Replacing might_cancel with an
atomic (atomic_t or atomic bit) does not help either because it still can
race vs. the actual list operation.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "linux-fsdevel@vger.kernel.org"
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701311521430.3457@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* lsk-44/linux-linaro-lsk-v4.4:
Linux 4.4.3
modules: fix modparam async_probe request
module: wrapper for symbol name.
itimers: Handle relative timers with CONFIG_TIME_LOW_RES proper
posix-timers: Handle relative timers with CONFIG_TIME_LOW_RES proper
timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper
prctl: take mmap sem for writing to protect against others
xfs: log mount failures don't wait for buffers to be released
Revert "xfs: clear PF_NOFREEZE for xfsaild kthread"
xfs: inode recovery readahead can race with inode buffer creation
libxfs: pack the agfl header structure so XFS_AGFL_SIZE is correct
ovl: setattr: check permissions before copy-up
ovl: root: copy attr
ovl: check dentry positiveness in ovl_cleanup_whiteouts()
ovl: use a minimal buffer in ovl_copy_xattr
ovl: allow zero size xattr
futex: Drop refcount if requeue_pi() acquired the rtmutex
devm_memremap_release(): fix memremap'd addr handling
ipc/shm: handle removed segments gracefully in shm_mmap()
intel_scu_ipcutil: underflow in scu_reg_access()
mm,thp: khugepaged: call pte flush at the time of collapse
dump_stack: avoid potential deadlocks
radix-tree: fix oops after radix_tree_iter_retry
drivers/hwspinlock: fix race between radix tree insertion and lookup
radix-tree: fix race in gang lookup
MAINTAINERS: return arch/sh to maintained state, with new maintainers
memcg: only free spare array when readers are done
numa: fix /proc/<pid>/numa_maps for hugetlbfs on s390
fs/hugetlbfs/inode.c: fix bugs in hugetlb_vmtruncate_list()
scripts/bloat-o-meter: fix python3 syntax error
dma-debug: switch check from _text to _stext
m32r: fix m32104ut_defconfig build fail
xhci: Fix list corruption in urb dequeue at host removal
Revert "xhci: don't finish a TD if we get a short-transfer event mid TD"
iommu/vt-d: Clear PPR bit to ensure we get more page request interrupts
iommu/vt-d: Fix 64-bit accesses to 32-bit DMAR_GSTS_REG
iommu/vt-d: Fix mm refcounting to hold mm_count not mm_users
iommu/amd: Correct the wrong setting of alias DTE in do_attach
iommu/vt-d: Don't skip PCI devices when disabling IOTLB
Input: vmmouse - fix absolute device registration
string_helpers: fix precision loss for some inputs
Input: i8042 - add Fujitsu Lifebook U745 to the nomux list
Input: elantech - mark protocols v2 and v3 as semi-mt
mm: fix regression in remap_file_pages() emulation
mm: replace vma_lock_anon_vma with anon_vma_lock_read/write
mm: fix mlock accouting
libnvdimm: fix namespace object confusion in is_uuid_busy()
mm: soft-offline: check return value in second __get_any_page() call
perf kvm record/report: 'unprocessable sample' error while recording/reporting guest data
KVM: PPC: Fix ONE_REG AltiVec support
KVM: PPC: Fix emulation of H_SET_DABR/X on POWER8
KVM: arm/arm64: Fix reference to uninitialised VGIC
arm64: dma-mapping: fix handling of devices registered before arch_initcall
ARM: OMAP2+: Fix ppa_zero_params and ppa_por_params for rodata
ARM: OMAP2+: Fix save_secure_ram_context for rodata
ARM: OMAP2+: Fix l2dis_3630 for rodata
ARM: OMAP2+: Fix l2_inv_api_params for rodata
ARM: OMAP2+: Fix wait_dll_lock_timed for rodata
ARM: dts: at91: sama5d4ek: add phy address and IRQ for macb0
ARM: dts: at91: sama5d4 xplained: fix phy0 IRQ type
ARM: dts: at91: sama5d4: fix instance id of DBGU
ARM: dts: at91: sama5d4 xplained: properly mux phy interrupt
ARM: dts: omap5-board-common: enable rtc and charging of backup battery
ARM: dts: Fix omap5 PMIC control lines for RTC writes
ARM: dts: Fix wl12xx missing clocks that cause hangs
ARM: nomadik: fix up SD/MMC DT settings
ARM: 8517/1: ICST: avoid arithmetic overflow in icst_hz()
ARM: 8519/1: ICST: try other dividends than 1
arm64: mm: avoid calling apply_to_page_range on empty range
ARM: mvebu: remove duplicated regulator definition in Armada 388 GP
powerpc/ioda: Set "read" permission when "write" is set
powerpc/powernv: Fix stale PE primary bus
powerpc/eeh: Fix stale cached primary bus
powerpc/eeh: Fix PE location code
SUNRPC: Fixup socket wait for memory
udf: Check output buffer length when converting name to CS0
udf: Prevent buffer overrun with multi-byte characters
udf: limit the maximum number of indirect extents in a row
pNFS/flexfiles: Fix an XDR encoding bug in layoutreturn
nfs: Fix race in __update_open_stateid()
pNFS/flexfiles: Fix an Oopsable typo in ff_mirror_match_fh()
NFS: Fix attribute cache revalidation
cifs: fix erroneous return value
cifs_dbg() outputs an uninitialized buffer in cifs_readdir()
cifs: fix race between call_async() and reconnect()
cifs: Ratelimit kernel log messages
iio: inkern: fix a NULL dereference on error
iio: pressure: mpl115: fix temperature offset sign
iio: light: acpi-als: Report data as processed
iio: dac: mcp4725: set iio name property in sysfs
iio: add IIO_TRIGGER dependency to STK8BA50
iio: add HAS_IOMEM dependency to VF610_ADC
iio-light: Use a signed return type for ltr501_match_samp_freq()
iio:adc:ti_am335x_adc Fix buffered mode by identifying as software buffer.
iio: adis_buffer: Fix out-of-bounds memory access
scsi: fix soft lockup in scsi_remove_target() on module removal
SCSI: Add Marvell Console to VPD blacklist
scsi_dh_rdac: always retry MODE SELECT on command lock violation
drivers/scsi/sg.c: mark VMA as VM_IO to prevent migration
SCSI: fix crashes in sd and sr runtime PM
iscsi-target: Fix potential dead-lock during node acl delete
scsi: add Synology to 1024 sector blacklist
klist: fix starting point removed bug in klist iterators
tracepoints: Do not trace when cpu is offline
tracing: Fix freak link error caused by branch tracer
perf tools: tracepoint_error() can receive e=NULL, robustify it
tools lib traceevent: Fix output of %llu for 64 bit values read on 32 bit machines
ptrace: use fsuid, fsgid, effective creds for fs access checks
Btrfs: fix direct IO requests not reporting IO error to user space
Btrfs: fix hang on extent buffer lock caused by the inode_paths ioctl
Btrfs: fix page reading in extent_same ioctl leading to csum errors
Btrfs: fix invalid page accesses in extent_same (dedup) ioctl
btrfs: properly set the termination value of ctx->pos in readdir
Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"
Btrfs: fix fitrim discarding device area reserved for boot loader's use
btrfs: handle invalid num_stripes in sys_array
ext4: don't read blocks from disk after extents being swapped
ext4: fix potential integer overflow
ext4: fix scheduling in atomic on group checksum failure
serial: omap: Prevent DoS using unprivileged ioctl(TIOCSRS485)
serial: 8250_pci: Add Intel Broadwell ports
tty: Add support for PCIe WCH382 2S multi-IO card
pty: make sure super_block is still valid in final /dev/tty close
pty: fix possible use after free of tty->driver_data
staging/speakup: Use tty_ldisc_ref() for paste kworker
phy: twl4030-usb: Fix unbalanced pm_runtime_enable on module reload
phy: twl4030-usb: Relase usb phy on unload
ALSA: seq: Fix double port list deletion
ALSA: seq: Fix leak of pool buffer at concurrent writes
ALSA: pcm: Fix rwsem deadlock for non-atomic PCM stream
ALSA: hda - Cancel probe work instead of flush at remove
x86/mm: Fix vmalloc_fault() to handle large pages properly
x86/uaccess/64: Handle the caching of 4-byte nocache copies properly in __copy_user_nocache()
x86/uaccess/64: Make the __copy_user_nocache() assembly code more readable
x86/mm/pat: Avoid truncation when converting cpa->numpages to address
x86/mm: Fix types used in pgprot cacheability flags translations
Linux 4.4.2
HID: multitouch: fix input mode switching on some Elan panels
mm, vmstat: fix wrong WQ sleep when memory reclaim doesn't make any progress
zsmalloc: fix migrate_zspage-zs_free race condition
zram: don't call idr_remove() from zram_remove()
zram: try vmalloc() after kmalloc()
zram/zcomp: use GFP_NOIO to allocate streams
rtlwifi: rtl8821ae: Fix 5G failure when EEPROM is incorrectly encoded
rtlwifi: rtl8821ae: Fix errors in parameter initialization
crypto: marvell/cesa - fix test in mv_cesa_dev_dma_init()
crypto: atmel-sha - remove calls of clk_prepare() from atomic contexts
crypto: atmel-sha - fix atmel_sha_remove()
crypto: algif_skcipher - Do not set MAY_BACKLOG on the async path
crypto: algif_skcipher - Do not dereference ctx without socket lock
crypto: algif_skcipher - Do not assume that req is unchanged
crypto: user - lock crypto_alg_list on alg dump
EVM: Use crypto_memneq() for digest comparisons
crypto: algif_hash - wait for crypto_ahash_init() to complete
crypto: shash - Fix has_key setting
crypto: chacha20-ssse3 - Align stack pointer to 64 bytes
crypto: caam - make write transactions bufferable on PPC platforms
crypto: algif_skcipher - sendmsg SG marking is off by one
crypto: algif_skcipher - Load TX SG list after waiting
crypto: crc32c - Fix crc32c soft dependency
crypto: algif_skcipher - Fix race condition in skcipher_check_key
crypto: algif_hash - Fix race condition in hash_check_key
crypto: af_alg - Forbid bind(2) when nokey child sockets are present
crypto: algif_skcipher - Remove custom release parent function
crypto: algif_hash - Remove custom release parent function
crypto: af_alg - Allow af_af_alg_release_parent to be called on nokey path
ahci: Intel DNV device IDs SATA
libata: disable forced PORTS_IMPL for >= AHCI 1.3
crypto: algif_skcipher - Add key check exception for cipher_null
crypto: skcipher - Add crypto_skcipher_has_setkey
crypto: algif_hash - Require setkey before accept(2)
crypto: hash - Add crypto_ahash_has_setkey
crypto: algif_skcipher - Add nokey compatibility path
crypto: af_alg - Add nokey compatibility path
crypto: af_alg - Fix socket double-free when accept fails
crypto: af_alg - Disallow bind/setkey/... after accept(2)
crypto: algif_skcipher - Require setkey before accept(2)
sched: Fix crash in sched_init_numa()
ext4 crypto: add missing locking for keyring_key access
iommu/io-pgtable-arm: Ensure we free the final level on teardown
tty: Fix unsafe ldisc reference via ioctl(TIOCGETD)
tty: Retry failed reopen if tty teardown in-progress
tty: Wait interruptibly for tty lock on reopen
n_tty: Fix unsafe reference to "other" ldisc
usb: xhci: apply XHCI_PME_STUCK_QUIRK to Intel Broxton-M platforms
usb: xhci: handle both SSIC ports in PME stuck quirk
usb: phy: msm: fix error handling in probe.
usb: cdc-acm: send zero packet for intel 7260 modem
usb: cdc-acm: handle unlinked urb in acm read callback
USB: option: fix Cinterion AHxx enumeration
USB: serial: option: Adding support for Telit LE922
USB: cp210x: add ID for IAI USB to RS485 adaptor
USB: serial: ftdi_sio: add support for Yaesu SCU-18 cable
usb: hub: do not clear BOS field during reset device
USB: visor: fix null-deref at probe
USB: serial: visor: fix crash on detecting device without write_urbs
ASoC: rt5645: fix the shift bit of IN1 boost
saa7134-alsa: Only frees registered sound cards
ALSA: dummy: Implement timer backend switching more safely
ALSA: hda - Fix bad dereference of jack object
ALSA: hda - Fix speaker output from VAIO AiO machines
Revert "ALSA: hda - Fix noise on Gigabyte Z170X mobo"
ALSA: hda - Fix static checker warning in patch_hdmi.c
ALSA: hda - Add fixup for Mac Mini 7,1 model
ALSA: timer: Fix race between stop and interrupt
ALSA: timer: Fix wrong instance passed to slave callbacks
ALSA: timer: Fix race at concurrent reads
ALSA: timer: Fix link corruption due to double start or stop
ALSA: timer: Fix leftover link at closing
ALSA: timer: Code cleanup
ALSA: seq: Fix lockdep warnings due to double mutex locks
ALSA: seq: Fix race at closing in virmidi driver
ALSA: seq: Fix yet another races among ALSA timer accesses
ASoC: dpcm: fix the BE state on hw_free
ALSA: pcm: Fix potential deadlock in OSS emulation
ALSA: hda/realtek - Support Dell headset mode for ALC225
ALSA: hda/realtek - Support headset mode for ALC225
ALSA: hda/realtek - New codec support of ALC225
ALSA: rawmidi: Fix race at copying & updating the position
ALSA: rawmidi: Remove kernel WARNING for NULL user-space buffer check
ALSA: rawmidi: Make snd_rawmidi_transmit() race-free
ALSA: seq: Degrade the error message for too many opens
ALSA: seq: Fix incorrect sanity check at snd_seq_oss_synth_cleanup()
ALSA: dummy: Disable switching timer backend via sysfs
ALSA: compress: Disable GET_CODEC_CAPS ioctl for some architectures
ALSA: hda - disable dynamic clock gating on Broxton before reset
ALSA: Add missing dependency on CONFIG_SND_TIMER
ALSA: bebob: Use a signed return type for get_formation_index
ALSA: usb-audio: avoid freeing umidi object twice
ALSA: usb-audio: Add native DSD support for PS Audio NuWave DAC
ALSA: usb-audio: Fix OPPO HA-1 vendor ID
ALSA: usb-audio: Add quirk for Microsoft LifeCam HD-6000
ALSA: usb-audio: Fix TEAC UD-501/UD-503/NT-503 usb delay
hrtimer: Handle remaining time proper for TIME_LOW_RES
md/raid: only permit hot-add of compatible integrity profiles
media: i2c: Don't export ir-kbd-i2c module alias
parisc: Fix __ARCH_SI_PREAMBLE_SIZE
parisc: Protect huge page pte changes with spinlocks
printk: do cond_resched() between lines while outputting to consoles
tracing/stacktrace: Show entire trace if passed in function not found
tracing: Fix stacktrace skip depth in trace_buffer_unlock_commit_regs()
PCI: Fix minimum allocation address overwrite
PCI: host: Mark PCIe/PCI (MSI) IRQ cascade handlers as IRQF_NO_THREAD
mtd: nand: assign reasonable default name for NAND drivers
wlcore/wl12xx: spi: fix NULL pointer dereference (Oops)
wlcore/wl12xx: spi: fix oops on firmware load
ocfs2/dlm: clear refmap bit of recovery lock while doing local recovery cleanup
ocfs2/dlm: ignore cleaning the migration mle that is inuse
ALSA: hda - Implement loopback control switch for Realtek and other codecs
block: fix bio splitting on max sectors
base/platform: Fix platform drivers with no probe callback
HID: usbhid: fix recursive deadlock
ocfs2: NFS hangs in __ocfs2_cluster_lock due to race with ocfs2_unblock_lock
block: split bios to max possible length
NFSv4.1/pnfs: Fixup an lo->plh_block_lgets imbalance in layoutreturn
crypto: sun4i-ss - add missing statesize
Linux 4.4.1
arm64: kernel: fix architected PMU registers unconditional access
arm64: kernel: enforce pmuserenr_el0 initialization and restore
arm64: mm: ensure that the zero page is visible to the page table walker
arm64: Clear out any singlestep state on a ptrace detach operation
powerpc/module: Handle R_PPC64_ENTRY relocations
scripts/recordmcount.pl: support data in text section on powerpc
powerpc: Make {cmp}xchg* and their atomic_ versions fully ordered
powerpc: Make value-returning atomics fully ordered
powerpc/tm: Check for already reclaimed tasks
batman-adv: Drop immediate orig_node free function
batman-adv: Drop immediate batadv_hard_iface free function
batman-adv: Drop immediate neigh_ifinfo free function
batman-adv: Drop immediate batadv_neigh_node free function
batman-adv: Drop immediate batadv_orig_ifinfo free function
batman-adv: Avoid recursive call_rcu for batadv_nc_node
batman-adv: Avoid recursive call_rcu for batadv_bla_claim
team: Replace rcu_read_lock with a mutex in team_vlan_rx_kill_vid
net/mlx5_core: Fix trimming down IRQ number
bridge: fix lockdep addr_list_lock false positive splat
ipv6: update skb->csum when CE mark is propagated
net: bpf: reject invalid shifts
phonet: properly unshare skbs in phonet_rcv()
dwc_eth_qos: Fix dma address for multi-fragment skbs
bonding: Prevent IPv6 link local address on enslaved devices
net: preserve IP control block during GSO segmentation
udp: disallow UFO for sockets with SO_NO_CHECK option
net: pktgen: fix null ptr deref in skb allocation
sched,cls_flower: set key address type when present
tcp_yeah: don't set ssthresh below 2
ipv6: tcp: add rcu locking in tcp_v6_send_synack()
net: sctp: prevent writes to cookie_hmac_alg from accessing invalid memory
vxlan: fix test which detect duplicate vxlan iface
unix: properly account for FDs passed over unix sockets
xhci: refuse loading if nousb is used
usb: core: lpm: fix usb3_hardware_lpm sysfs node
USB: cp210x: add ID for ELV Marble Sound Board 1
rtlwifi: fix memory leak for USB device
ASoC: compress: Fix compress device direction check
ASoC: wm5110: Fix PGA clear when disabling DRE
ALSA: timer: Handle disconnection more safely
ALSA: hda - Flush the pending probe work at remove
ALSA: hda - Fix missing module loading with model=generic option
ALSA: hda - Fix bass pin fixup for ASUS N550JX
ALSA: control: Avoid kernel warnings from tlv ioctl with numid 0
ALSA: hrtimer: Fix stall by hrtimer_cancel()
ALSA: pcm: Fix snd_pcm_hw_params struct copy in compat mode
ALSA: seq: Fix snd_seq_call_port_info_ioctl in compat mode
ALSA: hda - Add fixup for Dell Latitidue E6540
ALSA: timer: Fix double unlink of active_list
ALSA: timer: Fix race among timer ioctls
ALSA: hda - fix the headset mic detection problem for a Dell laptop
ALSA: timer: Harden slave timer list handling
ALSA: usb-audio: Fix mixer ctl regression of Native Instrument devices
ALSA: hda - Fix white noise on Dell Latitude E5550
ALSA: seq: Fix race at timer setup and close
ALSA: usb-audio: Avoid calling usb_autopm_put_interface() at disconnect
ALSA: seq: Fix missing NULL check at remove_events ioctl
ALSA: hda - Fixup inverted internal mic for Lenovo E50-80
ALSA: usb: Add native DSD support for Oppo HA-1
x86/mm: Improve switch_mm() barrier comments
x86/mm: Add barriers and document switch_mm()-vs-flush synchronization
x86/boot: Double BOOT_HEAP_SIZE to 64KB
x86/reboot/quirks: Add iMac10,1 to pci_reboot_dmi_table[]
kvm: x86: Fix vmwrite to SECONDARY_VM_EXEC_CONTROL
KVM: x86: correctly print #AC in traces
KVM: x86: expose MSR_TSC_AUX to userspace
x86/xen: don't reset vcpu_info on a cancelled suspend
KEYS: Fix keyring ref leak in join_session_keyring()
Conflicts:
arch/arm64/kernel/perf_event.c
drivers/scsi/sd.c
sound/core/compress_offload.c
Change-Id: I9f77fe42aaae249c24cd6e170202110ab1426878
Signed-off-by: Trilok Soni <tsoni@codeaurora.org>
Android does not support powering-up the phone through alarm.
Set rtc alarm in timerfd to power-up the phone after alarm
expiration.
Change-Id: I781389c658fb00ba7f0ce089d706c10f202a7dc6
Signed-off-by: Mao Jinlong <c_jmao@codeaurora.org>
commit b62526ed11a1fe3861ab98d40b7fdab8981d788a upstream.
Helge reported that a relative timer can return a remaining time larger than
the programmed relative time on parisc and other architectures which have
CONFIG_TIME_LOW_RES set. This happens because we add a jiffie to the resulting
expiry time to prevent short timeouts.
Use the new function hrtimer_expires_remaining_adjusted() to calculate the
remaining time. It takes that extra added time into account for relative
timers.
Reported-and-tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Link: http://lkml.kernel.org/r/20160114164159.354500742@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
seq_printf functions shouldn't really check the return value.
Checking seq_has_overflowed() occasionally is used instead.
Update vfs documentation.
Link: http://lkml.kernel.org/p/e37e6e7b76acbdcc3bb4ab2a57c8f8ca1ae11b9a.1412031505.git.joe@perches.com
Cc: David S. Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Joe Perches <joe@perches.com>
[ did a few clean ups ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
We would have returned -EINVAL earlier if ticks wasn't set.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Link: http://lkml.kernel.org/r/20140801082848.GF28869@mwanda
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
We have a few other use cases of ktime_get_monotonic_offset() which
can be optimized with ktime_mono_to_real(). The timerfd code uses the
offset only for comparison, so we can use ktime_mono_to_real(0) for
this as well.
Funny enough text size shrinks with that on ARM and x8664 !?
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The read() of timerfd files allows to fetch the number of timer ticks
while there is no way to set it back from userspace.
To restore the timer's state as it was at checkpoint moment we need
a path to bring @ticks back. Initially I thought about writing ticks
back via write() interface but it seems such API is somehow obscure.
Instead implement timerfd_ioctl() method with TFD_IOC_SET_TICKS
command which allows to adjust @ticks into non-zero value waking
up the waiters.
I wrapped code with CONFIG_CHECKPOINT_RESTORE which can be
dropped off if there users except c/r camp appear.
v2 (by akpm@):
- Use define timerfd_ioctl NULL for non c/r config
v3:
- Use copy_from_user for @ticks fetching since
not all arch support get_user for 8 byte argument
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christopher Covington <cov@codeaurora.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Link: http://lkml.kernel.org/r/20140715215703.285617923@openvz.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
For checkpoint/restore of timerfd files we need to know how exactly
the timer were armed, to be able to recreate it on restore stage.
Thus implement show_fdinfo method which provides enough information
for that.
One of significant changes I think is the addition of @settime_flags
member. Currently there are two flags TFD_TIMER_ABSTIME and
TFD_TIMER_CANCEL_ON_SET, and the second can be found from
@might_cancel variable but in case if the flags will be extended
in future we most probably will have to somehow remember them
explicitly anyway so I guss doing that right now won't hurt.
To not bloat the timerfd_ctx structure I've converted @expired
to short integer and defined @settime_flags as short too.
v2 (by avagin@, vdavydov@ and tglx@):
- Add it_value/it_interval fields
- Save flags being used in timerfd_setup in context
v3 (by tglx@):
- don't forget to use CONFIG_PROC_FS
v4 (by akpm@):
-Use define timerfd_show NULL for non c/r config
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Link: http://lkml.kernel.org/r/20140715215703.114365649@openvz.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Add support for clocks CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM,
thereby enabling wakeup alarm timers via file descriptors.
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Both compat syscalls got lost with 9d94b9e2 "switch timerfd compat syscalls
to COMPAT_SYSCALL_DEFINE" because of a typo:
COMPAT instead of CONFIG_COMPAT.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently processes waiting with poll on cancelable timerfd timers are
not woken up when the timers are canceled. When the system time is set
the clock_was_set() function calls timerfd_clock_was_set() to cancel
and wake up processes waiting on potential cancelable timerfd
timers. However the wake up currently has no effect because in the
case of timerfd_read it is dependent on ctx->ticks not being
0. timerfd_poll also requires ctx->ticks being non zero. As a
consequence processes waiting on cancelable timers only get woken up
when the timers expire. This patch fixes this by incrementing
ctx->ticks before calling wake_up.
Signed-off-by: Max Asbock <masbock@linux.vnet.ibm.com>
Cc: kay.sievers@vrfy.org
Cc: virtuoso@slind.org
Cc: johnstul <johnstul@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1307985512.4710.41.camel@w-amax.beaverton.ibm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Peter is concerned about the extra scan of CLOCK_REALTIME_COS in the
timer interrupt. Yes, I did not think about it, because the solution
was so elegant. I didn't like the extra list in timerfd when it was
proposed some time ago, but with a rcu based list the list walk it's
less horrible than the original global lock, which was held over the
list iteration.
Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
Some applications must be aware of clock realtime being set
backward. A simple example is a clock applet which arms a timer for
the next minute display. If clock realtime is set backward then the
applet displays a stale time for the amount of time which the clock
was set backwards. Due to that applications poll the time because we
don't have an interface.
Extend the timerfd interface by adding a flag which puts the timer
onto a different internal realtime clock. All timers on this clock are
expired whenever the clock was set.
The timerfd core records the monotonic offset when the timer is
created. When the timer is armed, then the current offset is compared
to the previous recorded offset. When it has changed, then
timerfd_settime returns -ECANCELED. When a timer is read the offset is
compared and if it changed -ECANCELED returned to user space. Periodic
timers are not rearmed in the cancelation case.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
Cc: Chris Friesen <chris.friesen@genband.com>
Tested-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Reviewed-by: Alexander Shishkin <virtuoso@slind.org>
Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104271359580.3323%40ionos%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.
The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.
New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.
The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.
Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.
Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.
===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}
@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}
@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}
@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}
@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};
@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};
@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};
@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};
@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};
// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};
@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};
// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};
// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};
// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};
@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};
// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////
@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};
@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};
@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};
@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
This patch modifies the fs/timerfd.c to use the newly created
wait_event_interruptible_locked_irq() macro. This replaces an open
code implementation with a single macro call.
Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
It seems a couple places such as arch/ia64/kernel/perfmon.c and
drivers/infiniband/core/uverbs_main.c could use anon_inode_getfile()
instead of a private pseudo-fs + alloc_file(), if only there were a way
to get a read-only file. So provide this by having anon_inode_getfile()
create a read-only file if we pass O_RDONLY in flags.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
As requested by Michael, add a missing check for valid flags in
timerfd_settime(), and make it return EINVAL in case some extra bits are
set.
Michael said:
If this is to be any use to userland apps that want to check flag
support (perhaps it is too late already), then the sooner we get it
into the kernel the better: 2.6.29 would be good; earlier stables as
well would be even better.
[akpm@linux-foundation.org: remove unused TFD_FLAGS_SET]
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: <stable@kernel.org> [2.6.27.x, 2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In order to be able to do range hrtimers we need to use accessor functions
to the "expire" member of the hrtimer struct.
This patch converts timerfd to these accessors.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
This patch adds test that ensure the boundary conditions for the various
constants introduced in the previous patches is met. No code is generated.
[akpm@linux-foundation.org: fix alpha]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The timerfd_create syscall already has a flags parameter. It just is
unused so far. This patch changes this by introducing the TFD_CLOEXEC
flag to set the close-on-exec flag for the returned file descriptor.
A new name TFD_CLOEXEC is introduced which in this implementation must
have the same value as O_CLOEXEC.
The following test must be adjusted for architectures other than x86 and
x86-64 and in case the syscall numbers changed.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <fcntl.h>
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include <sys/syscall.h>
#ifndef __NR_timerfd_create
# ifdef __x86_64__
# define __NR_timerfd_create 283
# elif defined __i386__
# define __NR_timerfd_create 322
# else
# error "need __NR_timerfd_create"
# endif
#endif
#define TFD_CLOEXEC O_CLOEXEC
int
main (void)
{
int fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, 0);
if (fd == -1)
{
puts ("timerfd_create(0) failed");
return 1;
}
int coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if (coe & FD_CLOEXEC)
{
puts ("timerfd_create(0) set close-on-exec flag");
return 1;
}
close (fd);
fd = syscall (__NR_timerfd_create, CLOCK_REALTIME, TFD_CLOEXEC);
if (fd == -1)
{
puts ("timerfd_create(TFD_CLOEXEC) failed");
return 1;
}
coe = fcntl (fd, F_GETFD);
if (coe == -1)
{
puts ("fcntl failed");
return 1;
}
if ((coe & FD_CLOEXEC) == 0)
{
puts ("timerfd_create(TFD_CLOEXEC) set close-on-exec flag");
return 1;
}
close (fd);
puts ("OK");
return 0;
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch just extends the anon_inode_getfd interface to take an additional
parameter with a flag value. The flag value is passed on to
get_unused_fd_flags in anticipation for a use with the O_CLOEXEC flag.
No actual semantic changes here, the changed callers all pass 0 for now.
[akpm@linux-foundation.org: KVM fix]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
a) none of the callers even looks at inode or file returned by anon_inode_getfd()
b) any caller that would try to look at those would be racy, since by the time
it returns we might have raced with close() from another thread and that
file would be pining for fjords.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Every file should include the headers containing the prototypes for its global
functions (in this case for sys_timerfd_*()).
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the new timerfd API as it is implemented by the following patch:
int timerfd_create(int clockid, int flags);
int timerfd_settime(int ufd, int flags,
const struct itimerspec *utmr,
struct itimerspec *otmr);
int timerfd_gettime(int ufd, struct itimerspec *otmr);
The timerfd_create() API creates an un-programmed timerfd fd. The "clockid"
parameter can be either CLOCK_MONOTONIC or CLOCK_REALTIME.
The timerfd_settime() API give new settings by the timerfd fd, by optionally
retrieving the previous expiration time (in case the "otmr" parameter is not
NULL).
The time value specified in "utmr" is absolute, if the TFD_TIMER_ABSTIME bit
is set in the "flags" parameter. Otherwise it's a relative time.
The timerfd_gettime() API returns the next expiration time of the timer, or
{0, 0} if the timerfd has not been set yet.
Like the previous timerfd API implementation, read(2) and poll(2) are
supported (with the same interface). Here's a simple test program I used to
exercise the new timerfd APIs:
http://www.xmailserver.org/timerfd-test2.c
[akpm@linux-foundation.org: coding-style cleanups]
[akpm@linux-foundation.org: fix ia64 build]
[akpm@linux-foundation.org: fix m68k build]
[akpm@linux-foundation.org: fix mips build]
[akpm@linux-foundation.org: fix alpha, arm, blackfin, cris, m68k, s390, sparc and sparc64 builds]
[heiko.carstens@de.ibm.com: fix s390]
[akpm@linux-foundation.org: fix powerpc build]
[akpm@linux-foundation.org: fix sparc64 more]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Davi fixed a missing cast in the __put_user(), that was making timerfd
return a single byte instead of the full value.
Talking with Michael about the timerfd man page, we think it'd be better to
use a u64 for the returned value, to align it with the eventfd
implementation.
This is an ABI change. The timerfd code is new in 2.6.22 and if we merge this
into 2.6.23 then we should also merge it into 2.6.22.x. That will leave a few
early 2.6.22 kernels out in the wild which might misbehave when a future
timerfd-enabled glibc is run on them.
mtk says: The difference would be that read() will only return 4 bytes, while
the application will expect 8. If the application is checking the size of
returned value, as it should, then it will be able to detect the problem (it
could even be sophisticated enough to know that if this is a 4-byte return,
then it is running on an old 2.6.22 kernel). If the application is not
checking the return from read(), then its 8-byte buffer will not be filled --
the contents of the last 4 bytes will be undefined, so the u64 value as a
whole will be junk.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Davi Arnaut <davi@haxent.com.br>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The timerfd was using the unlocked waitqueue operations, but it was
using a different lock, so poll_wait() would race with it.
This makes timerfd directly use the waitqueue lock.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch introduces a new system call for timers events delivered though
file descriptors. This allows timer event to be used with standard POSIX
poll(2), select(2) and read(2). As a consequence of supporting the Linux
f_op->poll subsystem, they can be used with epoll(2) too.
The system call is defined as:
int timerfd(int ufd, int clockid, int flags, const struct itimerspec *utmr);
The "ufd" parameter allows for re-use (re-programming) of an existing timerfd
w/out going through the close/open cycle (same as signalfd). If "ufd" is -1,
s new file descriptor will be created, otherwise the existing "ufd" will be
re-programmed.
The "clockid" parameter is either CLOCK_MONOTONIC or CLOCK_REALTIME. The time
specified in the "utmr->it_value" parameter is the expiry time for the timer.
If the TFD_TIMER_ABSTIME flag is set in "flags", this is an absolute time,
otherwise it's a relative time.
If the time specified in the "utmr->it_interval" is not zero (.tv_sec == 0,
tv_nsec == 0), this is the period at which the following ticks should be
generated.
The "utmr->it_interval" should be set to zero if only one tick is requested.
Setting the "utmr->it_value" to zero will disable the timer, or will create a
timerfd without the timer enabled.
The function returns the new (or same, in case "ufd" is a valid timerfd
descriptor) file, or -1 in case of error.
As stated before, the timerfd file descriptor supports poll(2), select(2) and
epoll(2). When a timer event happened on the timerfd, a POLLIN mask will be
returned.
The read(2) call can be used, and it will return a u32 variable holding the
number of "ticks" that happened on the interface since the last call to
read(2). The read(2) call supportes the O_NONBLOCK flag too, and EAGAIN will
be returned if no ticks happened.
A quick test program, shows timerfd working correctly on my amd64 box:
http://www.xmailserver.org/timerfd-test.c
[akpm@linux-foundation.org: add sys_timerfd to sys_ni.c]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
