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2020-08-13doc: dt: bindings: usb: dwc3: Update entries for disabling SS instances in ↵Neil Armstrong
park mode commit 3d157c28d2289edf0439e8308e8de3a06acaaf0e upstream. This patch updates the documentation with the information related to the quirks that needs to be added for disabling all SuperSpeed XHCI instances in park mode. Cc: Dongjin Kim <tobetter@gmail.com> Cc: Jianxin Pan <jianxin.pan@amlogic.com> Cc: Thinh Nguyen <thinhn@synopsys.com> Cc: Jun Li <lijun.kernel@gmail.com> Reported-by: Tim <elatllat@gmail.com> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Felipe Balbi <balbi@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-08-13dt-bindings: mailbox: zynqmp_ipi: fix unit addressKangmin Park
commit 35b9c0fdb9f666628ecda02b1fc44306933a2d97 upstream. Fix unit address to match the first address specified in the reg property of the node in example. Signed-off-by: Kangmin Park <l4stpr0gr4m@gmail.com> Link: https://lore.kernel.org/r/20200625135158.5861-1-l4stpr0gr4m@gmail.com Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-11dt-bindings: display: mediatek: control dpi pins mode to avoid leakageJitao Shi
commit b0ff9b590733079f7f9453e5976a9dd2630949e3 upstream. Add property "pinctrl-names" to swap pin mode between gpio and dpi mode. Set the dpi pins to gpio mode and output-low to avoid leakage current when dpi disabled. Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com> Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-11x86/kvm/hyper-v: Explicitly align hcall param for kvm_hyperv_exitJon Doron
commit f7d31e65368aeef973fab788aa22c4f1d5a6af66 upstream. The problem the patch is trying to address is the fact that 'struct kvm_hyperv_exit' has different layout on when compiling in 32 and 64 bit modes. In 64-bit mode the default alignment boundary is 64 bits thus forcing extra gaps after 'type' and 'msr' but in 32-bit mode the boundary is at 32 bits thus no extra gaps. This is an issue as even when the kernel is 64 bit, the userspace using the interface can be both 32 and 64 bit but the same 32 bit userspace has to work with 32 bit kernel. The issue is fixed by forcing the 64 bit layout, this leads to ABI change for 32 bit builds and while we are obviously breaking '32 bit userspace with 32 bit kernel' case, we're fixing the '32 bit userspace with 64 bit kernel' one. As the interface has no (known) users and 32 bit KVM is rather baroque nowadays, this seems like a reasonable decision. Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Jon Doron <arilou@gmail.com> Message-Id: <20200424113746.3473563-2-arilou@gmail.com> Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-07ALSA: hda/realtek - Remove now-unnecessary XPS 13 headphone noise fixupsThomas Hebb
commit f36938aa7440f46a0a365f1cfde5f5985af2bef3 upstream. patch_realtek.c has historically failed to properly configure the PC Beep Hidden Register for the ALC256 codec (among others). Depending on your kernel version, symptoms of this misconfiguration can range from chassis noise, picked up by a poorly-shielded PCBEEP trace, getting amplified and played on your internal speaker and/or headphones to loud feedback, which responds to the "Headphone Mic Boost" ALSA control, getting played through your headphones. For details of the problem, see the patch in this series titled "ALSA: hda/realtek - Set principled PC Beep configuration for ALC256", which fixes the configuration. These symptoms have been most noticed on the Dell XPS 13 9350 and 9360, popular laptops that use the ALC256. As a result, several model-specific fixups have been introduced to try and fix the problem, the most egregious of which locks the "Headphone Mic Boost" control as a hack to minimize noise from a feedback loop that shouldn't have been there in the first place. Now that the underlying issue has been fixed, remove all these fixups. Remaining fixups needed by the XPS 13 are all picked up by existing pin quirks. This change should, for the XPS 13 9350/9360 - Significantly increase volume and audio quality on headphones - Eliminate headphone popping on suspend/resume - Allow "Headphone Mic Boost" to be set again, making the headphone jack fully usable as a microphone jack too. Fixes: 8c69729b4439 ("ALSA: hda - Fix headphone noise after Dell XPS 13 resume back from S3") Fixes: 423cd785619a ("ALSA: hda - Fix headphone noise on Dell XPS 13 9360") Fixes: e4c9fd10eb21 ("ALSA: hda - Apply headphone noise quirk for another Dell XPS 13 variant") Fixes: 1099f48457d0 ("ALSA: hda/realtek: Reduce the Headphone static noise on XPS 9350/9360") Cc: stable@vger.kernel.org Signed-off-by: Thomas Hebb <tommyhebb@gmail.com> Link: https://lore.kernel.org/r/b649a00edfde150cf6eebbb4390e15e0c2deb39a.1585584498.git.tommyhebb@gmail.com Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-07dt-bindings: usb: Bring back phy-namesMaxime Ripard
commit 3aa3c66aedef6a21ea1ad53f5b4491430ef0c84e upstream. While the original bindings that were superseeded by the YAML schemas didn't mention that phy-names was needed, it turns out that phy-names is required if phys is set according to phy/phy-bindings.txt. Let's add back those properties. Fixes: 14ec072a19ad ("dt-bindings: usb: Convert USB HCD generic binding to YAML") Fixes: c93bcace1098 ("dt-bindings: usb: Convert the generic OHCI binding to YAML") Fixes: c3e2485d5f4f ("dt-bindings: usb: Convert the generic EHCI binding to YAML") Reported-by: Emmanuel Vadot <manu@bidouilliste.com> Signed-off-by: Maxime Ripard <mripard@kernel.org> Link: https://lore.kernel.org/r/20191002112651.100504-2-mripard@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-07dt-bindings: usb: Fix references to usb-hcd.yamlJonathan Neuschäfer
commit 0aa760382040cc3d70b538ade56ba9c37ed8b702 upstream. usb-hcd.txt has been converted to YAML. Update references accordingly. Fixes: 14ec072a19ad ("dt-bindings: usb: Convert USB HCD generic binding to YAML") Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Link: https://lore.kernel.org/r/20191003193132.17758-1-j.neuschaefer@gmx.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-07dt-bindings: usb: ehci: Fix example warningsMaxime Ripard
commit 5ff88144f5880f7fafcb6a8e913eadca4cb233c8 upstream. The example of the EHCI binding generates a bunch of warnings now that the examples are validated too. Most notably, phy-names isn't used at all, and the node name should be USB. Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-07dt-bindings: anybus-controller: move to staging/ treeSven Van Asbroeck
commit 5e0127455737d43d4ac45ecdcee42c7521aefe1a upstream. The devicetree bindings for anybus-controller were mistakenly merged into the main Linux tree. Its driver resides in staging/, so the bindings belong in staging/ too. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Fixes: 20a980e957bf ("dt-bindings: anybus-controller: document devicetree binding") Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com> Link: https://lore.kernel.org/r/20190908134805.30957-1-TheSven73@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-07docs: packing: move it to core-api book and adjust markupsMauro Carvalho Chehab
commit 1ec779b9fabcdbfaa06971b5c2a4d9a6e4b45b3a upstream. The packing.txt file was misplaced, as docs should be part of a documentation book, and not at the root dir. So, move it to the core-api directory and add to its index. Also, ensure that the file will be properly parsed and the bitmap ascii artwork will use a monotonic font. Fixes: 554aae35007e ("lib: Add support for generic packing operations") Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Reviewed-by: Vladimir Oltean <olteanv@gmail.com> Tested-by: Vladimir Oltean <olteanv@gmail.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-07docs: cgroup-v1/blkio-controller.rst: remove a CFQ left overMauro Carvalho Chehab
commit 23aa16489c06e6739c7c99e9fdccf723d2691a5d upstream. changeset fb5772cbfe48 ("blkio-controller.txt: Remove references to CFQ") removed cgroup references to CFQ, but it kept one left. Get rid of it. Fixes: fb5772cbfe48 ("blkio-controller.txt: Remove references to CFQ") Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-07-07lib/lzo: fix ambiguous encoding bug in lzo-rleDave Rodgman
commit b5265c813ce4efbfa2e46fd27cdf9a7f44a35d2e upstream. In some rare cases, for input data over 32 KB, lzo-rle could encode two different inputs to the same compressed representation, so that decompression is then ambiguous (i.e. data may be corrupted - although zram is not affected because it operates over 4 KB pages). This modifies the compressor without changing the decompressor or the bitstream format, such that: - there is no change to how data produced by the old compressor is decompressed - an old decompressor will correctly decode data from the updated compressor - performance and compression ratio are not affected - we avoid introducing a new bitstream format In testing over 12.8M real-world files totalling 903 GB, three files were affected by this bug. I also constructed 37M semi-random 64 KB files totalling 2.27 TB, and saw no affected files. Finally I tested over files constructed to contain each of the ~1024 possible bad input sequences; for all of these cases, updated lzo-rle worked correctly. There is no significant impact to performance or compression ratio. Signed-off-by: Dave Rodgman <dave.rodgman@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Dave Rodgman <dave.rodgman@arm.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Markus F.X.J. Oberhumer <markus@oberhumer.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Chao Yu <yuchao0@huawei.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200507100203.29785-1-dave.rodgman@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-24Documentation: fix vfio-ccw docCornelia Huck
commit 4c4cbbaa693a5cc435664f2f220c8b0be873abd1 upstream. *Really* mark the literal block as such. Fixes: 127e62174041 ("vfio-ccw: Update documentation for csch/hsch") Signed-off-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-24Documentation: TLS: fix stat counters descriptionTariq Toukan
commit 280c089916228a005af7f95c1716ea1fea1027b5 upstream. Add missing description of counters. Split tx_tls_encrypted counter into two, to give packets and bytes indications. Fixes: f42c104f2ec9 ("Documentation: add TLS offload documentation") Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-24dt-bindings: iio: avia-hx711: Fix avdd-supply typo in exampleRob Herring
commit fbbf2b6e9b74ffa79bef5e3da91200195045379e upstream. Now that examples are validated against the DT schema, a typo in avia-hx711 example generates a warning: Documentation/devicetree/bindings/iio/adc/avia-hx711.example.dt.yaml: weight: 'avdd-supply' is a required property Fix the typo. Fixes: 5150ec3fe125 ("avia-hx711.yaml: transform DT binding to YAML") Cc: Andreas Klinger <ak@it-klinger.de> Cc: Jonathan Cameron <jic23@kernel.org> Cc: linux-iio@vger.kernel.org Signed-off-by: Rob Herring <robh@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-24vfio-ccw: Update documentation for csch/hschFarhan Ali
commit 127e62174041496b383f82d696e1592ce6838604 upstream. We now support CLEAR SUBCHANNEL and HALT SUBCHANNEL via ccw_cmd_region. Fixes: d5afd5d135c8 ("vfio-ccw: add handling for async channel instructions") Signed-off-by: Farhan Ali <alifm@linux.ibm.com> Message-Id: <7d977612c3f3152ffb950d77ae11b4b25c1e20c4.1562854091.git.alifm@linux.ibm.com> [CH: properly mark region as literal block] Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Eric Farman <farman@linux.ibm.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-24docs: driver-api: generic-counter: fix file path to ABI docMarcus Folkesson
commit 224d5fd43d250f850d64fb6d668114aff29d7022 upstream. Fixes: 09e7d4ed8991 ("docs: Add Generic Counter interface documentation") Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com> Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-24dt-bindings: pinctrl: Modify pinctrl memory mapManivannan Sadhasivam
commit 13531e5d359e30d9e3d1cabd246a24cf6fdf084a upstream. Earlier, the PWM registers were included as part of the pinctrl memory map, but this turned to be useless as the muxing is being handled by the SoC pin controller itself. So, lets modify the pinctrl memory map to reflect the same. Fixes: 07b734fbdea2 ("dt-bindings: pinctrl: Add BM1880 pinctrl binding") Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-09x86/speculation: Add Ivy Bridge to affected listJosh Poimboeuf
commit 3798cc4d106e91382bfe016caa2edada27c2bb3f upstream. Make the docs match the code. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-09x86/speculation: Add SRBDS vulnerability and mitigation documentationMark Gross
commit 7222a1b5b87417f22265c92deea76a6aecd0fb0f upstream. Add documentation for the SRBDS vulnerability and its mitigation. [ bp: Massage. jpoimboe: sysfs table strings. ] Signed-off-by: Mark Gross <mgross@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-09x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigationMark Gross
commit 7e5b3c267d256822407a22fdce6afdf9cd13f9fb upstream. SRBDS is an MDS-like speculative side channel that can leak bits from the random number generator (RNG) across cores and threads. New microcode serializes the processor access during the execution of RDRAND and RDSEED. This ensures that the shared buffer is overwritten before it is released for reuse. While it is present on all affected CPU models, the microcode mitigation is not needed on models that enumerate ARCH_CAPABILITIES[MDS_NO] in the cases where TSX is not supported or has been disabled with TSX_CTRL. The mitigation is activated by default on affected processors and it increases latency for RDRAND and RDSEED instructions. Among other effects this will reduce throughput from /dev/urandom. * Enable administrator to configure the mitigation off when desired using either mitigations=off or srbds=off. * Export vulnerability status via sysfs * Rename file-scoped macros to apply for non-whitelist table initializations. [ bp: Massage, - s/VULNBL_INTEL_STEPPING/VULNBL_INTEL_STEPPINGS/g, - do not read arch cap MSR a second time in tsx_fused_off() - just pass it in, - flip check in cpu_set_bug_bits() to save an indentation level, - reflow comments. jpoimboe: s/Mitigated/Mitigation/ in user-visible strings tglx: Dropped the fused off magic for now ] Signed-off-by: Mark Gross <mgross@linux.intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Neelima Krishnan <neelima.krishnan@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [PG: use v4.19-stable version ; pre rename in v5.4-rc1~172^2~9.] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-04USB: hub: Revert commit bd0e6c9614b9 ("usb: hub: try old enumeration scheme ↵Alan Stern
first for high speed devices") commit 3155f4f40811c5d7e3c686215051acf504e05565 upstream. Commit bd0e6c9614b9 ("usb: hub: try old enumeration scheme first for high speed devices") changed the way the hub driver enumerates high-speed devices. Instead of using the "new" enumeration scheme first and switching to the "old" scheme if that doesn't work, we start with the "old" scheme. In theory this is better because the "old" scheme is slightly faster -- it involves resetting the device only once instead of twice. However, for a long time Windows used only the "new" scheme. Zeng Tao said that Windows 8 and later use the "old" scheme for high-speed devices, but apparently there are some devices that don't like it. William Bader reports that the Ricoh webcam built into his Sony Vaio laptop not only doesn't enumerate under the "old" scheme, it gets hung up so badly that it won't then enumerate under the "new" scheme! Only a cold reset will fix it. Therefore we will revert the commit and go back to trying the "new" scheme first for high-speed devices. Reported-and-tested-by: William Bader <williambader@hotmail.com> Ref: https://bugzilla.kernel.org/show_bug.cgi?id=207219 Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Fixes: bd0e6c9614b9 ("usb: hub: try old enumeration scheme first for high speed devices") CC: Zeng Tao <prime.zeng@hisilicon.com> CC: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2004221611230.11262-100000@iolanthe.rowland.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-04arm64: errata: Hide CTR_EL0.DIC on systems affected by Neoverse-N1 #1542419James Morse
commit 05460849c3b51180d5ada3373d0449aea19075e4 upstream. Cores affected by Neoverse-N1 #1542419 could execute a stale instruction when a branch is updated to point to freshly generated instructions. To workaround this issue we need user-space to issue unnecessary icache maintenance that we can trap. Start by hiding CTR_EL0.DIC. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-06-01ALSA: doc: Document PC Beep Hidden Register on Realtek ALC256Thomas Hebb
commit f128090491c3f5aacef91a863f8c52abf869c436 upstream. This codec (among others) has a hidden set of audio routes, apparently designed to allow PC Beep output without a mixer widget on the output path, which are controlled by an undocumented Realtek vendor register. The default configuration of these routes means that certain inputs aren't accessible, necessitating driver control of the register. However, Realtek has provided no documentation of the register, instead opting to fix issues by providing magic numbers, most of which have been at least somewhat erroneous. These magic numbers then get copied by others into model-specific fixups, leading to a fragmented and buggy set of configurations. To get out of this situation, I've reverse engineered the register by flipping bits and observing how the codec's behavior changes. This commit documents my findings. It does not change any code. Cc: stable@vger.kernel.org Signed-off-by: Thomas Hebb <tommyhebb@gmail.com> Link: https://lore.kernel.org/r/bd69dfdeaf40ff31c4b7b797c829bb320031739c.1585584498.git.tommyhebb@gmail.com Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-05-21dt-bindings: net: FMan erratum A050385Madalin Bucur
commit 26d5bb9e4c4b541c475751e015072eb2cbf70d15 upstream. FMAN DMA read or writes under heavy traffic load may cause FMAN internal resource leak; thus stopping further packet processing. The FMAN internal queue can overflow when FMAN splits single read or write transactions into multiple smaller transactions such that more than 17 AXI transactions are in flight from FMAN to interconnect. When the FMAN internal queue overflows, it can stall further packet processing. The issue can occur with any one of the following three conditions: 1. FMAN AXI transaction crosses 4K address boundary (Errata A010022) 2. FMAN DMA address for an AXI transaction is not 16 byte aligned, i.e. the last 4 bits of an address are non-zero 3. Scatter Gather (SG) frames have more than one SG buffer in the SG list and any one of the buffers, except the last buffer in the SG list has data size that is not a multiple of 16 bytes, i.e., other than 16, 32, 48, 64, etc. With any one of the above three conditions present, there is likelihood of stalled FMAN packet processing, especially under stress with multiple ports injecting line-rate traffic. To avoid situations that stall FMAN packet processing, all of the above three conditions must be avoided; therefore, configure the system with the following rules: 1. Frame buffers must not span a 4KB address boundary, unless the frame start address is 256 byte aligned 2. All FMAN DMA start addresses (for example, BMAN buffer address, FD[address] + FD[offset]) are 16B aligned 3. SG table and buffer addresses are 16B aligned and the size of SG buffers are multiple of 16 bytes, except for the last SG buffer that can be of any size. Additional workaround notes: - Address alignment of 64 bytes is recommended for maximally efficient system bus transactions (although 16 byte alignment is sufficient to avoid the stall condition) - To support frame sizes that are larger than 4K bytes, there are two options: 1. Large single buffer frames that span a 4KB page boundary can be converted into SG frames to avoid transaction splits at the 4KB boundary, 2. Align the large single buffer to 256B address boundaries, ensure that the frame address plus offset is 256B aligned. - If software generated SG frames have buffers that are unaligned and with random non-multiple of 16 byte lengths, before transmitting such frames via FMAN, frames will need to be copied into a new single buffer or multiple buffer SG frame that is compliant with the three rules listed above. Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-05-21ACPI: watchdog: Allow disabling WDAT at bootJean Delvare
commit 3f9e12e0df012c4a9a7fd7eb0d3ae69b459d6b2c upstream. In case the WDAT interface is broken, give the user an option to ignore it to let a native driver bind to the watchdog device instead. Signed-off-by: Jean Delvare <jdelvare@suse.de> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-05-21cifs_atomic_open(): fix double-put on late allocation failureAl Viro
commit d9a9f4849fe0c9d560851ab22a85a666cddfdd24 upstream. several iterations of ->atomic_open() calling conventions ago, we used to need fput() if ->atomic_open() failed at some point after successful finish_open(). Now (since 2016) it's not needed - struct file carries enough state to make fput() work regardless of the point in struct file lifecycle and discarding it on failure exits in open() got unified. Unfortunately, I'd missed the fact that we had an instance of ->atomic_open() (cifs one) that used to need that fput(), as well as the stale comment in finish_open() demanding such late failure handling. Trivially fixed... Fixes: fe9ec8291fca "do_last(): take fput() on error after opening to out:" Cc: stable@kernel.org # v4.7+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-05-21treewide: Rename rcu_dereference_raw_notrace() to _check()Joel Fernandes (Google)
commit 0a5b99f57873e233ad42ef71e23c629f6ea1fcfe upstream. The rcu_dereference_raw_notrace() API name is confusing. It is equivalent to rcu_dereference_raw() except that it also does sparse pointer checking. There are only a few users of rcu_dereference_raw_notrace(). This patches renames all of them to be rcu_dereference_raw_check() with the "_check()" indicating sparse checking. Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> [ paulmck: Fix checkpatch warnings about parentheses. ] Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-05-15netfilter: nf_flowtable: fix documentationMatteo Croce
commit 78e06cf430934fc3768c342cbebdd1013dcd6fa7 upstream. In the flowtable documentation there is a missing semicolon, the command as is would give this error: nftables.conf:5:27-33: Error: syntax error, unexpected devices, expecting newline or semicolon hook ingress priority 0 devices = { br0, pppoe-data }; ^^^^^^^ nftables.conf:4:12-13: Error: invalid hook (null) flowtable ft { ^^ Fixes: 19b351f16fd9 ("netfilter: add flowtable documentation") Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-05-15fbdev: fix numbering of fbcon optionsPeter Rosin
commit fd933c00ebe220060e66fb136a7050a242456566 upstream. Three shall be the number thou shalt count, and the number of the counting shall be three. Four shalt thou not count... One! Two! Five! Fixes: efb985f6b265 ("[PATCH] fbcon: Console Rotation - Add framebuffer console documentation") Signed-off-by: Peter Rosin <peda@axentia.se> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190827110854.12574-2-peda@axentia.se Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-04-16PM / devfreq: Add new name attribute for sysfsChanwoo Choi
commit 2fee1a7cc6b1ce6634bb0f025be2c94a58dfa34d upstream. The commit 4585fbcb5331 ("PM / devfreq: Modify the device name as devfreq(X) for sysfs") changed the node name to devfreq(x). After this commit, it is not possible to get the device name through /sys/class/devfreq/devfreq(X)/*. Add new name attribute in order to get device name. Cc: stable@vger.kernel.org Fixes: 4585fbcb5331 ("PM / devfreq: Modify the device name as devfreq(X) for sysfs") Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-04-12hwrng: omap3-rom - Fix missing clock by probing with device treeTony Lindgren
commit 0c0ef9ea6f3f0d5979dc7b094b0a184c1a94716b upstream. Commit 0ed266d7ae5e ("clk: ti: omap3: cleanup unnecessary clock aliases") removed old omap3 clock framework aliases but caused omap3-rom-rng to stop working with clock not found error. Based on discussions on the mailing list it was requested by Tero Kristo that it would be best to fix this issue by probing omap3-rom-rng using device tree to provide a proper clk property. The other option would be to add back the missing clock alias, but that does not help moving things forward with removing old legacy platform_data. Let's also add a proper device tree binding and keep it together with the fix. Cc: devicetree@vger.kernel.org Cc: Aaro Koskinen <aaro.koskinen@iki.fi> Cc: Adam Ford <aford173@gmail.com> Cc: Pali Rohár <pali.rohar@gmail.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Sebastian Reichel <sre@kernel.org> Cc: Tero Kristo <t-kristo@ti.com> Fixes: 0ed266d7ae5e ("clk: ti: omap3: cleanup unnecessary clock aliases") Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-04-12docs: admin-guide: Remove threads-max auto-tuningMasanari Iida
commit e80d89380c5a8553f208d002ee0f7877ed08eb6c upstream. Since following path was merged in 5.4-rc3, auto-tuning feature in threads-max does not exist any more. Fix the admin-guide document as is. kernel/sysctl.c: do not override max_threads provided by userspace b0f53dbc4bc4c371f38b14c391095a3bb8a0bb40 Fixes: b0f53dbc4bc4 ("kernel/sysctl.c: do not override max_threads provided by userspace") Signed-off-by: Masanari Iida <standby24x7@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-04-12docs: admin-guide: Fix min value of threads-max in kernel.rstMasanari Iida
commit 73eb802ad97f814aa86d83cfd1d139cadbb4f0fb upstream. Since following patch was merged 5.4-rc3, minimum value for threads-max changed to 1. kernel/sysctl.c: do not override max_threads provided by userspace b0f53dbc4bc4c371f38b14c391095a3bb8a0bb40 Fixes: b0f53dbc4bc4 ("kernel/sysctl.c: do not override max_threads provided by userspace") Signed-off-by: Masanari Iida <standby24x7@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-03-30mei: fix modalias documentationAlexander Usyskin
commit 73668309215285366c433489de70d31362987be9 upstream. mei client bus added the client protocol version to the device alias, but ABI documentation was not updated. Fixes: b26864cad1c9 (mei: bus: add client protocol version to the device alias) Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> Link: https://lore.kernel.org/r/20191008005735.12707-1-tomas.winkler@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-03-30Documentation/ABI: Add missed attribute for mlxreg-io sysfs interfacesVadim Pasternak
commit f3efc406d67e6236b513c4302133b0c9be74fd99 upstream. Add missed "cpld4_version" attribute. Fixes: 52675da1d087 ("Documentation/ABI: Add new attribute for mlxreg-io sysfs interfaces") Signed-off-by: Vadim Pasternak <vadimp@mellanox.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-03-30Documentation/ABI: Fix documentation inconsistency for mlxreg-io sysfs ↵Vadim Pasternak
interfaces commit f4094826779dcafe7087e80850513b923eeefdeb upstream. Fix attribute name from "jtag_enable", which described twice to "cpld3_version", which is expected to be instead of second appearance of "jtag_enable". Fixes: 2752e34442b5 ("Documentation/ABI: Add new attribute for mlxreg-io sysfs interfaces") Signed-off-by: Vadim Pasternak <vadimp@mellanox.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-03-30dt-bindings: reset: Fix brcmstb-reset exampleFlorian Fainelli
commit 392a9f63058f2cdcec8363b849a25532ee40da9f upstream. The reset controller has a #reset-cells value of 1, so we should see a phandle plus a register identifier, fix the example. Fixes: 0807caf647dd ("dt-bindings: reset: Add document for Broadcom STB reset controller") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-03-20dt-bindings: clock: renesas: rcar-usb2-clock-sel: Fix typo in exampleGeert Uytterhoeven
commit 830dbce7c76ea529decac7d23b808c1e7da3d891 upstream. The documented compatible value for R-Car H3 is "renesas,r8a7795-rcar-usb2-clock-sel", not "renesas,r8a77950-rcar-usb2-clock-sel". Fixes: 311accb64570db45 ("clk: renesas: rcar-usb2-clock-sel: Add R-Car USB 2.0 clock selector PHY") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Acked-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20191016145650.30003-1-geert+renesas@glider.be Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-03-20ACPI: sysfs: Change ACPI_MASKABLE_GPE_MAX to 0x100Yunfeng Ye
commit a7583e72a5f22470d3e6fd3b6ba912892242339f upstream. The commit 0f27cff8597d ("ACPI: sysfs: Make ACPI GPE mask kernel parameter cover all GPEs") says: "Use a bitmap of size 0xFF instead of a u64 for the GPE mask so 256 GPEs can be masked" But the masking of GPE 0xFF it not supported and the check condition "gpe > ACPI_MASKABLE_GPE_MAX" is not valid because the type of gpe is u8. So modify the macro ACPI_MASKABLE_GPE_MAX to 0x100, and drop the "gpe > ACPI_MASKABLE_GPE_MAX" check. In addition, update the docs "Format" for acpi_mask_gpe parameter. Fixes: 0f27cff8597d ("ACPI: sysfs: Make ACPI GPE mask kernel parameter cover all GPEs") Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> [ rjw: Use u16 as gpe data type in acpi_gpe_apply_masked_gpes() ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-01-31USB: documentation: flags on usb-storage versus UASOliver Neukum
commit 65cc8bf99349f651a0a2cee69333525fe581f306 upstream. Document which flags work storage, UAS or both Signed-off-by: Oliver Neukum <oneukum@suse.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20191114112758.32747-4-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-01-09ath10k: Fix HOST capability QMI incompatibilityBjorn Andersson
commit 7165ef890a4c44cf16db66b82fd78448f4bde6ba upstream. The introduction of 768ec4c012ac ("ath10k: update HOST capability QMI message") served the purpose of supporting the new and extended HOST capability QMI message. But while the new message adds a slew of optional members it changes the data type of the "daemon_support" member, which means that older versions of the firmware will fail to decode the incoming request message. There is no way to detect this breakage from Linux and there's no way to recover from sending the wrong message (i.e. we can't just try one format and then fallback to the other), so a quirk is introduced in DeviceTree to indicate to the driver that the firmware requires the 8bit version of this message. Cc: stable@vger.kernel.org Fixes: 768ec4c012ac ("ath10k: update HOST capability qmi message") Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Kalle Valo <kvalo@codeaurora.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-01-09x86/speculation: Fix incorrect MDS/TAA mitigation statusWaiman Long
commit 64870ed1b12e235cfca3f6c6da75b542c973ff78 upstream. For MDS vulnerable processors with TSX support, enabling either MDS or TAA mitigations will enable the use of VERW to flush internal processor buffers at the right code path. IOW, they are either both mitigated or both not. However, if the command line options are inconsistent, the vulnerabilites sysfs files may not report the mitigation status correctly. For example, with only the "mds=off" option: vulnerabilities/mds:Vulnerable; SMT vulnerable vulnerabilities/tsx_async_abort:Mitigation: Clear CPU buffers; SMT vulnerable The mds vulnerabilities file has wrong status in this case. Similarly, the taa vulnerability file will be wrong with mds mitigation on, but taa off. Change taa_select_mitigation() to sync up the two mitigation status and have them turned off if both "mds=off" and "tsx_async_abort=off" are present. Update documentation to emphasize the fact that both "mds=off" and "tsx_async_abort=off" have to be specified together for processors that are affected by both TAA and MDS to be effective. [ bp: Massage and add kernel-parameters.txt change too. ] Fixes: 1b42f017415b ("x86/speculation/taa: Add mitigation for TSX Async Abort") Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: linux-doc@vger.kernel.org Cc: Mark Gross <mgross@linux.intel.com> Cc: <stable@vger.kernel.org> Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20191115161445.30809-2-longman@redhat.com Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2020-01-09Documentation/x86: Fix path to entry_32.SIra Weiny
commit 9db9b76767f133d0e1ce19f01117c83221641899 upstream. Signed-off-by: Ira Weiny <ira.weiny@intel.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-doc@vger.kernel.org Link: http://lkml.kernel.org/r/20190520205253.23762-1-ira.weiny@intel.com [ Adjusted the patch to the RST conversion. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2019-12-29arm64: apply ARM64_ERRATUM_843419 workaround for Brahma-B53 coreFlorian Fainelli
commit 1cf45b8fdbb87040e1d1bd793891089f4678aa41 upstream. The Broadcom Brahma-B53 core is susceptible to the issue described by ARM64_ERRATUM_843419 so this commit enables the workaround to be applied when executing on that core. Since there are now multiple entries to match, we must convert the existing ARM64_ERRATUM_843419 into an erratum list and use cpucap_multi_entry_cap_matches to match our entries. Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2019-12-29arm64: apply ARM64_ERRATUM_845719 workaround for Brahma-B53 coreDoug Berger
commit bfc97f9f199cb041cf897af3af096540948cc705 upstream. The Broadcom Brahma-B53 core is susceptible to the issue described by ARM64_ERRATUM_845719 so this commit enables the workaround to be applied when executing on that core. Since there are now multiple entries to match, we must convert the existing ARM64_ERRATUM_845719 into an erratum list. Signed-off-by: Doug Berger <opendmb@gmail.com> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2019-12-29arm64: cpufeature: Enable Qualcomm Falkor errata 1009 for KryoBjorn Andersson
commit 36c602dcdd872e9f9b91aae5266b6d7d72b69b96 upstream. The Kryo cores share errata 1009 with Falkor, so add their model definitions and enable it for them as well. Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> [will: Update entry in silicon-errata.rst] Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2019-12-10sched/fair: Fix low cpu usage with high throttling by removing expiration of ↵Dave Chiluk
cpu-local slices commit de53fd7aedb100f03e5d2231cfce0e4993282425 upstream. It has been observed, that highly-threaded, non-cpu-bound applications running under cpu.cfs_quota_us constraints can hit a high percentage of periods throttled while simultaneously not consuming the allocated amount of quota. This use case is typical of user-interactive non-cpu bound applications, such as those running in kubernetes or mesos when run on multiple cpu cores. This has been root caused to cpu-local run queue being allocated per cpu bandwidth slices, and then not fully using that slice within the period. At which point the slice and quota expires. This expiration of unused slice results in applications not being able to utilize the quota for which they are allocated. The non-expiration of per-cpu slices was recently fixed by 'commit 512ac999d275 ("sched/fair: Fix bandwidth timer clock drift condition")'. Prior to that it appears that this had been broken since at least 'commit 51f2176d74ac ("sched/fair: Fix unlocked reads of some cfs_b->quota/period")' which was introduced in v3.16-rc1 in 2014. That added the following conditional which resulted in slices never being expired. if (cfs_rq->runtime_expires != cfs_b->runtime_expires) { /* extend local deadline, drift is bounded above by 2 ticks */ cfs_rq->runtime_expires += TICK_NSEC; Because this was broken for nearly 5 years, and has recently been fixed and is now being noticed by many users running kubernetes (https://github.com/kubernetes/kubernetes/issues/67577) it is my opinion that the mechanisms around expiring runtime should be removed altogether. This allows quota already allocated to per-cpu run-queues to live longer than the period boundary. This allows threads on runqueues that do not use much CPU to continue to use their remaining slice over a longer period of time than cpu.cfs_period_us. However, this helps prevent the above condition of hitting throttling while also not fully utilizing your cpu quota. This theoretically allows a machine to use slightly more than its allotted quota in some periods. This overflow would be bounded by the remaining quota left on each per-cpu runqueueu. This is typically no more than min_cfs_rq_runtime=1ms per cpu. For CPU bound tasks this will change nothing, as they should theoretically fully utilize all of their quota in each period. For user-interactive tasks as described above this provides a much better user/application experience as their cpu utilization will more closely match the amount they requested when they hit throttling. This means that cpu limits no longer strictly apply per period for non-cpu bound applications, but that they are still accurate over longer timeframes. This greatly improves performance of high-thread-count, non-cpu bound applications with low cfs_quota_us allocation on high-core-count machines. In the case of an artificial testcase (10ms/100ms of quota on 80 CPU machine), this commit resulted in almost 30x performance improvement, while still maintaining correct cpu quota restrictions. That testcase is available at https://github.com/indeedeng/fibtest. Fixes: 512ac999d275 ("sched/fair: Fix bandwidth timer clock drift condition") Signed-off-by: Dave Chiluk <chiluk+linux@indeed.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Phil Auld <pauld@redhat.com> Reviewed-by: Ben Segall <bsegall@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: John Hammond <jhammond@indeed.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kyle Anderson <kwa@yelp.com> Cc: Gabriel Munos <gmunoz@netflix.com> Cc: Peter Oskolkov <posk@posk.io> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Brendan Gregg <bgregg@netflix.com> Link: https://lkml.kernel.org/r/1563900266-19734-2-git-send-email-chiluk+linux@indeed.com Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2019-12-10x86/xen: Return from panic notifierBoris Ostrovsky
commit c6875f3aacf2a5a913205accddabf0bfb75cac76 upstream. Currently execution of panic() continues until Xen's panic notifier (xen_panic_event()) is called at which point we make a hypercall that never returns. This means that any notifier that is supposed to be called later as well as significant part of panic() code (such as pstore writes from kmsg_dump()) is never executed. There is no reason for xen_panic_event() to be this last point in execution since panic()'s emergency_restart() will call into xen_emergency_restart() from where we can perform our hypercall. Nevertheless, we will provide xen_legacy_crash boot option that will preserve original behavior during crash. This option could be used, for example, if running kernel dumper (which happens after panic notifiers) is undesirable. Reported-by: James Dingwall <james@dingwall.me.uk> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2019-12-10dm snapshot: add optional discard support featuresMike Snitzer
commit 2e6023850e177dbaca21498ada04c5a5ac93f812 upstream. discard_zeroes_cow - a discard issued to the snapshot device that maps to entire chunks to will zero the corresponding exception(s) in the snapshot's exception store. discard_passdown_origin - a discard to the snapshot device is passed down to the snapshot-origin's underlying device. This doesn't cause copy-out to the snapshot exception store because the snapshot-origin target is bypassed. The discard_passdown_origin feature depends on the discard_zeroes_cow feature being enabled. When these 2 features are enabled they allow a temporarily read-only device that has completely exhausted its free space to recover space. To do so dm-snapshot provides temporary buffer to accommodate writes that the temporarily read-only device cannot handle yet. Once the upper layer frees space (e.g. fstrim to XFS) the discards issued to the dm-snapshot target will be issued to underlying read-only device whose free space was exhausted. In addition those discards will also cause zeroes to be written to the snapshot exception store if corresponding exceptions exist. If the underlying origin device provides deduplication for zero blocks then if/when the snapshot is merged backed to the origin those blocks will become unused. Once the origin has gained adequate space, merging the snapshot back to the thinly provisioned device will permit continued use of that device without the temporary space provided by the snapshot. Requested-by: John Dorminy <jdorminy@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>