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* mmc: sdhci-pci: add platform dataAdrian Hunter2012-01-116-7/+54
| | | | | | | | | | | | | | Add a means of getting platform data for the SDHCI PCI devices. The data is stored against the slot not the device in order to support multi-slot devices. The data allows platform-specific setup (such as getting GPIO numbers from firmware or setting up wl12xx for SDIO) to be done in platform support files instead of the sdhci-pci driver. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdhci: prevent card detection activity for non-removable cardsAdrian Hunter2012-01-111-4/+3
| | | | | | | Do not enable card detection interrupts for non-removable cards. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdhci: fix vmmc handlingAdrian Hunter2012-01-111-22/+21
| | | | | | | | | | Presently the vmmc regulator is enabled when the host controller is added and disabled when it is removed. However, the vmmc regulator should be under the control of the upper layers via ->set_ios(). Make it so. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: core: Add claiming of hosts during mmc_cache_ctrlSeungwon Jeon2012-01-111-1/+7
| | | | | | | | While calling mmc_cache_ctrl() a host is not claimed. This patch adds the mmc_try_claim_host() for quick response in suspend. Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: omap: remove clock rate hard codingBalaji TK2012-01-111-4/+3
| | | | | | | | | | | MMC master clock rate can vary for each instance of the MMC controller on the device. Use clk_get_rate instead to get the value. Signed-off-by: Balaji TK <balajitk@ti.com> Reviewed-by: Venkatraman S <svenkatr@ti.com> Tested-by: Hebbar, Gururaja <gururaja.hebbar@ti.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sh_mmcif: remove now superfluous sh_mmcif_host::data memberGuennadi Liakhovetski2012-01-111-44/+50
| | | | | Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sh_mmcif: process requests asynchronouslyGuennadi Liakhovetski2012-01-111-172/+416
| | | | | | | | | This patch converts the sh_mmcif MMC host driver to process requests asynchronously instead of waiting in its .request() method for completion. This is achieved by using threaded IRQs. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sh_mmcif: cosmetic clean upGuennadi Liakhovetski2012-01-111-45/+34
| | | | | | | | This patch doesn't introduce any functional changes, it only simplifies some code fragments, removes superfluous parameters, fixes typos. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sh_mmcif: process error interrupts firstGuennadi Liakhovetski2012-01-111-6/+6
| | | | | | | | | | | If an interrupt is coming with both error and data completion status bits set, it has to be handled as an error interrupt, for which error interrupts have to be processed first. The current version of the driver on the contrary doesn't recognise such interrupts as an error event, which leads to data corruption and breaks the error recovery. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: add a generic GPIO card-detect helperGuennadi Liakhovetski2012-01-113-1/+94
| | | | | | | | | This patch adds a primitive helper to support card hotplug detection on platforms, where a GPIO, capable of producing interrupts, is used for detection of card-insertion and -removal events. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: add a card hotplug handler contextGuennadi Liakhovetski2012-01-111-0/+6
| | | | | | | | | | | | | | | SD/MMC controllers provide different card insertion and removal detection methods. On some of them the controller itself issues an interrupt, on others polling is used, on yet others auxiliary means are used for this purpose, e.g., a GPIO IRQ. Further, on some systems one of those methods can be chosen at driver probing time and configured in software. E.g., on some systems the SD/MMC controller card hot-plug detection pin can be configured either as a respective controller functions, or an IRQ-capable GPIO. To support such flexible configurations a card hot-plug context is added by this patch. Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: tmio_mmc: Hotplug code regroupingBastian Hecht2012-01-111-9/+21
| | | | | | | | | | This patch regroups the code slightly, adds documentation and allows the rtpm counter of MMC_CAP_NEEDS_POLL devices to reach 0 again. Signed-off-by: Bastian Hecht <hechtb@gmail.com> [g.liakhovetski@gmx.de: restore pm_runtime_get_noresume()] Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: core: Fix voltage select in DDR modeGirish K S2012-01-111-1/+1
| | | | | | | | | | | | | | | This patch fixes the wrong comparison before setting the interface voltage in DDR mode. The assignment to the variable ddr before comaprison is either ddr = MMC_1_2V_DDR_MODE; or ddr == MMC_1_8V_DDR_MODE. But the comparison is done with the extended csd value if ddr == EXT_CSD_CARD_TYPE_DDR_1_2V. Signed-off-by: Girish K S <girish.shivananjappa@linaro.org> Acked-by: Subhash Jadavani <subhashj@codeaurora.org> Acked-by: Philip Rakity <prakity@marvell.com> Cc: <stable@kernel.org> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdhci-s3c: use S3C_SDHCI_CONTROL2 instead of hardcoded offset valueJingoo Han2012-01-111-1/+1
| | | | | Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: dw_mmc: Support predefined mutiple block transfersSeungwon Jeon2012-01-111-6/+28
| | | | | | | | | This patch adds the support for predefined multiple block r/w. dw_mmc can support MMC_CAP_CMD23 capability. Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com> Acked-by: Will Newton <will.newton@imgtec.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: dw_mmc: Remove unnecessary else clausesChris Ball2012-01-111-5/+0
| | | | Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: dw_mmc: Add more capabilities fieldSeungwon Jeon2012-01-112-0/+7
| | | | | | | This patch adds another capabilities field for MMC_CAPS2_XXX. Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: dw_mmc: use dev_pm_ops for dw_mmc controllersJaehoon Chung2012-01-111-9/+10
| | | | | | | | | This patch modifies dw_mmc to use dev_pm_ops. Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: card: Kill block requests if card is removedSujit Reddy Thumma2012-01-112-1/+21
| | | | | | | | | | | Kill block requests when the host realizes that the card is removed from the slot and is sure that subsequent requests are bound to fail. Do this silently so that the block layer doesn't output unnecessary error messages. Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: core: Fixup delayed work clock gating patchStephen Boyd2012-01-112-6/+2
| | | | | | | | | | | | | | | | | c31b50e (mmc: core: Use delayed work in clock gating framework, 2011-11-14) missed a few things during review: o A useless pr_info() o milliseconds was written as two words o The sysfs file had units in its output Fix all three problems. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Sujit Reddy Thumma <sthumma@codeaurora.org> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdhci-pci: simplify error handlingAxel Lin2012-01-111-20/+18
| | | | | | Signed-off-by: Axel Lin <axel.lin@gmail.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: boot partition ro lock supportJohan Rudholm2012-01-115-11/+153
| | | | | | | | | | | | | Enable boot partitions to be read-only locked until next power on via a sysfs entry. There will be one sysfs entry for each boot partition: /sys/block/mmcblkXbootY/ro_lock_until_next_power_on Each boot partition is locked by writing 1 to its file. Signed-off-by: Johan Rudholm <johan.rudholm@stericsson.com> Signed-off-by: John Beckett <john.beckett@stericsson.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* ARM: SAMSUNG: Add pm_caps into platform dataSangwook Lee2012-01-112-0/+3
| | | | | | | | | Add pm_caps into platform_data. This is power management, usually for SDIO device such as SDIO WLAN. Signed-off-by: Sangwook Lee <sangwook.lee@samsung.com> Acked-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdhci-s3c: Add pm_caps into SD/MMC hostSangwook Lee2012-01-111-0/+3
| | | | | | | sdhci-s3c updates pm_caps from platform data for SDIO PM. Signed-off-by: Sangwook Lee <sangwook.lee@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: allow upper layers to know immediately if card has been removedAdrian Hunter2012-01-118-6/+89
| | | | | | | | | | | | Add a function mmc_detect_card_removed() which upper layers can use to determine immediately if a card has been removed. This function should be called after an I/O request fails so that all queued I/O requests can be errored out immediately instead of waiting for the card device to be removed. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Acked-by: Sujit Reddy Thumma <sthumma@codeaurora.org> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: remove the second argument of k[un]map_atomic()Cong Wang2012-01-115-19/+19
| | | | | | Signed-off-by: Cong Wang <amwang@redhat.com> Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: convert drivers/mmc/host/* to use module_platform_driver()Axel Lin2012-01-1121-243/+21
| | | | | | | | | | | | | | | | This patch converts the drivers in drivers/mmc/host/* to use the module_platform_driver() macro which makes the code smaller and a bit simpler. Signed-off-by: Axel Lin <axel.lin@gmail.com> Acked-by: "Michał Mirosław" <mirq-linux@rere.qmqm.pl> Acked-by: David Brown <davidb@codeaurora.org> Acked-by: Viresh Kumar <viresh.kumar@st.com> Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Acked-by: Sascha Hauer <s.hauer@pengutronix.de> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Anton Vorontsov <cbouatmailru@gmail.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: Remove redundant spi driver bus initializationLars-Peter Clausen2012-01-111-1/+0
| | | | | | | | | | | | | | | | | | | | | In ancient times it was necessary to manually initialize the bus field of an spi_driver to spi_bus_type. These days this is done in spi_driver_register(), so we can drop the manual assignment. The patch was generated using the following coccinelle semantic patch: // <smpl> @@ identifier _driver; @@ struct spi_driver _driver = { .driver = { - .bus = &spi_bus_type, }, }; // </smpl> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sh_mmcif: simplify clock divisor calculationGuennadi Liakhovetski2012-01-111-1/+2
| | | | | | | | | Replace ilog2(__rounddown_pow_of_two(x)) with the equivalent but much simpler fls(x) - 1. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: core: check for zero length ioctl dataJohan Rudholm2012-01-111-37/+45
| | | | | | | | | | | If the read or write buffer size associated with the command sent through the mmc_blk_ioctl is zero, do not prepare data buffer. This enables a ioctl(2) call to for instance send a MMC_SWITCH to set a byte in the ext_csd. Signed-off-by: Johan Rudholm <johan.rudholm@stericsson.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdhci-esdhc: Change delay after setting clock from 100ms to 1msTony Lin2012-01-111-1/+1
| | | | | | | | | | 1ms is enough for hardware to change the clock to stable. 100ms is too long in the tasklet. Signed-off-by: Tony Lin <tony.lin@freescale.com> CC: Xiaobo Xie <X.Xie@freescale.com> CC: Anton Vorontsov <avorontsov@ru.mvista.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: mmc_test: align max_seg_sizePer Forlin2012-01-111-0/+1
| | | | | | | | | If max_seg_size is unaligned, mmc_test_map_sg() may create sg element sizes that are not aligned with 512 byte. Fix, align max_seg_size at mmc_test_area_init(). Signed-off-by: Per Forlin <per.forlin@stericsson.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: mmci: add capabilities2 for MMC_CAP2Per Forlin2012-01-112-0/+3
| | | | | Signed-off-by: Per Forlin <per.forlin@stericsson.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdio: support SDIO UHS cardsPhilip Rakity2012-01-115-30/+336
| | | | | | | | | | | | | | | | | | | This patch adds support for sdio UHS cards per the version 3.0 spec. UHS mode is only enabled for version 3.0 cards when both the host and the controller support UHS modes. 1.8v signaling support is removed if both the card and the host do not support UHS. This is done to maintain compatibility and some system/card combinations break when 1.8v signaling is enabled when the host does not support UHS. Signed-off-by: Philip Rakity <prakity@marvell.com> Signed-off-by: Aaron Lu <Aaron.lu@amd.com> Reviewed-by: Arindam Nath <arindam.nath@amd.com> Tested-by: Bing Zhao <bzhao@marvell.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdhci-spear: Implement suspend/resumeViresh Kumar2012-01-111-0/+40
| | | | | | | | Suspend/Resume is missing from sdhci-spear driver. This patch adds support for suspend/resume for this driver. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: core: Use delayed work in clock gating frameworkSujit Reddy Thumma2012-01-113-5/+66
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current clock gating framework disables the MCI clock as soon as the request is completed and enables it when a request arrives. This aggressive clock gating framework, when enabled, cause following issues: When there are back-to-back requests from the Queue layer, we unnecessarily end up disabling and enabling the clocks between these requests since 8MCLK clock cycles is a very short duration compared to the time delay between back to back requests reaching the MMC layer. This overhead can effect the overall performance depending on how long the clock enable and disable calls take which is platform dependent. For example on some platforms we can have clock control not on the local processor, but on a different subsystem and the time taken to perform the clock enable/disable can add significant overhead. Also if the host controller driver decides to disable the host clock too when mmc_set_ios function is called with ios.clock=0, it adds additional delay and it is highly possible that the next request had already arrived and unnecessarily blocked in enabling the clocks. This is seen frequently when the processor is executing at high speeds and in multi-core platforms thus reduces the overall throughput compared to if clock gating is disabled. Fix this by delaying turning off the clocks by posting request on delayed workqueue. Also cancel the unscheduled pending work, if any, when there is access to card. sysfs entry is provided to tune the delay as needed, default value set to 200ms. Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: card: Use manufacturer ID symbols in card quirks.Chris Ball2012-01-111-9/+18
| | | | | | | | No functional change; adds macros for card manufacturer IDs. Signed-off-by: Chris Ball <cjb@laptop.org> Cc: Andrei E. Warkentin <andrey.warkentin@gmail.com> Cc: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com>
* mmc: debugfs: expose the SDCLK frq in sys iosGiuseppe CAVALLARO2012-01-113-0/+14
| | | | | | | | | | | | | | This patch is to expose the actual SDCLK frequency in /sys/kernel/debug/mmcX/ios entry. For example, if the max clk for a normal speed card is 20MHz this is reported in /sys/kernel/debug/mmcX/ios. Unfortunately the actual SDCLK frequency (i.e. Baseclock / divisor) is not reported at all: for example, in that case, on Arasan HC, it should be 48/4=12 (MHz). Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sdio: Fix to support any block size optimallyStefan Nilsson XK2012-01-112-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | This patch allows any block size to be set on the SDIO link, and still have an arbitrary sized packet (adjusted in size by using sdio_align_size) transferred in an optimal way (preferably one transfer). Previously if the block size was larger than the default of 512 bytes and the transfer size was exactly one block size (possibly thanks to using sdio_align_size to get an optimal transfer size), it was sent as a number of byte transfers instead of one block transfer. Also if the number of blocks was (max_blocks * N) + 1, the tranfer would be conducted with a number of blocks and finished off with a number of byte transfers. When doing this change it was also possible to break out the quirk for broken byte mode in a much cleaner way, and collect the logic of when to do byte or block transfer in one function instead of two. Signed-off-by: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com> Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Chris Ball <cjb@laptop.org>
* mmc: sd: Macro name cleanup for high speed dtrQiang Liu2012-01-112-2/+5
| | | | | | | | Add new macros for the high speed 50MHz case, rather than having a confusing reuse of the value for UHS SDR50, which is 100MHz. Reported-by: Aaron Lu <aaron.lu@amd.com> Signed-off-by: Chris Ball <cjb@laptop.org>
* m68k: remove duplicate asm offset for task thread.infoGreg Ungerer2011-12-242-2/+1
| | | | | | | | | We have a duplicate name and definition for the offset of the thread.info struct within the task struct in our asm-offsets.c code. Remove one of them, and consolidate to use a single define, TASK_INFO. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
* m68k: merge the init_task code for mmu and non-mmu targetsGreg Ungerer2011-12-243-23/+3
| | | | | | | | | | | | | The init_task code can be the same for both mmu and non-mmu targets. None of the alignment carried out in the the current init_task code is necessary. The linker script takes care of aligning the init_thread structure to a THREAD SIZE boundary, and that is all we need. So use the init_task.c code for all target types, that makes m68k code consistent with what most other architectures do. Signed-off-by: Greg Ungerer <gerg@uclinux.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
* m68knommu: remove unused fasthandler declarationGreg Ungerer2011-12-241-1/+0
| | | | | | | The fasthandler code was removed long ago. Remove the now unused declaration of it. Signed-off-by: Greg Ungerer <gerg@uclinux.org>
* m68k: Fall back to __gpio_to_irq() for non-arch GPIOsMark Brown2011-12-241-1/+2
| | | | | | | | gpiolib provides __gpio_to_irq() to map gpiolib gpios to interrupts - hook that up on m68k. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Greg Ungerer <gerg@uclinux.org>
* clocksource: m86k: Convert to clocksource_register_hz/khzjohn stultz2011-12-245-16/+5
| | | | | | | | | | | | | Updated to merge the valid bits of the two m68k patches. This converts the m86k clocksources to use clocksource_register_hz/khz This is untested, so any assistance in testing would be appreciated! CC: Geert Uytterhoeven <geert@linux-m68k.org> CC: Greg Ungerer <gerg@uclinux.org> Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Greg Ungerer <gerg@uclinux.org>
* Linux 3.2-rc7v3.2-rc7Linus Torvalds2011-12-231-1/+1
|
* Merge branch 'for-linus' of ↵Linus Torvalds2011-12-231-4/+32
|\ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: VFS: Fix race between CPU hotplug and lglocks
| * VFS: Fix race between CPU hotplug and lglocksSrivatsa S. Bhat2011-12-221-4/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the *_global_[un]lock_online() routines are not at all synchronized with CPU hotplug. Soft-lockups detected as a consequence of this race was reported earlier at https://lkml.org/lkml/2011/8/24/185. (Thanks to Cong Meng for finding out that the root-cause of this issue is the race condition between br_write_[un]lock() and CPU hotplug, which results in the lock states getting messed up). Fixing this race by just adding {get,put}_online_cpus() at appropriate places in *_global_[un]lock_online() is not a good option, because, then suddenly br_write_[un]lock() would become blocking, whereas they have been kept as non-blocking all this time, and we would want to keep them that way. So, overall, we want to ensure 3 things: 1. br_write_lock() and br_write_unlock() must remain as non-blocking. 2. The corresponding lock and unlock of the per-cpu spinlocks must not happen for different sets of CPUs. 3. Either prevent any new CPU online operation in between this lock-unlock, or ensure that the newly onlined CPU does not proceed with its corresponding per-cpu spinlock unlocked. To achieve all this: (a) We introduce a new spinlock that is taken by the *_global_lock_online() routine and released by the *_global_unlock_online() routine. (b) We register a callback for CPU hotplug notifications, and this callback takes the same spinlock as above. (c) We maintain a bitmap which is close to the cpu_online_mask, and once it is initialized in the lock_init() code, all future updates to it are done in the callback, under the above spinlock. (d) The above bitmap is used (instead of cpu_online_mask) while locking and unlocking the per-cpu locks. The callback takes the spinlock upon the CPU_UP_PREPARE event. So, if the br_write_lock-unlock sequence is in progress, the callback keeps spinning, thus preventing the CPU online operation till the lock-unlock sequence is complete. This takes care of requirement (3). The bitmap that we maintain remains unmodified throughout the lock-unlock sequence, since all updates to it are managed by the callback, which takes the same spinlock as the one taken by the lock code and released only by the unlock routine. Combining this with (d) above, satisfies requirement (2). Overall, since we use a spinlock (mentioned in (a)) to prevent CPU hotplug operations from racing with br_write_lock-unlock, requirement (1) is also taken care of. By the way, it is to be noted that a CPU offline operation can actually run in parallel with our lock-unlock sequence, because our callback doesn't react to notifications earlier than CPU_DEAD (in order to maintain our bitmap properly). And this means, since we use our own bitmap (which is stale, on purpose) during the lock-unlock sequence, we could end up unlocking the per-cpu lock of an offline CPU (because we had locked it earlier, when the CPU was online), in order to satisfy requirement (2). But this is harmless, though it looks a bit awkward. Debugged-by: Cong Meng <mc@linux.vnet.ibm.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org
* | Merge tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linuxLinus Torvalds2011-12-232-13/+13
|\ \ | | | | | | | | | | | | | | | | | | for linus: writeback reason binary tracing format fix * tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux: writeback: show writeback reason with __print_symbolic
| * | writeback: show writeback reason with __print_symbolicWu Fengguang2011-12-182-13/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | This makes the binary trace understandable by trace-cmd. CC: Dave Chinner <david@fromorbit.com> CC: Curt Wohlgemuth <curtw@google.com> CC: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
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