Commit a82afdf (block: use the same failfast bits for bio and request)
moved BIO_RW_* bits around such that they match up with REQ_* bits.
Unfortunately, fs.h hard coded RW_MASK, RWA_MASK, READ, WRITE, READA
and SWRITE as 0, 1, 2 and 3, and expected them to match with BIO_RW_*
bits. READ/WRITE didn't change but BIO_RW_AHEAD was moved to bit 4
instead of bit 1, breaking RWA_MASK, READA and SWRITE.
This patch updates RWA_MASK, READA and SWRITE such that they match the
BIO_RW_* bits again. A follow up patch will update the definitions to
directly use BIO_RW_* bits so that this kind of breakage won't happen
again.
Neil also spotted missing RWA_MASK conversion.
Stable: The offending commit a82afdf was released with v2.6.32, so
this patch should be applied to all kernels since then but it must
_NOT_ be applied to kernels earlier than that.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-bisected-by: Vladislav Bolkhovitin <vst@vlnb.net>
Root-caused-by: Neil Brown <neilb@suse.de>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Filesystems can call sb_issue_discard on a memory reclaim path
(e.g. ext4 calls sb_issue_discard during journal commit).
Use GFP_NOFS in sb_issue_discard to avoid recursing back into the FS.
Reported-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
include/trace/events/writeback.h uses dev_name(), so it needs to
include linux/device.h.
include/trace/events/writeback.h:12: error: implicit declaration of function 'dev_name'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
block/compat_ioctl.c: In function 'compat_blkdev_ioctl':
block/compat_ioctl.c:754: error: 'BLKTRACESETUP32' undeclared (first use in this function)
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The blktrace driver currently needs the BKL, but
we should not need to take that in the block layer,
so just push it down into the driver itself.
It is quite likely that the BKL is not actually
required in blktrace code and could be removed
in a follow-on patch.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
As a preparation for the removal of the big kernel
lock in the block layer, this removes the BKL
from the common ioctl handling code, moving it
into every single driver still using it.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Add a trace event to the ->writepage loop in write_cache_pages to give
visibility into how the ->writepage call is changing variables within the
writeback control structure. Of most interest is how wbc->nr_to_write changes
from call to call, especially with filesystems that write multiple pages
in ->writepage.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Tracing high level background writeback events is good, but it doesn't
give the entire picture. Add visibility into write throttling to catch IO
dispatched by foreground throttling of processing dirtying lots of pages.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Trace queue/sched/exec parts of the writeback loop. This provides
insight into when and why flusher threads are scheduled to run. e.g
a sync invocation leaves traces like:
sync-[...]: writeback_queue: bdi 8:0: sb_dev 8:1 nr_pages=7712 sync_mode=0 kupdate=0 range_cyclic=0 background=0
flush-8:0-[...]: writeback_exec: bdi 8:0: sb_dev 8:1 nr_pages=7712 sync_mode=0 kupdate=0 range_cyclic=0 background=0
This also lays the foundation for adding more writeback tracing to
provide deeper insight into the whole writeback path.
The original tracing code is from Jens Axboe, though this version is
a rewrite as a result of the code being traced changing
significantly.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
SCSI-ml needs a way to mark a request as flush request in
q->prepare_flush_fn because it needs to identify them later (e.g. in
q->request_fn or prep_rq_fn).
queue_flush sets REQ_HARDBARRIER in rq->cmd_flags however the block
layer also sends normal REQ_TYPE_FS requests with REQ_HARDBARRIER. So
SCSI-ml can't use REQ_HARDBARRIER to identify flush requests.
We could change the block layer to clear REQ_HARDBARRIER bit before
sending non flush requests to the lower layers. However, intorudcing
the new flag looks cleaner (surely easier).
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Alasdair G Kergon <agk@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
No real bugs I believe, just some dead code, and some
shut up code.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Allocating a fixed payload for discard requests always was a horrible hack,
and it's not coming to byte us when adding support for discard in DM/MD.
So change the code to leave the allocation of a payload to the lowlevel
driver. Unfortunately that means we'll need another hack, which allows
us to update the various block layer length fields indicating that we
have a payload. Instead of hiding this in sd.c, which we already partially
do for UNMAP support add a documented helper in the core block layer for it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Move all code for the writeback thread into fs/fs-writeback.c instead of
splitting it over two functions in two files.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The wb_list member of struct backing_device_info always has exactly one
element. Just use the direct bdi->wb pointer instead and simplify some
code.
Also remove bdi_task_init which is now trivial to prepare for the next
patch.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
down to the block driver. There were two flags in the bio that were
missing in the requests: BIO_RW_UNPLUG and BIO_RW_AHEAD. Also I've
renamed two request flags that had a superflous RW in them.
Note that the flags are in bio.h despite having the REQ_ name - as
blkdev.h includes bio.h that is the only way to go for now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Remove all the trivial wrappers for the cmd_type and cmd_flags fields in
struct requests. This allows much easier grepping for different request
types instead of unwinding through macros.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
block uses ISA_DMA_THRESHOLD for BLK_BOUNCE_ISA. Only SCSI uses
ISA_DMA_THRESHOLD for ancient drivers with non-zero
unchecked_isa_dma. Nowadays drivers (and subsystems) use dma_mask
properly instead of ISA_DMA_THRESHOLD.
Documentation/scsi/scsi_mid_low_api.txt says:
unchecked_isa_dma - 1=>only use bottom 16 MB of ram (ISA DMA addressing
restriction), 0=>can use full 32 bit (or better) DMA
address space
So block simply uses DMA_BIT_MASK(24) for BLK_BOUNCE_ISA for SCSI.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
A barrier request should by defintion have priority in get_request
and let the queue be unplugged immediately as it's blocking all forward
progress due to the queue draining.
Most filesystems already get this implicitly by the way how submit_bh
treats the buffer_ordered flag, and gfs2 sets it explicitly. But btrfs
and XFS are still forgetting to set the flag, as is blkdev_issue_flush
and some places in DM/MD.
For XFS on metadata heavy workloads this gives a consistent speedup
in the 2-3% range.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
There are two reasons for doing this:
- On SSD disks, the completion times aren't as random as they
are for rotational drives. So it's questionable whether they
should contribute to the random pool in the first place.
- Calling add_disk_randomness() has a lot of overhead.
This adds /sys/block/<dev>/queue/add_random that will allow you to
switch off on a per-device basis. The default setting is on, so there
should be no functional changes from this patch.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
nfs_commit_inode() needs to be defined irrespectively of whether or not
we are supporting NFSv3 and NFSv4.
Allow the compiler to optimise away code in the NFSv2-only case by
converting it into an inlined stub function.
Reported-and-tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
See https://bugzilla.kernel.org/show_bug.cgi?id=16056
If other processes are blocked waiting for kswapd to free up some memory so
that they can make progress, then we cannot allow kswapd to block on those
processes.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
Fix __task_cred()'s lockdep check by removing the following validation
condition:
lockdep_tasklist_lock_is_held()
as commit_creds() does not take the tasklist_lock, and nor do most of the
functions that call it, so this check is pointless and it can prevent
detection of the RCU lock not being held if the tasklist_lock is held.
Instead, add the following validation condition:
task->exit_state >= 0
to permit the access if the target task is dead and therefore unable to change
its own credentials.
Fix __task_cred()'s comment to:
(1) discard the bit that says that the caller must prevent the target task
from being deleted. That shouldn't need saying.
(2) Add a comment indicating the result of __task_cred() should not be passed
directly to get_cred(), but rather than get_task_cred() should be used
instead.
Also put a note into the documentation to enforce this point there too.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's possible for get_task_cred() as it currently stands to 'corrupt' a set of
credentials by incrementing their usage count after their replacement by the
task being accessed.
What happens is that get_task_cred() can race with commit_creds():
TASK_1 TASK_2 RCU_CLEANER
-->get_task_cred(TASK_2)
rcu_read_lock()
__cred = __task_cred(TASK_2)
-->commit_creds()
old_cred = TASK_2->real_cred
TASK_2->real_cred = ...
put_cred(old_cred)
call_rcu(old_cred)
[__cred->usage == 0]
get_cred(__cred)
[__cred->usage == 1]
rcu_read_unlock()
-->put_cred_rcu()
[__cred->usage == 1]
panic()
However, since a tasks credentials are generally not changed very often, we can
reasonably make use of a loop involving reading the creds pointer and using
atomic_inc_not_zero() to attempt to increment it if it hasn't already hit zero.
If successful, we can safely return the credentials in the knowledge that, even
if the task we're accessing has released them, they haven't gone to the RCU
cleanup code.
We then change task_state() in procfs to use get_task_cred() rather than
calling get_cred() on the result of __task_cred(), as that suffers from the
same problem.
Without this change, a BUG_ON in __put_cred() or in put_cred_rcu() can be
tripped when it is noticed that the usage count is not zero as it ought to be,
for example:
kernel BUG at kernel/cred.c:168!
invalid opcode: 0000 [#1] SMP
last sysfs file: /sys/kernel/mm/ksm/run
CPU 0
Pid: 2436, comm: master Not tainted 2.6.33.3-85.fc13.x86_64 #1 0HR330/OptiPlex
745
RIP: 0010:[<ffffffff81069881>] [<ffffffff81069881>] __put_cred+0xc/0x45
RSP: 0018:ffff88019e7e9eb8 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff880161514480 RCX: 00000000ffffffff
RDX: 00000000ffffffff RSI: ffff880140c690c0 RDI: ffff880140c690c0
RBP: ffff88019e7e9eb8 R08: 00000000000000d0 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000040 R12: ffff880140c690c0
R13: ffff88019e77aea0 R14: 00007fff336b0a5c R15: 0000000000000001
FS: 00007f12f50d97c0(0000) GS:ffff880007400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f461bc000 CR3: 00000001b26ce000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process master (pid: 2436, threadinfo ffff88019e7e8000, task ffff88019e77aea0)
Stack:
ffff88019e7e9ec8 ffffffff810698cd ffff88019e7e9ef8 ffffffff81069b45
<0> ffff880161514180 ffff880161514480 ffff880161514180 0000000000000000
<0> ffff88019e7e9f28 ffffffff8106aace 0000000000000001 0000000000000246
Call Trace:
[<ffffffff810698cd>] put_cred+0x13/0x15
[<ffffffff81069b45>] commit_creds+0x16b/0x175
[<ffffffff8106aace>] set_current_groups+0x47/0x4e
[<ffffffff8106ac89>] sys_setgroups+0xf6/0x105
[<ffffffff81009b02>] system_call_fastpath+0x16/0x1b
Code: 48 8d 71 ff e8 7e 4e 15 00 85 c0 78 0b 8b 75 ec 48 89 df e8 ef 4a 15 00
48 83 c4 18 5b c9 c3 55 8b 07 8b 07 48 89 e5 85 c0 74 04 <0f> 0b eb fe 65 48 8b
04 25 00 cc 00 00 48 3b b8 58 04 00 00 75
RIP [<ffffffff81069881>] __put_cred+0xc/0x45
RSP <ffff88019e7e9eb8>
---[ end trace df391256a100ebdd ]---
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lrg/voltage-2.6:
davinci: da850/omap-l138 evm: account for DEFDCDC{2,3} being tied high
regulator: tps6507x: allow driver to use DEFDCDC{2,3}_HIGH register
wm8350-regulator: fix wm8350_register_regulator error handling
ab3100: fix off-by-one value range checking for voltage selector
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
In TPS6507x, depending on the status of DEFDCDC{2,3} pin either
DEFDCDC{2,3}_LOW or DEFDCDC{2,3}_HIGH register needs to be read or
programmed to change the output voltage.
The current driver assumes DEFDCDC{2,3} pins are always tied low
and thus operates only on DEFDCDC{2,3}_LOW register. This need
not always be the case (as is found on OMAP-L138 EVM).
Unfortunately, software cannot read the status of DEFDCDC{2,3} pins.
So, this information is passed through platform data depending on
how the board is wired.
Signed-off-by: Anuj Aggarwal <anuj.aggarwal@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
s2io: fixing DBG_PRINT() macro
ath9k: fix dma direction for map/unmap in ath_rx_tasklet
net: dev_forward_skb should call nf_reset
net sched: fix race in mirred device removal
tun: avoid BUG, dump packet on GSO errors
bonding: set device in RLB ARP packet handler
wimax/i2400m: Add PID & VID for Intel WiMAX 6250
ipv6: Don't add routes to ipv6 disabled interfaces.
net: Fix skb_copy_expand() handling of ->csum_start
net: Fix corruption of skb csum field in pskb_expand_head() of net/core/skbuff.c
macvtap: Limit packet queue length
ixgbe/igb: catch invalid VF settings
bnx2x: Advance a module version
bnx2x: Protect statistics ramrod and sequence number
bnx2x: Protect a SM state change
wireless: use netif_rx_ni in ieee80211_send_layer2_update
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
ACPI / Sleep: Allow the NVS saving to be skipped during suspend to RAM
ACPI: create "processor.bm_check_disable" boot param
ACPI: skip checking BM_STS if the BIOS doesn't ask for it
ACPI: fix unused function warning
ACPI: processor: fix processor_physically_present on UP
ACPI video: fix string mismatch for Sony SR290 laptop
ACPI battery: don't invoke power_supply_changed twice when battery is hot-added
ACPI: handle systems which asynchoronously enable ACPI mode
This fixes hang when target device of mirred packet classifier
action is removed.
If a mirror or redirection action is configured to cause packets
to go to another device, the classifier holds a ref count, but was assuming
the adminstrator cleaned up all redirections before removing. The fix
is to add a notifier and cleanup during unregister.
The new list is implicitly protected by RTNL mutex because
it is held during filter add/delete as well as notifier.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 2a6b69765a
(ACPI: Store NVS state even when entering suspend to RAM) caused the
ACPI suspend code save the NVS area during suspend and restore it
during resume unconditionally, although it is known that some systems
need to use acpi_sleep=s4_nonvs for hibernation to work. To allow
the affected systems to avoid saving and restoring the NVS area
during suspend to RAM and resume, introduce kernel command line
option acpi_sleep=nonvs and make acpi_sleep=s4_nonvs work as its
alias temporarily (add acpi_sleep=s4_nonvs to the feature removal
file).
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16396 .
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: tomas m <tmezzadra@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf tools: Fix fallback to cplus_demangle() when bfd_demangle() is not available
perf annotate: Fix handling of goto labels that are valid hex numbers
tracing: Properly align linker defined symbols
perf symbols: Fix directory descriptor leaking
perf: Fix various display bugs with parent filtering
The .data..init_task output section was missing
a load offset causing a popwerpc target to fail to boot.
Sean MacLennan tracked it down to the definition of
INIT_TASK_DATA_SECTION().
There are only two users of INIT_TASK_DATA_SECTION()
in the kernel today: cris and popwerpc.
cris do not support relocatable kernels and is thus not
impacted by this change.
Fix INIT_TASK_DATA_SECTION() to specify load offset like
all other output sections.
Reported-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
It turns out that there is a bit in the _CST for Intel FFH C3
that tells the OS if we should be checking BM_STS or not.
Linux has been unconditionally checking BM_STS.
If the chip-set is configured to enable BM_STS,
it can retard or completely prevent entry into
deep C-states -- as illustrated by turbostat:
http://userweb.kernel.org/~lenb/acpi/utils/pmtools/turbostat/
ref: Intel Processor Vendor-Specific ACPI Interface Specification
table 4 "_CST FFH GAS Field Encoding"
Bit 1: Set to 1 if OSPM should use Bus Master avoidance for this C-state
https://bugzilla.kernel.org/show_bug.cgi?id=15886
Signed-off-by: Len Brown <len.brown@intel.com>
Mark Wagner reported OOM symptoms when sending UDP traffic over
a macvtap link to a kvm receiver.
This appears to be caused by the fact that macvtap packet queues
are unlimited in length. This means that if the receiver can't
keep up with the rate of flow, then we will hit OOM. Of course
it gets worse if the OOM killer then decides to kill the receiver.
This patch imposes a cap on the packet queue length, in the same
way as the tuntap driver, using the device TX queue length.
Please note that macvtap currently has no way of giving congestion
notification, that means the software device TX queue cannot be
used and packets will always be dropped once the macvtap driver
queue fills up.
This shouldn't be a great problem for the scenario where macvtap
is used to feed a kvm receiver, as the traffic is most likely
external in origin so congestion notification can't be applied
anyway.
Of course, if anybody decides to complain about guest-to-guest
UDP packet loss down the track, then we may have to revisit this.
Incidentally, this patch also fixes a real memory leak when
macvtap_get_queue fails.
Chris Wright noticed that for this patch to work, we need a
non-zero TX queue length. This patch includes his work to change
the default macvtap TX queue length to 500.
Reported-by: Mark Wagner <mwagner@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
sysrq,kdb: Use __handle_sysrq() for kdb's sysrq function
debug_core,kdb: fix kgdb_connected bit set in the wrong place
Fix merge regression from external kdb to upstream kdb
repair gdbstub to match the gdbserial protocol specification
kdb: break out of kdb_ll() when command is terminated
The kdb code should not toggle the sysrq state in case an end user
wants to try and resume the normal kernel execution.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
math-emu: correct test for downshifting fraction in _FP_FROM_INT()
perf: Add DWARF register lookup for sparc
MAINTAINERS: Add SBUS driver path to sparc entry.
drivers/sbus: Remove unnecessary casts of private_data
sparc: remove homegrown L1_CACHE_ALIGN macro
sparc64: fix the build error due to smp_kgdb_capture_client()
sparc64: Fix maybe_change_configuration() PCR setting.
arch/sparc/kernel: Eliminate what looks like a NULL pointer dereference
sparc64: Update defconfig.
sunsu: Fix use after free in su_remove().
sunserial: Don't call add_preferred_console() when console= is specified.
sparc32: Kill none_mask, it's bogus.
The kernel's math-emu code contains a macro _FP_FROM_INT() which is
used to convert an integer to a raw normalized floating-point value.
It does this basically in three steps:
1. Compute the exponent from the number of leading zero bits.
2. Downshift large fractions to put the MSB in the right position
for normalized fractions.
3. Upshift small fractions to put the MSB in the right position.
There is an boundary error in step 2, causing a fraction with its
MSB exactly one bit above the normalized MSB position to not be
downshifted. This results in a non-normalized raw float, which when
packed becomes a massively inaccurate representation for that input.
The impact of this depends on a number of arch-specific factors,
but it is known to have broken emulation of FXTOD instructions
on UltraSPARC III, which was originally reported as GCC bug 44631
<http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44631>.
Any arch which uses math-emu to emulate conversions from integers to
same-size floats may be affected.
The fix is simple: the exponent comparison used to determine if the
fraction should be downshifted must be "<=" not "<".
I'm sending a kernel module to test this as a reply to this message.
There are also SPARC user-space test cases in the GCC bug entry.
Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/r600: fix possible NULL pointer derefernce
drm/radeon/kms: add quirk for ASUS HD 3600 board
include/linux/vgaarb.h: add missing part of include guard
drm/nouveau: Fix crashes during fbcon init on single head cards.
drm/nouveau: fix pcirom vbios shadow breakage from acpi rom patch
drm/radeon/kms: fix shared ddc harder
drm/i915: enable low power render writes on GEN3 hardware.
drm/i915: Define MI_ARB_STATE bits
vmwgfx: return -EFAULT if copy_to_user fails
fb: handle allocation failure in alloc_apertures()
drm: radeon: check kzalloc() result
drm/ttm: Fix build on architectures without AGP
drm/radeon/kms: fix gtt MC base alignment on rs4xx/rs690/rs740 asics
drm/radeon/kms: fix possible mis-detection of sideport on rs690/rs740
drm/radeon/kms: fix legacy tv-out pal mode
vgaarb.h was missing the #define of the #ifndef at the top for the guard
to prevent multiple #include's from causing re-define errors
Signed-off-by: Doug Goldstein <cardoe@gentoo.org>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (24 commits)
bridge: Partially disable netpoll support
tcp: fix crash in tcp_xmit_retransmit_queue
IPv6: fix CoA check in RH2 input handler (mip6_rthdr_input())
ibmveth: lost IRQ while closing/opening device leads to service loss
rt2x00: Fix lockdep warning in rt2x00lib_probe_dev()
vhost: avoid pr_err on condition guest can trigger
ipmr: Don't leak memory if fib lookup fails.
vhost-net: avoid flush under lock
net: fix problem in reading sock TX queue
net/core: neighbour update Oops
net: skb_tx_hash() fix relative to skb_orphan_try()
rfs: call sock_rps_record_flow() in tcp_splice_read()
xfrm: do not assume that template resolving always returns xfrms
hostap_pci: set dev->base_addr during probe
axnet_cs: use spin_lock_irqsave in ax_interrupt
dsa: Fix Kconfig dependencies.
act_nat: not all of the ICMP packets need an IP header payload
r8169: incorrect identifier for a 8168dp
Phonet: fix skb leak in pipe endpoint accept()
Bluetooth: Update sec_level/auth_type for already existing connections
...
If a single-threaded process does a file-descriptor operation, and some
other process accesses that same file descriptor via /proc, the current
rcu_dereference_check_fdtable() can give a false-positive RCU-lockdep
splat due to the reference count being increased by the /proc access after
the reference-count check in fget_light() but before the check in
rcu_dereference_check_fdtable().
This commit prevents this false positive by checking for a single-threaded
process. To avoid #include hell, this commit uses the wrapper for
thread_group_empty(current) defined by rcu_my_thread_group_empty()
provided in a separate commit.
Located-by: Miles Lane <miles.lane@gmail.com>
Located-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We define a number of symbols in the linker scipt like this:
__start_syscalls_metadata = .;
*(__syscalls_metadata)
But we do not know the alignment of "." when we assign
the __start_syscalls_metadata symbol.
gcc started to uses bigger alignment for structs (32 bytes),
so we saw situations where the linker due to alignment
constraints increased the value of "." after the symbol assignment.
This resulted in boot fails.
Fix this by forcing a 32 byte alignment of "." before the
assignment.
This patch introduces the forced alignment for
ftrace_events and syscalls_metadata.
It may be required in more places.
Reported-by: Zeev Tarantov <zeev.tarantov@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
LKML-Reference: <20100710063459.GA14596@merkur.ravnborg.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If the kzalloc() fails we should return NULL. All the places that call
alloc_apertures() check for this already.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: James Simmons <jsimmons@infradead.org>
Acked-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The current shrinker implementation requires the registered callback
to have global state to work from. This makes it difficult to shrink
caches that are not global (e.g. per-filesystem caches). Pass the shrinker
structure to the callback so that users can embed the shrinker structure
in the context the shrinker needs to operate on and get back to it in the
callback via container_of().
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
