This patch supports polling I/O via virtio-blk driver. Polling
feature is enabled by module parameter "poll_queues" and it sets
dedicated polling queues for virtio-blk. This patch improves the
polling I/O throughput and latency.
The virtio-blk driver doesn't not have a poll function and a poll
queue and it has been operating in interrupt driven method even if
the polling function is called in the upper layer.
virtio-blk polling is implemented upon 'batched completion' of block
layer. virtblk_poll() queues completed request to io_comp_batch->req_list
and later, virtblk_complete_batch() calls unmap function and ends
the requests in batch.
virtio-blk reads the number of poll queues from module parameter
"poll_queues". If VM sets queue parameter as below,
("num-queues=N" [QEMU property], "poll_queues=M" [module parameter])
It allocates N virtqueues to virtio_blk->vqs[N] and it uses [0..(N-M-1)]
as default queues and [(N-M)..(N-1)] as poll queues. Unlike the default
queues, the poll queues have no callback function.
Regarding HW-SW queue mapping, the default queue mapping uses the
existing method that condsiders MSI irq vector. But the poll queue
doesn't have an irq, so it uses the regular blk-mq cpu mapping.
For verifying the improvement, I did Fio polling I/O performance test
with io_uring engine with the options below.
(io_uring, hipri, randread, direct=1, bs=512, iodepth=64 numjobs=N)
I set 4 vcpu and 4 virtio-blk queues - 2 default queues and 2 poll
queues for VM.
As a result, IOPS and average latency improved about 10%.
Test result:
- Fio io_uring poll without virtio-blk poll support
-- numjobs=1 : IOPS = 339K, avg latency = 188.33us
-- numjobs=2 : IOPS = 367K, avg latency = 347.33us
-- numjobs=4 : IOPS = 383K, avg latency = 682.06us
- Fio io_uring poll with virtio-blk poll support
-- numjobs=1 : IOPS = 385K, avg latency = 165.94us
-- numjobs=2 : IOPS = 408K, avg latency = 313.28us
-- numjobs=4 : IOPS = 424K, avg latency = 613.05us
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Suwan Kim <suwan.kim027@gmail.com>
Message-Id: <20220406153207.163134-2-suwan.kim027@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Let the caller set it together with the end_io_data instead of passing
a pointless argument. Note the the target code did in fact already
set it and then just overrode it again by calling blk_execute_rq_nowait.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220524121530.943123-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of using the long printk(KERN_ERR "nbd: ...") to
output error message, defining pr_fmt and using
the short pr_err("") to do that. The replacemen is done
by using the following command:
sed -i 's/printk(KERN_ERR "nbd: /pr_err("/g' \
drivers/block/nbd.c
This patch also rewrap to 80 columns where possible.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20220521073749.3146892-7-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When 'index' is a big numbers, it may become negative which forced
to 'int'. then 'index << part_shift' might overflow to a positive
value that is not greater than '0xfffff', then sysfs might complains
about duplicate creation. Because of this, move the 'index' judgment
to the front will fix it and be better.
Fixes: b0d9111a2d53 ("nbd: use an idr to keep track of nbd devices")
Fixes: 940c264984fd ("nbd: fix possible overflow for 'first_minor' in nbd_dev_add()")
Signed-off-by: Zhang Wensheng <zhangwensheng5@huawei.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20220521073749.3146892-6-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In our tests, "qemu-nbd" triggers a io hung:
INFO: task qemu-nbd:11445 blocked for more than 368 seconds.
Not tainted 5.18.0-rc3-next-20220422-00003-g2176915513ca #884
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:qemu-nbd state:D stack: 0 pid:11445 ppid: 1 flags:0x00000000
Call Trace:
<TASK>
__schedule+0x480/0x1050
? _raw_spin_lock_irqsave+0x3e/0xb0
schedule+0x9c/0x1b0
blk_mq_freeze_queue_wait+0x9d/0xf0
? ipi_rseq+0x70/0x70
blk_mq_freeze_queue+0x2b/0x40
nbd_add_socket+0x6b/0x270 [nbd]
nbd_ioctl+0x383/0x510 [nbd]
blkdev_ioctl+0x18e/0x3e0
__x64_sys_ioctl+0xac/0x120
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fd8ff706577
RSP: 002b:00007fd8fcdfebf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000040000000 RCX: 00007fd8ff706577
RDX: 000000000000000d RSI: 000000000000ab00 RDI: 000000000000000f
RBP: 000000000000000f R08: 000000000000fbe8 R09: 000055fe497c62b0
R10: 00000002aff20000 R11: 0000000000000246 R12: 000000000000006d
R13: 0000000000000000 R14: 00007ffe82dc5e70 R15: 00007fd8fcdff9c0
"qemu-ndb -d" will call ioctl 'NBD_DISCONNECT' first, however, following
message was found:
block nbd0: Send disconnect failed -32
Which indicate that something is wrong with the server. Then,
"qemu-nbd -d" will call ioctl 'NBD_CLEAR_SOCK', however ioctl can't clear
requests after commit 2516ab1543fd("nbd: only clear the queue on device
teardown"). And in the meantime, request can't complete through timeout
because nbd_xmit_timeout() will always return 'BLK_EH_RESET_TIMER', which
means such request will never be completed in this situation.
Now that the flag 'NBD_CMD_INFLIGHT' can make sure requests won't
complete multiple times, switch back to call nbd_clear_sock() in
nbd_clear_sock_ioctl(), so that inflight requests can be cleared.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20220521073749.3146892-5-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Otherwise io will hung because request will only be completed if the
cmd has the flag 'NBD_CMD_INFLIGHT'.
Fixes: 07175cb1baf4 ("nbd: make sure request completion won't concurrent")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20220521073749.3146892-4-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When nbd module is being removing, nbd_alloc_config() may be
called concurrently by nbd_genl_connect(), although try_module_get()
will return false, but nbd_alloc_config() doesn't handle it.
The race may lead to the leak of nbd_config and its related
resources (e.g, recv_workq) and oops in nbd_read_stat() due
to the unload of nbd module as shown below:
BUG: kernel NULL pointer dereference, address: 0000000000000040
Oops: 0000 [#1] SMP PTI
CPU: 5 PID: 13840 Comm: kworker/u17:33 Not tainted 5.14.0+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Workqueue: knbd16-recv recv_work [nbd]
RIP: 0010:nbd_read_stat.cold+0x130/0x1a4 [nbd]
Call Trace:
recv_work+0x3b/0xb0 [nbd]
process_one_work+0x1ed/0x390
worker_thread+0x4a/0x3d0
kthread+0x12a/0x150
ret_from_fork+0x22/0x30
Fixing it by checking the return value of try_module_get()
in nbd_alloc_config(). As nbd_alloc_config() may return ERR_PTR(-ENODEV),
assign nbd->config only when nbd_alloc_config() succeeds to ensure
the value of nbd->config is binary (valid or NULL).
Also adding a debug message to check the reference counter
of nbd_config during module removal.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20220521073749.3146892-3-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Historically we did distinguish between a flag that surpressed partition
scanning, and a combinations of the minors variable and another flag if
any partitions were supported. This was generally confusing and doesn't
make much sense, but some corner case uses of the loop driver actually
do want to support manually added partitions on a device that does not
actively scan for partitions. To make things worsee the loop driver
also wants to dynamically toggle the scanning for partitions on a live
gendisk, which makes the disk->flags updates non-atomic.
Introduce a new GD_SUPPRESS_PART_SCAN bit in disk->state that disables
just scanning for partitions, and toggle that instead of GENHD_FL_NO_PART
in the loop driver.
Fixes: 1ebe2e5f9d68 ("block: remove GENHD_FL_EXT_DEVT")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220527055806.1972352-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of a virtual kernel address use a pointer of the associated
struct page as second parameter of gnttab_end_foreign_access().
Most users have that pointer available already and are creating the
virtual address from it, risking problems in case the memory is
located in highmem.
gnttab_end_foreign_access() itself won't need to get the struct page
from the address again.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
file-backed transparent hugepages.
Johannes Weiner has arranged for zswap memory use to be tracked and
managed on a per-cgroup basis.
Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for runtime
enablement of the recent huge page vmemmap optimization feature.
Baolin Wang contributes a series to fix some issues around hugetlb
pagetable invalidation.
Zhenwei Pi has fixed some interactions between hwpoisoned pages and
virtualization.
Tong Tiangen has enabled the use of the presently x86-only
page_table_check debugging feature on arm64 and riscv.
David Vernet has done some fixup work on the memcg selftests.
Peter Xu has taught userfaultfd to handle write protection faults against
shmem- and hugetlbfs-backed files.
More DAMON development from SeongJae Park - adding online tuning of the
feature and support for monitoring of fixed virtual address ranges. Also
easier discovery of which monitoring operations are available.
Nadav Amit has done some optimization of TLB flushing during mprotect().
Neil Brown continues to labor away at improving our swap-over-NFS support.
David Hildenbrand has some fixes to anon page COWing versus
get_user_pages().
Peng Liu fixed some errors in the core hugetlb code.
Joao Martins has reduced the amount of memory consumed by device-dax's
compound devmaps.
Some cleanups of the arch-specific pagemap code from Anshuman Khandual.
Muchun Song has found and fixed some errors in the TLB flushing of
transparent hugepages.
Roman Gushchin has done more work on the memcg selftests.
And, of course, many smaller fixes and cleanups. Notably, the customary
million cleanup serieses from Miaohe Lin.
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Merge tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Almost all of MM here. A few things are still getting finished off,
reviewed, etc.
- Yang Shi has improved the behaviour of khugepaged collapsing of
readonly file-backed transparent hugepages.
- Johannes Weiner has arranged for zswap memory use to be tracked and
managed on a per-cgroup basis.
- Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for
runtime enablement of the recent huge page vmemmap optimization
feature.
- Baolin Wang contributes a series to fix some issues around hugetlb
pagetable invalidation.
- Zhenwei Pi has fixed some interactions between hwpoisoned pages and
virtualization.
- Tong Tiangen has enabled the use of the presently x86-only
page_table_check debugging feature on arm64 and riscv.
- David Vernet has done some fixup work on the memcg selftests.
- Peter Xu has taught userfaultfd to handle write protection faults
against shmem- and hugetlbfs-backed files.
- More DAMON development from SeongJae Park - adding online tuning of
the feature and support for monitoring of fixed virtual address
ranges. Also easier discovery of which monitoring operations are
available.
- Nadav Amit has done some optimization of TLB flushing during
mprotect().
- Neil Brown continues to labor away at improving our swap-over-NFS
support.
- David Hildenbrand has some fixes to anon page COWing versus
get_user_pages().
- Peng Liu fixed some errors in the core hugetlb code.
- Joao Martins has reduced the amount of memory consumed by
device-dax's compound devmaps.
- Some cleanups of the arch-specific pagemap code from Anshuman
Khandual.
- Muchun Song has found and fixed some errors in the TLB flushing of
transparent hugepages.
- Roman Gushchin has done more work on the memcg selftests.
... and, of course, many smaller fixes and cleanups. Notably, the
customary million cleanup serieses from Miaohe Lin"
* tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (381 commits)
mm: kfence: use PAGE_ALIGNED helper
selftests: vm: add the "settings" file with timeout variable
selftests: vm: add "test_hmm.sh" to TEST_FILES
selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests
selftests: vm: add migration to the .gitignore
selftests/vm/pkeys: fix typo in comment
ksm: fix typo in comment
selftests: vm: add process_mrelease tests
Revert "mm/vmscan: never demote for memcg reclaim"
mm/kfence: print disabling or re-enabling message
include/trace/events/percpu.h: cleanup for "percpu: improve percpu_alloc_percpu event trace"
include/trace/events/mmflags.h: cleanup for "tracing: incorrect gfp_t conversion"
mm: fix a potential infinite loop in start_isolate_page_range()
MAINTAINERS: add Muchun as co-maintainer for HugeTLB
zram: fix Kconfig dependency warning
mm/shmem: fix shmem folio swapoff hang
cgroup: fix an error handling path in alloc_pagecache_max_30M()
mm: damon: use HPAGE_PMD_SIZE
tracing: incorrect isolate_mote_t cast in mm_vmscan_lru_isolate
nodemask.h: fix compilation error with GCC12
...
To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.
To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean.
This removes the need to use a found variable and simply checking if
the variable was set, can determine if the break/goto was hit.
Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
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Merge tag 'for-linus-5.19-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- decouple the PV interface from kernel internals in the Xen
scsifront/scsiback pv drivers
- harden the Xen scsifront PV driver against a malicious backend driver
- simplify Xen PV frontend driver ring page setup
- support Xen setups with multiple domains created at boot time to
tolerate Xenstore coming up late
- two small cleanup patches
* tag 'for-linus-5.19-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (29 commits)
xen: add support for initializing xenstore later as HVM domain
xen: sync xs_wire.h header with upstream xen
x86: xen: remove STACK_FRAME_NON_STANDARD from xen_cpuid
xen-blk{back,front}: Update contact points for buffer_squeeze_duration_ms and feature_persistent
xen/xenbus: eliminate xenbus_grant_ring()
xen/sndfront: use xenbus_setup_ring() and xenbus_teardown_ring()
xen/usbfront: use xenbus_setup_ring() and xenbus_teardown_ring()
xen/scsifront: use xenbus_setup_ring() and xenbus_teardown_ring()
xen/pcifront: use xenbus_setup_ring() and xenbus_teardown_ring()
xen/drmfront: use xenbus_setup_ring() and xenbus_teardown_ring()
xen/tpmfront: use xenbus_setup_ring() and xenbus_teardown_ring()
xen/netfront: use xenbus_setup_ring() and xenbus_teardown_ring()
xen/blkfront: use xenbus_setup_ring() and xenbus_teardown_ring()
xen/xenbus: add xenbus_setup_ring() service function
xen: update ring.h
xen/shbuf: switch xen-front-pgdir-shbuf to use INVALID_GRANT_REF
xen/dmabuf: switch gntdev-dmabuf to use INVALID_GRANT_REF
xen/sound: switch xen_snd_front to use INVALID_GRANT_REF
xen/drm: switch xen_drm_front to use INVALID_GRANT_REF
xen/usb: switch xen-hcd to use INVALID_GRANT_REF
...
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Merge tag 'for-5.19/drivers-2022-05-22' of git://git.kernel.dk/linux-block
Pull block driver updates from Jens Axboe:
"Here are the driver updates queued up for 5.19. This contains:
- NVMe pull requests via Christoph:
- tighten the PCI presence check (Stefan Roese)
- fix a potential NULL pointer dereference in an error path (Kyle
Miller Smith)
- fix interpretation of the DMRSL field (Tom Yan)
- relax the data transfer alignment (Keith Busch)
- verbose error logging improvements (Max Gurtovoy, Chaitanya
Kulkarni)
- misc cleanups (Chaitanya Kulkarni, Christoph)
- set non-mdts limits in nvme_scan_work (Chaitanya Kulkarni)
- add support for TP4084 - Time-to-Ready Enhancements (Christoph)
- MD pull request via Song:
- Improve annotation in raid5 code, by Logan Gunthorpe
- Support MD_BROKEN flag in raid-1/5/10, by Mariusz Tkaczyk
- Other small fixes/cleanups
- null_blk series making the configfs side much saner (Damien)
- Various minor drbd cleanups and fixes (Haowen, Uladzislau, Jiapeng,
Arnd, Cai)
- Avoid using the system workqueue (and hence flushing it) in rnbd
(Jack)
- Avoid using the system workqueue (and hence flushing it) in aoe
(Tetsuo)
- Series fixing discard_alignment issues in drivers (Christoph)
- Small series fixing drivers poking at disk->part0 for openers
information (Christoph)
- Series fixing deadlocks in loop (Christoph, Tetsuo)
- Remove loop.h and add SPDX headers (Christoph)
- Various fixes and cleanups (Julia, Xie, Yu)"
* tag 'for-5.19/drivers-2022-05-22' of git://git.kernel.dk/linux-block: (72 commits)
mtip32xx: fix typo in comment
nvme: set non-mdts limits in nvme_scan_work
nvme: add support for TP4084 - Time-to-Ready Enhancements
nvme: split the enum used for various register constants
nbd: Fix hung on disconnect request if socket is closed before
nvme-fabrics: add a request timeout helper
nvme-pci: harden drive presence detect in nvme_dev_disable()
nvme-pci: fix a NULL pointer dereference in nvme_alloc_admin_tags
nvme: mark internal passthru request RQF_QUIET
nvme: remove unneeded include from constants file
nvme: add missing status values to verbose logging
nvme: set dma alignment to dword
nvme: fix interpretation of DMRSL
loop: remove most the top-of-file boilerplate comment from the UAPI header
loop: remove most the top-of-file boilerplate comment
loop: add a SPDX header
loop: remove loop.h
block: null_blk: Improve device creation with configfs
block: null_blk: Cleanup messages
block: null_blk: Cleanup device creation and deletion
...
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Merge tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
"Here are the core block changes for 5.19. This contains:
- blk-throttle accounting fix (Laibin)
- Series removing redundant assignments (Michal)
- Expose bio cache via the bio_set, so that DM can use it (Mike)
- Finish off the bio allocation interface cleanups by dealing with
the weirdest member of the family. bio_kmalloc combines a kmalloc
for the bio and bio_vecs with a hidden bio_init call and magic
cleanup semantics (Christoph)
- Clean up the block layer API so that APIs consumed by file systems
are (almost) only struct block_device based, so that file systems
don't have to poke into block layer internals like the
request_queue (Christoph)
- Clean up the blk_execute_rq* API (Christoph)
- Clean up various lose end in the blk-cgroup code to make it easier
to follow in preparation of reworking the blkcg assignment for bios
(Christoph)
- Fix use-after-free issues in BFQ when processes with merged queues
get moved to different cgroups (Jan)
- BFQ fixes (Jan)
- Various fixes and cleanups (Bart, Chengming, Fanjun, Julia, Ming,
Wolfgang, me)"
* tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-block: (83 commits)
blk-mq: fix typo in comment
bfq: Remove bfq_requeue_request_body()
bfq: Remove superfluous conversion from RQ_BIC()
bfq: Allow current waker to defend against a tentative one
bfq: Relax waker detection for shared queues
blk-cgroup: delete rcu_read_lock_held() WARN_ON_ONCE()
blk-throttle: Set BIO_THROTTLED when bio has been throttled
blk-cgroup: Remove unnecessary rcu_read_lock/unlock()
blk-cgroup: always terminate io.stat lines
block, bfq: make bfq_has_work() more accurate
block, bfq: protect 'bfqd->queued' by 'bfqd->lock'
block: cleanup the VM accounting in submit_bio
block: Fix the bio.bi_opf comment
block: reorder the REQ_ flags
blk-iocost: combine local_stat and desc_stat to stat
block: improve the error message from bio_check_eod
block: allow passing a NULL bdev to bio_alloc_clone/bio_init_clone
block: remove superfluous calls to blkcg_bio_issue_init
kthread: unexport kthread_blkcg
blk-cgroup: cleanup blkcg_maybe_throttle_current
...
- CONFIG_ZRAM: Zram is a user-facing feature, whereas zsmalloc is
not. Don't make the user chase down a technical dependency like
that, just select it in automatically when zram is requested. The
CONFIG_CRYPTO dependency is redundant due to more specific deps.
- CONFIG_ZPOOL: This is not a user-facing feature. Hide the symbol and
have it selected in as needed.
- CONFIG_ZSWAP: Select CRYPTO instead of depend. Common pattern.
- Make the ZSWAP suboptions and their descriptions (compression,
allocation backend) a bit more straight-forward for the user.
Link: https://lkml.kernel.org/r/20220510152847.230957-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Simplify blkfront's ring creation and removal via xenbus_setup_ring()
and xenbus_teardown_ring().
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Instead of using a private macro for an invalid grant reference use
the common one.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
When userspace closes the socket before sending a disconnect
request, the following I/O requests will be blocked in
wait_for_reconnect() until dead timeout. This will cause the
following disconnect request also hung on blk_mq_quiesce_queue().
That means we have no way to disconnect a nbd device if there
are some I/O requests waiting for reconnecting until dead timeout.
It's not expected. So let's wake up the thread waiting for
reconnecting directly when a disconnect request is sent.
Reported-by: Xu Jianhai <zero.xu@bytedance.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20220322080639.142-1-xieyongji@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The last traces of the IDE driver went away in commit b7fb14d3ac63
("ide: remove the legacy ide driver") but it left behind some traces
of old documentation.
As luck would have it Randy and I would submit similar changes within
a week of each other to address this. As Randy's commit is in the doc
tree already - this delta is just the stuff my removal contained that
was not in Randy's IDE doc removal.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Phillip Potter <phil@philpotter.co.uk>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: https://lore.kernel.org/all/20220427165917.GE12977@windriver.com
[phil@philpotter.co.uk: removed diffs already added by others]
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20220515205833.944139-5-phil@philpotter.co.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The 2nd trial allocation under per-cpu presumption has been used to
prevent regression of allocation failure. However, it makes trouble for
maintenance without significant benefit. The slowpath branch is executed
extremely rarely: getting there is problematic. Therefore, we delete this
branch.
Since b09ab054b69b ("zram: support BDI_CAP_STABLE_WRITES"), zram has used
QUEUE_FLAG_STABLE_WRITES to prevent buffer change between 1st and 2nd
memory allocations. Since we remove second trial memory allocation logic,
we could remove the STABLE_WRITES flag because there is no change buffer
to be modified under us.
Link: https://lkml.kernel.org/r/20220505094443.11728-1-avromanov@sberdevices.ru
Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove the irrelevant changelogs and todo notes and just leave the SPDX
marker and the copyright notice.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220419063303.583106-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The copyright statement says:
"Redistribution of this file is permitted under the GNU General Public
License." and was added by Ted in 1993, at which point GPLv2 only
was the default Linux license.
Replace it with the usual GPLv2 only SPDX header.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220419063303.583106-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge loop.h into loop.c as all the content is only used there.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220419063303.583106-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently various places test if direct IO is possible on a file by
checking for the existence of the direct_IO address space operation.
This is a poor choice, as the direct_IO operation may not be used - it is
only used if the generic_file_*_iter functions are called for direct IO
and some filesystems - particularly NFS - don't do this.
Instead, introduce a new f_mode flag: FMODE_CAN_ODIRECT and change the
various places to check this (avoiding pointer dereferences).
do_dentry_open() will set this flag if ->direct_IO is present, so
filesystems do not need to be changed.
NFS *is* changed, to set the flag explicitly and discard the direct_IO
entry in the address_space_operations for files.
Other filesystems which currently use noop_direct_IO could usefully be
changed to set this flag instead.
Link: https://lkml.kernel.org/r/164859778128.29473.15189737957277399416.stgit@noble.brown
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: NeilBrown <neilb@suse.de>
Tested-by: David Howells <dhowells@redhat.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This is the last driver making use of fd_request->error_count, which is
easy to get wrong as was shown in floppy.c. We don't need to keep it
there, it can be moved to the atari_floppy_struct instead, so let's do
this.
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Cc: Minh Yuan <yuanmingbuaa@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Interrupt handler bad_flp_intr() may cause a UAF on the recently freed
request just to increment the error count. There's no point keeping
that one in the request anyway, and since the interrupt handler uses a
static pointer to the error which cannot be kept in sync with the
pending request, better make it use a static error counter that's reset
for each new request. This reset now happens when entering
redo_fd_request() for a new request via set_next_request().
One initial concern about a single error counter was that errors on one
floppy drive could be reported on another one, but this problem is not
real given that the driver uses a single drive at a time, as that
PC-compatible controllers also have this limitation by using shared
signals. As such the error count is always for the "current" drive.
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Tested-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, the directory name used to create a nullb device through
sysfs is not used as the device name, potentially causing headaches for
users if devices are already created through the modprobe operation
withe the nr_device module parameter not set to 0. E.g. a user can do
"mkdir /sys/kernel/config/nullb/nullb0" to create a nullb device even
though /dev/nullb0 was already created by modprobe. In this case, the
configfs nullb device will be named nullb1, causing confusion for the
user.
Simplify this by using the configfs directory name as the nullb device
name, always, unless another nullb device is already using the same
name. E.g. if modprobe created nullb0, then:
$ mkdir /sys/kernel/config/nullb/nullb0
mkdir: cannot create directory '/sys/kernel/config/nullb/nullb0': File
exists
will be reported to the user.
To implement this, the function null_find_dev_by_name() is added to
check for the existence of a nullb device with the name used for a new
configfs device directory. nullb_group_make_item() uses this new
function to check if the directory name can be used as the disk name.
Finally, null_add_dev() is modified to use the device config item name
as the disk name for a new nullb device created using configfs.
The naming of devices created though modprobe remains unchanged.
Of note is that it is possible for a user to create through configfs a
nullb device with the same name as an existing device. E.g.
$ mkdir /sys/kernel/config/nullb/null
will successfully create the nullb device named "null" but this block
device will however not appear under /dev/ since /dev/null already
exists.
Suggested-by: Joseph Bacik <josef@toxicpanda.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220420005718.3780004-5-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use the pr_fmt() macro to prefix all null_blk pr_xxx() messages with
"null_blk:" to clarify which module is printing the messages. Also add
a pr_info() message in null_add_dev() to print the name of a newly
created disk.
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220420005718.3780004-4-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Introduce the null_create_dev() and null_destroy_dev() helper functions
to respectivel create nullb devices on modprobe and destroy them on
rmmod. The null_destroy_dev() helper avoids duplicated code in the
null_init() and null_exit() functions for deleting devices.
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220420005718.3780004-3-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use bdev_discard_alignment to calculate the correct discard alignment
offset even for partitions instead of just looking at the queue limit.
Also switch to use bdev_discard_granularity to get rid of the last direct
queue reference in xen_blkbk_discard.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220418045314.360785-12-hch@lst.de
[axboe: fold in 'q' removal as it's now unused]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use bdev_discard_alignment to calculate the correct discard alignment
offset even for partitions instead of just looking at the queue limit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220418045314.360785-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The loop driver never sets a discard_alignment, so it also doens't need
to clear it to zero.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220418045314.360785-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The discard_alignment queue limit is named a bit misleading means the
offset into the block device at which the discard granularity starts.
On the other hand the discard_sector_alignment from the virtio 1.1 looks
similar to what Linux uses as discard granularity (even if not very well
described):
"discard_sector_alignment can be used by OS when splitting a request
based on alignment. "
And at least qemu does set it to the discard granularity.
So stop setting the discard_alignment and use the virtio
discard_sector_alignment to set the discard granularity.
Fixes: 1f23816b8eb8 ("virtio_blk: add discard and write zeroes support")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220418045314.360785-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The discard_alignment queue limit is named a bit misleading means the
offset into the block device at which the discard granularity starts.
Setting it to the discard granularity as done by null_blk is mostly
harmless but also useless.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220418045314.360785-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The discard_alignment queue limit is named a bit misleading means the
offset into the block device at which the discard granularity starts.
Setting it to the discard granularity as done by nbd is mostly harmless
but also useless.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220418045314.360785-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All callers of bio_blkcg actually want the CSS, so replace it with an
interface that does return the CSS. This now allows to move
struct blkcg_gq to block/blk-cgroup.h instead of exposing it in a
public header.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Today it's only possible to write back as a page, idle, or huge. A user
might want to writeback pages which are huge and idle first as these idle
pages do not require decompression and make a good first pass for
writeback.
Idle writeback specifically has the advantage that a refault is unlikely
given that the page has been swapped for some amount of time without being
refaulted.
Huge writeback has the advantage that you're guaranteed to get the maximum
benefit from a single page writeback, that is, you're reclaiming one full
page of memory. Pages which are compressed in zram being written back
result in some benefit which is always less than a page size because of
the fact that it was compressed.
The primary use of this is for minimizing refaults in situations where the
device has to be sensitive to storage endurance. On ChromeOS we have
devices with slow eMMC and repeated writes and refaults can negatively
affect performance and endurance.
Link: https://lkml.kernel.org/r/20220322215821.1196994-1-bgeffon@google.com
Signed-off-by: Brian Geffon <bgeffon@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Minh Yuan reported a concurrency use-after-free issue in the floppy code
between raw_cmd_ioctl and seek_interrupt.
[ It turns out this has been around, and that others have reported the
KASAN splats over the years, but Minh Yuan had a reproducer for it and
so gets primary credit for reporting it for this fix - Linus ]
The problem is, this driver tends to break very easily and nowadays,
nobody is expected to use FDRAWCMD anyway since it was used to
manipulate non-standard formats. The risk of breaking the driver is
higher than the risk presented by this race, and accessing the device
requires privileges anyway.
Let's just add a config option to completely disable this ioctl and
leave it disabled by default. Distros shouldn't use it, and only those
running on antique hardware might need to enable it.
Link: https://lore.kernel.org/all/000000000000b71cdd05d703f6bf@google.com/
Link: https://lore.kernel.org/lkml/CAKcFiNC=MfYVW-Jt9A3=FPJpTwCD2PL_ULNCpsCVE5s8ZeBQgQ@mail.gmail.com
Link: https://lore.kernel.org/all/CAEAjamu1FRhz6StCe_55XY5s389ZP_xmCF69k987En+1z53=eg@mail.gmail.com
Reported-by: Minh Yuan <yuanmingbuaa@gmail.com>
Reported-by: syzbot+8e8958586909d62b6840@syzkaller.appspotmail.com
Reported-by: cruise k <cruise4k@gmail.com>
Reported-by: Kyungtae Kim <kt0755@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Tested-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Total 16 bytes can be saved in two ways:
1) The field 'bio' will only be used in bio based mode, and the field
'rq' will only be used in mq mode. Since they won't be used in the
same time, declare a union for them.
2) The field 'bool fake_timeout' can be placed in the hole after the
field 'error'.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20220426022133.3999006-1-yukuai3@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
lo_refcount counts how many openers a loop device has, but that count
is already provided by the block layer in the bd_openers field of the
whole-disk block_device. Remove lo_refcount and allow opens to
succeed even on devices beeing deleted - now that ->free_disk is
implemented we can handle that race gracefull and all I/O on it will
just fail. Similarly there is a small race window now where
loop_control_remove does not synchronize the delete vs the remove
due do bd_openers not being under lo_mutex protection, but we can
handle that just as gracefully.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220330052917.2566582-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since ->release is called with disk->open_mutex held, and __loop_clr_fd()
from lo_release() is called via ->release when disk_openers() == 0, we are
guaranteed that "struct file" which will be passed to loop_validate_file()
via fget() cannot be the loop device __loop_clr_fd(lo, true) will clear.
Thus, there is no need to hold loop_validate_mutex from __loop_clr_fd()
if release == true.
When I made commit 3ce6e1f662a91097 ("loop: reintroduce global lock for
safe loop_validate_file() traversal"), I wrote "It is acceptable for
loop_validate_file() to succeed, for actual clear operation has not started
yet.". But now I came to feel why it is acceptable to succeed.
It seems that the loop driver was added in Linux 1.3.68, and
if (lo->lo_refcnt > 1)
return -EBUSY;
check in loop_clr_fd() was there from the beginning. The intent of this
check was unclear. But now I think that current
disk_openers(lo->lo_disk) > 1
form is there for three reasons.
(1) Avoid I/O errors when some process which opens and reads from this
loop device in response to uevent notification (e.g. systemd-udevd),
as described in commit a1ecac3b0656a682 ("loop: Make explicit loop
device destruction lazy"). This opener is short-lived because it is
likely that the file descriptor used by that process is closed soon.
(2) Avoid I/O errors caused by underlying layer of stacked loop devices
(i.e. ioctl(some_loop_fd, LOOP_SET_FD, other_loop_fd)) being suddenly
disappeared. This opener is long-lived because this reference is
associated with not a file descriptor but lo->lo_backing_file.
(3) Avoid I/O errors caused by underlying layer of mounted loop device
(i.e. mount(some_loop_device, some_mount_point)) being suddenly
disappeared. This opener is long-lived because this reference is
associated with not a file descriptor but mount.
While race in (1) might be acceptable, (2) and (3) should be checked
racelessly. That is, make sure that __loop_clr_fd() will not run if
loop_validate_file() succeeds, by doing refcount check with global lock
held when explicit loop device destruction is requested.
As a result of no longer waiting for lo->lo_mutex after setting Lo_rundown,
we can remove pointless BUG_ON(lo->lo_state != Lo_rundown) check.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220330052917.2566582-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, udev change event is generated for a loop device before the
device is ready for IO. Due to serialization on lo->lo_mutex in
lo_open() this does not matter because anybody is able to open the
device and do IO only after the configuration is finished. However this
synchronization in lo_open() is going away so make sure userspace
reacting to the change event will see the new device state by generating
the event only when the device is setup.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220330052917.2566582-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ensure that the lo_device which is stored in the gendisk private
data is valid until the gendisk is freed. Currently the loop driver
uses a lot of effort to make sure a device is not freed when it is
still in use, but to to fix a potential deadlock this will be relaxed
a bit soon.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220330052917.2566582-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
