1. 16 12月, 2014 2 次提交
    • L
      x86: mm: consolidate VM_FAULT_RETRY handling · 26178ec1
      Linus Torvalds 提交于
      The VM_FAULT_RETRY handling was confusing and incorrect for the case of
      returning to kernel mode.  We need to handle the exception table fixup
      if we return to kernel mode due to a fatal signal - it will basically
      look to the kernel user mode access like the access failed due to the VM
      going away from udner it.  Which is correct - the process is dying - and
      avoids the whole "repeat endless kernel page faults" case.
      
      Handling the VM_FAULT_RETRY early and in just one place also simplifies
      the mmap_sem handling, since once we've taken care of VM_FAULT_RETRY we
      know that we can just drop the lock.  The remaining accounting and
      possible error handling is thread-local and does not need the mmap_sem.
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      26178ec1
    • L
      x86: mm: move mmap_sem unlock from mm_fault_error() to caller · 7fb08eca
      Linus Torvalds 提交于
      This replaces four copies in various stages of mm_fault_error() handling
      with just a single one.  It will also allow for more natural placement
      of the unlocking after some further cleanup.
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7fb08eca
  2. 15 12月, 2014 11 次提交
    • L
      Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security · 67e2c388
      Linus Torvalds 提交于
      Pull security layer updates from James Morris:
       "In terms of changes, there's general maintenance to the Smack,
        SELinux, and integrity code.
      
        The IMA code adds a new kconfig option, IMA_APPRAISE_SIGNED_INIT,
        which allows IMA appraisal to require signatures.  Support for reading
        keys from rootfs before init is call is also added"
      
      * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (23 commits)
        selinux: Remove security_ops extern
        security: smack: fix out-of-bounds access in smk_parse_smack()
        VFS: refactor vfs_read()
        ima: require signature based appraisal
        integrity: provide a hook to load keys when rootfs is ready
        ima: load x509 certificate from the kernel
        integrity: provide a function to load x509 certificate from the kernel
        integrity: define a new function integrity_read_file()
        Security: smack: replace kzalloc with kmem_cache for inode_smack
        Smack: Lock mode for the floor and hat labels
        ima: added support for new kernel cmdline parameter ima_template_fmt
        ima: allocate field pointers array on demand in template_desc_init_fields()
        ima: don't allocate a copy of template_fmt in template_desc_init_fields()
        ima: display template format in meas. list if template name length is zero
        ima: added error messages to template-related functions
        ima: use atomic bit operations to protect policy update interface
        ima: ignore empty and with whitespaces policy lines
        ima: no need to allocate entry for comment
        ima: report policy load status
        ima: use path names cache
        ...
      67e2c388
    • L
      Merge tag 'char-misc-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc · 6ae840e7
      Linus Torvalds 提交于
      Pull char/misc driver updates from Greg KH:
       "Here's the big char/misc driver update for 3.19-rc1
      
        Lots of little things all over the place in different drivers, and a
        new subsystem, "coresight" has been added.  Full details are in the
        shortlog"
      
      * tag 'char-misc-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (73 commits)
        parport: parport_pc, do not remove parent devices early
        spmi: Remove shutdown/suspend/resume kernel-doc
        carma-fpga-program: drop videobuf dependency
        carma-fpga: drop videobuf dependency
        carma-fpga-program.c: fix compile errors
        i8k: Fix temperature bug handling in i8k_get_temp()
        cxl: Name interrupts in /proc/interrupt
        CXL: Return error to PSL if IRQ demultiplexing fails & print clearer warning
        coresight-replicator: remove .owner field for driver
        coresight: fixed comments in coresight.h
        coresight: fix typo in comment in coresight-priv.h
        coresight: bindings for coresight drivers
        coresight: Adding ABI documentation
        w1: support auto-load of w1_bq27000 module.
        w1: avoid potential u16 overflow
        cn: verify msg->len before making callback
        mei: export fw status registers through sysfs
        mei: read and print all six FW status registers
        mei: txe: add cherrytrail device id
        mei: kill cached host and me csr values
        ...
      6ae840e7
    • L
      Merge tag 'driver-core-3.19-rc1' of... · e6b5be2b
      Linus Torvalds 提交于
      Merge tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
      
      Pull driver core update from Greg KH:
       "Here's the set of driver core patches for 3.19-rc1.
      
        They are dominated by the removal of the .owner field in platform
        drivers.  They touch a lot of files, but they are "simple" changes,
        just removing a line in a structure.
      
        Other than that, a few minor driver core and debugfs changes.  There
        are some ath9k patches coming in through this tree that have been
        acked by the wireless maintainers as they relied on the debugfs
        changes.
      
        Everything has been in linux-next for a while"
      
      * tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits)
        Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries"
        fs: debugfs: add forward declaration for struct device type
        firmware class: Deletion of an unnecessary check before the function call "vunmap"
        firmware loader: fix hung task warning dump
        devcoredump: provide a one-way disable function
        device: Add dev_<level>_once variants
        ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries
        ath: use seq_file api for ath9k debugfs files
        debugfs: add helper function to create device related seq_file
        drivers/base: cacheinfo: remove noisy error boot message
        Revert "core: platform: add warning if driver has no owner"
        drivers: base: support cpu cache information interface to userspace via sysfs
        drivers: base: add cpu_device_create to support per-cpu devices
        topology: replace custom attribute macros with standard DEVICE_ATTR*
        cpumask: factor out show_cpumap into separate helper function
        driver core: Fix unbalanced device reference in drivers_probe
        driver core: fix race with userland in device_add()
        sysfs/kernfs: make read requests on pre-alloc files use the buffer.
        sysfs/kernfs: allow attributes to request write buffer be pre-allocated.
        fs: sysfs: return EGBIG on write if offset is larger than file size
        ...
      e6b5be2b
    • L
      Merge tag 'tty-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty · 37da7bbb
      Linus Torvalds 提交于
      Pull tty/serial driver updates from Greg KH:
       "Here's the big tty/serial driver update for 3.19-rc1.
      
        There are a number of TTY core changes/fixes in here from Peter Hurley
        that have all been teted in linux-next for a long time now.  There are
        also the normal serial driver updates as well, full details in the
        changelog below"
      
      * tag 'tty-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (219 commits)
        serial: pxa: hold port.lock when reporting modem line changes
        tty-hvsi_lib: Deletion of an unnecessary check before the function call "tty_kref_put"
        tty: Deletion of unnecessary checks before two function calls
        n_tty: Fix read_buf race condition, increment read_head after pushing data
        serial: of-serial: add PM suspend/resume support
        Revert "serial: of-serial: add PM suspend/resume support"
        Revert "serial: of-serial: fix up PM ops on no_console_suspend and port type"
        serial: 8250: don't attempt a trylock if in sysrq
        serial: core: Add big-endian iotype
        serial: samsung: use port->fifosize instead of hardcoded values
        serial: samsung: prefer to use fifosize from driver data
        serial: samsung: fix style problems
        serial: samsung: wait for transfer completion before clock disable
        serial: icom: fix error return code
        serial: tegra: clean up tty-flag assignments
        serial: Fix io address assign flow with Fintek PCI-to-UART Product
        serial: mxs-auart: fix tx_empty against shift register
        serial: mxs-auart: fix gpio change detection on interrupt
        serial: mxs-auart: Fix mxs_auart_set_ldisc()
        serial: 8250_dw: Use 64-bit access for OCTEON.
        ...
      37da7bbb
    • L
      Merge tag 'usb-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb · e7cf773d
      Linus Torvalds 提交于
      Pull USB updates from Greg KH:
       "Here's the big set of USB and PHY patches for 3.19-rc1.
      
        The normal churn in the USB gadget area is in here, as well as xhci
        and other individual USB driver updates.  The PHY tree is also in
        here, as there were dependancies on the USB tree.
      
        All of these have been in linux-next"
      
      * tag 'usb-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (351 commits)
        arm: omap3: twl: remove usb phy init data
        usbip: fix error handling in stub_probe()
        usb: gadget: udc: missing curly braces
        USB: mos7720: delete some unneeded code
        wusb: replace memset by memzero_explicit
        usbip: remove unneeded structure
        usb: xhci: fix comment for PORT_DEV_REMOVE
        xhci: don't use the same variable for stopped and halted rings current TD
        xhci: clear extra bits from slot context when setting max exit latency
        xhci: cleanup finish_td function
        USB: adutux: NULL dereferences on disconnect
        usb: chipidea: fix platform_no_drv_owner.cocci warnings
        usb: chipidea: Fixed a few typos in comments
        Documentation: bindings: add doc for the USB2 ChipIdea USB driver
        usb: chipidea: add a usb2 driver for ci13xxx
        usb: chipidea: fix phy handling
        usb: chipidea: remove duplicate dev_set_drvdata for host_start
        usb: chipidea: parameter 'mode' isn't needed for hw_device_reset
        usb: chipidea: add controller reset API
        usb: chipidea: remove flag CI_HDRC_REQUIRE_TRANSCEIVER
        ...
      e7cf773d
    • L
      Merge tag 'squashfs-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next · 7a02d089
      Linus Torvalds 提交于
      Pull squashfs update from Phillip Lougher:
       "These patches optionally add LZ4 compression support to Squashfs.
      
        LZ4 is a lightweight compression algorithm which can be used on
        embedded systems to reduce CPU and memory overhead (in comparison to
        the standard zlib compression).
      
        These patches add the wrapper code to allow Squashfs to use the
        existing LZ4 decompression code, and the necessary configuration
        option"
      
      * tag 'squashfs-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next:
        Squashfs: Add LZ4 compression configuration option
        Squashfs: add LZ4 compression support
      7a02d089
    • L
      Merge tag 'gpio-v3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio · 980f3c34
      Linus Torvalds 提交于
      Pull take two of the GPIO updates:
       "Same stuff as last time, now with a fixup patch for the previous
        compile error plus I ran a few extra rounds of compile-testing.
      
        This is the bulk of GPIO changes for the v3.19 series:
      
         - A new API that allows setting more than one GPIO at the time.  This
           is implemented for the new descriptor-based API only and makes it
           possible to e.g. toggle a clock and data line at the same time, if
           the hardware can do this with a single register write.  Both
           consumers and drivers need new calls, and the core will fall back
           to driving individual lines where needed.  Implemented for the
           MPC8xxx driver initially
      
         - Patched the mdio-mux-gpio and the serial mctrl driver that drives
           modems to use the new multiple-setting API to set several signals
           simultaneously
      
         - Get rid of the global GPIO descriptor array, and instead allocate
           descriptors dynamically for each GPIO on a certain GPIO chip.  This
           moves us closer to getting rid of the limitation of using the
           global, static GPIO numberspace
      
         - New driver and device tree bindings for 74xx ICs
      
         - New driver and device tree bindings for the VF610 Vybrid
      
         - Support the RCAR r8a7793 and r8a7794
      
         - Guidelines for GPIO device tree bindings trying to get things a bit
           more strict with the advent of combined device properties
      
         - Suspend/resume support for the MVEBU driver
      
         - A slew of minor fixes and improvements"
      
      * tag 'gpio-v3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (33 commits)
        gpio: mcp23s08: fix up compilation error
        gpio: pl061: document gpio-ranges property for bindings file
        gpio: pl061: hook request if gpio-ranges avaiable
        gpio: mcp23s08: Add option to configure IRQ output polarity as active high
        gpio: fix deferred probe detection for legacy API
        serial: mctrl_gpio: use gpiod_set_array function
        mdio-mux-gpio: Use GPIO descriptor interface and new gpiod_set_array function
        gpio: remove const modifier from gpiod_get_direction()
        gpio: remove gpio_descs global array
        gpio: mxs: implement get_direction callback
        gpio: em: Use dynamic allocation of GPIOs
        gpio: Check if base is positive before calling gpio_is_valid()
        gpio: mcp23s08: Add simple IRQ support for SPI devices
        gpio: mcp23s08: request a shared interrupt
        gpio: mcp23s08: Do not free unrequested interrupt
        gpio: rcar: Add r8a7793 and r8a7794 support
        gpio-mpc8xxx: add mpc8xxx_gpio_set_multiple function
        gpiolib: allow simultaneous setting of multiple GPIO outputs
        gpio: mvebu: add suspend/resume support
        gpio: gpio-davinci: remove duplicate check on resource
        ..
      980f3c34
    • L
      Merge git://git.kvack.org/~bcrl/aio-next · 7d22286f
      Linus Torvalds 提交于
      Pull aio updates from Benjamin LaHaise.
      
      * git://git.kvack.org/~bcrl/aio-next:
        aio: Skip timer for io_getevents if timeout=0
        aio: Make it possible to remap aio ring
      7d22286f
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      Merge branch 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux · 96895199
      Linus Torvalds 提交于
      Pull i2c updates from Wolfram Sang:
       "For 3.19, the I2C subsystem has to offer special candy this time.
        Right in time for Christmas :)
      
         - I2C slave framework: finally, a generic mechanism for Linux being
           an I2C slave (if the bus driver supports that).  Docs are still
           missing but will come later this cycle, the code is good enough to
           go.
         - I2C muxes represent their topology in sysfs much more detailed.
           This will help users to navigate around much easier.
         - irq population of i2c clients is now done at probe time, not device
           creation time, to have better support for deferred probing.
         - new drivers for Imagination SCB, Amlogic Meson
         - DMA support added for Freescale IMX, Renesas SHMobile
         - slightly bigger driver updates to OMAP, i801, AT91, and rk3x
           (mostly quirk handling, timing updates, and using better kernel
           interfaces)
         - eeprom driver can now write with byte-access (very slow, but OK to
           have)
         - and the bunch of smaller fixes, cleanups, ID updates..."
      
      * 'i2c/for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (56 commits)
        i2c: sh_mobile: remove unneeded DMA mask
        i2c: rcar: add slave support
        i2c: slave-eeprom: add eeprom simulator driver
        i2c: core changes for slave support
        MAINTAINERS: add I2C dt bindings also to I2C realm
        i2c: designware: Fix falling time bindings doc
        i2c: davinci: switch to use platform_get_irq
        Documentation: i2c: Use PM ops instead of legacy suspend/resume
        i2c: sh_mobile: optimize irq entry
        i2c: pxa: add support for SCCB devices
        omap: i2c: don't check bus state IP rev3.3 and earlier
        i2c: s3c2410: Handle i2c sys_cfg register in i2c driver
        i2c: rk3x: add Kconfig dependency on COMMON_CLK
        i2c: omap: add notes related to i2c multimaster mode
        i2c: omap: don't reset controller if Arbitration Lost detected
        i2c: omap: implement workaround for handling invalid BB-bit values
        i2c: omap: cleanup register definitions
        i2c: rk3x: handle dynamic clock rate changes correctly
        i2c: at91: enable probe deferring on dma channel request
        i2c: at91: remove legacy DMA support
        ...
      96895199
    • L
      Merge tag 'md/3.19' of git://neil.brown.name/md · 8fd9589c
      Linus Torvalds 提交于
      Pull md updates from Neil Brown:
       "Three fixes for md.
      
         I did have a largish set of locking changes queued, but late testing
        showed they weren't quite as stable as I thought and while I fixed
        what I found, I decided it safer to delay them a release ...
        particularly as I'll be AFK for a few weeks.  So expect a larger batch
        next time :-)"
      
      * tag 'md/3.19' of git://neil.brown.name/md:
        md: Check MD_RECOVERY_RUNNING as well as ->sync_thread.
        md: fix semicolon.cocci warnings
        md/raid5: fetch_block must fetch all the blocks handle_stripe_dirtying wants.
      8fd9589c
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      Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 536e89ee
      Linus Torvalds 提交于
      Pull x86 fixes from Ingo Molnar:
       "Misc fixes (mainly Andy's TLS fixes), plus a cleanup"
      
      * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        x86/tls: Disallow unusual TLS segments
        x86/tls: Validate TLS entries to protect espfix
        MAINTAINERS: Add me as x86 VDSO submaintainer
        x86/asm: Unify segment selector defines
        x86/asm: Guard against building the 32/64-bit versions of the asm-offsets*.c file directly
        x86_64, switch_to(): Load TLS descriptors before switching DS and ES
        x86/mm: Use min() instead of min_t() in the e820 printout code
        x86/mm: Fix zone ranges boot printout
        x86/doc: Update documentation after file shuffling
      536e89ee
  3. 14 12月, 2014 27 次提交
    • A
      x86/tls: Disallow unusual TLS segments · 0e58af4e
      Andy Lutomirski 提交于
      Users have no business installing custom code segments into the
      GDT, and segments that are not present but are otherwise valid
      are a historical source of interesting attacks.
      
      For completeness, block attempts to set the L bit.  (Prior to
      this patch, the L bit would have been silently dropped.)
      
      This is an ABI break.  I've checked glibc, musl, and Wine, and
      none of them look like they'll have any trouble.
      
      Note to stable maintainers: this is a hardening patch that fixes
      no known bugs.  Given the possibility of ABI issues, this
      probably shouldn't be backported quickly.
      Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
      Acked-by: NH. Peter Anvin <hpa@zytor.com>
      Cc: stable@vger.kernel.org # optional
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: security@kernel.org <security@kernel.org>
      Cc: Willy Tarreau <w@1wt.eu>
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      0e58af4e
    • A
      x86/tls: Validate TLS entries to protect espfix · 41bdc785
      Andy Lutomirski 提交于
      Installing a 16-bit RW data segment into the GDT defeats espfix.
      AFAICT this will not affect glibc, Wine, or dosemu at all.
      Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
      Acked-by: NH. Peter Anvin <hpa@zytor.com>
      Cc: stable@vger.kernel.org
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: security@kernel.org <security@kernel.org>
      Cc: Willy Tarreau <w@1wt.eu>
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      41bdc785
    • A
    • F
      aio: Skip timer for io_getevents if timeout=0 · 5f785de5
      Fam Zheng 提交于
      In this case, it is basically a polling. Let's not involve timer at all
      because that would hurt performance for application event loops.
      
      In an arbitrary test I've done, io_getevents syscall elapsed time
      reduces from 50000+ nanoseconds to a few hundereds.
      Signed-off-by: NFam Zheng <famz@redhat.com>
      Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
      5f785de5
    • P
      aio: Make it possible to remap aio ring · e4a0d3e7
      Pavel Emelyanov 提交于
      There are actually two issues this patch addresses. Let me start with
      the one I tried to solve in the beginning.
      
      So, in the checkpoint-restore project (criu) we try to dump tasks'
      state and restore one back exactly as it was. One of the tasks' state
      bits is rings set up with io_setup() call. There's (almost) no problems
      in dumping them, there's a problem restoring them -- if I dump a task
      with aio ring originally mapped at address A, I want to restore one
      back at exactly the same address A. Unfortunately, the io_setup() does
      not allow for that -- it mmaps the ring at whatever place mm finds
      appropriate (it calls do_mmap_pgoff() with zero address and without
      the MAP_FIXED flag).
      
      To make restore possible I'm going to mremap() the freshly created ring
      into the address A (under which it was seen before dump). The problem is
      that the ring's virtual address is passed back to the user-space as the
      context ID and this ID is then used as search key by all the other io_foo()
      calls. Reworking this ID to be just some integer doesn't seem to work, as
      this value is already used by libaio as a pointer using which this library
      accesses memory for aio meta-data.
      
      So, to make restore work we need to make sure that
      
      a) ring is mapped at desired virtual address
      b) kioctx->user_id matches this value
      
      Having said that, the patch makes mremap() on aio region update the
      kioctx's user_id and mmap_base values.
      
      Here appears the 2nd issue I mentioned in the beginning of this mail.
      If (regardless of the C/R dances I do) someone creates an io context
      with io_setup(), then mremap()-s the ring and then destroys the context,
      the kill_ioctx() routine will call munmap() on wrong (old) address.
      This will result in a) aio ring remaining in memory and b) some other
      vma get unexpectedly unmapped.
      
      What do you think?
      Signed-off-by: NPavel Emelyanov <xemul@parallels.com>
      Acked-by: NDmitry Monakhov <dmonakhov@openvz.org>
      Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
      e4a0d3e7
    • L
      Merge branch 'for-3.19/drivers' of git://git.kernel.dk/linux-block · 9ea18f8c
      Linus Torvalds 提交于
      Pull block layer driver updates from Jens Axboe:
      
       - NVMe updates:
              - The blk-mq conversion from Matias (and others)
      
              - A stack of NVMe bug fixes from the nvme tree, mostly from Keith.
      
              - Various bug fixes from me, fixing issues in both the blk-mq
                conversion and generic bugs.
      
              - Abort and CPU online fix from Sam.
      
              - Hot add/remove fix from Indraneel.
      
       - A couple of drbd fixes from the drbd team (Andreas, Lars, Philipp)
      
       - With the generic IO stat accounting from 3.19/core, converting md,
         bcache, and rsxx to use those.  From Gu Zheng.
      
       - Boundary check for queue/irq mode for null_blk from Matias.  Fixes
         cases where invalid values could be given, causing the device to hang.
      
       - The xen blkfront pull request, with two bug fixes from Vitaly.
      
      * 'for-3.19/drivers' of git://git.kernel.dk/linux-block: (56 commits)
        NVMe: fix race condition in nvme_submit_sync_cmd()
        NVMe: fix retry/error logic in nvme_queue_rq()
        NVMe: Fix FS mount issue (hot-remove followed by hot-add)
        NVMe: fix error return checking from blk_mq_alloc_request()
        NVMe: fix freeing of wrong request in abort path
        xen/blkfront: remove redundant flush_op
        xen/blkfront: improve protection against issuing unsupported REQ_FUA
        NVMe: Fix command setup on IO retry
        null_blk: boundary check queue_mode and irqmode
        block/rsxx: use generic io stats accounting functions to simplify io stat accounting
        md: use generic io stats accounting functions to simplify io stat accounting
        drbd: use generic io stats accounting functions to simplify io stat accounting
        md/bcache: use generic io stats accounting functions to simplify io stat accounting
        NVMe: Update module version major number
        NVMe: fail pci initialization if the device doesn't have any BARs
        NVMe: add ->exit_hctx() hook
        NVMe: make setup work for devices that don't do INTx
        NVMe: enable IO stats by default
        NVMe: nvme_submit_async_admin_req() must use atomic rq allocation
        NVMe: replace blk_put_request() with blk_mq_free_request()
        ...
      9ea18f8c
    • L
      Merge branch 'for-3.19/core' of git://git.kernel.dk/linux-block · caf292ae
      Linus Torvalds 提交于
      Pull block driver core update from Jens Axboe:
       "This is the pull request for the core block IO changes for 3.19.  Not
        a huge round this time, mostly lots of little good fixes:
      
         - Fix a bug in sysfs blktrace interface causing a NULL pointer
           dereference, when enabled/disabled through that API.  From Arianna
           Avanzini.
      
         - Various updates/fixes/improvements for blk-mq:
      
              - A set of updates from Bart, mostly fixing buts in the tag
                handling.
      
              - Cleanup/code consolidation from Christoph.
      
              - Extend queue_rq API to be able to handle batching issues of IO
                requests. NVMe will utilize this shortly. From me.
      
              - A few tag and request handling updates from me.
      
              - Cleanup of the preempt handling for running queues from Paolo.
      
              - Prevent running of unmapped hardware queues from Ming Lei.
      
              - Move the kdump memory limiting check to be in the correct
                location, from Shaohua.
      
              - Initialize all software queues at init time from Takashi. This
                prevents a kobject warning when CPUs are brought online that
                weren't online when a queue was registered.
      
         - Single writeback fix for I_DIRTY clearing from Tejun.  Queued with
           the core IO changes, since it's just a single fix.
      
         - Version X of the __bio_add_page() segment addition retry from
           Maurizio.  Hope the Xth time is the charm.
      
         - Documentation fixup for IO scheduler merging from Jan.
      
         - Introduce (and use) generic IO stat accounting helpers for non-rq
           drivers, from Gu Zheng.
      
         - Kill off artificial limiting of max sectors in a request from
           Christoph"
      
      * 'for-3.19/core' of git://git.kernel.dk/linux-block: (26 commits)
        bio: modify __bio_add_page() to accept pages that don't start a new segment
        blk-mq: Fix uninitialized kobject at CPU hotplugging
        blktrace: don't let the sysfs interface remove trace from running list
        blk-mq: Use all available hardware queues
        blk-mq: Micro-optimize bt_get()
        blk-mq: Fix a race between bt_clear_tag() and bt_get()
        blk-mq: Avoid that __bt_get_word() wraps multiple times
        blk-mq: Fix a use-after-free
        blk-mq: prevent unmapped hw queue from being scheduled
        blk-mq: re-check for available tags after running the hardware queue
        blk-mq: fix hang in bt_get()
        blk-mq: move the kdump check to blk_mq_alloc_tag_set
        blk-mq: cleanup tag free handling
        blk-mq: use 'nr_cpu_ids' as highest CPU ID count for hwq <-> cpu map
        blk: introduce generic io stat accounting help function
        blk-mq: handle the single queue case in blk_mq_hctx_next_cpu
        genhd: check for int overflow in disk_expand_part_tbl()
        blk-mq: add blk_mq_free_hctx_request()
        blk-mq: export blk_mq_free_request()
        blk-mq: use get_cpu/put_cpu instead of preempt_disable/preempt_enable
        ...
      caf292ae
    • L
      Merge tag 'trace-seq-buf-3.19-v2' of... · 8f4385d5
      Linus Torvalds 提交于
      Merge tag 'trace-seq-buf-3.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
      
      Pull tracing fixlet from Steven Rostedt:
       "Remove unnecessary preempt_disable in printk()"
      
      * tag 'trace-seq-buf-3.19-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
        printk: Do not disable preemption for accessing printk_func
      8f4385d5
    • L
      Merge tag 'trace-fixes-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace · 52bb4525
      Linus Torvalds 提交于
      Pull tracing fixes from Steven Rostedt:
       "Here's two fixes:
      
        1) Discovered by Fengguang Wu's tests.  I changed the parameters to
           the function graph x86 prepare_ftrace_return call but forgot to
           update the call from entry_32 (i386 version).  This patch corrects
           that.
      
        2) I was tracing some code and found that the sched_switch tracepoint
           was showing tasks in the INTERRUPTIBLE state as RUNNING.  This was
           due to the updates to convert preempt_count into a per_cpu
           variable.  The tracepoint logic was made to use the tasks
           saved_preempt_count which could hold a stale "PREEMPT_ACTIVE",
           instead of using the current preempt_count() call"
      
      * tag 'trace-fixes-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
        tracing/sched: Check preempt_count() for current when reading task->state
        ftrace/x86: Update i386 call to prepare_ftrace_return()
      52bb4525
    • L
      Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit · a99abce2
      Linus Torvalds 提交于
      Pull audit updates from Paul Moore:
       "Two small patches from the audit next branch; only one of which has
        any real significant code changes, the other is simply a MAINTAINERS
        update for audit.
      
        The single code patch is pretty small and rather straightforward, it
        changes the audit "version" number reported to userspace from an
        integer to a bitmap which is used to indicate the functionality of the
        running kernel.  This really doesn't have much impact on the kernel,
        but it will make life easier for the audit userspace folks.
      
        Thankfully we were still on a version number which allowed us to do
        this without breaking userspace"
      
      * 'upstream' of git://git.infradead.org/users/pcmoore/audit:
        audit: convert status version to a feature bitmap
        audit: add Paul Moore to the MAINTAINERS entry
      a99abce2
    • L
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 · e3aa91a7
      Linus Torvalds 提交于
      Pull crypto update from Herbert Xu:
       - The crypto API is now documented :)
       - Disallow arbitrary module loading through crypto API.
       - Allow get request with empty driver name through crypto_user.
       - Allow speed testing of arbitrary hash functions.
       - Add caam support for ctr(aes), gcm(aes) and their derivatives.
       - nx now supports concurrent hashing properly.
       - Add sahara support for SHA1/256.
       - Add ARM64 version of CRC32.
       - Misc fixes.
      
      * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (77 commits)
        crypto: tcrypt - Allow speed testing of arbitrary hash functions
        crypto: af_alg - add user space interface for AEAD
        crypto: qat - fix problem with coalescing enable logic
        crypto: sahara - add support for SHA1/256
        crypto: sahara - replace tasklets with kthread
        crypto: sahara - add support for i.MX53
        crypto: sahara - fix spinlock initialization
        crypto: arm - replace memset by memzero_explicit
        crypto: powerpc - replace memset by memzero_explicit
        crypto: sha - replace memset by memzero_explicit
        crypto: sparc - replace memset by memzero_explicit
        crypto: algif_skcipher - initialize upon init request
        crypto: algif_skcipher - removed unneeded code
        crypto: algif_skcipher - Fixed blocking recvmsg
        crypto: drbg - use memzero_explicit() for clearing sensitive data
        crypto: drbg - use MODULE_ALIAS_CRYPTO
        crypto: include crypto- module prefix in template
        crypto: user - add MODULE_ALIAS
        crypto: sha-mb - remove a bogus NULL check
        crytpo: qat - Fix 64 bytes requests
        ...
      e3aa91a7
    • L
      Merge branch 'akpm' (second patch-bomb from Andrew) · 78a45c6f
      Linus Torvalds 提交于
      Merge second patchbomb from Andrew Morton:
       - the rest of MM
       - misc fs fixes
       - add execveat() syscall
       - new ratelimit feature for fault-injection
       - decompressor updates
       - ipc/ updates
       - fallocate feature creep
       - fsnotify cleanups
       - a few other misc things
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (99 commits)
        cgroups: Documentation: fix trivial typos and wrong paragraph numberings
        parisc: percpu: update comments referring to __get_cpu_var
        percpu: update local_ops.txt to reflect this_cpu operations
        percpu: remove __get_cpu_var and __raw_get_cpu_var macros
        fsnotify: remove destroy_list from fsnotify_mark
        fsnotify: unify inode and mount marks handling
        fallocate: create FAN_MODIFY and IN_MODIFY events
        mm/cma: make kmemleak ignore CMA regions
        slub: fix cpuset check in get_any_partial
        slab: fix cpuset check in fallback_alloc
        shmdt: use i_size_read() instead of ->i_size
        ipc/shm.c: fix overly aggressive shmdt() when calls span multiple segments
        ipc/msg: increase MSGMNI, remove scaling
        ipc/sem.c: increase SEMMSL, SEMMNI, SEMOPM
        ipc/sem.c: change memory barrier in sem_lock() to smp_rmb()
        lib/decompress.c: consistency of compress formats for kernel image
        decompress_bunzip2: off by one in get_next_block()
        usr/Kconfig: make initrd compression algorithm selection not expert
        fault-inject: add ratelimit option
        ratelimit: add initialization macro
        ...
      78a45c6f
    • S
      cgroups: Documentation: fix trivial typos and wrong paragraph numberings · 29d293b6
      SeongJae Park 提交于
      Signed-off-by: NSeongJae Park <sj38.park@gmail.com>
      Cc: Jonathan Corbet <corbet@lwn.net>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      29d293b6
    • C
      parisc: percpu: update comments referring to __get_cpu_var · 6ddb798f
      Christoph Lameter 提交于
      __get_cpu_var was removed. Update comments to refer to
      this_cpu_ptr() instead.
      Signed-off-by: NChristoph Lameter <cl@linux.com>
      Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6ddb798f
    • C
      percpu: update local_ops.txt to reflect this_cpu operations · 7d94a82e
      Christoph Lameter 提交于
      Update the documentation to reflect changes due to the availability of
      this_cpu operations.
      Signed-off-by: NChristoph Lameter <cl@linux.com>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7d94a82e
    • C
      percpu: remove __get_cpu_var and __raw_get_cpu_var macros · 6c51ec4d
      Christoph Lameter 提交于
      No user is left in the kernel source tree.  Therefore we can drop the
      definitions.
      
      This is the final merge of the transition away from __get_cpu_var.  After
      this patch the kernel will not build if anyone uses __get_cpu_var.
      Signed-off-by: NChristoph Lameter <cl@linux.com>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6c51ec4d
    • J
      fsnotify: remove destroy_list from fsnotify_mark · 37d469e7
      Jan Kara 提交于
      destroy_list is used to track marks which still need waiting for srcu
      period end before they can be freed.  However by the time mark is added to
      destroy_list it isn't in group's list of marks anymore and thus we can
      reuse fsnotify_mark->g_list for queueing into destroy_list.  This saves
      two pointers for each fsnotify_mark.
      Signed-off-by: NJan Kara <jack@suse.cz>
      Cc: Eric Paris <eparis@redhat.com>
      Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      37d469e7
    • J
      fsnotify: unify inode and mount marks handling · 0809ab69
      Jan Kara 提交于
      There's a lot of common code in inode and mount marks handling.  Factor it
      out to a common helper function.
      Signed-off-by: NJan Kara <jack@suse.cz>
      Cc: Eric Paris <eparis@redhat.com>
      Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0809ab69
    • H
      fallocate: create FAN_MODIFY and IN_MODIFY events · 820c12d5
      Heinrich Schuchardt 提交于
      The fanotify and the inotify API can be used to monitor changes of the
      file system.  System call fallocate() modifies files.  Hence it should
      trigger the corresponding fanotify (FAN_MODIFY) and inotify (IN_MODIFY)
      events.  The most interesting case is FALLOC_FL_COLLAPSE_RANGE because
      this value allows to create arbitrary file content from random data.
      
      This patch adds the missing call to fsnotify_modify().
      
      The FAN_MODIFY and IN_MODIFY event will be created when fallocate()
      succeeds.  It will even be created if the file length remains unchanged,
      e.g.  when calling fanotify with flag FALLOC_FL_KEEP_SIZE.
      
      This logic was primarily chosen to keep the coding simple.
      
      It resembles the logic of the write() system call.
      
      When we call write() we always create a FAN_MODIFY event, even in the case
      of overwriting with identical data.
      
      Events FAN_MODIFY and IN_MODIFY do not provide any guarantee that data was
      actually changed.
      
      Furthermore even if if the filesize remains unchanged, fallocate() may
      influence whether a subsequent write() will succeed and hence the
      fallocate() call may be considered a modification.
      
      The fallocate(2) man page teaches: After a successful call, subsequent
      writes into the range specified by offset and len are guaranteed not to
      fail because of lack of disk space.
      
      So calling fallocate(fd, FALLOC_FL_KEEP_SIZE, offset, len) may result in
      different outcomes of a subsequent write depending on the values of offset
      and len.
      Signed-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
      Reviewed-by: NJan Kara <jack@suse.cz>
      Cc: Jan Kara <jack@suse.cz>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Eric Paris <eparis@parisplace.org>
      Cc: John McCutchan <john@johnmccutchan.com>
      Cc: Robert Love <rlove@rlove.org>
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: Theodore Ts'o <tytso@mit.edu>
      Cc: Dave Chinner <david@fromorbit.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      820c12d5
    • T
      mm/cma: make kmemleak ignore CMA regions · 620951e2
      Thierry Reding 提交于
      kmemleak will add allocations as objects to a pool.  The memory allocated
      for each object in this pool is periodically searched for pointers to
      other allocated objects.  This only works for memory that is mapped into
      the kernel's virtual address space, which happens not to be the case for
      most CMA regions.
      
      Furthermore, CMA regions are typically used to store data transferred to
      or from a device and therefore don't contain pointers to other objects.
      
      Without this, the kernel crashes on the first execution of the
      scan_gray_list() because it tries to access highmem.  Perhaps a more
      appropriate fix would be to reject any object that can't map to a kernel
      virtual address?
      
      [akpm@linux-foundation.org: add comment]
      [akpm@linux-foundation.org: fix comment, per Catalin]
      [sfr@canb.auug.org.au: include linux/io.h for phys_to_virt()]
      Signed-off-by: NThierry Reding <treding@nvidia.com>
      Cc: Michal Nazarewicz <mina86@mina86.com>
      Cc: Marek Szyprowski <m.szyprowski@samsung.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      620951e2
    • V
      slub: fix cpuset check in get_any_partial · dee2f8aa
      Vladimir Davydov 提交于
      If we fail to allocate from the current node's stock, we look for free
      objects on other nodes before calling the page allocator (see
      get_any_partial).  While checking other nodes we respect cpuset
      constraints by calling cpuset_zone_allowed.  We enforce hardwall check.
      As a result, we will fallback to the page allocator even if there are some
      pages cached on other nodes, but the current cpuset doesn't have them set.
       However, the page allocator uses softwall check for kernel allocations,
      so it may allocate from one of the other nodes in this case.
      
      Therefore we should use softwall cpuset check in get_any_partial to
      conform with the cpuset check in the page allocator.
      Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
      Acked-by: NZefan Li <lizefan@huawei.com>
      Acked-by: NChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      dee2f8aa
    • V
      slab: fix cpuset check in fallback_alloc · 061d7074
      Vladimir Davydov 提交于
      fallback_alloc is called on kmalloc if the preferred node doesn't have
      free or partial slabs and there's no pages on the node's free list
      (GFP_THISNODE allocations fail).  Before invoking the reclaimer it tries
      to locate a free or partial slab on other allowed nodes' lists.  While
      iterating over the preferred node's zonelist it skips those zones which
      hardwall cpuset check returns false for.  That means that for a task bound
      to a specific node using cpusets fallback_alloc will always ignore free
      slabs on other nodes and go directly to the reclaimer, which, however, may
      allocate from other nodes if cpuset.mem_hardwall is unset (default).  As a
      result, we may get lists of free slabs grow without bounds on other nodes,
      which is bad, because inactive slabs are only evicted by cache_reap at a
      very slow rate and cannot be dropped forcefully.
      
      To reproduce the issue, run a process that will walk over a directory tree
      with lots of files inside a cpuset bound to a node that constantly
      experiences memory pressure.  Look at num_slabs vs active_slabs growth as
      reported by /proc/slabinfo.
      
      To avoid this we should use softwall cpuset check in fallback_alloc.
      Signed-off-by: NVladimir Davydov <vdavydov@parallels.com>
      Acked-by: NZefan Li <lizefan@huawei.com>
      Acked-by: NChristoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      061d7074
    • D
      shmdt: use i_size_read() instead of ->i_size · 07a46ed2
      Dave Hansen 提交于
      Andrew Morton noted
      
      	http://lkml.kernel.org/r/20141104142027.a7a0d010772d84560b445f59@linux-foundation.org
      
      that the shmdt uses inode->i_size outside of i_mutex being held.
      There is one more case in shm.c in shm_destroy().  This converts
      both users over to use i_size_read().
      Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
      Cc: Manfred Spraul <manfred@colorfullife.com>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      07a46ed2
    • D
      ipc/shm.c: fix overly aggressive shmdt() when calls span multiple segments · d3c97900
      Dave Hansen 提交于
      This is a highly-contrived scenario.  But, a single shmdt() call can be
      induced in to unmapping memory from mulitple shm segments.  Example code
      is here:
      
      	http://www.sr71.net/~dave/intel/shmfun.c
      
      The fix is pretty simple: Record the 'struct file' for the first VMA we
      encounter and then stick to it.  Decline to unmap anything not from the
      same file and thus the same segment.
      
      I found this by inspection and the odds of anyone hitting this in practice
      are pretty darn small.
      
      Lightly tested, but it's a pretty small patch.
      Signed-off-by: NDave Hansen <dave.hansen@linux.intel.com>
      Cc: Manfred Spraul <manfred@colorfullife.com>
      Reviewed-by: NDavidlohr Bueso <dave@stgolabs.net>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d3c97900
    • M
      ipc/msg: increase MSGMNI, remove scaling · 0050ee05
      Manfred Spraul 提交于
      SysV can be abused to allocate locked kernel memory.  For most systems, a
      small limit doesn't make sense, see the discussion with regards to SHMMAX.
      
      Therefore: increase MSGMNI to the maximum supported.
      
      And: If we ignore the risk of locking too much memory, then an automatic
      scaling of MSGMNI doesn't make sense.  Therefore the logic can be removed.
      
      The code preserves auto_msgmni to avoid breaking any user space applications
      that expect that the value exists.
      
      Notes:
      1) If an administrator must limit the memory allocations, then he can set
      MSGMNI as necessary.
      
      Or he can disable sysv entirely (as e.g. done by Android).
      
      2) MSGMAX and MSGMNB are intentionally not increased, as these values are used
      to control latency vs. throughput:
      If MSGMNB is large, then msgsnd() just returns and more messages can be queued
      before a task switch to a task that calls msgrcv() is forced.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Cc: Rafael Aquini <aquini@redhat.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0050ee05
    • M
      ipc/sem.c: increase SEMMSL, SEMMNI, SEMOPM · e843e7d2
      Manfred Spraul 提交于
      a)
      
      SysV can be abused to allocate locked kernel memory.  For most systems, a
      small limit doesn't make sense, see the discussion with regards to SHMMAX.
      
      Therefore: Increase the sysv sem limits so that all known applications
      will work with these defaults.
      
      b)
      
      With regards to the maximum supported:
      Some of the specified hard limits are not correct anymore, therefore the
      patch updates the documentation.
      
      - SEMMNI must stay below IPCMNI, which is 32768.
        As for SHMMAX: Stay a bit below this limit.
      
      - SEMMSL was limited to 8k, to ensure that the kmalloc for the kernel array
        was limited to 16 kB (order=2)
      
        This doesn't apply anymore:
         - the allocation size isn't sizeof(short)*nsems anymore.
         - ipc_alloc falls back to vmalloc
      
      - SEMOPM should stay below 1000, to limit the kmalloc in semtimedop() to an
        order=1 allocation.
        Therefore: Leave it at 500 (order=0 allocation).
      
      Note:
      If an administrator must limit the memory allocations, then he can set the
      values as necessary.
      
      Or he can disable sysv entirely (as e.g. done by Android).
      Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
      Cc: Davidlohr Bueso <dave@stgolabs.net>
      Acked-by: NRafael Aquini <aquini@redhat.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e843e7d2
    • M
      ipc/sem.c: change memory barrier in sem_lock() to smp_rmb() · 2e094abf
      Manfred Spraul 提交于
      When I fixed bugs in the sem_lock() logic, I was more conservative than
      necessary.  Therefore it is safe to replace the smp_mb() with smp_rmb().
      And: With smp_rmb(), semop() syscalls are up to 10% faster.
      
      The race we must protect against is:
      
      	sem->lock is free
      	sma->complex_count = 0
      	sma->sem_perm.lock held by thread B
      
      thread A:
      
      A: spin_lock(&sem->lock)
      
      			B: sma->complex_count++; (now 1)
      			B: spin_unlock(&sma->sem_perm.lock);
      
      A: spin_is_locked(&sma->sem_perm.lock);
      A: XXXXX memory barrier
      A: if (sma->complex_count == 0)
      
      Thread A must read the increased complex_count value, i.e. the read must
      not be reordered with the read of sem_perm.lock done by spin_is_locked().
      
      Since it's about ordering of reads, smp_rmb() is sufficient.
      
      [akpm@linux-foundation.org: update sem_lock() comment, from Davidlohr]
      Signed-off-by: NManfred Spraul <manfred@colorfullife.com>
      Reviewed-by: NDavidlohr Bueso <dave@stgolabs.net>
      Acked-by: NRafael Aquini <aquini@redhat.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2e094abf