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2013-04-30Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKSStephen Boyd
The help text for this config is duplicated across the x86, parisc, and s390 Kconfig.debug files. Arnd Bergman noted that the help text was slightly misleading and should be fixed to state that enabling this option isn't a problem when using pre 4.4 gcc. To simplify the rewording, consolidate the text into lib/Kconfig.debug and modify it there to be more explicit about when you should say N to this config. Also, make the text a bit more generic by stating that this option enables compile time checks so we can cover architectures which emit warnings vs. ones which emit errors. The details of how an architecture decided to implement the checks isn't as important as the concept of compile time checking of copy_from_user() calls. While we're doing this, remove all the copy_from_user_overflow() code that's duplicated many times and place it into lib/ so that any architecture supporting this option can get the function for free. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: H. Peter Anvin <hpa@zytor.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Helge Deller <deller@gmx.de> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30lib/string_helpers: introduce generic string_unescapeAndy Shevchenko
There are several places in kernel where modules unescapes input to convert C-Style Escape Sequences into byte codes. The patch provides generic implementation of such approach. Test cases are also included into the patch. [akpm@linux-foundation.org: clarify comment] [akpm@linux-foundation.org: export get_random_int() to modules] Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: William Hubbs <w.d.hubbs@gmail.com> Cc: Chris Brannon <chris@the-brannons.com> Cc: Kirk Reiser <kirk@braille.uwo.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-15Move utf16 functions to kernel core and renameMatthew Garrett
We want to be able to use the utf16 functions that are currently present in the EFI variables code in platform-specific code as well. Move them to the kernel core, and in the process rename them to accurately describe what they do - they don't handle UTF16, only UCS2. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-02-27kfifo: move kfifo.c from kernel/ to lib/Stefani Seibold
Move kfifo.c from kernel/ to lib/ Signed-off-by: Stefani Seibold <stefani@seibold.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18Merge branch 'next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc Pull powerpc update from Benjamin Herrenschmidt: "The main highlight is probably some base POWER8 support. There's more to come such as transactional memory support but that will wait for the next one. Overall it's pretty quiet, or rather I've been pretty poor at picking things up from patchwork and reviewing them this time around and Kumar no better on the FSL side it seems..." * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (73 commits) powerpc+of: Rename and fix OF reconfig notifier error inject module powerpc: mpc5200: Add a3m071 board support powerpc/512x: don't compile any platform DIU code if the DIU is not enabled powerpc/mpc52xx: use module_platform_driver macro powerpc+of: Export of_reconfig_notifier_[register,unregister] powerpc/dma/raidengine: add raidengine device powerpc/iommu/fsl: Add PAMU bypass enable register to ccsr_guts struct powerpc/mpc85xx: Change spin table to cached memory powerpc/fsl-pci: Add PCI controller ATMU PM support powerpc/86xx: fsl_pcibios_fixup_bus requires CONFIG_PCI drivers/virt: the Freescale hypervisor driver doesn't need to check MSR[GS] powerpc/85xx: p1022ds: Use NULL instead of 0 for pointers powerpc: Disable relocation on exceptions when kexecing powerpc: Enable relocation on during exceptions at boot powerpc: Move get_longbusy_msecs into hvcall.h and remove duplicate function powerpc: Add wrappers to enable/disable relocation on exceptions powerpc: Add set_mode hcall powerpc: Setup relocation on exceptions for bare metal systems powerpc: Move initial mfspr LPCR out of __init_LPCR powerpc: Add relocation on exception vector handlers ...
2012-12-17percpu_rw_semaphore: introduce CONFIG_PERCPU_RWSEMOleg Nesterov
Currently only block_dev and uprobes use percpu_rw_semaphore, add the config option selected by BLOCK || UPROBES. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Anton Arapov <anton@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-17percpu_rw_semaphore: reimplement to not block the readers unnecessarilyOleg Nesterov
Currently the writer does msleep() plus synchronize_sched() 3 times to acquire/release the semaphore, and during this time the readers are blocked completely. Even if the "write" section was not actually started or if it was already finished. With this patch down_write/up_write does synchronize_sched() twice and down_read/up_read are still possible during this time, just they use the slow path. percpu_down_write() first forces the readers to use rw_semaphore and increment the "slow" counter to take the lock for reading, then it takes that rw_semaphore for writing and blocks the readers. Also. With this patch the code relies on the documented behaviour of synchronize_sched(), it doesn't try to pair synchronize_sched() with barrier. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anton Arapov <anton@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-14Merge branch 'x86-acpi-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 ACPI update from Peter Anvin: "This is a patchset which didn't make the last merge window. It adds a debugging capability to feed ACPI tables via the initramfs. On a grander scope, it formalizes using the initramfs protocol for feeding arbitrary blobs which need to be accessed early to the kernel: they are fed first in the initramfs blob (lots of bootloaders can concatenate this at boot time, others can use a single file) in an uncompressed cpio archive using filenames starting with "kernel/". The ACPI maintainers requested that this patchset be fed via the x86 tree rather than the ACPI tree as the footprint in the general x86 code is much bigger than in the ACPI code proper." * 'x86-acpi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: X86 ACPI: Use #ifdef not #if for CONFIG_X86 check ACPI: Fix build when disabled ACPI: Document ACPI table overriding via initrd ACPI: Create acpi_table_taint() function to avoid code duplication ACPI: Implement physical address table override ACPI: Store valid ACPI tables passed via early initrd in reserved memblock areas x86, acpi: Introduce x86 arch specific arch_reserve_mem_area() for e820 handling lib: Add early cpio decoder
2012-12-14powerpc+of: Rename and fix OF reconfig notifier error inject moduleBenjamin Herrenschmidt
This module used to inject errors in the pSeries specific dynamic reconfiguration notifiers. Those are gone however, replaced by generic notifiers for changes to the device-tree. So let's update the module to deal with these instead and rename it along the way. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
2012-12-11Merge tag 'driver-core-3.8-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg Kroah-Hartman: "Here's the large driver core updates for 3.8-rc1. The biggest thing here is the various __dev* marking removals. This is going to be a pain for the merge with different subsystem trees, I know, but all of the patches included here have been ACKed by their various subsystem maintainers, as they wanted them to go through here. If this is too much of a pain, I can pull all of them out of this tree and just send you one with the other fixes/updates and then, after 3.8-rc1 is out, do the rest of the removals to ensure we catch them all, it's up to you. The merges should all be trivial, and Stephen has been doing them all in linux-next for a few weeks now quite easily. Other than the __dev* marking removals, there's nothing major here, some firmware loading updates and other minor things in the driver core. All of these have (much to Stephen's annoyance), been in linux-next for a while. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" Fixed up trivial conflicts in drivers/gpio/gpio-{em,stmpe}.c due to gpio update. * tag 'driver-core-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (93 commits) modpost.c: Stop checking __dev* section mismatches init.h: Remove __dev* sections from the kernel acpi: remove use of __devinit PCI: Remove __dev* markings PCI: Always build setup-bus when PCI is enabled PCI: Move pci_uevent into pci-driver.c PCI: Remove CONFIG_HOTPLUG ifdefs unicore32/PCI: Remove CONFIG_HOTPLUG ifdefs sh/PCI: Remove CONFIG_HOTPLUG ifdefs powerpc/PCI: Remove CONFIG_HOTPLUG ifdefs mips/PCI: Remove CONFIG_HOTPLUG ifdefs microblaze/PCI: Remove CONFIG_HOTPLUG ifdefs dma: remove use of __devinit dma: remove use of __devexit_p firewire: remove use of __devinitdata firewire: remove use of __devinit leds: remove use of __devexit leds: remove use of __devinit leds: remove use of __devexit_p mmc: remove use of __devexit ...
2012-12-06lib/Makefile: Fix oid_registry build dependencyTim Gardner
It is $(obj)/oid_registry.o that is dependent on $(obj)/oid_registry_data.c. The object file cannot be built until $(obj)/oid_registry_data.c has been generated. A periodic and hard to reproduce parallel build failure is due to this incorrect lib/Makefile dependency. The compile error is completely disingenuous. GEN lib/oid_registry_data.c Compiling 49 OIDs CC lib/oid_registry.o gcc: error: lib/oid_registry.c: No such file or directory gcc: fatal error: no input files compilation terminated. make[3]: *** [lib/oid_registry.o] Error 4 Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Michel Lespinasse <walken@google.com> Cc: David Howells <dhowells@redhat.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Tim Gardner <tim.gardner@canonical.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-11-28lib: kobject_uevent is no longer dependant on CONFIG_HOTPLUGBill Pemberton
CONFIG_HOTPLUG is being removed so kobject_uevent needs to always be part of the library. Signed-off-by: Bill Pemberton <wfp5p@virginia.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-10-14Merge branch 'modules-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull module signing support from Rusty Russell: "module signing is the highlight, but it's an all-over David Howells frenzy..." Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG. * 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits) X.509: Fix indefinite length element skip error handling X.509: Convert some printk calls to pr_devel asymmetric keys: fix printk format warning MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking MODSIGN: Make mrproper should remove generated files. MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs MODSIGN: Use the same digest for the autogen key sig as for the module sig MODSIGN: Sign modules during the build process MODSIGN: Provide a script for generating a key ID from an X.509 cert MODSIGN: Implement module signature checking MODSIGN: Provide module signing public keys to the kernel MODSIGN: Automatically generate module signing keys if missing MODSIGN: Provide Kconfig options MODSIGN: Provide gitignore and make clean rules for extra files MODSIGN: Add FIPS policy module: signature checking hook X.509: Add a crypto key parser for binary (DER) X.509 certificates MPILIB: Provide a function to read raw data into an MPI X.509: Add an ASN.1 decoder X.509: Add simple ASN.1 grammar compiler ...
2012-10-09prio_tree: removeMichel Lespinasse
After both prio_tree users have been converted to use red-black trees, there is no need to keep around the prio tree library anymore. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09rbtree: add prio tree and interval tree testsMichel Lespinasse
Patch 1 implements support for interval trees, on top of the augmented rbtree API. It also adds synthetic tests to compare the performance of interval trees vs prio trees. Short answers is that interval trees are slightly faster (~25%) on insert/erase, and much faster (~2.4 - 3x) on search. It is debatable how realistic the synthetic test is, and I have not made such measurements yet, but my impression is that interval trees would still come out faster. Patch 2 uses a preprocessor template to make the interval tree generic, and uses it as a replacement for the vma prio_tree. Patch 3 takes the other prio_tree user, kmemleak, and converts it to use a basic rbtree. We don't actually need the augmented rbtree support here because the intervals are always non-overlapping. Patch 4 removes the now-unused prio tree library. Patch 5 proposes an additional optimization to rb_erase_augmented, now providing it as an inline function so that the augmented callbacks can be inlined in. This provides an additional 5-10% performance improvement for the interval tree insert/erase benchmark. There is a maintainance cost as it exposes augmented rbtree users to some of the rbtree library internals; however I think this cost shouldn't be too high as I expect the augmented rbtree will always have much less users than the base rbtree. I should probably add a quick summary of why I think it makes sense to replace prio trees with augmented rbtree based interval trees now. One of the drivers is that we need augmented rbtrees for Rik's vma gap finding code, and once you have them, it just makes sense to use them for interval trees as well, as this is the simpler and more well known algorithm. prio trees, in comparison, seem *too* clever: they impose an additional 'heap' constraint on the tree, which they use to guarantee a faster worst-case complexity of O(k+log N) for stabbing queries in a well-balanced prio tree, vs O(k*log N) for interval trees (where k=number of matches, N=number of intervals). Now this sounds great, but in practice prio trees don't realize this theorical benefit. First, the additional constraint makes them harder to update, so that the kernel implementation has to simplify things by balancing them like a radix tree, which is not always ideal. Second, the fact that there are both index and heap properties makes both tree manipulation and search more complex, which results in a higher multiplicative time constant. As it turns out, the simple interval tree algorithm ends up running faster than the more clever prio tree. This patch: Add two test modules: - prio_tree_test measures the performance of lib/prio_tree.c, both for insertion/removal and for stabbing searches - interval_tree_test measures the performance of a library of equivalent functionality, built using the augmented rbtree support. In order to support the second test module, lib/interval_tree.c is introduced. It is kept separate from the interval_tree_test main file for two reasons: first we don't want to provide an unfair advantage over prio_tree_test by having everything in a single compilation unit, and second there is the possibility that the interval tree functionality could get some non-test users in kernel over time. Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-09rbtree: performance and correctness testMichel Lespinasse
This small module helps measure the performance of rbtree insert and erase. Additionally, we run a few correctness tests to check that the rbtrees have all desired properties: - contains the right number of nodes in the order desired, - never two consecutive red nodes on any path, - all paths to leaf nodes have the same number of black nodes, - root node is black [akpm@linux-foundation.org: fix printk warning: sparc64 cycles_t is unsigned long] Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-10-08X.509: Add an ASN.1 decoderDavid Howells
Add an ASN.1 BER/DER/CER decoder. This uses the bytecode from the ASN.1 compiler in the previous patch to inform it as to what to expect to find in the encoded byte stream. The output from the compiler also tells it what functions to call on what tags, thus allowing the caller to retrieve information. The decoder is called as follows: int asn1_decoder(const struct asn1_decoder *decoder, void *context, const unsigned char *data, size_t datalen); The decoder argument points to the bytecode from the ASN.1 compiler. context is the caller's context and is passed to the action functions. data and datalen define the byte stream to be decoded. Note that the decoder is currently limited to datalen being less than 64K. This reduces the amount of stack space used by the decoder because ASN.1 is a nested construct. Similarly, the decoder is limited to a maximum of 10 levels of constructed data outside of a leaf node also in an effort to keep stack usage down. These restrictions can be raised if necessary. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-10-08X.509: Implement simple static OID registryDavid Howells
Implement a simple static OID registry that allows the mapping of an encoded OID to an enum value for ease of use. The OID registry index enum appears in the: linux/oid_registry.h header file. A script generates the registry from lines in the header file that look like: <sp*>OID_foo,<sp*>/*<sp*>1.2.3.4<sp*>*/ The actual OID is taken to be represented by the numbers with interpolated dots in the comment. All other lines in the header are ignored. The registry is queries by calling: OID look_up_oid(const void *data, size_t datasize); This returns a number from the registry enum representing the OID if found or OID__NR if not. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-30lib: Add early cpio decoderH. Peter Anvin
Add a simple cpio decoder without library dependencies for the purpose of extracting components from the initramfs blob for early kernel uses. Intended consumers so far are microcode and ACPI override. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1349043837-22659-2-git-send-email-trenn@suse.de Cc: Len Brown <lenb@kernel.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2012-07-30Merge tag 'writeback-proportions' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux Pull writeback updates from Wu Fengguang: "Use time based periods to age the writeback proportions, which can adapt equally well to fast/slow devices." Fix up trivial conflict in comment in fs/sync.c * tag 'writeback-proportions' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux: writeback: Fix some comment errors block: Convert BDI proportion calculations to flexible proportions lib: Fix possible deadlock in flexible proportion code lib: Proportions with flexible period
2012-07-30Merge branch 'akpm' (Andrew's patch-bomb)Linus Torvalds
Merge Andrew's first set of patches: "Non-MM patches: - lots of misc bits - tree-wide have_clk() cleanups - quite a lot of printk tweaks. I draw your attention to "printk: convert the format for KERN_<LEVEL> to a 2 byte pattern" which looks a bit scary. But afaict it's solid. - backlight updates - lib/ feature work (notably the addition and use of memweight()) - checkpatch updates - rtc updates - nilfs updates - fatfs updates (partial, still waiting for acks) - kdump, proc, fork, IPC, sysctl, taskstats, pps, etc - new fault-injection feature work" * Merge emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits) drivers/misc/lkdtm.c: fix missing allocation failure check lib/scatterlist: do not re-write gfp_flags in __sg_alloc_table() fault-injection: add tool to run command with failslab or fail_page_alloc fault-injection: add selftests for cpu and memory hotplug powerpc: pSeries reconfig notifier error injection module memory: memory notifier error injection module PM: PM notifier error injection module cpu: rewrite cpu-notifier-error-inject module fault-injection: notifier error injection c/r: fcntl: add F_GETOWNER_UIDS option resource: make sure requested range is included in the root range include/linux/aio.h: cpp->C conversions fs: cachefiles: add support for large files in filesystem caching pps: return PTR_ERR on error in device_create taskstats: check nla_reserve() return sysctl: suppress kmemleak messages ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION ipc: compat: use signed size_t types for msgsnd and msgrcv ipc: allow compat IPC version field parsing if !ARCH_WANT_OLD_COMPAT_IPC ipc: add COMPAT_SHMLBA support ...
2012-07-30powerpc: pSeries reconfig notifier error injection moduleAkinobu Mita
This provides the ability to inject artifical errors to pSeries reconfig notifier chain callbacks. It is controlled through debugfs interface under /sys/kernel/debug/notifier-error-inject/pSeries-reconfig If the notifier call chain should be failed with some events notified, write the error code to "actions/<notifier event>/error". Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30memory: memory notifier error injection moduleAkinobu Mita
This provides the ability to inject artifical errors to memory hotplug notifier chain callbacks. It is controlled through debugfs interface under /sys/kernel/debug/notifier-error-inject/memory If the notifier call chain should be failed with some events notified, write the error code to "actions/<notifier event>/error". Example: Inject memory hotplug offline error (-12 == -ENOMEM) # cd /sys/kernel/debug/notifier-error-inject/memory # echo -12 > actions/MEM_GOING_OFFLINE/error # echo offline > /sys/devices/system/memory/memoryXXX/state bash: echo: write error: Cannot allocate memory Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30PM: PM notifier error injection moduleAkinobu Mita
This provides the ability to inject artifical errors to PM notifier chain callbacks. It is controlled through debugfs interface under /sys/kernel/debug/notifier-error-inject/pm Each of the files in "error" directory represents an event which can be failed and contains the error code. If the notifier call chain should be failed with some events notified, write the error code to the files. If the notifier call chain should be failed with some events notified, write the error code to "actions/<notifier event>/error". Example: Inject PM suspend error (-12 = -ENOMEM) # cd /sys/kernel/debug/notifier-error-inject/pm # echo -12 > actions/PM_SUSPEND_PREPARE/error # echo mem > /sys/power/state bash: echo: write error: Cannot allocate memory Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30fault-injection: notifier error injectionAkinobu Mita
This patchset provides kernel modules that can be used to test the error handling of notifier call chain failures by injecting artifical errors to the following notifier chain callbacks. * CPU notifier * PM notifier * memory hotplug notifier * powerpc pSeries reconfig notifier Example: Inject CPU offline error (-1 == -EPERM) # cd /sys/kernel/debug/notifier-error-inject/cpu # echo -1 > actions/CPU_DOWN_PREPARE/error # echo 0 > /sys/devices/system/cpu/cpu1/online bash: echo: write error: Operation not permitted The patchset also adds cpu and memory hotplug tests to tools/testing/selftests These tests first do simple online and offline test and then do fault injection tests if notifier error injection module is available. This patch: The notifier error injection provides the ability to inject artifical errors to specified notifier chain callbacks. It is useful to test the error handling of notifier call chain failures. This adds common basic functions to define which type of events can be fail and to initialize the debugfs interface to control what error code should be returned and which event should be failed. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30string: introduce memweight()Akinobu Mita
memweight() is the function that counts the total number of bits set in memory area. Unlike bitmap_weight(), memweight() takes pointer and size in bytes to specify a memory area which does not need to be aligned to long-word boundary. [akpm@linux-foundation.org: rename `w' to `ret'] Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Anders Larsen <al@alarsen.net> Cc: Alasdair Kergon <agk@redhat.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Tony Luck <tony.luck@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-23of/lib: Allow scripts/dtc/libfdt to be used from kernel codeDavid Daney
libfdt is part of the device tree support in scripts/dtc/libfdt. For some platforms that use the Device Tree, we want to be able to edit the flattened device tree form. We don't want to burden kernel builds that do not require it, so we gate compilation of libfdt files with CONFIG_LIBFDT. So if it is needed, you need to do this in your Kconfig: select LIBFDT And in the Makefile of the code using libfdt something like: ccflags-y := -I$(src)/../../../scripts/dtc/libfdt Signed-off-by: David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Cc: devicetree-discuss@lists.ozlabs.org Cc: Grant Likely <grant.likely@secretlab.ca> Cc: linux-kernel@vger.kernel.org Acked-by: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2012-06-09lib: Proportions with flexible periodJan Kara
Implement code computing proportions of events of different type (like code in lib/proportions.c) but allowing periods to have different lengths. This allows us to have aging periods of fixed wallclock time which gives better proportion estimates given the hugely varying throughput of different devices - previous measuring of aging period by number of events has the problem that a reasonable period length for a system with low-end USB stick is not a reasonable period length for a system with high-end storage array resulting either in too slow proportion updates or too fluctuating proportion updates. Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
2012-05-26Merge branch 'generic-string-functions'Linus Torvalds
This makes <asm/word-at-a-time.h> actually live up to its promise of allowing architectures to help tune the string functions that do their work a word at a time. David had already taken the x86 strncpy_from_user() function, modified it to work on sparc, and then done the extra work to make it generically useful. This then expands on that work by making x86 use that generic version, completing the circle. But more importantly, it fixes up the word-at-a-time interfaces so that it's now easy to also support things like strnlen_user(), and pretty much most random string functions. David reports that it all works fine on sparc, and Jonas Bonn reported that an earlier version of this worked on OpenRISC too. It's pretty easy for architectures to add support for this and just replace their private versions with the generic code. * generic-string-functions: sparc: use the new generic strnlen_user() function x86: use the new generic strnlen_user() function lib: add generic strnlen_user() function word-at-a-time: make the interfaces truly generic x86: use generic strncpy_from_user routine
2012-05-26Merge tag 'stmp-dev' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc Pull arm-soc stmp-dev library code from Olof Johansson: "A number of devices are using a common register layout, this adds support code for it in lib/stmp_device.c so we do not need to duplicate it in each driver." Fix up trivial conflicts in drivers/i2c/busses/i2c-mxs.c and lib/Makefile * tag 'stmp-dev' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: i2c: mxs: use global reset function lib: add support for stmp-style devices
2012-05-26lib: add generic strnlen_user() functionLinus Torvalds
This adds a new generic optimized strnlen_user() function that uses the <asm/word-at-a-time.h> infrastructure to portably do efficient string handling. In many ways, strnlen is much simpler than strncpy, and in particular we can always pre-align the words we load from memory. That means that all the worries about alignment etc are a non-issue, so this one can easily be used on any architecture. You obviously do have to do the appropriate word-at-a-time.h macros. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparcLinus Torvalds
Pull sparc changes from David S. Miller: "This has the generic strncpy_from_user() implementation architectures can now use, which we've been developing on linux-arch over the past few days. For good measure I ran both a 32-bit and a 64-bit glibc testsuite run, and the latter of which pointed out an adjustment I needed to make to sparc's user_addr_max() definition. Linus, you were right, STACK_TOP was not the right thing to use, even on sparc itself :-) From Sam Ravnborg, we have a conversion of sparc32 over to the common alloc_thread_info_node(), since the aspect which originally blocked our doing so (sun4c) has been removed." Fix up trivial arch/sparc/Kconfig and lib/Makefile conflicts. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc: sparc: Fix user_addr_max() definition. lib: Sparc's strncpy_from_user is generic enough, move under lib/ kernel: Move REPEAT_BYTE definition into linux/kernel.h sparc: Increase portability of strncpy_from_user() implementation. sparc: Optimize strncpy_from_user() zero byte search. sparc: Add full proper error handling to strncpy_from_user(). sparc32: use the common implementation of alloc_thread_info_node()
2012-05-24lib: Sparc's strncpy_from_user is generic enough, move under lib/David S. Miller
To use this, an architecture simply needs to: 1) Provide a user_addr_max() implementation via asm/uaccess.h 2) Add "select GENERIC_STRNCPY_FROM_USER" to their arch Kcnfig 3) Remove the existing strncpy_from_user() implementation and symbol exports their architecture had. Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: David Howells <dhowells@redhat.com>
2012-05-02ddr: add LPDDR2 data from JESD209-2Aneesh V
add LPDDR2 data from the JEDEC spec JESD209-2. The data includes: 1. Addressing information for LPDDR2 memories of different densities and types(S2/S4) 2. AC timing data. This data will useful for memory controller device drivers. Right now this is used by the TI EMIF SDRAM controller driver. Signed-off-by: Aneesh V <aneesh@ti.com> Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Benoit Cousson <b-cousson@ti.com> [santosh.shilimkar@ti.com: Moved to drivers/memory from drivers/misc] Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Tested-by: Lokesh Vutla <lokeshvutla@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-20lib: add support for stmp-style devicesWolfram Sang
MX23/28 use IP cores which follow a register layout I have first seen on STMP3xxx SoCs. In this layout, every register actually has four u32: 1.) to store a value directly 2.) a SET register where every 1-bit sets the corresponding bit, others are unaffected 3.) same with a CLR register 4.) same with a TOG (toggle) register Also, the 2 MSBs in register 0 are always the same and can be used to reset the IP core. All this is strictly speaking not mach-specific (but IP core specific) and, thus, doesn't need to be in mach-mxs/include. At least mx6 also uses IP cores following this stmp-style. So: Introduce a stmp-style device, put the code and defines for that in a public place (lib/), and let drivers for stmp-style devices select that code. To avoid regressions and ease reviewing, the actual code is simply copied from mach-mxs. It definately wants updates, but those need a seperate patch series. Voila, mach dependency gone, reusable code introduced. Note that I didn't remove the duplicated code from mach-mxs yet, first the drivers have to be converted. Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Shawn Guo <shawn.guo@linaro.org> Acked-by: Dong Aisheng <dong.aisheng@linaro.org>
2012-02-02lib: Fix multiple definitions of clz_tabDavid Miller
Both sparc 32-bit's software divide assembler and MPILIB provide clz_tab[] with identical contents. Break it out into a seperate object file and select it when SPARC32 or MPILIB is set. Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: James Morris <jmorris@namei.org>
2012-01-18lib: digital signature config option name changeDmitry Kasatkin
It was reported that DIGSIG is confusing name for digital signature module. It was suggested to rename DIGSIG to SIGNATURE. Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Suggested-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Signed-off-by: James Morris <jmorris@namei.org>
2012-01-10Merge branch 'for-linus' of git://selinuxproject.org/~jmorris/linux-securityLinus Torvalds
* 'for-linus' of git://selinuxproject.org/~jmorris/linux-security: (32 commits) ima: fix invalid memory reference ima: free duplicate measurement memory security: update security_file_mmap() docs selinux: Casting (void *) value returned by kmalloc is useless apparmor: fix module parameter handling Security: tomoyo: add .gitignore file tomoyo: add missing rcu_dereference() apparmor: add missing rcu_dereference() evm: prevent racing during tfm allocation evm: key must be set once during initialization mpi/mpi-mpow: NULL dereference on allocation failure digsig: build dependency fix KEYS: Give key types their own lockdep class for key->sem TPM: fix transmit_cmd error logic TPM: NSC and TIS drivers X86 dependency fix TPM: Export wait_for_stat for other vendor specific drivers TPM: Use vendor specific function for status probe tpm_tis: add delay after aborting command tpm_tis: Check return code from getting timeouts/durations tpm: Introduce function to poll for result of self test ... Fix up trivial conflict in lib/Makefile due to addition of CONFIG_MPI and SIGSIG next to CONFIG_DQL addition.
2012-01-10Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds
lib: use generic pci_iomap on all architectures Many architectures don't want to pull in iomap.c, so they ended up duplicating pci_iomap from that file. That function isn't trivial, and we are going to modify it https://lkml.org/lkml/2011/11/14/183 so the duplication hurts. This reduces the scope of the problem significantly, by moving pci_iomap to a separate file and referencing that from all architectures. * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: alpha: drop pci_iomap/pci_iounmap from pci-noop.c mn10300: switch to GENERIC_PCI_IOMAP mn10300: add missing __iomap markers frv: switch to GENERIC_PCI_IOMAP tile: switch to GENERIC_PCI_IOMAP tile: don't panic on iomap sparc: switch to GENERIC_PCI_IOMAP sh: switch to GENERIC_PCI_IOMAP powerpc: switch to GENERIC_PCI_IOMAP parisc: switch to GENERIC_PCI_IOMAP mips: switch to GENERIC_PCI_IOMAP microblaze: switch to GENERIC_PCI_IOMAP arm: switch to GENERIC_PCI_IOMAP alpha: switch to GENERIC_PCI_IOMAP lib: add GENERIC_PCI_IOMAP lib: move GENERIC_IOMAP to lib/Kconfig Fix up trivial conflicts due to changes nearby in arch/{m68k,score}/Kconfig
2012-01-07Merge branch 'driver-core-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core * 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (73 commits) arm: fix up some samsung merge sysdev conversion problems firmware: Fix an oops on reading fw_priv->fw in sysfs loading file Drivers:hv: Fix a bug in vmbus_driver_unregister() driver core: remove __must_check from device_create_file debugfs: add missing #ifdef HAS_IOMEM arm: time.h: remove device.h #include driver-core: remove sysdev.h usage. clockevents: remove sysdev.h arm: convert sysdev_class to a regular subsystem arm: leds: convert sysdev_class to a regular subsystem kobject: remove kset_find_obj_hinted() m86k: gpio - convert sysdev_class to a regular subsystem mips: txx9_sram - convert sysdev_class to a regular subsystem mips: 7segled - convert sysdev_class to a regular subsystem sh: dma - convert sysdev_class to a regular subsystem sh: intc - convert sysdev_class to a regular subsystem power: suspend - convert sysdev_class to a regular subsystem power: qe_ic - convert sysdev_class to a regular subsystem power: cmm - convert sysdev_class to a regular subsystem s390: time - convert sysdev_class to a regular subsystem ... Fix up conflicts with 'struct sysdev' removal from various platform drivers that got changed: - arch/arm/mach-exynos/cpu.c - arch/arm/mach-exynos/irq-eint.c - arch/arm/mach-s3c64xx/common.c - arch/arm/mach-s3c64xx/cpu.c - arch/arm/mach-s5p64x0/cpu.c - arch/arm/mach-s5pv210/common.c - arch/arm/plat-samsung/include/plat/cpu.h - arch/powerpc/kernel/sysfs.c and fix up cpu_is_hotpluggable() as per Greg in include/linux/cpu.h
2011-12-13kref: Inline all functionsPeter Zijlstra
These are tiny functions, there's no point in having them out-of-line. Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-8eccvi2ur2fzgi00xdjlbf5z@git.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-29dql: Dynamic queue limitsTom Herbert
Implementation of dynamic queue limits (dql). This is a libary which allows a queue limit to be dynamically managed. The goal of dql is to set the queue limit, number of objects to the queue, to be minimized without allowing the queue to be starved. dql would be used with a queue which has these properties: 1) Objects are queued up to some limit which can be expressed as a count of objects. 2) Periodically a completion process executes which retires consumed objects. 3) Starvation occurs when limit has been reached, all queued data has actually been consumed but completion processing has not yet run, so queuing new data is blocked. 4) Minimizing the amount of queued data is desirable. A canonical example of such a queue would be a NIC HW transmit queue. The queue limit is dynamic, it will increase or decrease over time depending on the workload. The queue limit is recalculated each time completion processing is done. Increases occur when the queue is starved and can exponentially increase over successive intervals. Decreases occur when more data is being maintained in the queue than needed to prevent starvation. The number of extra objects, or "slack", is measured over successive intervals, and to avoid hysteresis the limit is only reduced by the miminum slack seen over a configurable time period. dql API provides routines to manage the queue: - dql_init is called to intialize the dql structure - dql_reset is called to reset dynamic values - dql_queued called when objects are being enqueued - dql_avail returns availability in the queue - dql_completed is called when objects have be consumed in the queue Configuration consists of: - max_limit, maximum limit - min_limit, minimum limit - slack_hold_time, time to measure instances of slack before reducing queue limit Signed-off-by: Tom Herbert <therbert@google.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2011-11-28lib: add GENERIC_PCI_IOMAPMichael S. Tsirkin
Many architectures want a generic pci_iomap but not the rest of iomap.c. Split that to a separate .c file and add a new config symbol. select automatically by GENERIC_IOMAP. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2011-11-09crypto: digital signature verification supportDmitry Kasatkin
This patch implements RSA digital signature verification using GnuPG library. The format of the signature and the public key is defined by their respective headers. The signature header contains version information, algorithm, and keyid, which was used to generate the signature. The key header contains version and algorythim type. The payload of the signature and the key are multi-precision integers. The signing and key management utilities evm-utils provide functionality to generate signatures and load keys into the kernel keyring. When the key is added to the kernel keyring, the keyid defines the name of the key. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com> Acked-by: Mimi Zohar <zohar@us.ibm.com>
2011-11-09crypto: GnuPG based MPI lib - make files (part 3)Dmitry Kasatkin
Adds the multi-precision-integer maths library which was originally taken from GnuPG and ported to the kernel by (among others) David Howells. This version is taken from Fedora kernel 2.6.32-71.14.1.el6. The difference is that checkpatch reported errors and warnings have been fixed. This library is used to implemenet RSA digital signature verification used in IMA/EVM integrity protection subsystem. Due to patch size limitation, the patch is divided into 4 parts. Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-10-04llist: Make some llist functions inlineHuang Ying
Because llist code will be used in performance critical scheduler code path, make llist_add() and llist_del_all() inline to avoid function calling overhead and related 'glue' overhead. Signed-off-by: Huang Ying <ying.huang@intel.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1315461646-1379-2-git-send-email-ying.huang@intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-08-30bitops: Move find_next_bit.o from lib-y to obj-yGeert Uytterhoeven
If there are no builtin users of find_next_bit_le() and find_next_zero_bit_le(), these functions are not present in the kernel image, causing m68k allmodconfig to fail with: ERROR: "find_next_zero_bit_le" [fs/ufs/ufs.ko] undefined! ERROR: "find_next_bit_le" [fs/udf/udf.ko] undefined! ... This started to happen after commit 171d809df189 ("m68k: merge mmu and non-mmu bitops.h"), as m68k had its own inline versions before. commit 63e424c84429 ("arch: remove CONFIG_GENERIC_FIND_{NEXT_BIT, BIT_LE, LAST_BIT}") added find_last_bit.o to obj-y (so it's always included), but find_next_bit.o to lib-y (so it gets removed by the linker if there are no builtin users). Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-06crypto: Move md5_transform to lib/md5.cDavid S. Miller
We are going to use this for TCP/IP sequence number and fragment ID generation. Signed-off-by: David S. Miller <davem@davemloft.net>
2011-08-03Merge branch 'apei' into apei-releaseLen Brown
Some trivial conflicts due to other various merges adding to the end of common lists sooner than this one. arch/ia64/Kconfig arch/powerpc/Kconfig arch/x86/Kconfig lib/Kconfig lib/Makefile Signed-off-by: Len Brown <len.brown@intel.com>
2011-08-03lib, Add lock-less NULL terminated single listHuang Ying
Cmpxchg is used to implement adding new entry to the list, deleting all entries from the list, deleting first entry of the list and some other operations. Because this is a single list, so the tail can not be accessed in O(1). If there are multiple producers and multiple consumers, llist_add can be used in producers and llist_del_all can be used in consumers. They can work simultaneously without lock. But llist_del_first can not be used here. Because llist_del_first depends on list->first->next does not changed if list->first is not changed during its operation, but llist_del_first, llist_add, llist_add (or llist_del_all, llist_add, llist_add) sequence in another consumer may violate that. If there are multiple producers and one consumer, llist_add can be used in producers and llist_del_all or llist_del_first can be used in the consumer. This can be summarized as follow: | add | del_first | del_all add | - | - | - del_first | | L | L del_all | | | - Where "-" stands for no lock is needed, while "L" stands for lock is needed. The list entries deleted via llist_del_all can be traversed with traversing function such as llist_for_each etc. But the list entries can not be traversed safely before deleted from the list. The order of deleted entries is from the newest to the oldest added one. If you want to traverse from the oldest to the newest, you must reverse the order by yourself before traversing. The basic atomic operation of this list is cmpxchg on long. On architectures that don't have NMI-safe cmpxchg implementation, the list can NOT be used in NMI handler. So code uses the list in NMI handler should depend on CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG. Signed-off-by: Huang Ying <ying.huang@intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>