Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
code
Clone this repository
https://tangled.org/tjh.dev/kernel
git@gordian.tjh.dev:tjh.dev/kernel
For self-hosted knots, clone URLs may differ based on your setup.
Pull Kbuild fixes from Masahiro Yamada:
- Search for <ncurses.h> in the default header path of HOSTCC
- Tweak the option order to be kind to old BSD awk
- Remove 'kvmconfig' and 'xenconfig' shorthands
- Fix documentation
* tag 'kbuild-fixes-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
Documentation: kbuild: Fix section reference
kconfig: remove 'kvmconfig' and 'xenconfig' shorthands
lib/raid6: Let $(UNROLL) rules work with macOS userland
kconfig: Support building mconf with vendor sysroot ncurses
kconfig: config script: add a little user help
MAINTAINERS: adjust GCC PLUGINS after gcc-plugin.sh removal
Pull SCSI fixes from James Bottomley:
"This is two driver fixes (megaraid_sas and hisi_sas).
The megaraid one is a revert of a previous revert of a cpu hotplug fix
which exposed a bug in the block layer which has been fixed in this
merge window.
The hisi_sas performance enhancement comes from switching to interrupt
managed completion queues, which depended on the addition of
devm_platform_get_irqs_affinity() which is now upstream via the irq
tree in the last merge window"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: hisi_sas: Expose HW queues for v2 hw
Revert "Revert "scsi: megaraid_sas: Added support for shared host tagset for cpuhotplug""
Section 3.11 was incorrectly called 3.9, fix it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull block fixes from Jens Axboe:
- Missing CRC32 selections (Arnd)
- Fix for a merge window regression with bdev inode init (Christoph)
- bcache fixes
- rnbd fixes
- NVMe pull request from Christoph:
- fix a race in the nvme-tcp send code (Sagi Grimberg)
- fix a list corruption in an nvme-rdma error path (Israel Rukshin)
- avoid a possible double fetch in nvme-pci (Lalithambika Krishnakumar)
- add the susystem NQN quirk for a Samsung driver (Gopal Tiwari)
- fix two compiler warnings in nvme-fcloop (James Smart)
- don't call sleeping functions from irq context in nvme-fc (James Smart)
- remove an unused argument (Max Gurtovoy)
- remove unused exports (Minwoo Im)
- Use-after-free fix for partition iteration (Ming)
- Missing blk-mq debugfs flag annotation (John)
- Bdev freeze regression fix (Satya)
- blk-iocost NULL pointer deref fix (Tejun)
* tag 'block-5.11-2021-01-10' of git://git.kernel.dk/linux-block: (26 commits)
bcache: set bcache device into read-only mode for BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET
bcache: introduce BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE for large bucket
bcache: check unsupported feature sets for bcache register
bcache: fix typo from SUUP to SUPP in features.h
bcache: set pdev_set_uuid before scond loop iteration
blk-mq-debugfs: Add decode for BLK_MQ_F_TAG_HCTX_SHARED
block/rnbd-clt: avoid module unload race with close confirmation
block/rnbd: Adding name to the Contributors List
block/rnbd-clt: Fix sg table use after free
block/rnbd-srv: Fix use after free in rnbd_srv_sess_dev_force_close
block/rnbd: Select SG_POOL for RNBD_CLIENT
block: pre-initialize struct block_device in bdev_alloc_inode
fs: Fix freeze_bdev()/thaw_bdev() accounting of bd_fsfreeze_sb
nvme: remove the unused status argument from nvme_trace_bio_complete
nvmet-rdma: Fix list_del corruption on queue establishment failure
nvme: unexport functions with no external caller
nvme: avoid possible double fetch in handling CQE
nvme-tcp: Fix possible race of io_work and direct send
nvme-pci: mark Samsung PM1725a as IGNORE_DEV_SUBNQN
nvme-fcloop: Fix sscanf type and list_first_entry_or_null warnings
...
Merge two commits that had dependencies on other 5.11 trees (the block
and the irq trees respectively).
- We reverted a megaraid_sas change in 5.10 due to missing block
layer plumbing. Now that this is in place, reinstate the change.
- The hisi_sas driver had a dependency on a driver core irq change
that went in through Thomas' tree.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux 5.10 is out. Remove the 'kvmconfig' and 'xenconfig' shorthands
as previously announced.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull io_uring fixes from Jens Axboe:
"A bit larger than I had hoped at this point, but it's all changes that
will be directed towards stable anyway. In detail:
- Fix a merge window regression on error return (Matthew)
- Remove useless variable declaration/assignment (Ye Bin)
- IOPOLL fixes (Pavel)
- Exit and cancelation fixes (Pavel)
- fasync lockdep complaint fix (Pavel)
- Ensure SQPOLL is synchronized with creator life time (Pavel)"
* tag 'io_uring-5.11-2021-01-10' of git://git.kernel.dk/linux-block:
io_uring: stop SQPOLL submit on creator's death
io_uring: add warn_once for io_uring_flush()
io_uring: inline io_uring_attempt_task_drop()
io_uring: io_rw_reissue lockdep annotations
io_uring: synchronise ev_posted() with waitqueues
io_uring: dont kill fasync under completion_lock
io_uring: trigger eventfd for IOPOLL
io_uring: Fix return value from alloc_fixed_file_ref_node
io_uring: Delete useless variable ‘id’ in io_prep_async_work
io_uring: cancel more aggressively in exit_work
io_uring: drop file refs after task cancel
io_uring: patch up IOPOLL overflow_flush sync
io_uring: synchronise IOPOLL on task_submit fail
If BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET is set in incompat feature
set, it means the cache device is created with obsoleted layout with
obso_bucket_site_hi. Now bcache does not support this feature bit, a new
BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE incompat feature bit is added
for a better layout to support large bucket size.
For the legacy compatibility purpose, if a cache device created with
obsoleted BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET feature bit, all bcache
devices attached to this cache set should be set to read-only. Then the
dirty data can be written back to backing device before re-create the
cache device with BCH_FEATURE_INCOMPAT_LOG_LARGE_BUCKET_SIZE feature bit
by the latest bcache-tools.
This patch checks BCH_FEATURE_INCOMPAT_OBSO_LARGE_BUCKET feature bit
when running a cache set and attach a bcache device to the cache set. If
this bit is set,
- When run a cache set, print an error kernel message to indicate all
following attached bcache device will be read-only.
- When attach a bcache device, print an error kernel message to indicate
the attached bcache device will be read-only, and ask users to update
to latest bcache-tools.
Such change is only for cache device whose bucket size >= 32MB, this is
for the zoned SSD and almost nobody uses such large bucket size at this
moment. If you don't explicit set a large bucket size for a zoned SSD,
such change is totally transparent to your bcache device.
Fixes: ffa470327572 ("bcache: add bucket_size_hi into struct cache_sb_disk for large bucket")
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As a performance enhancement, make the completion queue interrupts managed.
In addition, in commit bf0beec0607d ("blk-mq: drain I/O when all CPUs in a
hctx are offline"), CPU hotplug for MQ devices using managed interrupts is
made safe. So expose HW queues to blk-mq to take advantage of this.
Flag Scsi_host.host_tagset is also set to ensure that the HBA is not sent
more commands than it can handle. However the driver still does not use
request tag for IPTT as there are many HW bugs means that special rules
apply for IPTT allocation.
Link: https://lore.kernel.org/r/1606905417-183214-6-git-send-email-john.garry@huawei.com
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Older versions of BSD awk are fussy about the order of '-v' and '-f'
flags, and require a space after the flag name. This causes build
failures on platforms with an old awk, such as macOS and NetBSD.
Since GNU awk and modern versions of BSD awk (distributed with
FreeBSD/OpenBSD) are fine with either form, the definition of
'cmd_unroll' can be trivially tweaked to let the lib/raid6 Makefile
work with both old and new awk flag dialects.
Signed-off-by: John Millikin <john@john-millikin.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull USB fixes from Greg KH:
"Here are a number of small USB driver fixes for 5.11-rc3.
Include in here are:
- USB gadget driver fixes for reported issues
- new usb-serial driver ids
- dma from stack bugfixes
- typec bugfixes
- dwc3 bugfixes
- xhci driver bugfixes
- other small misc usb driver bugfixes
All of these have been in linux-next with no reported issues"
* tag 'usb-5.11-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (35 commits)
usb: dwc3: gadget: Clear wait flag on dequeue
usb: typec: Send uevent for num_altmodes update
usb: typec: Fix copy paste error for NVIDIA alt-mode description
usb: gadget: enable super speed plus
kcov, usb: hide in_serving_softirq checks in __usb_hcd_giveback_urb
usb: uas: Add PNY USB Portable SSD to unusual_uas
usb: gadget: configfs: Preserve function ordering after bind failure
usb: gadget: select CONFIG_CRC32
usb: gadget: core: change the comment for usb_gadget_connect
usb: gadget: configfs: Fix use-after-free issue with udc_name
usb: dwc3: gadget: Restart DWC3 gadget when enabling pullup
usb: usbip: vhci_hcd: protect shift size
USB: usblp: fix DMA to stack
USB: serial: iuu_phoenix: fix DMA from stack
USB: serial: option: add LongSung M5710 module support
USB: serial: option: add Quectel EM160R-GL
USB: Gadget: dummy-hcd: Fix shift-out-of-bounds bug
usb: gadget: f_uac2: reset wMaxPacketSize
usb: dwc3: ulpi: Fix USB2.0 HS/FS/LS PHY suspend regression
usb: dwc3: ulpi: Replace CPU-based busyloop with Protocol-based one
...
When the creator of SQPOLL io_uring dies (i.e. sqo_task), we don't want
its internals like ->files and ->mm to be poked by the SQPOLL task, it
have never been nice and recently got racy. That can happen when the
owner undergoes destruction and SQPOLL tasks tries to submit new
requests in parallel, and so calls io_sq_thread_acquire*().
That patch halts SQPOLL submissions when sqo_task dies by introducing
sqo_dead flag. Once set, the SQPOLL task must not do any submission,
which is synchronised by uring_lock as well as the new flag.
The tricky part is to make sure that disabling always happens, that
means either the ring is discovered by creator's do_exit() -> cancel,
or if the final close() happens before it's done by the creator. The
last is guaranteed by the fact that for SQPOLL the creator task and only
it holds exactly one file note, so either it pins up to do_exit() or
removed by the creator on the final put in flush. (see comments in
uring_flush() around file->f_count == 2).
One more place that can trigger io_sq_thread_acquire_*() is
__io_req_task_submit(). Shoot off requests on sqo_dead there, even
though actually we don't need to. That's because cancellation of
sqo_task should wait for the request before going any further.
note 1: io_disable_sqo_submit() does io_ring_set_wakeup_flag() so the
caller would enter the ring to get an error, but it still doesn't
guarantee that the flag won't be cleared.
note 2: if final __userspace__ close happens not from the creator
task, the file note will pin the ring until the task dies.
Fixed: b1b6b5a30dce8 ("kernel/io_uring: cancel io_uring before task works")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>