In block/blk-mq-sysfs.c, struct blk_mq_ctx_sysfs_entry is not used to
define any attribute since the "mq" sysfs directory contains only
sub-directories (no attribute files). As a result, blk_mq_sysfs_show(),
blk_mq_sysfs_store(), and struct sysfs_ops blk_mq_sysfs_ops are all
unused and unnecessary. Remove all this unused code.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Link: https://lore.kernel.org/r/20210713081837.524422-1-damien.lemoal@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a new sysfs handle to export the new diskseq value.
Place it in <sysfs>/block/<disk>/diskseq and document it.
$ grep . /sys/class/block/*/diskseq
/sys/class/block/loop0/diskseq:13
/sys/class/block/loop1/diskseq:14
/sys/class/block/loop2/diskseq:5
/sys/class/block/loop3/diskseq:6
/sys/class/block/ram0/diskseq:1
/sys/class/block/ram1/diskseq:2
/sys/class/block/vda/diskseq:7
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matteo Croce <mcroce@microsoft.com>
Tested-by: Luca Boccassi <bluca@debian.org>
Link: https://lore.kernel.org/r/20210712230530.29323-5-mcroce@linux.microsoft.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Associating uevents with block devices in userspace is difficult and racy:
the uevent netlink socket is lossy, and on slow and overloaded systems
has a very high latency.
Block devices do not have exclusive owners in userspace, any process can
set one up (e.g. loop devices). Moreover, device names can be reused
(e.g. loop0 can be reused again and again). A userspace process setting
up a block device and watching for its events cannot thus reliably tell
whether an event relates to the device it just set up or another earlier
instance with the same name.
Being able to set a UUID on a loop device would solve the race conditions.
But it does not allow to derive orderings from uevents: if you see a
uevent with a UUID that does not match the device you are waiting for,
you cannot tell whether it's because the right uevent has not arrived yet,
or it was already sent and you missed it. So you cannot tell whether you
should wait for it or not.
Associating a unique, monotonically increasing sequential number to the
lifetime of each block device, which can be retrieved with an ioctl
immediately upon setting it up, allows to solve the race conditions with
uevents, and also allows userspace processes to know whether they should
wait for the uevent they need or if it was dropped and thus they should
move on.
Additionally, increment the disk sequence number when the media change,
i.e. on DISK_EVENT_MEDIA_CHANGE event.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matteo Croce <mcroce@microsoft.com>
Tested-by: Luca Boccassi <bluca@debian.org>
Link: https://lore.kernel.org/r/20210712230530.29323-2-mcroce@linux.microsoft.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
I have compiled the kernel with a cross compiler "hppa-linux-gnu-" v9.3.0
on x86-64 host machine. I got the following warning:
block/genhd.c: In function ‘diskstats_show’:
block/genhd.c:1227:1: warning: the frame size of 1688 bytes is larger
than 1280 bytes [-Wframe-larger-than=]
1227 | }
By Reduced the stack footprint by using the %pg printk specifier instead
of disk_name to remove the need for the on-stack buffer.
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210727062518.122108-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of acquiring an inode reference on open make sure partitions
always hold device model references to the disk while alive, and switch
open to grab only a device model reference to the opened block device.
If that is a partition the disk reference is transitively held by the
partition already.
Link: https://lore.kernel.org/r/20210722075402.983367-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Unhash the whole device inode early in del_gendisk. This allows to
remove the first GENHD_FL_UP check in the open path as we simply
won't find a just removed inode. The second non-racy check after
taking open_mutex is still kept.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210722075402.983367-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull perf tools fixes from Arnaldo Carvalho de Melo:
- Revert "perf map: Fix dso->nsinfo refcounting", this makes 'perf top'
abort, uncovering a design flaw on how namespace information is kept.
The fix for that is more than we can do right now, leave it for the
next merge window.
- Split --dump-raw-trace by AUX records for ARM's CoreSight, fixing up
the decoding of some records.
- Fix PMU alias matching.
Thanks to James Clark and John Garry for these fixes.
* tag 'perf-tools-fixes-for-v5.14-2021-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
Revert "perf map: Fix dso->nsinfo refcounting"
perf pmu: Fix alias matching
perf cs-etm: Split --dump-raw-trace by AUX records
Pull powerpc fixes from Michael Ellerman:
- Don't use r30 in VDSO code, to avoid breaking existing Go lang
programs.
- Change an export symbol to allow non-GPL modules to use spinlocks
again.
Thanks to Paul Menzel, and Srikar Dronamraju.
* tag 'powerpc-5.14-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/vdso: Don't use r30 to avoid breaking Go lang
powerpc/pseries: Fix regression while building external modules
Pull xfs fixes from Darrick Wong:
"This contains a bunch of bug fixes in XFS.
Dave and I have been busy the last couple of weeks to find and fix as
many log recovery bugs as we can find; here are the results so far. Go
fstests -g recoveryloop! ;)
- Fix a number of coordination bugs relating to cache flushes for
metadata writeback, cache flushes for multi-buffer log writes, and
FUA writes for single-buffer log writes
- Fix a bug with incorrect replay of attr3 blocks
- Fix unnecessary stalls when flushing logs to disk
- Fix spoofing problems when recovering realtime bitmap blocks"
* tag 'xfs-5.14-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: prevent spoofing of rtbitmap blocks when recovering buffers
xfs: limit iclog tail updates
xfs: need to see iclog flags in tracing
xfs: Enforce attr3 buffer recovery order
xfs: logging the on disk inode LSN can make it go backwards
xfs: avoid unnecessary waits in xfs_log_force_lsn()
xfs: log forces imply data device cache flushes
xfs: factor out forced iclog flushes
xfs: fix ordering violation between cache flushes and tail updates
xfs: fold __xlog_state_release_iclog into xlog_state_release_iclog
xfs: external logs need to flush data device
xfs: flush data dev on external log write
Pull cifs fixes from Steve French:
"Three cifs/smb3 fixes, including two for stable, and a fix for an
fallocate problem noticed by Clang"
* tag '5.14-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: add missing parsing of backupuid
smb3: rc uninitialized in one fallocate path
SMB3: fix readpage for large swap cache
Pull networking fixes from Jakub Kicinski:
"Networking fixes for 5.14-rc4, including fixes from bpf, can, WiFi
(mac80211) and netfilter trees.
Current release - regressions:
- mac80211: fix starting aggregation sessions on mesh interfaces
Current release - new code bugs:
- sctp: send pmtu probe only if packet loss in Search Complete state
- bnxt_en: add missing periodic PHC overflow check
- devlink: fix phys_port_name of virtual port and merge error
- hns3: change the method of obtaining default ptp cycle
- can: mcba_usb_start(): add missing urb->transfer_dma initialization
Previous releases - regressions:
- set true network header for ECN decapsulation
- mlx5e: RX, avoid possible data corruption w/ relaxed ordering and
LRO
- phy: re-add check for PHY_BRCM_DIS_TXCRXC_NOENRGY on the BCM54811
PHY
- sctp: fix return value check in __sctp_rcv_asconf_lookup
Previous releases - always broken:
- bpf:
- more spectre corner case fixes, introduce a BPF nospec
instruction for mitigating Spectre v4
- fix OOB read when printing XDP link fdinfo
- sockmap: fix cleanup related races
- mac80211: fix enabling 4-address mode on a sta vif after assoc
- can:
- raw: raw_setsockopt(): fix raw_rcv panic for sock UAF
- j1939: j1939_session_deactivate(): clarify lifetime of session
object, avoid UAF
- fix number of identical memory leaks in USB drivers
- tipc:
- do not blindly write skb_shinfo frags when doing decryption
- fix sleeping in tipc accept routine"
* tag 'net-5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (91 commits)
gve: Update MAINTAINERS list
can: esd_usb2: fix memory leak
can: ems_usb: fix memory leak
can: usb_8dev: fix memory leak
can: mcba_usb_start(): add missing urb->transfer_dma initialization
can: hi311x: fix a signedness bug in hi3110_cmd()
MAINTAINERS: add Yasushi SHOJI as reviewer for the Microchip CAN BUS Analyzer Tool driver
bpf: Fix leakage due to insufficient speculative store bypass mitigation
bpf: Introduce BPF nospec instruction for mitigating Spectre v4
sis900: Fix missing pci_disable_device() in probe and remove
net: let flow have same hash in two directions
nfc: nfcsim: fix use after free during module unload
tulip: windbond-840: Fix missing pci_disable_device() in probe and remove
sctp: fix return value check in __sctp_rcv_asconf_lookup
nfc: s3fwrn5: fix undefined parameter values in dev_err()
net/mlx5: Fix mlx5_vport_tbl_attr chain from u16 to u32
net/mlx5e: Fix nullptr in mlx5e_hairpin_get_mdev()
net/mlx5: Unload device upon firmware fatal error
net/mlx5e: Fix page allocation failure for ptp-RQ over SF
net/mlx5e: Fix page allocation failure for trap-RQ over SF
...
Pull ACPI fixes from Rafael Wysocki:
"These revert a recent IRQ resources handling modification that turned
out to be problematic, fix suspend-to-idle handling on AMD platforms
to take upcoming systems into account properly and fix the retrieval
of the DPTF attributes of the PCH FIVR.
Specifics:
- Revert recent change of the ACPI IRQ resources handling that
attempted to improve the ACPI IRQ override selection logic, but
introduced serious regressions on some systems (Hui Wang).
- Fix up quirks for AMD platforms in the suspend-to-idle support code
so as to take upcoming systems using uPEP HID AMDI007 into account
as appropriate (Mario Limonciello).
- Fix the code retrieving DPTF attributes of the PCH FIVR so that it
agrees on the return data type with the ACPI control method
evaluated for this purpose (Srinivas Pandruvada)"
* tag 'acpi-5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: DPTF: Fix reading of attributes
Revert "ACPI: resources: Add checks for ACPI IRQ override"
ACPI: PM: Add support for upcoming AMD uPEP HID AMDI007
Since commit 1b6b26ae70 ("pipe: fix and clarify pipe write wakeup
logic") we have sanitized the pipe write logic, and would only try to
wake up readers if they needed it.
In particular, if the pipe already had data in it before the write,
there was no point in trying to wake up a reader, since any existing
readers must have been aware of the pre-existing data already. Doing
extraneous wakeups will only cause potential thundering herd problems.
However, it turns out that some Android libraries have misused the EPOLL
interface, and expected "edge triggered" be to "any new write will
trigger it". Even if there was no edge in sight.
Quoting Sandeep Patil:
"The commit 1b6b26ae70 ('pipe: fix and clarify pipe write wakeup
logic') changed pipe write logic to wakeup readers only if the pipe
was empty at the time of write. However, there are libraries that
relied upon the older behavior for notification scheme similar to
what's described in [1]
One such library 'realm-core'[2] is used by numerous Android
applications. The library uses a similar notification mechanism as GNU
Make but it never drains the pipe until it is full. When Android moved
to v5.10 kernel, all applications using this library stopped working.
The library has since been fixed[3] but it will be a while before all
applications incorporate the updated library"
Our regression rule for the kernel is that if applications break from
new behavior, it's a regression, even if it was because the application
did something patently wrong. Also note the original report [4] by
Michal Kerrisk about a test for this epoll behavior - but at that point
we didn't know of any actual broken use case.
So add the extraneous wakeup, to approximate the old behavior.
[ I say "approximate", because the exact old behavior was to do a wakeup
not for each write(), but for each pipe buffer chunk that was filled
in. The behavior introduced by this change is not that - this is just
"every write will cause a wakeup, whether necessary or not", which
seems to be sufficient for the broken library use. ]
It's worth noting that this adds the extraneous wakeup only for the
write side, while the read side still considers the "edge" to be purely
about reading enough from the pipe to allow further writes.
See commit f467a6a664 ("pipe: fix and clarify pipe read wakeup logic")
for the pipe read case, which remains that "only wake up if the pipe was
full, and we read something from it".
Link: https://lore.kernel.org/lkml/CAHk-=wjeG0q1vgzu4iJhW5juPkTsjTYmiqiMUYAebWW+0bam6w@mail.gmail.com/ [1]
Link: https://github.com/realm/realm-core [2]
Link: https://github.com/realm/realm-core/issues/4666 [3]
Link: https://lore.kernel.org/lkml/CAKgNAkjMBGeAwF=2MKK758BhxvW58wYTgYKB2V-gY1PwXxrH+Q@mail.gmail.com/ [4]
Link: https://lore.kernel.org/lkml/20210729222635.2937453-1-sspatil@android.com/
Reported-by: Sandeep Patil <sspatil@android.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
