Using delayed-work for tty flip buffers ends up causing us to wait for
the next tick to complete some actions. That's usually not all that
noticeable, but for certain latency-critical workloads it ends up being
totally unacceptable.
As an extreme case of this, passing a token back-and-forth over a pty
will take two ticks per iteration, so even just a thousand iterations
will take 8 seconds assuming a common 250Hz configuration.
Avoiding the whole delayed work issue brings that ping-pong test-case
down to 0.009s on my machine.
In more practical terms, this latency has been a performance problem for
things like dive computer simulators (simulating the serial interface
using the ptys) and for other environments (Alan mentions a CP/M emulator).
Reported-by: Jef Driesen <jefdriesen@telenet.be>
Acked-by: Greg KH <gregkh@suse.de>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recent zerocopy work in the 9P VirtIO transport maps and pins
user buffers into kernel memory for the server to work on them.
Since the user process can initiate this kind of pinning with a simple
read/write call, thousands of IO threads initiated by the user process can
hog the system resources and could result into denial of service.
This patch introduces flow control to avoid that extreme scenario.
The ceiling limit to avoid denial of service attacks is set to relatively
high (nr_free_pagecache_pages()/4) so that it won't interfere with
regular usage, but can step in extreme cases to limit the total system
hang. Since we don't have a global structure to accommodate this variable,
I choose the virtio_chan as the home for this.
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Reviewed-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Without this fix, even if a file is opened in O_APPEND mode, data will be
written at current file position instead of end of file.
Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Given that the sprious wake-ups are common, we need to move the
condition setting right next to the wake_up(). After setting the condition
to req->status = REQ_STATUS_RCVD, sprious wakeups may cause the
virtqueue back on the free list for someone else to use.
This may result in kernel panic while relasing the pinned pages
in p9_release_req_pages().
Also rearranged the while loop in req_done() for better redability.
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Process may wait to get space on VirtIO ring to send a transaction to
VirtFS server. Current code just does a conditional wake_up() which
means only one process will be woken up even if multiple processes
are waiting.
This fix makes the wake_up unconditional. Hence we won't have any
processes waiting for-ever.
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Add the new static inline and use the same
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
We don't need writeback fid if we are only doing O_RDONLY open
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Older version of protocol don't support tsyncfs operation.
So for them force a O_SYNC flag on the server
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
convert vmtruncate usage to truncate_setsize. We also writeback
all dirty pages before doing 9p operations and on success call truncate_setsize.
This ensure that we continue sanely on failed truncate on the server. The
disadvantage is that we are now going to write back the content that get
thrown away later as a part of truncate.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
When two process open the same file we can end up with both of them
allocating the writeback_fid. Add a new mutex which can be used
for synchronizing v9fs_inode member values.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
OOM path is missing the irq restore in the CONFIG_CMPXCHG_LOCAL case.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Send notifications when we change the rbd header (e.g. create a snapshot)
and wait for such notifications. This allows synchronizing the snapshot
creation between different rbd clients/rools.
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
Lingering requests are requests that are sent to the OSD normally but
tracked also after we get a successful request. This keeps the OSD
connection open and resends the original request if the object moves to
another OSD. The OSD can then send notification messages back to us
if another client initiates a notify.
This framework will be used by RBD so that the client gets notification
when a snapshot is created by another node or tool.
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
xen: update mask_rw_pte after kernel page tables init changes
xen: set max_pfn_mapped to the last pfn mapped
x86: Cleanup highmap after brk is concluded
Fix up trivial onflict (added header file includes) in
arch/x86/mm/init_64.c
* 'next-samsung' of git://git.fluff.org/bjdooks/linux:
ARM: H1940/RX1950: Change default LED triggers
ARM: S3C2442: RX1950: Add support for LED blinking
ARM: S3C2442: RX1950: Retain LEDs state in suspend
ARM: S3C2410: H1940: Fix lcd_power_set function
ARM: S3C2410: H1940: Add battery support
ARM: S3C2410: H1940: Use leds-gpio driver for LEDs managing
ARM: S3C2410: H1940: Make h1940-bluetooth.c compile again
ARM: S3C2410: H1940: Add keys device
* 'for-linus/2639/i2c-2' of git://git.fluff.org/bjdooks/linux:
i2c-pxa2xx: Don't clear isr bits too early
i2c-pxa2xx: Fix register offsets
i2c-pxa2xx: pass of_node from platform driver to adapter and publish
i2c-pxa2xx: check timeout correctly
i2c-pxa2xx: add support for shared IRQ handler
i2c-pxa2xx: Add PCI support for PXA I2C controller
ARM: pxa2xx: reorganize I2C files
i2c-pxa2xx: use dynamic register layout
i2c-mxs: set controller to pio queue mode after reset
i2c-eg20t: support new device OKI SEMICONDUCTOR ML7213 IOH
i2c/busses: Add support for Diolan U2C-12 USB-I2C adapter
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
slub: Dont define useless label in the !CONFIG_CMPXCHG_LOCAL case
slab,rcu: don't assume the size of struct rcu_head
slub,rcu: don't assume the size of struct rcu_head
slub: automatically reserve bytes at the end of slab
Lockless (and preemptless) fastpaths for slub
slub: Get rid of slab_free_hook_irq()
slub: min_partial needs to be in first cacheline
slub: fix ksize() build error
slub: fix kmemcheck calls to match ksize() hints
Revert "slab: Fix missing DEBUG_SLAB last user"
mm: Remove support for kmem_cache_name()
Ensure that we kill discard requests after logical block provisioning
has been disabled in sysfs.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (33 commits)
IPVS: Use global mutex in ip_vs_app.c
ipvs: fix a typo in __ip_vs_control_init()
veth: Fix the byte counters
net ipv6: Fix duplicate /proc/sys/net/ipv6/neigh directory entries.
macvlan: Fix use after free of struct macvlan_port.
net: fix incorrect spelling in drop monitor protocol
can: c_can: Do basic c_can configuration _before_ enabling the interrupts
net/appletalk: fix atalk_release use after free
ipx: fix ipx_release()
snmp: SNMP_UPD_PO_STATS_BH() always called from softirq
l2tp: fix possible oops on l2tp_eth module unload
xfrm: Fix initialize repl field of struct xfrm_state
netfilter: ipt_CLUSTERIP: fix buffer overflow
netfilter: xtables: fix reentrancy
netfilter: ipset: fix checking the type revision at create command
netfilter: ipset: fix address ranges at hash:*port* types
niu: Rename NIU parent platform device name to fix conflict.
r8169: fix a bug in rtl8169_init_phy()
bonding: fix a typo in a comment
ftmac100: use resource_size()
...
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Julian Anastasov <ja@ssi.bg>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 44540960 "veth: move loopback logic to common location" introduced
a bug in the packet counters. I don't understand why that happened as it
is not explained in the comments and the mut check in dev_forward_skb
retains the assumption that skb->len is the total length of the packet.
I just measured this emperically by setting up a veth pair between two
noop network namespaces setting and attempting a telnet connection between
the two. I saw three packets in each direction and the byte counters were
exactly 14*3 = 42 bytes high in each direction. I got the actual
packet lengths with tcpdump.
So remove the extra ETH_HLEN from the veth byte count totals.
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When I was fixing issues with unregisgtering tables under /proc/sys/net/ipv6/neigh
by adding a mount point it appears I missed a critical ordering issue, in the
ipv6 initialization. I had not realized that ipv6_sysctl_register is called
at the very end of the ipv6 initialization and in particular after we call
neigh_sysctl_register from ndisc_init.
"neigh" needs to be initialized in ipv6_static_sysctl_register which is
the first ipv6 table to initialized, and definitely before ndisc_init.
This removes the weirdness of duplicate tables while still providing a
"neigh" mount point which prevents races in sysctl unregistering.
This was initially reported at https://bugzilla.kernel.org/show_bug.cgi?id=31232
Reported-by: sunkan@zappa.cx
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When the macvlan driver was extended to call unregisgter_netdevice_queue
in 23289a37e2, a use after free of struct
macvlan_port was introduced. The code in dellink relied on unregister_netdevice
actually unregistering the net device so it would be safe to free macvlan_port.
Since unregister_netdevice_queue can just queue up the unregister instead of
performing the unregiser immediately we free the macvlan_port too soon and
then the code in macvlan_stop removes the macaddress for the set of macaddress
to listen for and uses memory that has already been freed.
To fix this add a reference count to track when it is safe to free the macvlan_port
and move the call of macvlan_port_destroy into macvlan_uninit which is guaranteed
to be called after the final macvlan_port_close.
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It was pointed out to me recently that my spelling could be better :)
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I ran into some trouble while testing the SocketCAN driver for the BOSCH
C_CAN controller. The interface is not correctly initialized, if I put
some CAN traffic on the line, _while_ the interface is being started
(which means: the interface doesn't come up correcty, if there's some RX
traffic while doing 'ifconfig can0 up').
The current implementation enables the controller interrupts _before_
doing the basic c_can configuration. I think, this should be done the
other way round.
The patch below fixes things for me.
Signed-off-by: Jan Altenberg <jan@linutronix.de>
Acked-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The BKL removal in appletalk introduced a use-after-free problem,
where atalk_destroy_socket frees a sock, but we still release
the socket lock on it.
An easy fix is to take an extra reference on the sock and sock_put
it when returning from atalk_release.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit b0d0d915d1 (remove the BKL) added a regression, because
sock_put() can free memory while we are going to use it later.
Fix is to delay sock_put() _after_ release_sock().
Reported-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
We dont need to test if we run from softirq context, we definitely are.
This saves few instructions in ip_rcv() & ip_rcv_finish()
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A struct used in the l2tp_eth driver for registering network namespace
ops was incorrectly marked as __net_initdata, leading to oops when
module unloaded.
BUG: unable to handle kernel paging request at ffffffffa00ec098
IP: [<ffffffff8123dbd8>] ops_exit_list+0x7/0x4b
PGD 142d067 PUD 1431063 PMD 195da8067 PTE 0
Oops: 0000 [#1] SMP
last sysfs file: /sys/module/l2tp_eth/refcnt
Call Trace:
[<ffffffff8123dc94>] ? unregister_pernet_operations+0x32/0x93
[<ffffffff8123dd20>] ? unregister_pernet_device+0x2b/0x38
[<ffffffff81068b6e>] ? sys_delete_module+0x1b8/0x222
[<ffffffff810c7300>] ? do_munmap+0x254/0x318
[<ffffffff812c64e5>] ? page_fault+0x25/0x30
[<ffffffff812c6952>] ? system_call_fastpath+0x16/0x1b
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Change LED triggers to mimic WinMobile behavior:
red blinking when battery is charging,
orange solid when battery is charged.
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
isr is passed later into i2c_pxa_irq_txempty and
i2c_pxa_irq_rxfull and they may use some other bits
than irq sources.
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
kbuild: Make DEBUG_SECTION_MISMATCH selectable, but not on by default
genksyms: Regenerate lexer and parser
genksyms: Track changes to enum constants
genksyms: simplify usage of find_symbol()
genksyms: Add helpers for building string lists
genksyms: Simplify printing of symbol types
genksyms: Simplify lexer
genksyms: Do not paste the bison header file to lex.c
modpost: fix trailing comma
KBuild: silence "'scripts/unifdef' is up to date."
kbuild: Add extra gcc checks
kbuild: reenable section mismatch analysis
unifdef: update to upstream version 2.5
This patch reduces the number of sequential pointer derefs in
drivers/scsi/scsi_error.c
This has been submitted a number of times over a couple of years. I
believe this version adresses all comments it has gathered over time.
Please apply or reject with a reason.
The benefits are:
- makes the code easier to read. Lots of sequential derefs of the same
pointers is not easy on the eye.
- theoretically at least, just dereferencing the pointers once can
allow the compiler to generally slightly faster code, so in theory
this could also be a micro speed optimization.
- reduces size of object file (tiny effect: on x86-64, in at least one
configuration, the text size decreased from 9439 bytes to 9400)
- removes some pointless (mostly trailing) whitespace.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove incorrect Matrox G200eV support that was previously added by
commit e3a1938805
A serious issue with the incorrect G200eV support that reproduces on the
Matrox G200eV equipped IBM x3650 M2 is the total lack of text (login
banner, login prompt, etc) on the console when X is not running and
total lack of text on all of the virtual consoles after X is started.
Any concerns that the incorrect code (upstream since October 2008) has
been successfully used on non-IBM G200eV equipped system(s) appear to be
unwarranted. In addition to the serious/non-intermittent nature of
issues that have been spotted on IBM systems, complete removal of the
incorrect code is clearly supported by the following Matrox (Yannick
Heneault) provided input:
"It impossible that this patch should have work on a system.
The patch only declare the G200eV as a regular G200 which is
not case. Many registers are different, including at least the
PLL programming sequence. If the G200eV is programmed like a
regular G200, it will not display anything."
v1 - Initial patch that removed the incorrect code for _all_
G200eV equipped systems.
v2 - Darrick Wong provided patch that blacklisted the incorrect
code on G200eV equipped IBM systems leaving it enabled on
all G200eV equipped non-IBM systems.
v3 - Same code changes included with v1 plus additional
justification for complete removal of the incorrect code.
Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Petr Vandrovec <vandrove@vc.cvut.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Yannick Heneault <yannick_heneault@matrox.com>
Cc: Christian Toutant <ctoutant@matrox.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://oss.sgi.com/xfs/xfs: (23 commits)
xfs: don't name variables "panic"
xfs: factor agf counter updates into a helper
xfs: clean up the xfs_alloc_compute_aligned calling convention
xfs: kill support/debug.[ch]
xfs: Convert remaining cmn_err() callers to new API
xfs: convert the quota debug prints to new API
xfs: rename xfs_cmn_err_fsblock_zero()
xfs: convert xfs_fs_cmn_err to new error logging API
xfs: kill xfs_fs_mount_cmn_err() macro
xfs: kill xfs_fs_repair_cmn_err() macro
xfs: convert xfs_cmn_err to xfs_alert_tag
xfs: Convert xlog_warn to new logging interface
xfs: Convert linux-2.6/ files to new logging interface
xfs: introduce new logging API.
xfs: zero proper structure size for geometry calls
xfs: enable delaylog by default
xfs: more sensible inode refcounting for ialloc
xfs: stop using xfs_trans_iget in the RT allocator
xfs: check if device support discard in xfs_ioc_trim()
xfs: prevent leaking uninitialized stack memory in FSGEOMETRY_V1
...
Userland should be able to trust the pid and uid of the sender of a
signal if the si_code is SI_TKILL.
Unfortunately, the kernel has historically allowed sigqueueinfo() to
send any si_code at all (as long as it was negative - to distinguish it
from kernel-generated signals like SIGILL etc), so it could spoof a
SI_TKILL with incorrect siginfo values.
Happily, it looks like glibc has always set si_code to the appropriate
SI_QUEUE, so there are probably no actual user code that ever uses
anything but the appropriate SI_QUEUE flag.
So just tighten the check for si_code (we used to allow any negative
value), and add a (one-time) warning in case there are binaries out
there that might depend on using other si_code values.
Signed-off-by: Julien Tinnes <jln@google.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-ktest:
ktest: Add STOP_TEST_AFTER to stop the test after a period of time
ktest: Monitor kernel while running of user tests
ktest: Fix bug where the test would not end after failure
ktest: Add BISECT_FILES to run git bisect on paths
ktest: Add BISECT_SKIP
ktest: Add manual bisect
ktest: Handle kernels before make oldnoconfig
ktest: Start failure timeout on panic too
ktest: Print logfile name on failure
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
hwmon: (ads1015) Make gain and datarate configurable
hwmon: (ads1015) Drop dynamic attribute group
hwmon: Add support for Texas Instruments ADS1015
hwmon: New driver for SMSC SCH5627
hwmon: (abituguru*) Update my email address
hwmon: (lm75) Speed up detection
hwmon: (lm75) Add detection of the National Semiconductor LM75A
hp_accel: Fix driver name
Move lis3lv02d drivers to drivers/misc
Move hp_accel to drivers/platform/x86
Let Kconfig handle lis3lv02d dependencies
hwmon: (sht15) Fix integer overflow in humidity calculation
hwmon: (sht15) Spelling fix
hwmon: (w83795) Document pin mapping
/sys/fs is a somewhat strange way to tweak what could more
obviously be tuned with a mount option.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In sync_write_wait(), we assume that the newest request is at the
tail of unsafe write list. We should maintain the semantics here.
Signed-off-by: Henry C Chang <henry_c_chang@tcloudcomputing.com>
Signed-off-by: Sage Weil <sage@newdream.net>
