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2015-09-27ARM: dts: sun6i: Add accelerometer on Columbus A31Sander Vermin1-0/+7
Add mma8452 accelerometer to sun6i-a31-colombus.dts. Signed-off-by: Sander Vermin <sander@vermin.nl> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun5i: Add dts file for the Wobo i5 top set boxJelle van der Waa2-0/+225
The Wobo i5 top set box is a somewhat curious A10s based top set box, it uses an AXP209 rather then the AXP152 usually used in combination with the A10s. It has an ethernet phy connected to PORTD rather then PORTA, and its built-in usb wifi is connected via the otg controller. This commit adds a dts file adding support for this top set box. Signed-off-by: Jelle van der Waa <jelle@vdwaa.nl> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun5i: Add emac_pins_b definitionJelle van der Waa1-0/+11
The emac pins on an A10s can also be routed to the outside through PORTD rather then through PORTA, add a pinctrl node for this. Signed-off-by: Jelle van der Waa <jelle@vdwaa.nl> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27dts: sunxi: add eeprom to A20 OLinuXino micro boardOlliver Schinagl1-0/+6
The Olimex A20 OLinuXino Micro features an eeprom that is always on the board. This patch adds it to the dts. Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27dts: sunxi: add eeprom to A20 OLinuXino Lime2 boardOlliver Schinagl1-0/+6
The Olimex A20 OLinuXino Lime2 features an eeprom that is always on the board. This patch adds it to the dts. Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27dts: sunxi: add eeprom to A20 OLinuXino Lime boardOlliver Schinagl1-0/+12
The Olimex A20 OLinuXino Lime features an eeprom that is always on the board. This patch adds it to the dts. Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27dts: sunxi: correct vendor prefix on OLinuXino a10s microOlliver Schinagl1-1/+1
The OLinuXino A10S micro features an eeprom. According to the eeprom.txt binding document, we should use the manufacturer and 'at' is not the proper manufacturer id according to the vendor-prefixes. This patch takes the proper vendor-prefix and uses it for the eeprom node. Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27dts: sunxi: add eeprom to A10 OLinuXino Lime boardOlliver Schinagl1-0/+12
The Olimex A10 OLinuXino Lime features an eeprom that is always on the board. This patch adds it to the dts. Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun4i: Add dts file for iNet-1 based tabletsHans de Goede2-0/+227
The iNet-tek iNet-1 PCB is a PCB found in various generic 10.1" 1024x600 A10 based tablets such as the Point of View Protab2 XXL and the Cherry M1007. This patch has been tested on both rev2 and rev5 of this board / these tablets. It comes with a rtl8188cus usb wifi connected to ehci1, focal ft5406ee8 touchscreen connected to i2c2 addr 0x38, bosch bma 250 accelerometer connected to i2c1 addr 0x18 and the usual connectors: headphone, mini hdmi, power-barrel, mini-usb and a micro-sd slot. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun4i: Add dts file inet9f-rev03 based tabletsHans de Goede2-0/+228
The inet9f-rev03 pcb is specially designed for gaming tablets, such as the qware tb-g100 tablet. These 7" tablets feature a dpad, firebuttons and 2 joysticks on the sides of the screen. Besides this they have the usual connectors: power-barrel, mini usb, mini hdmi, headphone and micro-sd slot. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sunxi: Add sun?i-q8-common.dtsi files for q8 tabletsHans de Goede4-138/+162
Cheap allwinner based devices in the q8 enclosure come in many variants, all sharing the case and a number of other basic features. They differ in the display, touchscreen, accelerometer and wifi chips used. This commit adds 2 dtsi files defining the shared features of all the q8 tablets. sunxi-q8-common.dtsi defines features shared amongst all q8 tablets, sun8i-q8-common.dtsi defines features shared amongst all a23 / a33 based q8 tablets, but not with a13 q8 based tablets. a13 based tablets use a different card-detect pin for the mmc, and use uart1 instead of the r_uart for the serial console. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun5i: Add dts file for inet98v_rev2 based tabletsHans de Goede2-0/+228
The inet98v_rev2 is a pcb used in generic A13 based tablets. It features volume buttons, a power barrel, micro-usb otg, headphone connector and a power button. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun6i: Add mmc2 pins for 8 bit emmcChen-Yu Tsai1-0/+10
This also includes the reset pin for emmc. Signed-off-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun6i: Add lradc nodeChen-Yu Tsai1-0/+7
sun6i also has the LRADC for tablet buttons. Signed-off-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun4i: inet97fv2: Enable i2c1 and i2c2 controllersHans de Goede1-0/+12
Enable i2c1 and i2c2 controllers, these are used for the touchscreen resp. the accelerometer. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun4i: inet97fv2: Enable support for tablet keysHans de Goede1-0/+41
Enable support for the tablet keys which are connected via the lradc. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun4i: inet97fv2: Enable otg controllerHans de Goede1-0/+34
Enable the otg controller on the inet97fv2 tablet. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun4i: inet97fv2: Add regulator nodesHans de Goede1-4/+31
Use axp209.dtsi and add regulator nodes for the regulators used on the inet97fv2 tablet. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun4i: inet97fv2: Disable unused usb controllersHans de Goede1-17/+0
The inet97fv2 tablet only has a usb-2 wifi device connected to the second ehci controller, disable the first ehci controller and both ohci controllers. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun5i: Add support for the Auxtek-T003 HDMI stickHans de Goede2-0/+160
The Auxtek-T003 HDMI stick is an A10s based HDMI stick with USB wifi, and composite video out support. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun6i: hummingbird: Add missing pinmux setting for gmac phy resetChen-Yu Tsai1-1/+8
Signed-off-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun7i: Enable USB DRC on cubieboard2Ralph Benadski1-0/+19
Enable the otg/drc usb controller on the cubieboard2. Note this board has the otg-vbus connected directly to the 5v-dcc of the board, so there is no vbus0 regulator, nor vbus0-det. Signed-off-by: Ralph Benadski <benadski@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun7i: Enable USB DRC on pcDuino 3Jelle van der Waa1-0/+19
Enable the otg/drc usb controller on the pcDuino 3. Note this board has the otg-vbus connected directly to the 5v-dcc of the board, so there is no vbus0 regulator, nor vbus0-det. Signed-off-by: Jelle van der Waa <jelle@vdwaa.nl> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun8i: Add support for qt90h-v4 tabletsHans de Goede2-0/+146
The gt90h is a pcb found in generic 9" tablets with an A23 soc, 1G RAM and 8G nand, rtl8723as usb wifi, 1 micro usb port and 1 micro sd slot. This commit adds a dts for v4 of the gt90h pcb. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun7i: Add regulator configuration to the pcduino3 dts fileJelle van der Waa1-4/+31
Add regulator configuration to the pcduino3 dts file. Signed-off-by: Jelle van der Waa <jelle@vdwaa.nl> Signed-off-by: Hans de Goede <hdegoede@redhat.com> [Maxime: Removed usb_power_supply node that isn't defined in the DTSI] Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun5i: Add simplefb node for tvencoder outputHans de Goede1-0/+9
Add a simplefb node for tvencoder / composite-video output, such as found on the Auxtek-T003 and the CHIP. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-27ARM: dts: sun6i: Columbus: Add i2c controller for communicating with the LCDHans de Goede1-0/+17
The Colombus development kit uses an optional 2048x1536 edp panel using an anx9804 parallel lcd to edp converter. The anx9804 chip is controlled via an i2c bus which is connected to 2 regular gpio pins. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-13ARM: dts: sunxi: enable otg port on the sun7i-a20-olinuxino-lime2Olliver Schinagl1-0/+41
This patch enables the musb-otg USB controller on the Lime2. The Lime2 differs from the Lime1 series in pins used for usb0 power. Tested on a OlinuXino Lime2-4GB. Signed-off-by: Olliver Schinagl <oliver@schinagl.nl> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-13ARM: dts: sun4i: Enable i2c1 and i2c2 on the Chuwi V7-CW0825 tabletHans de Goede1-0/+12
i2c1 has a freescale mma7660 accelerometer connected to it at addr 0x4c, i2c2 has a ft5x touchscreen connected to it at addr 0x38. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-13ARM: dts: sun4i: Enable otg in host only mode on Jesurun Q5Hans de Goede1-0/+15
The Jesurun Q5 has the musb hooked up to an usb-a receptacle, enable it in host-only mode. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-13ARM: dts: Fix Makefile target for sun4i-a10-itead-iteaduino-plusJosh Boyer1-1/+1
Commit 79ae3e66f8d (ARM: dts: sun4i: Add Iteaduino Plus A10) added a new make target for the sun4i-a10-itead-iteaduino-plus dts file, but mistakenly used .dts instead of the correct .dtb suffix. This resulted in a build error like: scripts/Makefile.dtbinst:42: target 'sun4i-a10-itead-iteaduino-plus.dts' doesn't match the target pattern when doing a make dtbs_install. Fix it to use the proper file name. Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-13ARM: dts: sunxi: Raise minimum CPU voltage for sun7i-a20 to meet SoC specificationsTimo Sigurdsson1-1/+1
sun7i-a20.dtsi contains a cpufreq operating point at 0.9 volts. The minimum CPU voltage for the Allwinner A20 SoC, however, is 1.0 volts. Thus, raise the voltage for the lowest operating point to 1.0 volts in order to stay within the SoC specifications. It is an undervolted setting that isn't stable across all SoCs and boards out there. Cc: <stable@vger.kernel.org> # v4.0+ Fixes: d96b7161916f ("ARM: dts: sun7i: Add cpu clock reference and operating points to dtsi") Signed-off-by: Timo Sigurdsson <public_timo.s@silentcreek.de> Acked-by: Iain Paton <ipaton0@gmail.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
2015-09-12Linux 4.3-rc1Linus Torvalds1-2/+2
2015-09-12blk: rq_data_dir() should not return a booleanLinus Torvalds1-1/+1
rq_data_dir() returns either READ or WRITE (0 == READ, 1 == WRITE), not a boolean value. Now, admittedly the "!= 0" doesn't really change the value (0 stays as zero, 1 stays as one), but it's not only redundant, it confuses gcc, and causes gcc to warn about the construct switch (rq_data_dir(req)) { case READ: ... case WRITE: ... that we have in a few drivers. Now, the gcc warning is silly and stupid (it seems to warn not about the switch value having a different type from the case statements, but about _any_ boolean switch value), but in this case the code itself is silly and stupid too, so let's just change it, and get rid of warnings like this: drivers/block/hd.c: In function ‘hd_request’: drivers/block/hd.c:630:11: warning: switch condition has boolean value [-Wswitch-bool] switch (rq_data_dir(req)) { The odd '!= 0' came in when "cmd_flags" got turned into a "u64" in commit 5953316dbf90 ("block: make rq->cmd_flags be 64-bit") and is presumably because the old code (that just did a logical 'and' with 1) would then end up making the type of rq_data_dir() be u64 too. But if we want to retain the old regular integer type, let's just cast the result to 'int' rather than use that rather odd '!= 0'. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-12writeback: plug writeback in wb_writeback() and writeback_inodes_wb()Linus Torvalds1-0/+6
We had to revert the pluggin in writeback_sb_inodes() because the wb->list_lock is held, but we could easily plug at a higher level before taking that lock, and unplug after releasing it. This does that. Chris will run performance numbers, just to verify that this approach is comparable to the alternative (we could just drop and re-take the lock around the blk_finish_plug() rather than these two commits. I'd have preferred waiting for actual performance numbers before picking one approach over the other, but I don't want to release rc1 with the known "sleeping function called from invalid context" issue, so I'll pick this cleanup version for now. But if the numbers show that we really want to plug just at the writeback_sb_inodes() level, and we should just play ugly games with the spinlock, we'll switch to that. Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Neil Brown <neilb@suse.de> Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11thermal: fix intel PCH thermal driver mismergeLinus Torvalds1-7/+4
I didn't notice this when merging the thermal code from Zhang, but his merge (commit 5a924a07f882: "Merge branches 'thermal-core' and 'thermal-intel' of .git into next") of the thermal-core and thermal-intel branches was wrong. In thermal-core, commit 17e8351a7739 ("thermal: consistently use int for temperatures") converted the thermal layer to use "int" for temperatures. But in parallel, in the thermal-intel branch commit d0a12625d2ff ("thermal: Add Intel PCH thermal driver") added support for the intel PCH thermal sensor using the old interfaces that used "unsigned long" pointers. This resulted in warnings like this: drivers/thermal/intel_pch_thermal.c:184:14: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] .get_temp = pch_thermal_get_temp, ^ drivers/thermal/intel_pch_thermal.c:184:14: note: (near initialization for ‘tzd_ops.get_temp’) drivers/thermal/intel_pch_thermal.c:186:19: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] .get_trip_temp = pch_get_trip_temp, ^ drivers/thermal/intel_pch_thermal.c:186:19: note: (near initialization for ‘tzd_ops.get_trip_temp’) This fixes it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11ARCv2: [axs103_smp] Reduce clk for SMP FPGA configsVineet Gupta1-0/+2
Newer bitfiles needs the reduced clk even for SMP builds Cc: <stable@vger.kernel.org> #4.2 Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11revert "ocfs2/dlm: use list_for_each_entry instead of list_for_each"Andrew Morton1-2/+4
Revert commit f83c7b5e9fd6 ("ocfs2/dlm: use list_for_each_entry instead of list_for_each"). list_for_each_entry() will dereference its `pos' argument, which can be NULL in dlm_process_recovery_data(). Reported-by: Julia Lawall <julia.lawall@lip6.fr> Reported-by: Fengguang Wu <fengguang.wu@gmail.com> Cc: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11mm/early_ioremap: add explicit #include of asm/early_ioremap.hArd Biesheuvel1-0/+1
Commit 6b0f68e32ea8 ("mm: add utility for early copy from unmapped ram") introduces a function copy_from_early_mem() into mm/early_ioremap.c which itself calls early_memremap()/early_memunmap(). However, since early_memunmap() has not been declared yet at this point in the .c file, nor by any explicitly included header files, we are depending on a transitive include of asm/early_ioremap.h to declare it, which is fragile. So instead, include this header explicitly. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Mark Salter <msalter@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11fs/seq_file: convert int seq_vprint/seq_printf/etc... returns to voidJoe Perches4-50/+45
The seq_<foo> function return values were frequently misused. See: commit 1f33c41c03da ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") All uses of these return values have been removed, so convert the return types to void. Miscellanea: o Move seq_put_decimal_<type> and seq_escape prototypes closer the other seq_vprintf prototypes o Reorder seq_putc and seq_puts to return early on overflow o Add argument names to seq_vprintf and seq_printf o Update the seq_escape kernel-doc o Convert a couple of leading spaces to tabs in seq_escape Signed-off-by: Joe Perches <joe@perches.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mark Brown <broonie@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Joerg Roedel <jroedel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11selftests: enhance membarrier syscall testMathieu Desnoyers1-25/+75
Update the membarrier syscall self-test to match the membarrier interface. Extend coverage of the interface. Consider ENOSYS as a "SKIP" test, since it is a valid configuration, but does not allow testing the system call. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11selftests: add membarrier syscall testPranith Kumar4-0/+84
Add a self test for the membarrier system call. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11sys_membarrier(): system-wide memory barrier (generic, x86)Mathieu Desnoyers11-1/+151
Here is an implementation of a new system call, sys_membarrier(), which executes a memory barrier on all threads running on the system. It is implemented by calling synchronize_sched(). It can be used to distribute the cost of user-space memory barriers asymmetrically by transforming pairs of memory barriers into pairs consisting of sys_membarrier() and a compiler barrier. For synchronization primitives that distinguish between read-side and write-side (e.g. userspace RCU [1], rwlocks), the read-side can be accelerated significantly by moving the bulk of the memory barrier overhead to the write-side. The existing applications of which I am aware that would be improved by this system call are as follows: * Through Userspace RCU library (http://urcu.so) - DNS server (Knot DNS) https://www.knot-dns.cz/ - Network sniffer (http://netsniff-ng.org/) - Distributed object storage (https://sheepdog.github.io/sheepdog/) - User-space tracing (http://lttng.org) - Network storage system (https://www.gluster.org/) - Virtual routers (https://events.linuxfoundation.org/sites/events/files/slides/DPDK_RCU_0MQ.pdf) - Financial software (https://lkml.org/lkml/2015/3/23/189) Those projects use RCU in userspace to increase read-side speed and scalability compared to locking. Especially in the case of RCU used by libraries, sys_membarrier can speed up the read-side by moving the bulk of the memory barrier cost to synchronize_rcu(). * Direct users of sys_membarrier - core dotnet garbage collector (https://github.com/dotnet/coreclr/issues/198) Microsoft core dotnet GC developers are planning to use the mprotect() side-effect of issuing memory barriers through IPIs as a way to implement Windows FlushProcessWriteBuffers() on Linux. They are referring to sys_membarrier in their github thread, specifically stating that sys_membarrier() is what they are looking for. To explain the benefit of this scheme, let's introduce two example threads: Thread A (non-frequent, e.g. executing liburcu synchronize_rcu()) Thread B (frequent, e.g. executing liburcu rcu_read_lock()/rcu_read_unlock()) In a scheme where all smp_mb() in thread A are ordering memory accesses with respect to smp_mb() present in Thread B, we can change each smp_mb() within Thread A into calls to sys_membarrier() and each smp_mb() within Thread B into compiler barriers "barrier()". Before the change, we had, for each smp_mb() pairs: Thread A Thread B previous mem accesses previous mem accesses smp_mb() smp_mb() following mem accesses following mem accesses After the change, these pairs become: Thread A Thread B prev mem accesses prev mem accesses sys_membarrier() barrier() follow mem accesses follow mem accesses As we can see, there are two possible scenarios: either Thread B memory accesses do not happen concurrently with Thread A accesses (1), or they do (2). 1) Non-concurrent Thread A vs Thread B accesses: Thread A Thread B prev mem accesses sys_membarrier() follow mem accesses prev mem accesses barrier() follow mem accesses In this case, thread B accesses will be weakly ordered. This is OK, because at that point, thread A is not particularly interested in ordering them with respect to its own accesses. 2) Concurrent Thread A vs Thread B accesses Thread A Thread B prev mem accesses prev mem accesses sys_membarrier() barrier() follow mem accesses follow mem accesses In this case, thread B accesses, which are ensured to be in program order thanks to the compiler barrier, will be "upgraded" to full smp_mb() by synchronize_sched(). * Benchmarks On Intel Xeon E5405 (8 cores) (one thread is calling sys_membarrier, the other 7 threads are busy looping) 1000 non-expedited sys_membarrier calls in 33s =3D 33 milliseconds/call. * User-space user of this system call: Userspace RCU library Both the signal-based and the sys_membarrier userspace RCU schemes permit us to remove the memory barrier from the userspace RCU rcu_read_lock() and rcu_read_unlock() primitives, thus significantly accelerating them. These memory barriers are replaced by compiler barriers on the read-side, and all matching memory barriers on the write-side are turned into an invocation of a memory barrier on all active threads in the process. By letting the kernel perform this synchronization rather than dumbly sending a signal to every process threads (as we currently do), we diminish the number of unnecessary wake ups and only issue the memory barriers on active threads. Non-running threads do not need to execute such barrier anyway, because these are implied by the scheduler context switches. Results in liburcu: Operations in 10s, 6 readers, 2 writers: memory barriers in reader: 1701557485 reads, 2202847 writes signal-based scheme: 9830061167 reads, 6700 writes sys_membarrier: 9952759104 reads, 425 writes sys_membarrier (dyn. check): 7970328887 reads, 425 writes The dynamic sys_membarrier availability check adds some overhead to the read-side compared to the signal-based scheme, but besides that, sys_membarrier slightly outperforms the signal-based scheme. However, this non-expedited sys_membarrier implementation has a much slower grace period than signal and memory barrier schemes. Besides diminishing the number of wake-ups, one major advantage of the membarrier system call over the signal-based scheme is that it does not need to reserve a signal. This plays much more nicely with libraries, and with processes injected into for tracing purposes, for which we cannot expect that signals will be unused by the application. An expedited version of this system call can be added later on to speed up the grace period. Its implementation will likely depend on reading the cpu_curr()->mm without holding each CPU's rq lock. This patch adds the system call to x86 and to asm-generic. [1] http://urcu.so membarrier(2) man page: MEMBARRIER(2) Linux Programmer's Manual MEMBARRIER(2) NAME membarrier - issue memory barriers on a set of threads SYNOPSIS #include <linux/membarrier.h> int membarrier(int cmd, int flags); DESCRIPTION The cmd argument is one of the following: MEMBARRIER_CMD_QUERY Query the set of supported commands. It returns a bitmask of supported commands. MEMBARRIER_CMD_SHARED Execute a memory barrier on all threads running on the system. Upon return from system call, the caller thread is ensured that all running threads have passed through a state where all memory accesses to user-space addresses match program order between entry to and return from the system call (non-running threads are de facto in such a state). This covers threads from all pro=E2=80=90 cesses running on the system. This command returns 0. The flags argument needs to be 0. For future extensions. All memory accesses performed in program order from each targeted thread is guaranteed to be ordered with respect to sys_membarrier(). If we use the semantic "barrier()" to represent a compiler barrier forcing memory accesses to be performed in program order across the barrier, and smp_mb() to represent explicit memory barriers forcing full memory ordering across the barrier, we have the following ordering table for each pair of barrier(), sys_membarrier() and smp_mb(): The pair ordering is detailed as (O: ordered, X: not ordered): barrier() smp_mb() sys_membarrier() barrier() X X O smp_mb() X O O sys_membarrier() O O O RETURN VALUE On success, these system calls return zero. On error, -1 is returned, and errno is set appropriately. For a given command, with flags argument set to 0, this system call is guaranteed to always return the same value until reboot. ERRORS ENOSYS System call is not implemented. EINVAL Invalid arguments. Linux 2015-04-15 MEMBARRIER(2) Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Miell <nmiell@comcast.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11MODSIGN: fix a compilation warning in extract-certDavid Howells1-1/+1
Fix the following warning when compiling extract-cert: scripts/extract-cert.c: In function `write_cert': scripts/extract-cert.c:89:2: warning: format not a string literal and no format arguments [-Wformat-security] ERR(!i2d_X509_bio(wb, x509), cert_dst); ^ whereby the ERR() macro is taking cert_dst as the format string. "%s" should be used as the format string as the path could contain special characters. Signed-off-by: David Howells <dhowells@redhat.com> Reported-by: Jim Davis <jim.epost@gmail.com> Acked-by : David Woodhouse <david.woodhouse@intel.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11Revert "writeback: plug writeback at a high level"Linus Torvalds1-3/+4
This reverts commit d353d7587d02116b9732d5c06615aed75a4d3a47. Doing the block layer plug/unplug inside writeback_sb_inodes() is broken, because that function is actually called with a spinlock held: wb->list_lock, as pointed out by Chris Mason. Chris suggested just dropping and re-taking the spinlock around the blk_finish_plug() call (the plgging itself can happen under the spinlock), and that would technically work, but is just disgusting. We do something fairly similar - but not quite as disgusting because we at least have a better reason for it - in writeback_single_inode(), so it's not like the caller can depend on the lock being held over the call, but in this case there just isn't any good reason for that "release and re-take the lock" pattern. [ In general, we should really strive to avoid the "release and retake" pattern for locks, because in the general case it can easily cause subtle bugs when the caller caches any state around the call that might be invalidated by dropping the lock even just temporarily. ] But in this case, the plugging should be easy to just move up to the callers before the spinlock is taken, which should even improve the effectiveness of the plug. So there is really no good reason to play games with locking here. I'll send off a test-patch so that Dave Chinner can verify that that plug movement works. In the meantime this just reverts the problematic commit and adds a comment to the function so that we hopefully don't make this mistake again. Reported-by: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Neil Brown <neilb@suse.de> Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-11scsi_dh: fix randconfig build errorChristoph Hellwig1-1/+1
It looks like the Kconfig check that was meant to fix this (commit fe9233fb6914a0eb20166c967e3020f7f0fba2c9 [SCSI] scsi_dh: fix kconfig related build errors) was actually reversed, but no-one noticed until the new set of patches which separated DM and SCSI_DH). Fixes: fe9233fb6914a0eb20166c967e3020f7f0fba2c9 Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-09-11target: use stringify.h instead of own definitionDavid Disseldorp2-5/+2
Signed-off-by: David Disseldorp <ddiss@suse.de> Acked-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target/user: Fix UFLAG_UNKNOWN_OP handlingAndy Grover1-8/+2
Calling transport_generic_request_failure() from here causes list corruption. We should be using target_complete_cmd() instead. Which we do in all other cases, so the UNKNOWN_OP case can become just another member of the big else/if chain in tcmu_handle_completion(). Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target: Remove no-op conditionalAndy Grover1-2/+1
This does nothing, and there are many other places where transport_cmd_check_stop_to_fabric()'s retval is not checked>, If we wanted to check it here, we should probably do it those other places too. Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-09-11target/user: Remove unused variableAndy Grover1-1/+0
We don't use it any more. Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>