Change page_mkwrite to allow implementations to return with the page
locked, and also change it's callers (in page fault paths) to hold the
lock until the page is marked dirty. This allows the filesystem to have
full control of page dirtying events coming from the VM.
Rather than simply hold the page locked over the page_mkwrite call, we
call page_mkwrite with the page unlocked and allow callers to return with
it locked, so filesystems can avoid LOR conditions with page lock.
The problem with the current scheme is this: a filesystem that wants to
associate some metadata with a page as long as the page is dirty, will
perform this manipulation in its ->page_mkwrite. It currently then must
return with the page unlocked and may not hold any other locks (according
to existing page_mkwrite convention).
In this window, the VM could write out the page, clearing page-dirty. The
filesystem has no good way to detect that a dirty pte is about to be
attached, so it will happily write out the page, at which point, the
filesystem may manipulate the metadata to reflect that the page is no
longer dirty.
It is not always possible to perform the required metadata manipulation in
->set_page_dirty, because that function cannot block or fail. The
filesystem may need to allocate some data structure, for example.
And the VM cannot mark the pte dirty before page_mkwrite, because
page_mkwrite is allowed to fail, so we must not allow any window where the
page could be written to if page_mkwrite does fail.
This solution of holding the page locked over the 3 critical operations
(page_mkwrite, setting the pte dirty, and finally setting the page dirty)
closes out races nicely, preventing page cleaning for writeout being
initiated in that window. This provides the filesystem with a strong
synchronisation against the VM here.
- Sage needs this race closed for ceph filesystem.
- Trond for NFS (http://bugzilla.kernel.org/show_bug.cgi?id=12913).
- I need it for fsblock.
- I suspect other filesystems may need it too (eg. btrfs).
- I have converted buffer.c to the new locking. Even simple block allocation
under dirty pages might be susceptible to i_size changing under partial page
at the end of file (we also have a buffer.c-side problem here, but it cannot
be fixed properly without this patch).
- Other filesystems (eg. NFS, maybe btrfs) will need to change their
page_mkwrite functions themselves.
[ This also moves page_mkwrite another step closer to fault, which should
eventually allow page_mkwrite to be moved into ->fault, and thus avoiding a
filesystem calldown and page lock/unlock cycle in __do_fault. ]
[akpm@linux-foundation.org: fix derefs of NULL ->mapping]
Cc: Sage Weil <sage@newdream.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On a linux-next allyesconfig build:
kernel/trace/ring_buffer.c:1726:
warning: passing argument 1 of 'atomic_cmpxchg' from incompatible pointer type
linux-next/arch/s390/include/asm/atomic.h:112:
note: expected 'struct atomic_t *' but argument is of type 'struct atomic64_t *'
atomic_long_cmpxchg and atomic_long_xchg are incorrectly defined for 64
bit architectures. They should be mapped to the atomic64_* variants.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/serial/crisv10.c:4428: error: unknown field 'read_proc' specified in initializer
Commit 0f043a81eb ("proc tty: remove struct
tty_operations::read_proc") removes the read_proc entry from struct
tty_operations.
Rework the proc handling in the CRISv10 serial driver to use proc_fops
instead.
Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Mikael Starvik <starvik@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add Roland and Oleg as formal ptrace maintainers, they've been doing the
job for a while.
Includes the file patterns requested by Joe.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a bugfix for commit 3c776e6466
("memcg: charge swapcache to proper memcg").
Used bit of swapcache is solid under page lock, but considering
move_account, pc->mem_cgroup is not.
We need lock_page_cgroup() anyway.
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I will finish school soon, so replace my student address with this one.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix an obvious incorrect return status in autofs4_mount_busy().
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By the time the memory cgroup code is notified about a swapin we
already hold a reference on the fault page.
If the cgroup callback fails make sure to unlock AND release the page
reference which was taken by lookup_swap_cach(), or we leak the reference.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Doing it in reverse order causes uevent to be sent before
we have a MAC address, which confuses udev.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 0ba25ff4c6 ("br2684: convert to
net_device_ops") inadvertently deleted the initialization of the net_dev
pointer in the br2684_dev structure, leading to crashes. This patch
adds it back.
Reported-by: Mikko Vinni <mmvinni@yahoo.com>
Tested-by: Mikko Vinni <mmvinni@yahoo.com>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: David S. Miller <davem@davemloft.net>
The kernel should only be using the high 16 bits of a kernel
generated priority. Filter priorities in all other cases only
use the upper 16 bits of the u32 'prio' field of 'struct tcf_proto',
but when the kernel generates the priority of a filter is saves all
32 bits which can result in incorrect lookup failures when a filter
needs to be deleted or modified.
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
acpi_rs_get_pci_routing_table_length is not performing sufficient
validation on the package returned from _PRT. It assumes a package of
packages and fails/faults if this is not the case.
We should validate each subpackage when extracted from the parent
package, and not accept objects of the wrong type, since that will just
cause the scanning to fail (likely with a kernel oops).
This can only happen with a serious BIOS bug, and is accompanied by a
warning something like this:
ACPI Warning (nspredef-0949): \_SB_.PCI0.PEG4._PRT: Return Package type mismatch at index 0 - found Integer, expected Package [20090320]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace #x with __stringify(x).
Also, #ifndef __STR is removed and undefine __STR macro at the beginning.
The __STR() macro is still remained, because the assembler.h might be
included from assembly codes as well as C codes.
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
This patch fixes the following build error of 2.6.30-rc3-git2:
AS arch/m32r/kernel/head.o
In file included from /include/linux/init.h:7,
from /arch/m32r/kernel/head.S:11:
/include/linux/stringify.h:9: error: syntax error in macro parameter list
/include/linux/stringify.h:10: error: syntax error in macro parameter list
This build error was caused at __HEAD macro in arch/m32r/kernel/head.S,
which uses __stringify() macro.
Remove -traditional option from EXTRA_AFLAGS for the m32r,
because the __stringify() macro depends on the gcc's variadic macro
extension function, due to commit:
Make __stringify support variable argument macros too
commit: 8f7c2c3731
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
tick_handle_periodic() can lock up hard when a one shot clock event
device is used in combination with jiffies clocksource.
Avoid an endless loop issue by requiring that a highres valid
clocksource be installed before we call tick_periodic() in a loop when
using ONESHOT mode. The result is we will only increment jiffies once
per interrupt until a continuous hardware clocksource is available.
Without this, we can run into a endless loop, where each cycle through
the loop, jiffies is updated which increments time by tick_period or
more (due to clock steering), which can cause the event programming to
think the next event was before the newly incremented time and fail
causing tick_periodic() to be called again and the whole process loops
forever.
[ Impact: prevent hard lock up ]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
We were avoiding calling sg_init* on scatterlists passed
into virtnet_send_command to prevent extraneous end markers.
This caused build warnings for uninitialized variables.
Cleanup the code to create proper scatterlists.
Signed-off-by: Alex Williamson <alex.williamson@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch makes the cleanup in bond_create nicer :) Also now the forgotten
free_netdev is called.
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
virtio_net.h uses the macro ETH_ALEN which is defined in linux/if_ether.h.
Discovered when hacking on virtio-over-pci patches.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
LAN9512 and LAN9514 are USB hubs with an integrated 10/100 ethernet
controller. Logically this looks like an ethernet controller (similar
to LAN9500) permanently attached to one of the hub's downstream ports.
This patch adds the usb device id of the new ethernet controller to the
smsc95xx driver. This id is the same in both new devices.
Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
SMSC LAN9500 has dual purpose GPIO/LED pins, and by default at power-on
these are configured as GPIOs. This means that if LEDs are fitted they
won't ever light.
This patch sets them to be LED outputs for speed, duplex and
link/activity.
Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When netconsole is loaded and a network interface fades away (e.g. on
rmmod $interface_driver_module) the rmmod remains stuck and some locks
are taken that prevent any additional module loading/unloading as well
as interface up/down changes.
In addition kernel logs (and console) get flooded at 10s interval with
[ 122.464065] unregister_netdevice: waiting for eth0 to become free. Usage count = 1
[ 132.704059] unregister_netdevice: waiting for eth0 to become free. Usage count = 1
This patch lets netconsole take NETDEV_UNREGISTER event into account
and release the affected interface if it was in use.
Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
xt_socket can use connection tracking, and checks whether it is a module.
Signed-off-by: Laszlo Attila Toth <panther@balabit.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
bond_slave_info_query() should keep a read lock while accessing slave info,
or risk accessing stale data and corruption.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the device is not claimed by hid-input (i.e devices driver by userspace
hiddev/hidraw-based drivers, or completely detached from HID
and driver by libusb), we must not check the hid->inptus, as it
is not guaranteed to be initialized, as this is performed only for devices
handled by hid-input.
Reported-by: Guillaume Chazarain <guichaz@gmail.com>
Tested-by: Guillaume Chazarain <guichaz@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
commit db949bba3c (x86-32: use non-lazy
io bitmap context switching) broke ioperm for 32bit because it removed
the lazy initialization of io_bitmap_base and did not set it to the
real bitmap offset.
[ Impact: fix non-working sys_ioperm() on 32-bit kernels ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When multiply mounting from the same client to the same server, with
different userids, we create a vcnum which should be unique if
possible (this is not the same as the smb uid, which is the handle
to the security context). We were not endian converting additional
(beyond the first which is zero) vcnum properly.
CC: Stable <stable@kernel.org>
Acked-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Trivial: fixing gcc 4.4 compiler warning:
drivers/net/cxgb3/t3_hw.c: In function ‘t3_prep_adapter’:
drivers/net/cxgb3/t3_hw.c:3782: warning: suggest parentheses around operand of ‘!’ or change ‘|’ to ‘||’ or ‘!’ to ‘~’
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@mail.by>
Signed-off-by: David S. Miller <davem@davemloft.net>
When skb_rx_queue_recorded() is true, we dont want to use jash distribution
as the device driver exactly told us which queue was selected at RX time.
jhash makes a statistical shuffle, but this wont work with 8 static inputs.
Later improvements would be to compute reciprocal value of real_num_tx_queues
to avoid a divide here. But this computation should be done once,
when real_num_tx_queues is set. This needs a separate patch, and a new
field in struct net_device.
Reported-by: Andrew Dickinson <andrew@whydna.net>
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The C99 specification states in section 6.11.5:
The placement of a storage-class specifier other than at the
beginning of the declaration specifiers in a declaration is an
obsolescent feature.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Michal Simek <monstr@monstr.eu>
This reverts commit 044d408409.
The commit added a warning when handle_IRQ_event() is called outside
of hard interrupt context. This breaks the generic tasklet based
interrupt resend mechanism which is used when the hardware has no way
to retrigger the interrupt. So we get a warning for a use case which
is correct and worked for years. Remove it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The alterations to the suspend code missed adding a
call to the cache flushing routines during the suspend
path of the S3C2412.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Add support for the UDIVSLOT register on the newer UART blocks
which gives the capability of 1/16ths adjustment to the baud rate.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
When you put
.section ".foo"
in an assembly file instead of
.section "foo", "ax"
, one of the possible symptoms is that modpost will see an
ld-generated section name ".foo.1" in section_rel() or section_rela().
But this heuristic has two problems: it will miss a bad section that
has no relocations, and it will incorrectly flag many gcc-generated
sections as bad when compiling with -ffunction-sections
-fdata-sections.
On mips it fixes a lot of bogus warnings with gcc 4.4.0 lije this one:
WARNING: crypto/cryptd.o (.text.T.349): unexpected section name.
So instead of checking whether the section name matches a particular
pattern, we directly check for a missing SHF_ALLOC in the section
flags.
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Tested-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
There is some confusion on naming of the head section.
Correct naming is .head.text.
Fix comment so we use correct naming.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
When using trees like wireless-testing, which have untagged tags,
scripts/setlocalversion does not display any git indication for
localversion.
This patch fixes it: If git is available, but no usable tag is found,
it uses -g${head}. It skips the detection of unanottated tags via
git name-rev.
Signed-off-by: Nico Schottelius <nico@ikn.schottelius.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
While building the kernel, we end-up calling modpost with -K and -M
options for the same file (Modules.markers). This is resulting in
modpost's main function calling read_markers() and then write_markers() on
the same file.
We then have read_markers() mmap'ing the file, and writer_markers()
opening that same file for writing.
The issue is that read_markers() exits without munmap'ing the file and is
as a matter holding a reference on Modules.markers. When write_markers()
is opening that very same file for writing, we still have a reference on
it and cygwin (Windows?) is then making fopen() fail with EPERM.
Calling release_file() before exiting read_markers() clears that reference
(and memory leak) and fopen() then succeeds.
Tested on both cygwin (1.3.22) and Linux. Also ran modpost within
valgrind on Linux to make sure that the munmap'ed file was not accessed
after read_markers()
Signed-off-by: Cedric Hombourger <chombourger@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
If a tag file is not removed before it is regenerated, the newly
generated data is appended to the old, which preserves stale data and
makes the tag file grow over time.
Signed-off-by: Matt Kraai <kraai@ftbfs.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Correct the Makefile help text to read "make modules_prepare".
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
