From fd7cb3e4684f0c044a627dc33adb9f97c69f033f Mon Sep 17 00:00:00 2001 From: Conor Dooley Date: Wed, 10 Aug 2022 15:02:43 +0100 Subject: MAINTAINERS: add PolarFire SoC dt bindings MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit So far when I added bindings for the platform I never added them to our MAINTAINERS entry. No time like the present to improve the coverage. Suggested-by: Mark Brown Signed-off-by: Conor Dooley Acked-by: Marc Kleine-Budde # for can Acked-by: Uwe Kleine-König CC: Mark Brown CC: Wolfram Sang CC: Thierry Reding CC: Uwe Kleine-König CC: Jassi Brar CC: Linus Walleij CC: Bartosz Golaszewski CC: Greg Kroah-Hartman CC: Arnd Bergmann CC: Olof Johansson CC: Michael Turquette CC: Stephen Boyd Link: https://lore.kernel.org/r/20220810140243.2685416-2-conor.dooley@microchip.com' Signed-off-by: Arnd Bergmann --- MAINTAINERS | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 64379c699903..9dec9a56f8dd 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17277,6 +17277,15 @@ M: Conor Dooley M: Daire McNamara L: linux-riscv@lists.infradead.org S: Supported +F: Documentation/devicetree/bindings/clock/microchip,mpfs.yaml +F: Documentation/devicetree/bindings/gpio/microchip,mpfs-gpio.yaml +F: Documentation/devicetree/bindings/i2c/microchip,corei2c.yaml +F: Documentation/devicetree/bindings/mailbox/microchip,mpfs-mailbox.yaml +F: Documentation/devicetree/bindings/net/can/microchip,mpfs-can.yaml +F: Documentation/devicetree/bindings/pwm/microchip,corepwm.yaml +F: Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-sys-controller.yaml +F: Documentation/devicetree/bindings/spi/microchip,mpfs-spi.yaml +F: Documentation/devicetree/bindings/usb/microchip,mpfs-musb.yaml F: arch/riscv/boot/dts/microchip/ F: drivers/char/hw_random/mpfs-rng.c F: drivers/clk/microchip/clk-mpfs.c -- cgit From 3cbd673846772153a0aa85471aef5788f1a53dcd Mon Sep 17 00:00:00 2001 From: Conor Dooley Date: Wed, 10 Aug 2022 15:02:44 +0100 Subject: MAINTAINERS: add the Polarfire SoC's i2c driver Add the newly added i2c controller driver to the existing entry for PolarFire SoC. Signed-off-by: Conor Dooley Acked-by: Wolfram Sang Link: https://lore.kernel.org/r/20220810140243.2685416-3-conor.dooley@microchip.com' Signed-off-by: Arnd Bergmann --- MAINTAINERS | 1 + 1 file changed, 1 insertion(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 9dec9a56f8dd..aa6e11600d72 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17289,6 +17289,7 @@ F: Documentation/devicetree/bindings/usb/microchip,mpfs-musb.yaml F: arch/riscv/boot/dts/microchip/ F: drivers/char/hw_random/mpfs-rng.c F: drivers/clk/microchip/clk-mpfs.c +F: drivers/i2c/busses/i2c-microchip-core.c F: drivers/mailbox/mailbox-mpfs.c F: drivers/pci/controller/pcie-microchip-host.c F: drivers/soc/microchip/ -- cgit From ddc84c90538e1fdb0721cd41c313944c38449a34 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 16 Aug 2022 13:35:14 +0200 Subject: MAINTAINERS: update idmapping tree Since Seth joined as a maintainer in ba40a57ff08b ("Add Seth Forshee as co-maintainer for idmapped mounts") it was best to get a shared git tree instead of using our personal repositories. So we requested and Konstantin suggested and gave us a new "idmapping" repository under the pre-existing but mainly unused vfs namespace. Just makes it easier for Seth to send fixes in case I'm out or someone else ever takes over. Cc: Seth Forshee Signed-off-by: Christian Brauner (Microsoft) Link: https://lore.kernel.org/r/20220816113514.43304-2-brauner@kernel.org --- MAINTAINERS | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 8a5012ba6ff9..a558794dddf9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9780,7 +9780,7 @@ M: Christian Brauner M: Seth Forshee L: linux-fsdevel@vger.kernel.org S: Maintained -T: git git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git +T: git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping.git F: Documentation/filesystems/idmappings.rst F: tools/testing/selftests/mount_setattr/ F: include/linux/mnt_idmapping.h -- cgit From 636c3982d296a560aabcc5e462c3a6408389ffd2 Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Tue, 16 Aug 2022 09:39:52 +0200 Subject: MAINTAINERS: rectify entry for XILINX GPIO DRIVER Commit ba96b2e7974b ("dt-bindings: gpio: gpio-xilinx: Convert Xilinx axi gpio binding to YAML") converts gpio-xilinx.txt to xlnx,gpio-xilinx.yaml, but missed to adjust its reference in MAINTAINERS. Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a broken reference. Repair this file reference in XILINX GPIO DRIVER. Signed-off-by: Lukas Bulwahn Signed-off-by: Bartosz Golaszewski --- MAINTAINERS | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 8a5012ba6ff9..1f2530771ff4 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -22301,7 +22301,7 @@ M: Shubhrajyoti Datta R: Srinivas Neeli R: Michal Simek S: Maintained -F: Documentation/devicetree/bindings/gpio/gpio-xilinx.txt +F: Documentation/devicetree/bindings/gpio/xlnx,gpio-xilinx.yaml F: Documentation/devicetree/bindings/gpio/gpio-zynq.yaml F: drivers/gpio/gpio-xilinx.c F: drivers/gpio/gpio-zynq.c -- cgit From c078290a2b7618473a7d0a05334cc91fe0ac2949 Mon Sep 17 00:00:00 2001 From: Jonathan Toppins Date: Fri, 19 Aug 2022 11:15:12 -0400 Subject: selftests: include bonding tests into the kselftest infra This creates a test collection in drivers/net/bonding for bonding specific kernel selftests. The first test is a reproducer that provisions a bond and given the specific order in how the ip-link(8) commands are issued the bond never transmits an LACPDU frame on any of its slaves. Signed-off-by: Jonathan Toppins Acked-by: Jay Vosburgh Signed-off-by: Jakub Kicinski --- MAINTAINERS | 1 + tools/testing/selftests/Makefile | 1 + .../testing/selftests/drivers/net/bonding/Makefile | 6 ++ .../drivers/net/bonding/bond-break-lacpdu-tx.sh | 81 ++++++++++++++++++++++ tools/testing/selftests/drivers/net/bonding/config | 1 + .../testing/selftests/drivers/net/bonding/settings | 1 + 6 files changed, 91 insertions(+) create mode 100644 tools/testing/selftests/drivers/net/bonding/Makefile create mode 100755 tools/testing/selftests/drivers/net/bonding/bond-break-lacpdu-tx.sh create mode 100644 tools/testing/selftests/drivers/net/bonding/config create mode 100644 tools/testing/selftests/drivers/net/bonding/settings (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index f512b430c7cb..274b2c1e506e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3679,6 +3679,7 @@ F: Documentation/networking/bonding.rst F: drivers/net/bonding/ F: include/net/bond* F: include/uapi/linux/if_bonding.h +F: tools/testing/selftests/net/bonding/ BOSCH SENSORTEC BMA400 ACCELEROMETER IIO DRIVER M: Dan Robertson diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 10b34bb03bc1..c2064a35688b 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -12,6 +12,7 @@ TARGETS += cpu-hotplug TARGETS += damon TARGETS += drivers/dma-buf TARGETS += drivers/s390x/uvdevice +TARGETS += drivers/net/bonding TARGETS += efivarfs TARGETS += exec TARGETS += filesystems diff --git a/tools/testing/selftests/drivers/net/bonding/Makefile b/tools/testing/selftests/drivers/net/bonding/Makefile new file mode 100644 index 000000000000..ab6c54b12098 --- /dev/null +++ b/tools/testing/selftests/drivers/net/bonding/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for net selftests + +TEST_PROGS := bond-break-lacpdu-tx.sh + +include ../../../lib.mk diff --git a/tools/testing/selftests/drivers/net/bonding/bond-break-lacpdu-tx.sh b/tools/testing/selftests/drivers/net/bonding/bond-break-lacpdu-tx.sh new file mode 100755 index 000000000000..47ab90596acb --- /dev/null +++ b/tools/testing/selftests/drivers/net/bonding/bond-break-lacpdu-tx.sh @@ -0,0 +1,81 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +# Regression Test: +# Verify LACPDUs get transmitted after setting the MAC address of +# the bond. +# +# https://bugzilla.redhat.com/show_bug.cgi?id=2020773 +# +# +---------+ +# | fab-br0 | +# +---------+ +# | +# +---------+ +# | fbond | +# +---------+ +# | | +# +------+ +------+ +# |veth1 | |veth2 | +# +------+ +------+ +# +# We use veths instead of physical interfaces + +set -e +tmp=$(mktemp -q dump.XXXXXX) +cleanup() { + ip link del fab-br0 >/dev/null 2>&1 || : + ip link del fbond >/dev/null 2>&1 || : + ip link del veth1-bond >/dev/null 2>&1 || : + ip link del veth2-bond >/dev/null 2>&1 || : + modprobe -r bonding >/dev/null 2>&1 || : + rm -f -- ${tmp} +} + +trap cleanup 0 1 2 +cleanup +sleep 1 + +# create the bridge +ip link add fab-br0 address 52:54:00:3B:7C:A6 mtu 1500 type bridge \ + forward_delay 15 + +# create the bond +ip link add fbond type bond mode 4 miimon 200 xmit_hash_policy 1 \ + ad_actor_sys_prio 65535 lacp_rate fast + +# set bond address +ip link set fbond address 52:54:00:3B:7C:A6 +ip link set fbond up + +# set again bond sysfs parameters +ip link set fbond type bond ad_actor_sys_prio 65535 + +# create veths +ip link add name veth1-bond type veth peer name veth1-end +ip link add name veth2-bond type veth peer name veth2-end + +# add ports +ip link set fbond master fab-br0 +ip link set veth1-bond down master fbond +ip link set veth2-bond down master fbond + +# bring up +ip link set veth1-end up +ip link set veth2-end up +ip link set fab-br0 up +ip link set fbond up +ip addr add dev fab-br0 10.0.0.3 + +tcpdump -n -i veth1-end -e ether proto 0x8809 >${tmp} 2>&1 & +sleep 15 +pkill tcpdump >/dev/null 2>&1 +rc=0 +num=$(grep "packets captured" ${tmp} | awk '{print $1}') +if test "$num" -gt 0; then + echo "PASS, captured ${num}" +else + echo "FAIL" + rc=1 +fi +exit $rc diff --git a/tools/testing/selftests/drivers/net/bonding/config b/tools/testing/selftests/drivers/net/bonding/config new file mode 100644 index 000000000000..dc1c22de3c92 --- /dev/null +++ b/tools/testing/selftests/drivers/net/bonding/config @@ -0,0 +1 @@ +CONFIG_BONDING=y diff --git a/tools/testing/selftests/drivers/net/bonding/settings b/tools/testing/selftests/drivers/net/bonding/settings new file mode 100644 index 000000000000..867e118223cd --- /dev/null +++ b/tools/testing/selftests/drivers/net/bonding/settings @@ -0,0 +1 @@ +timeout=60 -- cgit From 4f3e509996a877dca1ddffc2abdbb5857727bfc4 Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Mon, 22 Aug 2022 21:44:50 -0700 Subject: MAINTAINERS: add include/dt-bindings/input to INPUT DRIVERS Maintainers of the directory Documentation/devicetree/bindings/input are also the maintainers of the corresponding directory include/dt-bindings/input. Add the file entry for include/dt-bindings/input to the appropriate section in MAINTAINERS. Signed-off-by: Lukas Bulwahn Link: https://lore.kernel.org/r/20220613115654.28117-1-lukas.bulwahn@gmail.com Signed-off-by: Dmitry Torokhov --- MAINTAINERS | 1 + 1 file changed, 1 insertion(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 66bffb24a348..18477041d70d 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9798,6 +9798,7 @@ F: Documentation/devicetree/bindings/input/ F: Documentation/devicetree/bindings/serio/ F: Documentation/input/ F: drivers/input/ +F: include/dt-bindings/input/ F: include/linux/input.h F: include/linux/input/ F: include/uapi/linux/input-event-codes.h -- cgit From c2fa700c5f7667800b6cfedcb9994eb5eb69e6cc Mon Sep 17 00:00:00 2001 From: Ammar Faizi Date: Tue, 23 Aug 2022 18:45:48 +0700 Subject: MAINTAINERS: Add `include/linux/io_uring_types.h` File include/linux/io_uring_types.h doesn't have a maintainer, add it to the io_uring section. Signed-off-by: Ammar Faizi Signed-off-by: Jens Axboe --- MAINTAINERS | 1 + 1 file changed, 1 insertion(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 8a5012ba6ff9..6dc55be41420 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -10657,6 +10657,7 @@ T: git git://git.kernel.dk/linux-block T: git git://git.kernel.dk/liburing F: io_uring/ F: include/linux/io_uring.h +F: include/linux/io_uring_types.h F: include/uapi/linux/io_uring.h F: tools/io_uring/ -- cgit From 5d7fef0804b0a72a7efe196cd23b438edf84726c Mon Sep 17 00:00:00 2001 From: Sander Vanheule Date: Tue, 23 Aug 2022 08:12:23 +0200 Subject: lib/cpumask_kunit: add tests file to MAINTAINERS cpumask related files are listed under the BITMAP API section, so the file with tests for cpumask should be added to that list. Signed-off-by: Sander Vanheule Reviewed-by: David Gow Acked-by: Yury Norov Signed-off-by: Yury Norov --- MAINTAINERS | 1 + 1 file changed, 1 insertion(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 9d7f64dc0efe..59b3718e66d1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3612,6 +3612,7 @@ F: include/linux/find.h F: include/linux/nodemask.h F: lib/bitmap.c F: lib/cpumask.c +F: lib/cpumask_kunit.c F: lib/find_bit.c F: lib/find_bit_benchmark.c F: lib/test_bitmap.c -- cgit From b09da0126ce09bd84545e4a8e8697f2a5bdeb745 Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Wed, 24 Aug 2022 09:29:45 +0200 Subject: MAINTAINERS: rectify file entry in BONDING DRIVER Commit c078290a2b76 ("selftests: include bonding tests into the kselftest infra") adds the bonding tests in the directory: tools/testing/selftests/drivers/net/bonding/ The file entry in MAINTAINERS for the BONDING DRIVER however refers to: tools/testing/selftests/net/bonding/ Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a broken file pattern. Repair this file entry in BONDING DRIVER. Signed-off-by: Lukas Bulwahn Acked-by: Jonathan Toppins Link: https://lore.kernel.org/r/20220824072945.28606-1-lukas.bulwahn@gmail.com Signed-off-by: Jakub Kicinski --- MAINTAINERS | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 274b2c1e506e..5a699275d9d1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3679,7 +3679,7 @@ F: Documentation/networking/bonding.rst F: drivers/net/bonding/ F: include/net/bond* F: include/uapi/linux/if_bonding.h -F: tools/testing/selftests/net/bonding/ +F: tools/testing/selftests/drivers/net/bonding/ BOSCH SENSORTEC BMA400 ACCELEROMETER IIO DRIVER M: Dan Robertson -- cgit From 7a3d2225f1ae9e591fefd65c3bb1715dc54d96f1 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Fri, 2 Sep 2022 23:23:02 +0800 Subject: Documentation: document ublk Add documentation for ublk subsystem. It was supposed to be documented when merging the driver, but missing at that time. Cc: Bagas Sanjaya Cc: Jonathan Corbet Cc: Richard W.M. Jones Cc: Xiaoguang Wang Reviewed-by: Stefan Hajnoczi Reviewed-by: ZiyangZhang Signed-off-by: Ming Lei [axboe: correct MAINTAINERS addition] Signed-off-by: Jens Axboe --- Documentation/block/index.rst | 1 + Documentation/block/ublk.rst | 253 ++++++++++++++++++++++++++++++++++++++++++ MAINTAINERS | 1 + 3 files changed, 255 insertions(+) create mode 100644 Documentation/block/ublk.rst (limited to 'MAINTAINERS') diff --git a/Documentation/block/index.rst b/Documentation/block/index.rst index 68f115f2b1c6..c4c73db748a8 100644 --- a/Documentation/block/index.rst +++ b/Documentation/block/index.rst @@ -23,3 +23,4 @@ Block stat switching-sched writeback_cache_control + ublk diff --git a/Documentation/block/ublk.rst b/Documentation/block/ublk.rst new file mode 100644 index 000000000000..2122d1a4a541 --- /dev/null +++ b/Documentation/block/ublk.rst @@ -0,0 +1,253 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========================================== +Userspace block device driver (ublk driver) +=========================================== + +Overview +======== + +ublk is a generic framework for implementing block device logic from userspace. +The motivation behind it is that moving virtual block drivers into userspace, +such as loop, nbd and similar can be very helpful. It can help to implement +new virtual block device such as ublk-qcow2 (there are several attempts of +implementing qcow2 driver in kernel). + +Userspace block devices are attractive because: + +- They can be written many programming languages. +- They can use libraries that are not available in the kernel. +- They can be debugged with tools familiar to application developers. +- Crashes do not kernel panic the machine. +- Bugs are likely to have a lower security impact than bugs in kernel + code. +- They can be installed and updated independently of the kernel. +- They can be used to simulate block device easily with user specified + parameters/setting for test/debug purpose + +ublk block device (``/dev/ublkb*``) is added by ublk driver. Any IO request +on the device will be forwarded to ublk userspace program. For convenience, +in this document, ``ublk server`` refers to generic ublk userspace +program. ``ublksrv`` [#userspace]_ is one of such implementation. It +provides ``libublksrv`` [#userspace_lib]_ library for developing specific +user block device conveniently, while also generic type block device is +included, such as loop and null. Richard W.M. Jones wrote userspace nbd device +``nbdublk`` [#userspace_nbdublk]_ based on ``libublksrv`` [#userspace_lib]_. + +After the IO is handled by userspace, the result is committed back to the +driver, thus completing the request cycle. This way, any specific IO handling +logic is totally done by userspace, such as loop's IO handling, NBD's IO +communication, or qcow2's IO mapping. + +``/dev/ublkb*`` is driven by blk-mq request-based driver. Each request is +assigned by one queue wide unique tag. ublk server assigns unique tag to each +IO too, which is 1:1 mapped with IO of ``/dev/ublkb*``. + +Both the IO request forward and IO handling result committing are done via +``io_uring`` passthrough command; that is why ublk is also one io_uring based +block driver. It has been observed that using io_uring passthrough command can +give better IOPS than block IO; which is why ublk is one of high performance +implementation of userspace block device: not only IO request communication is +done by io_uring, but also the preferred IO handling in ublk server is io_uring +based approach too. + +ublk provides control interface to set/get ublk block device parameters. +The interface is extendable and kabi compatible: basically any ublk request +queue's parameter or ublk generic feature parameters can be set/get via the +interface. Thus, ublk is generic userspace block device framework. +For example, it is easy to setup a ublk device with specified block +parameters from userspace. + +Using ublk +========== + +ublk requires userspace ublk server to handle real block device logic. + +Below is example of using ``ublksrv`` to provide ublk-based loop device. + +- add a device:: + + ublk add -t loop -f ublk-loop.img + +- format with xfs, then use it:: + + mkfs.xfs /dev/ublkb0 + mount /dev/ublkb0 /mnt + # do anything. all IOs are handled by io_uring + ... + umount /mnt + +- list the devices with their info:: + + ublk list + +- delete the device:: + + ublk del -a + ublk del -n $ublk_dev_id + +See usage details in README of ``ublksrv`` [#userspace_readme]_. + +Design +====== + +Control plane +------------- + +ublk driver provides global misc device node (``/dev/ublk-control``) for +managing and controlling ublk devices with help of several control commands: + +- ``UBLK_CMD_ADD_DEV`` + + Add a ublk char device (``/dev/ublkc*``) which is talked with ublk server + WRT IO command communication. Basic device info is sent together with this + command. It sets UAPI structure of ``ublksrv_ctrl_dev_info``, + such as ``nr_hw_queues``, ``queue_depth``, and max IO request buffer size, + for which the info is negotiated with the driver and sent back to the server. + When this command is completed, the basic device info is immutable. + +- ``UBLK_CMD_SET_PARAMS`` / ``UBLK_CMD_GET_PARAMS`` + + Set or get parameters of the device, which can be either generic feature + related, or request queue limit related, but can't be IO logic specific, + because the driver does not handle any IO logic. This command has to be + sent before sending ``UBLK_CMD_START_DEV``. + +- ``UBLK_CMD_START_DEV`` + + After the server prepares userspace resources (such as creating per-queue + pthread & io_uring for handling ublk IO), this command is sent to the + driver for allocating & exposing ``/dev/ublkb*``. Parameters set via + ``UBLK_CMD_SET_PARAMS`` are applied for creating the device. + +- ``UBLK_CMD_STOP_DEV`` + + Halt IO on ``/dev/ublkb*`` and remove the device. When this command returns, + ublk server will release resources (such as destroying per-queue pthread & + io_uring). + +- ``UBLK_CMD_DEL_DEV`` + + Remove ``/dev/ublkc*``. When this command returns, the allocated ublk device + number can be reused. + +- ``UBLK_CMD_GET_QUEUE_AFFINITY`` + + When ``/dev/ublkc`` is added, the driver creates block layer tagset, so + that each queue's affinity info is available. The server sends + ``UBLK_CMD_GET_QUEUE_AFFINITY`` to retrieve queue affinity info. It can + set up the per-queue context efficiently, such as bind affine CPUs with IO + pthread and try to allocate buffers in IO thread context. + +- ``UBLK_CMD_GET_DEV_INFO`` + + For retrieving device info via ``ublksrv_ctrl_dev_info``. It is the server's + responsibility to save IO target specific info in userspace. + +Data plane +---------- + +ublk server needs to create per-queue IO pthread & io_uring for handling IO +commands via io_uring passthrough. The per-queue IO pthread +focuses on IO handling and shouldn't handle any control & management +tasks. + +The's IO is assigned by a unique tag, which is 1:1 mapping with IO +request of ``/dev/ublkb*``. + +UAPI structure of ``ublksrv_io_desc`` is defined for describing each IO from +the driver. A fixed mmaped area (array) on ``/dev/ublkc*`` is provided for +exporting IO info to the server; such as IO offset, length, OP/flags and +buffer address. Each ``ublksrv_io_desc`` instance can be indexed via queue id +and IO tag directly. + +The following IO commands are communicated via io_uring passthrough command, +and each command is only for forwarding the IO and committing the result +with specified IO tag in the command data: + +- ``UBLK_IO_FETCH_REQ`` + + Sent from the server IO pthread for fetching future incoming IO requests + destined to ``/dev/ublkb*``. This command is sent only once from the server + IO pthread for ublk driver to setup IO forward environment. + +- ``UBLK_IO_COMMIT_AND_FETCH_REQ`` + + When an IO request is destined to ``/dev/ublkb*``, the driver stores + the IO's ``ublksrv_io_desc`` to the specified mapped area; then the + previous received IO command of this IO tag (either ``UBLK_IO_FETCH_REQ`` + or ``UBLK_IO_COMMIT_AND_FETCH_REQ)`` is completed, so the server gets + the IO notification via io_uring. + + After the server handles the IO, its result is committed back to the + driver by sending ``UBLK_IO_COMMIT_AND_FETCH_REQ`` back. Once ublkdrv + received this command, it parses the result and complete the request to + ``/dev/ublkb*``. In the meantime setup environment for fetching future + requests with the same IO tag. That is, ``UBLK_IO_COMMIT_AND_FETCH_REQ`` + is reused for both fetching request and committing back IO result. + +- ``UBLK_IO_NEED_GET_DATA`` + + With ``UBLK_F_NEED_GET_DATA`` enabled, the WRITE request will be firstly + issued to ublk server without data copy. Then, IO backend of ublk server + receives the request and it can allocate data buffer and embed its addr + inside this new io command. After the kernel driver gets the command, + data copy is done from request pages to this backend's buffer. Finally, + backend receives the request again with data to be written and it can + truly handle the request. + + ``UBLK_IO_NEED_GET_DATA`` adds one additional round-trip and one + io_uring_enter() syscall. Any user thinks that it may lower performance + should not enable UBLK_F_NEED_GET_DATA. ublk server pre-allocates IO + buffer for each IO by default. Any new project should try to use this + buffer to communicate with ublk driver. However, existing project may + break or not able to consume the new buffer interface; that's why this + command is added for backwards compatibility so that existing projects + can still consume existing buffers. + +- data copy between ublk server IO buffer and ublk block IO request + + The driver needs to copy the block IO request pages into the server buffer + (pages) first for WRITE before notifying the server of the coming IO, so + that the server can handle WRITE request. + + When the server handles READ request and sends + ``UBLK_IO_COMMIT_AND_FETCH_REQ`` to the server, ublkdrv needs to copy + the server buffer (pages) read to the IO request pages. + +Future development +================== + +Container-aware ublk deivice +---------------------------- + +ublk driver doesn't handle any IO logic. Its function is well defined +for now and very limited userspace interfaces are needed, which is also +well defined too. It is possible to make ublk devices container-aware block +devices in future as Stefan Hajnoczi suggested [#stefan]_, by removing +ADMIN privilege. + +Zero copy +--------- + +Zero copy is a generic requirement for nbd, fuse or similar drivers. A +problem [#xiaoguang]_ Xiaoguang mentioned is that pages mapped to userspace +can't be remapped any more in kernel with existing mm interfaces. This can +occurs when destining direct IO to ``/dev/ublkb*``. Also, he reported that +big requests (IO size >= 256 KB) may benefit a lot from zero copy. + + +References +========== + +.. [#userspace] https://github.com/ming1/ubdsrv + +.. [#userspace_lib] https://github.com/ming1/ubdsrv/tree/master/lib + +.. [#userspace_nbdublk] https://gitlab.com/rwmjones/libnbd/-/tree/nbdublk + +.. [#userspace_readme] https://github.com/ming1/ubdsrv/blob/master/README + +.. [#stefan] https://lore.kernel.org/linux-block/YoOr6jBfgVm8GvWg@stefanha-x1.localdomain/ + +.. [#xiaoguang] https://lore.kernel.org/linux-block/YoOr6jBfgVm8GvWg@stefanha-x1.localdomain/ diff --git a/MAINTAINERS b/MAINTAINERS index a6c5c29e5a0b..19a7be4447d7 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20722,6 +20722,7 @@ UBLK USERSPACE BLOCK DRIVER M: Ming Lei L: linux-block@vger.kernel.org S: Maintained +F: Documentation/block/ublk.rst F: drivers/block/ublk_drv.c F: include/uapi/linux/ublk_cmd.h -- cgit From bc7a2c9b17773c89f2f9c09ac9f9233716d6cd08 Mon Sep 17 00:00:00 2001 From: Wenpeng Liang Date: Mon, 5 Sep 2022 10:38:15 +0800 Subject: MAINTAINERS: Update maintainers of HiSilicon RoCE Weihang has moved to work in other technical areas, and Haoyue will maintain this module instead of him. Signed-off-by: Wenpeng Liang Link: https://lore.kernel.org/r/20220905023815.1477684-1-liangwenpeng@huawei.com Signed-off-by: Leon Romanovsky --- MAINTAINERS | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index 8a5012ba6ff9..6b26f4d5a1c9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9205,8 +9205,8 @@ F: Documentation/ABI/testing/debugfs-hisi-zip F: drivers/crypto/hisilicon/zip/ HISILICON ROCE DRIVER +M: Haoyue Xu M: Wenpeng Liang -M: Weihang Li L: linux-rdma@vger.kernel.org S: Maintained F: Documentation/devicetree/bindings/infiniband/hisilicon-hns-roce.txt -- cgit From fa4b9df00af4a749d4d715d7e11562121b7885ac Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Tue, 23 Aug 2022 17:33:16 +0200 Subject: MAINTAINERS: Add Runtime Verification (RV) entry Add a Runtime Verification (RV) entry in the MAINTAINERS file with Steven Rostedt and myself as maintainers. Link: https://lkml.kernel.org/r/b24c13553b6947a8da16d884ca464e4233eb8fb7.1661268579.git.bristot@kernel.org Cc: Joe Perches Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- MAINTAINERS | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index d30f26e07cd3..b89b70af0b07 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17735,6 +17735,17 @@ L: linux-rdma@vger.kernel.org S: Maintained F: drivers/infiniband/ulp/rtrs/ +RUNTIME VERIFICATION (RV) +M: Daniel Bristot de Oliveira +M: Steven Rostedt +L: linux-trace-devel@vger.kernel.org +S: Maintained +F: Documentation/trace/rv/ +F: include/linux/rv.h +F: include/rv/ +F: kernel/trace/rv/ +F: tools/verification/ + RXRPC SOCKETS (AF_RXRPC) M: David Howells M: Marc Dionne -- cgit From f72c3a2d344b3933dedd42fdaf7d3e1aa4b8cce1 Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Thu, 25 Aug 2022 13:59:27 +0200 Subject: MAINTAINERS: add scripts/tracing/ to TRACING The files in scripts/tracing/ belong to the TRACING subsystem. Add a corresponding file entry for TRACING. Link: https://lkml.kernel.org/r/20220825115927.20598-1-lukas.bulwahn@gmail.com Signed-off-by: Lukas Bulwahn Signed-off-by: Steven Rostedt (Google) --- MAINTAINERS | 1 + 1 file changed, 1 insertion(+) (limited to 'MAINTAINERS') diff --git a/MAINTAINERS b/MAINTAINERS index b89b70af0b07..93ffebc3e6c0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -20612,6 +20612,7 @@ F: include/*/ftrace.h F: include/linux/trace*.h F: include/trace/ F: kernel/trace/ +F: scripts/tracing/ F: tools/testing/selftests/ftrace/ TRACING MMIO ACCESSES (MMIOTRACE) -- cgit