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2013-09-03[SCSI] qla2xxx: Perform warm reset every 2 minutes if firmware load fails ↵Armen Baloyan
for ISPFX00. Signed-off-by: Armen Baloyan <armen.baloyan@qlogic.com> Acked-by: Srinivasa Rao <srinivasa.rao@qlogic.com> Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla2xxx: Set factory reset recovery timeout to 10 min. for ISPFX00.Armen Baloyan
Signed-off-by: Armen Baloyan <armen.baloyan@qlogic.com> Acked-by: Srinivasa Rao <srinivasa.rao@qlogic.com> Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla2xxx: Correct multiqueue offset calculations.Andrew Vasquez
Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com> Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla2xxx: Fix incorrect test after list_for_each_entry() exits.Joe Carnuccio
list_for_each_entry() never leaves the iterator pointing to null. Signed-off-by: Joe Carnuccio <joe.carnuccio@qlogic.com> Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla2xxx: Add support for ISP8044.Atul Deshmukh
[jejb: checkpatch fixes] Signed-off-by: Atul Deshmukh <atul.deshmukh@qlogic.com> Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla2xxx: Print some variables to hexadecimal string via %*phN formatOleksandr Khoshaba
The patch changes a specifier used to output some variables. Instead of using stack for each byte the '%*ph[CN]' allows to take a one pointer and prints entire buffer as a hexadecimal string with the separator ':' or ''. Signed-off-by: Oleksandr Khoshaba <Oleksandr.Khoshaba@gmail.com> Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt3sas: Remove phys on topology changeJan Vesely
Signed-off-by: Jan Vesely <jvesely@redhat.com> Acked-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: Remove phys on topology change.Jan Vesely
Signed-off-by: Jan Vesely <jvesely@redhat.com> Acked-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] bfa: firmware update to 3.2.1.1Rasesh Mody
This patch updates the firmware to address the thermal notification issue Signed-off-by: Rasesh Mody <rmody@brocade.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] esas2r: ATTO Technology ExpressSAS 6G SAS/SATA RAID Adapter DriverBradley Grove
This is a new driver for ATTO Technology's ExpressSAS series of hardware RAID adapters. It supports the following adapters: - ExpressSAS R60F - ExpressSAS R680 - ExpressSAS R608 - ExpressSAS R644 Signed-off-by: Bradley Grove <bgrove@attotech.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] eata_pio: off by one in eata_pio_detect()Dan Carpenter
Smatch complains that the reg_IRQ[] array only has MAXIRQ (16) elements so we are one space beyond the end of the array here. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla4xxx: Update driver version to 5.04.00-k1Vikas Chaudhary
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla4xxx: Return error if minidump data collection failsVikas Chaudhary
Return error from function qla4_8xxx_collect_md_data() if minidump data collection fails. Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla4xxx: Fix the minidump data collection check in for loopSantosh Vernekar
Signed-off-by: Santosh Vernekar <santosh.vernekar@qlogic.com> Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla4xxx: Add pex-dma support for capturing minidumpSantosh Vernekar
Add pex-dma support for ISP8324 and ISP8042 to improve the minidump capture time. Signed-off-by: Santosh Vernekar <santosh.vernekar@qlogic.com> Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] zfcp: enable FCP hardware data router by defaultSteffen Maier
Enabling the data router support by default can increase performance in certain situations. It is safe to do so and tolerated in LPAR and under z/VM in case there is no data router support in that environment. Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Reviewed-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] zfcp: dead code removalMartin Peschke
Get rid of unused function zfcp_fsf_get_req and corresponding prototype definition. Commit a54ca0f62f953898b05549391ac2a8a4dad6482b in v2.6.28 "[SCSI] zfcp: Redesign of the debug tracing for HBA records." accidentally introduced this code which was dead in the first place. Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] zfcp: cleanup use of obsolete strict_strto* functionsMartin Peschke
strict_strtoul and friends are obsolete. Use kstrtoul functions instead. Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] zfcp: consistently use appropriate SBAL flag definitionsMartin Peschke
minor cleanup for status read request Signed-off-by: Martin Peschke <mpeschke@linux.vnet.ibm.com> Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt3sas: Added a driver module parameter max_msix_vectorsSreekanth Reddy
Added a driver module parameter max_msix_vectors. Using this module parameter the maximum number of MSI-X vectors could be set. The number of MSI-X vectors used would be the minimum of MSI-X vectors supported by the HBA, the number of CPU cores and the value set to max_msix_vectors module parameter. The default value of this module parameter is set to 8. The default value of this parameter is set to 8 inorder to reduce the amount of memory required for Reply Descriptor Post queue. This is because with the higher MSI-X vectors, some times kernel is not able to allocate the requested amount of memory and crash is observed. To overcome this problem, the default value is set to 8. Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla4xxx: Update driver version to 5.04.00-k0Vikas Chaudhary
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla4xxx: Update Copyright headerVikas Chaudhary
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla4xxx: Implementation of ACB configuration during Loopback for ISP8042Nilesh Javali
While loopback diagnostic is in progress, disable the ACB which resets all the active connections to target. Disable ACB would filter out all the DHCP multicast and broadcast packets which otherwise cause the diagnostic test to take longer time to complete or failures in some other cases. Signed-off-by: Nilesh Javali <nilesh.javali@qlogic.com> Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] qla4xxx: Added support for ISP8042Vikas Chaudhary
Signed-off-by: Vikas Chaudhary <vikas.chaudhary@qlogic.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: Bump driver version to v16.100.00.00Sreekanth Reddy
Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: Fix for kernel panic when driver loads with HBA connected to ↵Sreekanth Reddy
non LUN 0 configured expander With some enclosures when LUN 0 is not created but LUN 1 or LUN X is created then SCSI scan procedure calls target_alloc, slave_alloc call back functions for LUN 0 and slave_destory() for same LUN 0. In these kind of cases within slave_destroy, pointer to scsi_target in _sas_device structure is set to NULL, following which when slave_alloc for LUN 1 is called then starget would not be set properly for this LUN. So, scsi_target pointer pointing to NULL value would lead to a crash later in the discovery procedure. To solve this issue set the sas_device's scsi_target pointer to scsi_device's scsi_target if it is NULL earlier in slave_alloc callback function. Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: when Async scanning is enabled then while scanning, devices ↵Sreekanth Reddy
are removed but their transport layer entries are not removed When Async scanning mode is enabled and device scanning is in progress then devices should not be removed. But in actuality, devices are removed but their transport layer entries are not removed. This causes error to add the same device to the transport layer after host reset or diagnostic reset. So, in this patch, modified the code in such a way that device is not removed when Async scanning mode is enabled and device scanning is in progress. Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: Infinite loop can occur if ↵Sreekanth Reddy
MPI2_IOCSTATUS_CONFIG_INVALID_PAGE is not returned Infinite loop can occur if IOCStatus is not equal to MPI2_IOCSTATUS_CONFIG_INVALID_PAGE value in the while loops in functions _scsih_search_responding_sas_devices, _scsih_search_responding_raid_devices and _scsih_search_responding_expanders So, Instead of checking for MPI2_IOCSTATUS_CONFIG_INVALID_PAGE value, in this patch code is modified to check for IOCStatus not equals to MPI2_IOCSTATUS_SUCCESS to break the while loop. Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: The copyright in driver sources is updated for the year 2013Sreekanth Reddy
The copyright in driver sources is updated for the year 2013. Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: MPI2 Rev X (2.00.16) specificationsSreekanth Reddy
Change set in MPI2 Rev x specification and 2.00.26 header files 1. Added two new AbortType values for TargetModeAbort Request: one to abort all IOs from a single initiator and other to abort only Command IUs. 2. Added Use Slot Information during Port Enable Event Reply flag to the Flags field of Manufacturing Page 7. 3. Added OEM Identifier to BiosOptions bits of BIOS Page 1. Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: Change in MPI2_RAID_ACTION_SYSTEM_SHUTDOWN_INITIATED ↵Sreekanth Reddy
notification methodology The intent of this patch is to perform a graceful shutdown of target drives even if volume doesn't exits. Changes done in this patch 1. Removed the check for the presence of volumes before sending down MPI2_RAID_ACTION_SYSTEM_SHUTDOWN_INITIATED. Therefore, this RAID action would be sent if the card is IR Firmware. 2. The MPI2_RAID_ACTION_SYSTEM_SHUTDOWN_INITIATED is sent even when the system undergoes suspend (in addition to remove/shutdown which was already present) Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03[SCSI] mpt2sas: Null pointer deference possibility in ↵Sreekanth Reddy
mpt2sas_ctl_event_callback function Added a check to identify if mpi_reply is NULL in mpt2sas_ctl_event_callback() and return without proceeding if it is the case. Also modified the following functions to return void instead of 0 or 1 as returning those values from events perspective doesn't make sense. * _base_async_event() * mpt2sas_ctl_event_callback() * mpt2sas_scsih_event_callback() Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@lsi.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-09-03pwm: pxa: Use module_platform_driverMike Dunn
Commit 76abbdde2d95a3807d0dc6bf9f84d03d0dbd4f3d pwm: Add sysfs interface causes a kernel oops due to a null pointer dereference on PXA platforms. This happens because the class added by the patch is registered in a subsys_initcall (initcall4), but the pxa pwm driver is registered in arch_initcall (initcall3). If the class is not registered before the driver probe function runs, the oops occurs in device_add() when the uninitialized pointers in struct class are dereferenced. I don't see a reason that the driver must be an arch_initcall, so this patch makes it a regular module_platform_driver (initcall6), preventing the oops. Signed-off-by: Mike Dunn <mikedunn@newsguy.com> Acked-by: Robert Jarzmik <robert.jarzmik@free.fr> Acked-by: Marek Vasut <marex@denx.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03pwm: tiehrpwm: add missing __iomem annotationJingoo Han
Fix the following sparse warnings: drivers/pwm/pwm-tiehrpwm.c:144:16: warning: incorrect type in argument 1 (different address spaces) drivers/pwm/pwm-tiehrpwm.c:144:16: expected void const volatile [noderef] <asn:2>*addr drivers/pwm/pwm-tiehrpwm.c:144:16: got void * drivers/pwm/pwm-tiehrpwm.c:149:9: warning: incorrect type in argument 2 (different address spaces) drivers/pwm/pwm-tiehrpwm.c:149:9: expected void volatile [noderef] <asn:2>*addr drivers/pwm/pwm-tiehrpwm.c:149:9: got void * drivers/pwm/pwm-tiehrpwm.c:157:18: warning: incorrect type in argument 1 (different address spaces) drivers/pwm/pwm-tiehrpwm.c:157:18: expected void const volatile [noderef] <asn:2>*addr drivers/pwm/pwm-tiehrpwm.c:157:18: got void * drivers/pwm/pwm-tiehrpwm.c:160:9: warning: incorrect type in argument 2 (different address spaces) drivers/pwm/pwm-tiehrpwm.c:160:9: expected void volatile [noderef] <asn:2>*addr drivers/pwm/pwm-tiehrpwm.c:160:9: got void * Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03pwm: tiecap: add CONFIG_PM_SLEEP to ecap_pwm_{save,restore}_context()Jingoo Han
ecap_pwm_save_context() and ecap_pwm_restore_context() are only used when CONFIG_PM_SLEEP is selected. drivers/pwm/pwm-tiecap.c:293:13: warning: 'ecap_pwm_save_context' defined but not used [-Wunused-function] drivers/pwm/pwm-tiecap.c:302:13: warning: 'ecap_pwm_restore_context' defined but not used [-Wunused-function] Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03pwm: simplify use of devm_ioremap_resourceJulia Lawall
Remove unneeded error handling on the result of a call to platform_get_resource when the value is passed to devm_ioremap_resource. Move the call to platform_get_resource adjacent to the call to devm_ioremap_resource to make the connection between them more clear. A simplified version of the semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression pdev,res,n,e,e1; expression ret != 0; identifier l; @@ - res = platform_get_resource(pdev, IORESOURCE_MEM, n); ... when != res - if (res == NULL) { ... \(goto l;\|return ret;\) } ... when != res + res = platform_get_resource(pdev, IORESOURCE_MEM, n); e = devm_ioremap_resource(e1, res); // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03pwm: renesas-tpu: Add DT supportLaurent Pinchart
Specify DT bindings for the TPU PWM controller and add OF support to the driver. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Acked-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03ARM: dts: Use the PWM polarity flagsLaurent Pinchart
Replace the numerical polarity flags with the PWM_POLARITY_INVERTED symbolic constant. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03pwm: Update DT bindings to reference pwm.txt for cells documentationLaurent Pinchart
The PWM client cells format is documented in the generic pwm.txt documentation and duplicated in all PWM driver bindings. Remove duplicate information and reference pwm.txt instead. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03pwm: Use the DT macro directly when parsing PWM DT flagsLaurent Pinchart
Don't redefine a PWM_SPEC_POLARITY macro with a value identical to PWM_POLARITY_INVERTED, use the PWM DT macro directly. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03pwm: Add PWM polarity flag macro for DTLaurent Pinchart
Define a PWM_POLARITY_INVERTED macro in include/dt-bindings/pwm/pwm.h to be used by device tree sources. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Reviewed-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03pwm: mxs: Check the return value from stmp_reset_block()Fabio Estevam
stmp_reset_block() may fail, so let's check its return value and propagate it in the case of error. Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2013-09-03Merge tag 'perf-core-for-mingo' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo: * 'perf trace' arg formatting improvements to allow masking arguments in syscalls such as futex and open, where the some arguments are ignored and thus should not be printed depending on other args. * Beautify futex open, openat, open_by_handle_at, lseek and futex syscalls. * Add dummy software event to use when wanting just to keep receiving PERF_RECORD_{MMAP,COMM,etc}, add test for it, from Adrian Hunter. * Fix symbol offset computation for some dsos in 'perf script', from David Ahern. * Skip unsupported hardware events in 'perf list', from Namhyung Kim. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-03Merge branch 'rcu/next' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney: " * Update RCU documentation. These were posted to LKML at https://lkml.org/lkml/2013/8/19/611. * Miscellaneous fixes. These were posted to LKML at https://lkml.org/lkml/2013/8/19/619. * Full-system idle detection. This is for use by Frederic Weisbecker's adaptive-ticks mechanism. Its purpose is to allow the timekeeping CPU to shut off its tick when all other CPUs are idle. These were posted to LKML at https://lkml.org/lkml/2013/8/19/648. * Improve rcutorture test coverage. These were posted to LKML at https://lkml.org/lkml/2013/8/19/675. " Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-02Linux 3.11v3.11Linus Torvalds
2013-09-02perf trace: Tell arg formatters the arg indexArnaldo Carvalho de Melo
... so that it can mask args relative to its position, like the 'mode' arg that may or not be printed according to the 'flags' (O_CREAT) value. [root@zoo ~]# perf trace -a -e openat,open_by_handle_at | head -1 469.754 ( 0.034 ms): 1183 openat(dfd: -100, filename: 0x7fbde40014b0, flags: CLOEXEC|DIRECTORY|NONBLOCK) = 23 [root@zoo ~]# Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-bgokqpkufd4sio7ixxknf1ux@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-09-02perf trace: Add beautifier for open's flags argArnaldo Carvalho de Melo
Suppressing the mode when O_CREAT not present, needs improvements on the arg masking mechanism to be reused in openat, open_by_handle_at, mq_open: [root@zoo ~]# perf trace -a -e open | grep -v 'flags: RDONLY' | head -5 147.541 ( 0.028 ms): 1188 open(filename: 0x33c17782fb, flags: CLOEXEC ) = 23 229.898 ( 0.020 ms): 2071 open(filename: 0x3d93c80, flags: NOATIME ) = -1 EPERM Operation not permitted [root@zoo ~]# perf trace -a -e open | grep CREAT 1406.697 ( 0.024 ms): 616 open(filename: 0x7fffc3a0f910, flags: CREAT|TRUNC|WRONLY, mode: 438 ) = -1 ENOENT No such file or directory 2032.770 ( 0.804 ms): 4354 open(filename: 0x7f33ac814368, flags: CREAT|EXCL|RDWR, mode: 384 ) = 115 ^C[root@zoo ~]# Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-c7vm6klaf995qw1vqdih5t7q@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-09-02lockref: implement lockless reference count updates using cmpxchg()Linus Torvalds
Instead of taking the spinlock, the lockless versions atomically check that the lock is not taken, and do the reference count update using a cmpxchg() loop. This is semantically identical to doing the reference count update protected by the lock, but avoids the "wait for lock" contention that you get when accesses to the reference count are contended. Note that a "lockref" is absolutely _not_ equivalent to an atomic_t. Even when the lockref reference counts are updated atomically with cmpxchg, the fact that they also verify the state of the spinlock means that the lockless updates can never happen while somebody else holds the spinlock. So while "lockref_put_or_lock()" looks a lot like just another name for "atomic_dec_and_lock()", and both optimize to lockless updates, they are fundamentally different: the decrement done by atomic_dec_and_lock() is truly independent of any lock (as long as it doesn't decrement to zero), so a locked region can still see the count change. The lockref structure, in contrast, really is a *locked* reference count. If you hold the spinlock, the reference count will be stable and you can modify the reference count without using atomics, because even the lockless updates will see and respect the state of the lock. In order to enable the cmpxchg lockless code, the architecture needs to do three things: (1) Make sure that the "arch_spinlock_t" and an "unsigned int" can fit in an aligned u64, and have a "cmpxchg()" implementation that works on such a u64 data type. (2) define a helper function to test for a spinlock being unlocked ("arch_spin_value_unlocked()") (3) select the "ARCH_USE_CMPXCHG_LOCKREF" config variable in its Kconfig file. This enables it for x86-64 (but not 32-bit, we'd need to make sure cmpxchg() turns into the proper cmpxchg8b in order to enable it for 32-bit mode). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-02lockref: uninline lockref helper functionsLinus Torvalds
They aren't very good to inline, since they already call external functions (the spinlock code), and we're going to create rather more complicated versions of them that can do the reference count updates locklessly. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-02vfs: reimplement d_rcu_to_refcount() using lockref_get_or_lock()Linus Torvalds
This moves __d_rcu_to_refcount() from <linux/dcache.h> into fs/namei.c and re-implements it using the lockref infrastructure instead. It also adds a lot of comments about what is actually going on, because turning a dentry that was looked up using RCU into a long-lived reference counted entry is one of the more subtle parts of the rcu walk. We also used to be _particularly_ subtle in unlazy_walk() where we re-validate both the dentry and its parent using the same sequence count. We used to do it by nesting the locks and then verifying the sequence count just once. That was silly, because nested locking is expensive, but the sequence count check is not. So this just re-validates the dentry and the parent separately, avoiding the nested locking, and making the lockref lookup possible. Acked-by: Waiman Long <waiman.long@hp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>