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2011-01-07Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds
* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (33 commits) usb: don't use flush_scheduled_work() speedtch: don't abuse struct delayed_work media/video: don't use flush_scheduled_work() media/video: explicitly flush request_module work ioc4: use static work_struct for ioc4_load_modules() init: don't call flush_scheduled_work() from do_initcalls() s390: don't use flush_scheduled_work() rtc: don't use flush_scheduled_work() mmc: update workqueue usages mfd: update workqueue usages dvb: don't use flush_scheduled_work() leds-wm8350: don't use flush_scheduled_work() mISDN: don't use flush_scheduled_work() macintosh/ams: don't use flush_scheduled_work() vmwgfx: don't use flush_scheduled_work() tpm: don't use flush_scheduled_work() sonypi: don't use flush_scheduled_work() hvsi: don't use flush_scheduled_work() xen: don't use flush_scheduled_work() gdrom: don't use flush_scheduled_work() ... Fixed up trivial conflict in drivers/media/video/bt8xx/bttv-input.c as per Tejun.
2011-01-07Merge branch 'mce-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp * 'mce-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp: EDAC, MCE: Fix NB error formatting EDAC, MCE: Use BIT_64() to eliminate warnings on 32-bit EDAC, MCE: Enable MCE decoding on F15h EDAC, MCE: Allow F15h bank 6 MCE injection EDAC, MCE: Shorten error report formatting EDAC, MCE: Overhaul error fields extraction macros EDAC, MCE: Add F15h FP MCE decoder EDAC, MCE: Add F15 EX MCE decoder EDAC, MCE: Add an F15h NB MCE decoder EDAC, MCE: No F15h LS MCE decoder EDAC, MCE: Add F15h CU MCE decoder EDAC, MCE: Add F15h IC MCE decoder EDAC, MCE: Add F15h DC MCE decoder EDAC, MCE: Select extended error code mask
2011-01-07Merge branch 'edac-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp * 'edac-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp: amd64_edac: Disable DRAM ECC injection on K8 EDAC: Fixup scrubrate manipulation amd64_edac: Remove two-stage initialization amd64_edac: Check ECC capabilities initially amd64_edac: Carve out ECC-related hw settings amd64_edac: Remove PCI ECS enabling functions amd64_edac: Remove explicit Kconfig PCI dependency amd64_edac: Allocate driver instances dynamically amd64_edac: Rework printk macros amd64_edac: Rename CPU PCI devices amd64_edac: Concentrate per-family init even more amd64_edac: Cleanup the CPU PCI device reservation amd64_edac: Simplify CPU family detection amd64_edac: Add per-family init function amd64_edac: Use cached extended CPU model amd64_edac: Remove F11h support
2011-01-07Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6Linus Torvalds
* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6: (65 commits) [S390] prevent unneccesary loops_per_jiffy recalculation [S390] cpuinfo: use get_online_cpus() instead of preempt_disable() [S390] smp: remove cpu hotplug messages [S390] mutex: enable spinning mutex on s390 [S390] mutex: Introduce arch_mutex_cpu_relax() [S390] cio: fix ccwgroup unregistration race condition [S390] perf: add DWARF register lookup for s390 [S390] cleanup ftrace backend functions [S390] ptrace cleanup [S390] smp/idle: call init_idle() before starting a new cpu [S390] smp: delay idle task creation [S390] dasd: Correct retry counter for terminated I/O. [S390] dasd: Add support for raw ECKD access. [S390] dasd: Prevent deadlock during suspend/resume. [S390] dasd: Improve handling of stolen DASD reservation [S390] dasd: do path verification for paths added at runtime [S390] dasd: add High Performance FICON multitrack support [S390] cio: reduce memory consumption of itcw structures [S390] nmi: enable machine checks early [S390] qeth: buffer count imbalance ...
2011-01-07Merge branch 'rmobile-latest' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 * 'rmobile-latest' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (67 commits) ARM: mach-shmobile: update for SMP changes. ARM: mach-shmobile: update for GIC changes. ARM: mach-shmobile: Fix up clkdev fallout for SH73A0. dma: shdma: don't register the global die notifier multiple times ARM: mach-shmobile: Rely on run-time IRQ handlers ARM: mach-shmobile: Run-time IRQ handler for GIC ARM: mach-shmobile: Run-time IRQ handler for INTCA ARM: mach-shmobile: Enable CONFIG_MULTI_IRQ_HANDLER ARM: mach-shmobile: Use shared GIC entry macros ARM: mach-shmobile: mackerel: Add zboot support ARM: mach-shmobile: mackerel: Add HDMI sound support ARM: mach-shmobile: mackerel: add HDMI video support ARM: mach-shmobile: ap4evb: fixup clk_put timing of fsib_clk ARM: mach-shmobile: sh73a0: fix div4 table ARM: mach-shmobile: ap4/mackerel: modify wrong comment out of USB ARM: mach-shmobile: Mackerel VGA camera support mmc: sh_mmcif: make DMA support by the driver unconditional ARM: mach-shmobile: Add eMMC support through MMCIF on AG5EVM ARM: mach-shmobile: Use pullups for AG5EVM KEYSC pins ARM: mach-shmobile: sh73a0 GPIO pullup improvement ...
2011-01-07Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (58 commits) Input: wacom_w8001 - support pen or touch only devices Input: wacom_w8001 - use __set_bit to set keybits Input: bu21013_ts - fix misuse of logical operation in place of bitop Input: i8042 - add Acer Aspire 5100 to the Dritek list Input: wacom - add support for digitizer in Lenovo W700 Input: psmouse - disable the synaptics extension on OLPC machines Input: psmouse - fix up Synaptics comment Input: synaptics - ignore bogus mt packet Input: synaptics - add multi-finger and semi-mt support Input: synaptics - report clickpad property input: mt: Document interface updates Input: fix double equality sign in uevent Input: introduce device properties hid: egalax: Add support for Wetab (726b) Input: include MT library as source for kerneldoc MAINTAINERS: Update input-mt entry hid: egalax: Add support for Samsung NB30 netbook hid: egalax: Document the new devices in Kconfig hid: egalax: Add support for Wetab hid: egalax: Convert to MT slots ... Fixed up trivial conflict in drivers/input/keyboard/Kconfig
2011-01-07Merge branch 'tty-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 * 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6: (36 commits) serial: apbuart: Fixup apbuart_console_init() TTY: Add tty ioctl to figure device node of the system console. tty: add 'active' sysfs attribute to tty0 and console device drivers: serial: apbuart: Handle OF failures gracefully Serial: Avoid unbalanced IRQ wake disable during resume tty: fix typos/errors in tty_driver.h comments pch_uart : fix warnings for 64bit compile 8250: fix uninitialized FIFOs ip2: fix compiler warning on ip2main_pci_tbl specialix: fix compiler warning on specialix_pci_tbl rocket: fix compiler warning on rocket_pci_ids 8250: add a UPIO_DWAPB32 for 32 bit accesses 8250: use container_of() instead of casting serial: omap-serial: Add support for kernel debugger serial: fix pch_uart kconfig & build drivers: char: hvc: add arm JTAG DCC console support RS485 documentation: add 16C950 UART description serial: ifx6x60: fix memory leak serial: ifx6x60: free IRQ on error Serial: EG20T: add PCH_UART driver ... Fixed up conflicts in drivers/serial/apbuart.c with evil merge that makes the code look fairly sane (unlike either side).
2011-01-07Merge branch 'usb-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 * 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (144 commits) USB: add support for Dream Cheeky DL100B Webmail Notifier (1d34:0004) USB: serial: ftdi_sio: add support for TIOCSERGETLSR USB: ehci-mxc: Setup portsc register prior to accessing OTG viewport USB: atmel_usba_udc: fix freeing irq in usba_udc_remove() usb: ehci-omap: fix tll channel enable mask usb: ohci-omap3: fix trivial typo USB: gadget: ci13xxx: don't assume that PAGE_SIZE is 4096 USB: gadget: ci13xxx: fix complete() callback for no_interrupt rq's USB: gadget: update ci13xxx to work with g_ether USB: gadgets: ci13xxx: fix probing of compiled-in gadget drivers Revert "USB: musb: pm: don't rely fully on clock support" Revert "USB: musb: blackfin: pm: make it work" USB: uas: Use GFP_NOIO instead of GFP_KERNEL in I/O submission path USB: uas: Ensure we only bind to a UAS interface USB: uas: Rename sense pipe and sense urb to status pipe and status urb USB: uas: Use kzalloc instead of kmalloc USB: uas: Fix up the Sense IU usb: musb: core: kill unneeded #include's DA8xx: assign name to MUSB IRQ resource usb: gadget: g_ncm added ... Manually fix up trivial conflicts in USB Kconfig changes in: arch/arm/mach-omap2/Kconfig arch/sh/Kconfig drivers/usb/Kconfig drivers/usb/host/ehci-hcd.c and annoying chip clock data conflicts in: arch/arm/mach-omap2/clock3xxx_data.c arch/arm/mach-omap2/clock44xx_data.c
2011-01-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (147 commits) [SCSI] arcmsr: fix write to device check [SCSI] lpfc: lower stack use in lpfc_fc_frame_check [SCSI] eliminate an unnecessary local variable from scsi_remove_target() [SCSI] libiscsi: use bh locking instead of irq with session lock [SCSI] libiscsi: do not take host lock in queuecommand [SCSI] be2iscsi: fix null ptr when accessing task hdr [SCSI] be2iscsi: fix gfp use in alloc_pdu [SCSI] libiscsi: add more informative failure message during iscsi scsi eh [SCSI] gdth: Add missing call to gdth_ioctl_free [SCSI] bfa: remove unused defintions and misc cleanups [SCSI] bfa: remove inactive functions [SCSI] bfa: replace bfa_assert with WARN_ON [SCSI] qla2xxx: Use sg_next to fetch next sg element while walking sg list. [SCSI] qla2xxx: Fix to avoid recursive lock failure during BSG timeout. [SCSI] qla2xxx: Remove code to not reset ISP82xx on failure. [SCSI] qla2xxx: Display mailbox register 4 during 8012 AEN for ISP82XX parts. [SCSI] qla2xxx: Don't perform a BIG_HAMMER if Get-ID (0x20) mailbox command fails on CNAs. [SCSI] qla2xxx: Remove redundant module parameter permission bits [SCSI] qla2xxx: Add sysfs node for displaying board temperature. [SCSI] qla2xxx: Code cleanup to remove unwanted comments and code. ...
2011-01-07input/tc3589x: fix compile errorDan Carpenter
There was a semi-colon missing and it broke the compile. Signed-off-by: Dan Carpenter <error27@gmail.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-07Merge branch 'vfs-scale-working' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin * 'vfs-scale-working' of git://git.kernel.org/pub/scm/linux/kernel/git/npiggin/linux-npiggin: (57 commits) fs: scale mntget/mntput fs: rename vfsmount counter helpers fs: implement faster dentry memcmp fs: prefetch inode data in dcache lookup fs: improve scalability of pseudo filesystems fs: dcache per-inode inode alias locking fs: dcache per-bucket dcache hash locking bit_spinlock: add required includes kernel: add bl_list xfs: provide simple rcu-walk ACL implementation btrfs: provide simple rcu-walk ACL implementation ext2,3,4: provide simple rcu-walk ACL implementation fs: provide simple rcu-walk generic_check_acl implementation fs: provide rcu-walk aware permission i_ops fs: rcu-walk aware d_revalidate method fs: cache optimise dentry and inode for rcu-walk fs: dcache reduce branches in lookup path fs: dcache remove d_mounted fs: fs_struct use seqlock fs: rcu-walk for path lookup ...
2011-01-07EDAC, MCE: Fix NB error formattingBorislav Petkov
Minor formatting fixup since the information which core was associated with the MCE is not always valid. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Use BIT_64() to eliminate warnings on 32-bitRandy Dunlap
Building for X86_32 produces shift count warnings, so use BIT_64() to eliminate the warnings. drivers/edac/mce_amd.c:778: warning: left shift count >= width of type drivers/edac/mce_amd.c:778: warning: left shift count >= width of type Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Doug Thompson <dougthompson@xmission.com> Cc: bluesmoke-devel@lists.sourceforge.net Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Enable MCE decoding on F15hBorislav Petkov
Now that everything is inplace, enable MCE decoding on F15h. Make initcall routine a bit more readable. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Allow F15h bank 6 MCE injectionBorislav Petkov
F15h adds a sixth MCE bank: adjust bank number check in the injection code. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Shorten error report formattingBorislav Petkov
Shorten up MCi_STATUS flags and add BD's new deferred and poison types. Also, simplify formatting. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Overhaul error fields extraction macrosBorislav Petkov
Make macro names shorter thus making code shorter and more clear. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Add F15h FP MCE decoderBorislav Petkov
Add decoder for FP MCEs. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Add F15 EX MCE decoderBorislav Petkov
Integrate the single FIROB signature into an expanded table along with the new BD MCE types. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Add an F15h NB MCE decoderBorislav Petkov
by (almost) reusing the F10h one since the signatures are the same. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: No F15h LS MCE decoderBorislav Petkov
F15h BD doesn't generate LS MCEs so warn about it. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Add F15h CU MCE decoderBorislav Petkov
MCE bank 2 is redefined from a BU to a CU (Combined Unit) bank on F15h. Add a decoder function for CU MCEs. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Add F15h IC MCE decoderBorislav Petkov
Add support for decoding F15h IC MCEs. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Add F15h DC MCE decoderBorislav Petkov
Add a decoder for F15h DC MCEs to support the new types of DC MCEs introduced by the BD microarchitecture. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC, MCE: Select extended error code maskBorislav Petkov
F15h enlarges the extended error code of an MCE to a 5-bit field (MCi_STATUS[20:16]). Add a mask variable which default 0xf is overridden on F15h. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Disable DRAM ECC injection on K8Borislav Petkov
K8 does not allow for an atomic RMW to a cacheline as F10h does so disable the error injection interface for it. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07EDAC: Fixup scrubrate manipulationBorislav Petkov
Make the ->{get|set}_sdram_scrub_rate return the actual scrub rate bandwidth it succeeded setting and remove superfluous arg pointer used for that. A negative value returned still means that an error occurred while setting the scrubrate. Document this for future reference. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Remove two-stage initializationBorislav Petkov
Now that all prerequisites are in place, drop the two-stage driver instances initialization in favor of the following simple init sequence: 1. Probe PCI device: we only test ECC capabilities here and if none exit early. 2. If the hw supports ECC and it is/can be enabled, we init the per-node instance. Remove "amd64_" prefix from static functions touched, while at it. There actually should be no visible functional change resulting from this patch. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Check ECC capabilities initiallyBorislav Petkov
Rework the code to check the hardware ECC capabilities at PCI probing time. We do all further initialization only if we actually can/have ECC enabled. While at it: 0. Fix function naming. 1. Simplify/clarify debug output. 2. Remove amd64_ prefix from the static functions 3. Reorganize code. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Carve out ECC-related hw settingsBorislav Petkov
This is in preparation for the init path reorganization where we want only to 1) test whether a particular node supports ECC 2) can it be enabled and only then do the necessary allocation/initialization. For that, we need to decouple the ECC settings of the node from the instance's descriptor. The should be no functional change introduced by this patch. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Remove PCI ECS enabling functionsBorislav Petkov
PCI ECS is being enabled by default since 2.6.26 on AMD so this code is just superfluous now, remove it. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Remove explicit Kconfig PCI dependencyBorislav Petkov
AMD_NB pulls in the dependency on PCI. Clarify/fix help text while at it. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Allocate driver instances dynamicallyBorislav Petkov
Remove static allocation in favor of dynamically allocating space for as many driver instances as northbridges present on the system. There should be no functional change resulting from this patch. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Rework printk macrosBorislav Petkov
Add a macro per printk level, shorten up error messages. Add relevant information to KERN_INFO level. No functional change. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Rename CPU PCI devicesBorislav Petkov
Rename variables representing PCI devices to their BKDG names for faster search and shorter, clearer code. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Concentrate per-family init even moreBorislav Petkov
Move the remaining per-family init code into the proper place and simplify the rest of the initialization. Reorganize error handling in amd64_init_one_instance(). Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Cleanup the CPU PCI device reservationBorislav Petkov
Shorten code and clarify comments, return proper -E* values on error. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Simplify CPU family detectionBorislav Petkov
Concentrate CPU family detection in the per-family init function. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Add per-family init functionBorislav Petkov
Run a per-family init function which does all the settings based on the family this driver instance is running on. Move the scrubrate calculation in it and simplify code. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Use cached extended CPU modelBorislav Petkov
... instead of computing it needlessly again. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07amd64_edac: Remove F11h supportBorislav Petkov
F11h doesn't support DRAM ECC so whack it away. Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2011-01-07fs: scale mntget/mntputNick Piggin
The problem that this patch aims to fix is vfsmount refcounting scalability. We need to take a reference on the vfsmount for every successful path lookup, which often go to the same mount point. The fundamental difficulty is that a "simple" reference count can never be made scalable, because any time a reference is dropped, we must check whether that was the last reference. To do that requires communication with all other CPUs that may have taken a reference count. We can make refcounts more scalable in a couple of ways, involving keeping distributed counters, and checking for the global-zero condition less frequently. - check the global sum once every interval (this will delay zero detection for some interval, so it's probably a showstopper for vfsmounts). - keep a local count and only taking the global sum when local reaches 0 (this is difficult for vfsmounts, because we can't hold preempt off for the life of a reference, so a counter would need to be per-thread or tied strongly to a particular CPU which requires more locking). - keep a local difference of increments and decrements, which allows us to sum the total difference and hence find the refcount when summing all CPUs. Then, keep a single integer "long" refcount for slow and long lasting references, and only take the global sum of local counters when the long refcount is 0. This last scheme is what I implemented here. Attached mounts and process root and working directory references are "long" references, and everything else is a short reference. This allows scalable vfsmount references during path walking over mounted subtrees and unattached (lazy umounted) mounts with processes still running in them. This results in one fewer atomic op in the fastpath: mntget is now just a per-CPU inc, rather than an atomic inc; and mntput just requires a spinlock and non-atomic decrement in the common case. However code is otherwise bigger and heavier, so single threaded performance is basically a wash. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: provide rcu-walk aware permission i_opsNick Piggin
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: rcu-walk aware d_revalidate methodNick Piggin
Require filesystems be aware of .d_revalidate being called in rcu-walk mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning -ECHILD from all implementations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache reduce branches in lookup pathNick Piggin
Reduce some branches and memory accesses in dcache lookup by adding dentry flags to indicate common d_ops are set, rather than having to check them. This saves a pointer memory access (dentry->d_op) in common path lookup situations, and saves another pointer load and branch in cases where we have d_op but not the particular operation. Patched with: git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: icache RCU free inodesNick Piggin
RCU free the struct inode. This will allow: - Subsequent store-free path walking patch. The inode must be consulted for permissions when walking, so an RCU inode reference is a must. - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want to take i_lock no longer need to take sb_inode_list_lock to walk the list in the first place. This will simplify and optimize locking. - Could remove some nested trylock loops in dcache code - Could potentially simplify things a bit in VM land. Do not need to take the page lock to follow page->mapping. The downsides of this is the performance cost of using RCU. In a simple creat/unlink microbenchmark, performance drops by about 10% due to inability to reuse cache-hot slab objects. As iterations increase and RCU freeing starts kicking over, this increases to about 20%. In cases where inode lifetimes are longer (ie. many inodes may be allocated during the average life span of a single inode), a lot of this cache reuse is not applicable, so the regression caused by this patch is smaller. The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU, however this adds some complexity to list walking and store-free path walking, so I prefer to implement this at a later date, if it is shown to be a win in real situations. I haven't found a regression in any non-micro benchmark so I doubt it will be a problem. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache rationalise dget variantsNick Piggin
dget_locked was a shortcut to avoid the lazy lru manipulation when we already held dcache_lock (lru manipulation was relatively cheap at that point). However, how that the lru lock is an innermost one, we never hold it at any caller, so the lock cost can now be avoided. We already have well working lazy dcache LRU, so it should be fine to defer LRU manipulations to scan time. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache remove dcache_lockNick Piggin
dcache_lock no longer protects anything. remove it. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: Use rename lock and RCU for multi-step operationsNick Piggin
The remaining usages for dcache_lock is to allow atomic, multi-step read-side operations over the directory tree by excluding modifications to the tree. Also, to walk in the leaf->root direction in the tree where we don't have a natural d_lock ordering. This could be accomplished by taking every d_lock, but this would mean a huge number of locks and actually gets very tricky. Solve this instead by using the rename seqlock for multi-step read-side operations, retry in case of a rename so we don't walk up the wrong parent. Concurrent dentry insertions are not serialised against. Concurrent deletes are tricky when walking up the directory: our parent might have been deleted when dropping locks so also need to check and retry for that. We can also use the rename lock in cases where livelock is a worry (and it is introduced in subsequent patch). Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2011-01-07fs: dcache scale subdirsNick Piggin
Protect d_subdirs and d_child with d_lock, except in filesystems that aren't using dcache_lock for these anyway (eg. using i_mutex). Note: if we change the locking rule in future so that ->d_child protection is provided only with ->d_parent->d_lock, it may allow us to reduce some locking. But it would be an exception to an otherwise regular locking scheme, so we'd have to see some good results. Probably not worthwhile. Signed-off-by: Nick Piggin <npiggin@kernel.dk>