Activation conditions for a workaround should not be encoded in the
workaround's direct dependencies if this makes otherwise reasonable
configuration choices impossible.
This patches uses the SMP/UP patching facilities instead to compile
out the workaround if the configuration means that it is definitely
not needed.
This means that configs for buggy silicon can simply select
ARM_ERRATA_751472, without preventing a UP kernel from being built
or duplicatiing knowledge about when to activate the workaround.
This seems the correct way to do things, because the erratum is a
property of the silicon, irrespective of what the kernel config
happens to be.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Activation conditions for a workaround should not be encoded in the
workaround's direct dependencies if this makes otherwise reasonable
configuration choices impossible.
The workaround for erratum 720789 only affects a code path which is
not active in UP kernels; hence it should be safe to turn on in UP
kernels, without penalty.
This patch simply removes the extra dependency on SMP from Kconfig.
This means that configs for buggy silicon can simply select
ARM_ERRATA_720789, without preventing a UP kernel from being built
or duplicatiing knowledge about when to activate the workaround.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This reverts commit e1b6eb3ccb.
This was causing a delay of 10 seconds in the resume process of a Thinkpad
laptop. I'm afraid this could affect more devices once 3.2 is released.
Reported-by: Tomáš Janoušek <tomi@nomi.cz>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
The current perf scripting facility only supports tracepoints. This
patch implements a generic perl handler to support other events than
tracepoints too.
This patch introduces a function process_event() that is called by perf
for each sample. The function is called with byte streams as arguments
containing information about the event, its attributes, the sample and
raw data. Perl's unpack() function can easily be used for byte decoding.
The following is the default implementation for process_event() that can
also be generated with perf script:
# Packed byte string args of process_event():
#
# $event: union perf_event util/event.h
# $attr: struct perf_event_attr linux/perf_event.h
# $sample: struct perf_sample util/event.h
# $raw_data: perf_sample->raw_data util/event.h
sub process_event
{
my ($event, $attr, $sample, $raw_data) = @_;
my @event = unpack("LSS", $event);
my @attr = unpack("LLQQQQQLLQQ", $attr);
my @sample = unpack("QLLQQQQQLL", $sample);
my @raw_data = unpack("C*", $raw_data);
use Data::Dumper;
print Dumper \@event, \@attr, \@sample, \@raw_data;
}
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323969824-9711-4-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch introduces the for_each_set_bit() macro and modifies feature
implementation to use it.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323248577-11268-8-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The features HEADER_TRACE_INFO and HEADER_BUILD_ID are handled
different when writing the feature section. All other features are
simply disabled on failure and writing the section goes on without
returning an error. There is no reason for these special cases. This
patch unifies handling of the features.
This should be ok since all features can be parsed independently.
Offset and size of a feature's block is stored in struct perf_file_
section right after the data block of perf.data (see perf_session__
write_header()). Thus, if a feature does not exist then other features
can be processed anyway.
Also moving special code for HEADER_BUILD_ID out to write_build_id().
v2:
* perf record throws an error now if buildids may not be generated,
which can be disabled with the --no-buildid option.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323248577-11268-6-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The default input file for perf report is not handled the same way as
perf record does it for its output file. This leads to unexpected
behavior of perf report, etc. E.g.:
# perf record -a -e cpu-cycles sleep 2 | perf report | cat
failed to open perf.data: No such file or directory (try 'perf record' first)
While perf record writes to a fifo, perf report expects perf.data to be
read. This patch changes this to accept fifos as input file.
Applies to the following commands:
perf annotate
perf buildid-list
perf evlist
perf kmem
perf lock
perf report
perf sched
perf script
perf timechart
Also fixes char const* -> const char* type declaration for filename
strings.
v2:
* Prevent potential null pointer access to input_name in
builtin-report.c. Needed due to removal of patch "perf report: Setup
browser if stdout is a pipe"
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323248577-11268-5-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If filename is NULL there is an out-of-bound access to struct
perf_session if it would be used with perf_session__open(). Shouldn't
actually happen in current implementation as filename is always !NULL.
Fixing this by always null-terminating filename.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323248577-11268-3-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
A feature may be unknown if perf.data is created and parsed on different
perf tool versions. This should not stop the header to be processed,
instead continue processing it.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323248577-11268-2-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reducing duplication and line size by extending function names for
print and write from a single name.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1323248577-11268-7-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Now that we automatically point users at it, let's provide them some
guidance so that they hopefully don't just get mysterious EINVAL's
from the kernel.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1324301972-22740-4-git-send-email-nelhage@nelhage.com
Signed-off-by: Nelson Elhage <nelhage@nelhage.com>
[ committer note: Made it work after 50a682c ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This failure is most likely due to running up against the
kernel.perf_event_mlock_kb sysctl, so we can tell the user what to do to
fix the issue.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1324301972-22740-3-git-send-email-nelhage@nelhage.com
Signed-off-by: Nelson Elhage <nelhage@nelhage.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
I get such truncated annotation results in 'perf top':
: Disassembly of section .text: ▒
: ▒
: ffffffff810966a8 <nr_iowait_cpu>: ▒
4.94 : ffffffff810966a8: movslq %edi,%rdi ▒
3.70 : ffffffff810966ab: mov $0x13700,%rax ▒
0.00 : ffffffff810966b2: add -0x7e32cb00(,%rdi,8),%rax ▒
8.64 : ffffffff810966ba: mov 0x7e0(%rax),%eax ▒
82.72 : ffffffff810966c0: cltq ▒
Note the missing 'retq' which is there in the original function:
ffffffff810966a8 <nr_iowait_cpu>:
ffffffff810966a8: 48 63 ff movslq %edi,%rdi
ffffffff810966ab: 48 c7 c0 00 37 01 00 mov $0x13700,%rax
ffffffff810966b2: 48 03 04 fd 00 35 cd add -0x7e32cb00(,%rdi,8),%rax
ffffffff810966b9: 81
ffffffff810966ba: 8b 80 e0 07 00 00 mov 0x7e0(%rax),%eax
ffffffff810966c0: 48 98 cltq
ffffffff810966c2: c3 retq
ffffffff810966c3 <this_cpu_load>:
I'm using a fairly recent binutils:
GNU objdump version 2.21.51.0.6-2.fc16 20110118
AFAICS the bug is simply that sym->end points to the last byte
of the symbol in question - while objdump's --stop-address
expects the last byte plus 1 to disassemble the full range.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111223130804.GA24305@elte.hu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This handles multithreaded processes with named threads when doing
system wide profiling: the comm for each thread is looked up allowing
them to be different from the thread group leader.
v2:
- fixed sizeof arg to perf_event__get_comm_tgid
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1324578603-12762-3-git-send-email-dsahern@gmail.com
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf does not properly handle monitoring of processes with named threads.
For example:
$ ps -C myapp -L
PID LWP TTY TIME CMD
25118 25118 ? 00:00:00 myapp
25118 25119 ? 00:00:00 myapp:worker
perf record -e cs -c 1 -fo /tmp/perf.data -p 25118 -- sleep 10
perf report --stdio -i /tmp/perf.data
100.00% myapp:worker [kernel.kallsyms] [k] perf_event_task_sched_out
The process name is set to the name of the last thread it finds for the
process.
The Problem:
perf-top and perf-record both create a thread_map of threads to be
monitored. That map is used in perf_event__synthesize_thread_map which
loops over the entries in thread_map and calls __event__synthesize_thread
to generate COMM and MMAP events.
__event__synthesize_thread calls perf_event__synthesize_comm which opens
/proc/pid/status, reads the name of the task and its thread group id.
That's all fine. The problem is that it then reads /proc/pid/task and
generates COMM events for each task it finds - but using the name found
in /proc/pid/status where pid is the thread of interest.
The end result (looping over thread_map + synthesizing comm events for
each thread each time) means the name of the last thread processed sets
the name for all threads in the process - which is not good for
multithreaded processes with named threads.
The Fix:
perf_event__synthesize_comm has an input argument (full) that decides
whether to process task entries for each pid it is passed. It currently
never set to 0 (perf_event__synthesize_comm has a single caller and it
always passes the value 1). Let's fix that.
Add the full input argument to __event__synthesize_thread which passes
it to perf_event__synthesize_comm. For thread/process monitoring set full
to 0 which means COMM and MMAP events are only generated for the pid
passed to it. For system wide monitoring set full to 1 so that COMM events
are generated for all threads in a process.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1324578603-12762-2-git-send-email-dsahern@gmail.com
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Broken in commit d1dc698a54
Signed-off-by: Joachim Eastwood <joachim.eastwood@jotron.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Use raw_spin_unlock_irqrestore() as equivalent to
raw_spin_lock_irqsave().
Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1324646665-13334-1-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
"! --connbytes 23:42" should match if the packet/byte count is not in range.
As there is no explict "invert match" toggle in the match structure,
userspace swaps the from and to arguments
(i.e., as if "--connbytes 42:23" were given).
However, "what <= 23 && what >= 42" will always be false.
Change things so we use "||" in case "from" is larger than "to".
This change may look like it breaks backwards compatibility when "to" is 0.
However, older iptables binaries will refuse "connbytes 42:0",
and current releases treat it to mean "! --connbytes 0:42",
so we should be fine.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This closes races where btrfs is calling d_instantiate too soon during
inode creation. All of the callers of btrfs_add_nondir are updated to
instantiate after the inode is fully setup in memory.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Dan Carpenter noticed that we were doing a double unlock on the worker
lock, and sometimes picking a worker thread without the lock held.
This fixes both errors.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
This change fixes a linking problem, which happens if oprofile
is selected to be compiled as built-in:
`oprofile_arch_exit' referenced in section `.init.text' of
arch/arm/oprofile/built-in.o: defined in discarded section
`.exit.text' of arch/arm/oprofile/built-in.o
The problem is appeared after commit 87121ca504, which
introduced oprofile_arch_exit() calls from __init function. Note
that the aforementioned commit has been backported to stable
branches, and the problem is known to be reproduced at least
with 3.0.13 and 3.1.5 kernels.
Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@nokia.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: oprofile-list <oprofile-list@lists.sourceforge.net>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/20111222151540.GB16765@erda.amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Make sure that mutex is released upon register writing failure.
This fixes boot freezing observed on ARM based OLPC
(http://dev.laptop.org/ticket/11357).
Signed-off-by: Paul Fox <pgf@laptop.org>
Signed-off-by: Tai-hwa Liang <avatar@sentelic.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
skb->truesize might be big even for a small packet.
Its even bigger after commit 87fb4b7b53 (net: more accurate skb
truesize) and big MTU.
We should allow queueing at least one packet per receiver, even with a
low RCVBUF setting.
Reported-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Setting a large rps_flow_cnt like (1 << 30) on 32-bit platform will
cause a kernel oops due to insufficient bounds checking.
if (count > 1<<30) {
/* Enforce a limit to prevent overflow */
return -EINVAL;
}
count = roundup_pow_of_two(count);
table = vmalloc(RPS_DEV_FLOW_TABLE_SIZE(count));
Note that the macro RPS_DEV_FLOW_TABLE_SIZE(count) is defined as:
... + (count * sizeof(struct rps_dev_flow))
where sizeof(struct rps_dev_flow) is 8. (1 << 30) * 8 will overflow
32 bits.
This patch replaces the magic number (1 << 30) with a symbolic bound.
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Userspace may not provide TCA_OPTIONS, in fact tc currently does
so not do so if no arguments are specified on the command line.
Return EINVAL instead of panicing.
Signed-off-by: Thomas Graf <tgraf@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 618f9bc74a (net: Move mtu handling down to the protocol
depended handlers) forgot the bridge netfilter case, adding a NULL
dereference in ip_fragment().
Reported-by: Chris Boot <bootc@bootc.net>
CC: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'for-linus' of git://neil.brown.name/md:
md/bitmap: It is OK to clear bits during recovery.
md: don't give up looking for spares on first failure-to-add
md/raid5: ensure correct assessment of drives during degraded reshape.
md/linear: fix hot-add of devices to linear arrays.
commit d0a4bb4927 introduced a
regression which is annoying but fairly harmless.
When writing to an array that is undergoing recovery (a spare
in being integrated into the array), writing to the array will
set bits in the bitmap, but they will not be cleared when the
write completes.
For bits covering areas that have not been recovered yet this is not a
problem as the recovery will clear the bits. However bits set in
already-recovered region will stay set and never be cleared.
This doesn't risk data integrity. The only negatives are:
- next time there is a crash, more resyncing than necessary will
be done.
- the bitmap doesn't look clean, which is confusing.
While an array is recovering we don't want to update the
'events_cleared' setting in the bitmap but we do still want to clear
bits that have very recently been set - providing they were written to
the recovering device.
So split those two needs - which previously both depended on 'success'
and always clear the bit of the write went to all devices.
Signed-off-by: NeilBrown <neilb@suse.de>
Before performing a recovery we try to remove any spares that
might not be working, then add any that might have become relevant.
Currently we abort on the first spare that cannot be added.
This is a false optimisation.
It is conceivable that - depending on rules in the personality - a
subsequent spare might be accepted.
Also the loop does other things like count the available spares and
reset the 'recovery_offset' value.
If we abort early these might not happen properly.
So remove the early abort.
In particular if you have an array what is undergoing recovery and
which has extra spares, then the recovery may not restart after as
reboot as the could of 'spares' might end up as zero.
Reported-by: Anssi Hannula <anssi.hannula@iki.fi>
Signed-off-by: NeilBrown <neilb@suse.de>
While reshaping a degraded array (as when reshaping a RAID0 by first
converting it to a degraded RAID4) we currently get confused about
which devices are in_sync. In most cases we get it right, but in the
region that is being reshaped we need to treat non-failed devices as
in-sync when we have the data but haven't actually written it out yet.
Reported-by: Adam Kwolek <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
commit d70ed2e4fa
broke hot-add to a linear array.
After that commit, metadata if not written to devices until they
have been fully integrated into the array as determined by
saved_raid_disk. That patch arranged to clear that field after
a recovery completed.
However for linear arrays, there is no recovery - the integration is
instantaneous. So we need to explicitly clear the saved_raid_disk
field.
Signed-off-by: NeilBrown <neilb@suse.de>
This silently was working for many years and stopped working on
Niagara-T3 machines.
We need to set the MSIQ to VALID before we can set it's state to IDLE.
On Niagara-T3, setting the state to IDLE first was causing HV_EINVAL
errors. The hypervisor documentation says, rather ambiguously, that
the MSIQ must be "initialized" before one can set the state.
I previously understood this to mean merely that a successful setconf()
operation has been performed on the MSIQ, which we have done at this
point. But it seems to also mean that it has been set VALID too.
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
USB: Fix usb/isp1760 build on sparc
usb: gadget: epautoconf: do not change number of streams
usb: dwc3: core: fix cached revision on our structure
usb: musb: fix reset issue with full speed device
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e133e737 didn't correctly fix the integer overflow issue.
- unsigned int required_size;
+ u64 required_size;
...
required_size = mode_cmd->pitch * mode_cmd->height;
- if (unlikely(required_size > dev_priv->vram_size)) {
+ if (unlikely(required_size > (u64) dev_priv->vram_size)) {
Note that both pitch and height are u32. Their product is still u32 and
would overflow before being assigned to required_size. A correct way is
to convert pitch and height to u64 before the multiplication.
required_size = (u64)mode_cmd->pitch * (u64)mode_cmd->height;
This patch calls the existing vmw_kms_validate_mode_vram() for
validation.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Reviewed-and-tested-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
We already do this for cayman, need to also do it for
BTC parts. The default memory and voltage setup is not
adequate for advanced operation. Continuing will
result in an unusable display.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@kernel.org
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
perf report does not take a command from command line.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1323703017-6060-8-git-send-email-namhyung@gmail.com
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently, the *_global_[un]lock_online() routines are not at all synchronized
with CPU hotplug. Soft-lockups detected as a consequence of this race was
reported earlier at https://lkml.org/lkml/2011/8/24/185. (Thanks to Cong Meng
for finding out that the root-cause of this issue is the race condition
between br_write_[un]lock() and CPU hotplug, which results in the lock states
getting messed up).
Fixing this race by just adding {get,put}_online_cpus() at appropriate places
in *_global_[un]lock_online() is not a good option, because, then suddenly
br_write_[un]lock() would become blocking, whereas they have been kept as
non-blocking all this time, and we would want to keep them that way.
So, overall, we want to ensure 3 things:
1. br_write_lock() and br_write_unlock() must remain as non-blocking.
2. The corresponding lock and unlock of the per-cpu spinlocks must not happen
for different sets of CPUs.
3. Either prevent any new CPU online operation in between this lock-unlock, or
ensure that the newly onlined CPU does not proceed with its corresponding
per-cpu spinlock unlocked.
To achieve all this:
(a) We introduce a new spinlock that is taken by the *_global_lock_online()
routine and released by the *_global_unlock_online() routine.
(b) We register a callback for CPU hotplug notifications, and this callback
takes the same spinlock as above.
(c) We maintain a bitmap which is close to the cpu_online_mask, and once it is
initialized in the lock_init() code, all future updates to it are done in
the callback, under the above spinlock.
(d) The above bitmap is used (instead of cpu_online_mask) while locking and
unlocking the per-cpu locks.
The callback takes the spinlock upon the CPU_UP_PREPARE event. So, if the
br_write_lock-unlock sequence is in progress, the callback keeps spinning,
thus preventing the CPU online operation till the lock-unlock sequence is
complete. This takes care of requirement (3).
The bitmap that we maintain remains unmodified throughout the lock-unlock
sequence, since all updates to it are managed by the callback, which takes
the same spinlock as the one taken by the lock code and released only by the
unlock routine. Combining this with (d) above, satisfies requirement (2).
Overall, since we use a spinlock (mentioned in (a)) to prevent CPU hotplug
operations from racing with br_write_lock-unlock, requirement (1) is also
taken care of.
By the way, it is to be noted that a CPU offline operation can actually run
in parallel with our lock-unlock sequence, because our callback doesn't react
to notifications earlier than CPU_DEAD (in order to maintain our bitmap
properly). And this means, since we use our own bitmap (which is stale, on
purpose) during the lock-unlock sequence, we could end up unlocking the
per-cpu lock of an offline CPU (because we had locked it earlier, when the
CPU was online), in order to satisfy requirement (2). But this is harmless,
though it looks a bit awkward.
Debugged-by: Cong Meng <mc@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
net: Add a flow_cache_flush_deferred function
ipv4: reintroduce route cache garbage collector
net: have ipconfig not wait if no dev is available
sctp: Do not account for sizeof(struct sk_buff) in estimated rwnd
asix: new device id
davinci-cpdma: fix locking issue in cpdma_chan_stop
sctp: fix incorrect overflow check on autoclose
r8169: fix Config2 MSIEnable bit setting.
llc: llc_cmsg_rcv was getting called after sk_eat_skb.
net: bpf_jit: fix an off-one bug in x86_64 cond jump target
iwlwifi: update SCD BC table for all SCD queues
Revert "Bluetooth: Revert: Fix L2CAP connection establishment"
Bluetooth: Clear RFCOMM session timer when disconnecting last channel
Bluetooth: Prevent uninitialized data access in L2CAP configuration
iwlwifi: allow to switch to HT40 if not associated
iwlwifi: tx_sync only on PAN context
mwifiex: avoid double list_del in command cancel path
ath9k: fix max phy rate at rate control init
nfc: signedness bug in __nci_request()
iwlwifi: do not set the sequence control bit is not needed
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: atmel/ac97c: using software reset instead hardware reset if not available
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6:
mfd: Include linux/io.h to jz4740-adc
mfd: Use request_threaded_irq for twl4030-irq instead of irq_set_chained_handler
mfd: Base interrupt for twl4030-irq must be one-shot
mfd: Handle tps65910 clear-mask correctly
mfd: add #ifdef CONFIG_DEBUG_FS guard for ab8500_debug_resources
mfd: Fix twl-core oops while calling twl_i2c_* for unbound driver
mfd: include linux/module.h for ab5500-debugfs
mfd: Update wm8994 active device checks for WM1811
mfd: Set tps6586x bits if new value is different from the old one
mfd: Set da903x bits if new value is different from the old one
mfd: Set adp5520 bits if new value is different from the old one
mfd: Add missed free_irq in da903x_remove
lockdep reports a deadlock in jfs because a special inode's rw semaphore
is taken recursively. The mapping's gfp mask is GFP_NOFS, but is not
used when __read_cache_page() calls add_to_page_cache_lru().
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-greg' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb:
usb: gadget: epautoconf: do not change number of streams
usb: dwc3: core: fix cached revision on our structure
usb: musb: fix reset issue with full speed device
This commit:
commit 8f5d621543
Author: Joachim Foerster <joachim.foerster@missinglinkelectronics.com>
Date: Mon Oct 10 18:06:54 2011 +0200
usb/isp1760: Let OF bindings depend on general CONFIG_OF instead of PPC_OF .
To be able to use the driver on other OF-aware architectures, too.
And add necessary OF related #includes to fix compilation error.
Signed-off-by: Joachim Foerster <joachim.foerster@missinglinkelectronics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
enabled the build on all CONFIG_OF architectures, but it cannot do
this.
This driver depends upon CONFIG_OF_IRQ but not all CONFIG_OF platforms
support that infrastructure, in particular Sparc does not so the
build fails.
Please push a patch like the following to Linus so that this code only
gets built where it actually should.
--------------------
usb/isp1760: Add missing CONFIG_OF_IRQ dependency on OF code.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
