Le mercredi 30 novembre 2011 à 14:36 -0800, Stephen Hemminger a écrit :
> (Almost) nobody uses RED because they can't figure it out.
> According to Wikipedia, VJ says that:
> "there are not one, but two bugs in classic RED."
RED is useful for high throughput routers, I doubt many linux machines
act as such devices.
I was considering adding Adaptative RED (Sally Floyd, Ramakrishna
Gummadi, Scott Shender), August 2001
In this version, maxp is dynamic (from 1% to 50%), and user only have to
setup min_th (target average queue size)
(max_th and wq (burst in linux RED) are automatically setup)
By the way it seems we have a small bug in red_change()
if (skb_queue_empty(&sch->q))
red_end_of_idle_period(&q->parms);
First, if queue is empty, we should call
red_start_of_idle_period(&q->parms);
Second, since we dont use anymore sch->q, but q->qdisc, the test is
meaningless.
Oh well...
[PATCH] sch_red: fix red_change()
Now RED is classful, we must check q->qdisc->q.qlen, and if queue is empty,
we start an idle period, not end it.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to leave a margin of 12.5% we should >> 3 not >> 5.
CC: stable@kernel.org
Signed-off-by: Yang Honggang (Joseph) <eagle.rtlinux@gmail.com>
[jstultz: Modified commit subject]
Signed-off-by: John Stultz <john.stultz@linaro.org>
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2: (31 commits)
ocfs2: avoid unaligned access to dqc_bitmap
ocfs2: Use filemap_write_and_wait() instead of write_inode_now()
ocfs2: honor O_(D)SYNC flag in fallocate
ocfs2: Add a missing journal credit in ocfs2_link_credits() -v2
ocfs2: send correct UUID to cleancache initialization
ocfs2: Commit transactions in error cases -v2
ocfs2: make direntry invalid when deleting it
fs/ocfs2/dlm/dlmlock.c: free kmem_cache_zalloc'd data using kmem_cache_free
ocfs2: Avoid livelock in ocfs2_readpage()
ocfs2: serialize unaligned aio
ocfs2: Implement llseek()
ocfs2: Fix ocfs2_page_mkwrite()
ocfs2: Add comment about orphan scanning
ocfs2: Clean up messages in the fs
ocfs2/cluster: Cluster up now includes network connections too
ocfs2/cluster: Add new function o2net_fill_node_map()
ocfs2/cluster: Fix output in file elapsed_time_in_ms
ocfs2/dlm: dlmlock_remote() needs to account for remastery
ocfs2/dlm: Take inflight reference count for remotely mastered resources too
ocfs2/dlm: Cleanup dlm_wait_for_node_death() and dlm_wait_for_node_recovery()
...
The dqc_bitmap field of struct ocfs2_local_disk_chunk is 32-bit aligned,
but not 64-bit aligned. The dqc_bitmap is accessed by ocfs2_set_bit(),
ocfs2_clear_bit(), ocfs2_test_bit(), or ocfs2_find_next_zero_bit(). These
are wrapper macros for ext2_*_bit() which need to take an unsigned long
aligned address (though some architectures are able to handle unaligned
address correctly)
So some 64bit architectures may not be able to access the dqc_bitmap
correctly.
This avoids such unaligned access by using another wrapper functions for
ext2_*_bit(). The code is taken from fs/ext4/mballoc.c which also need to
handle unaligned bitmap access.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Joel Becker <jlbec@evilplan.org>
Currently, the code assumes that the SEQUENCE status bits are mutually
exclusive. They are not...
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 2.6.34]
If we handled an error condition, then nfs4_recovery_handle_error should
return '0' so that the state recovery thread can continue.
Also ensure that nfs4_check_lease() continues to abort if we haven't got
any credentials by having it return ENOKEY (which is not handled).
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Fix the following compalitaion breakage:
In file included from linux/drivers/sh/pm_runtime.c:15:
linux/include/linux/pm_domain.h: In function 'dev_to_genpd':
linux/include/linux/pm_domain.h:142: error: implicit declaration of function 'ERR_PTR'
linux/include/linux/pm_domain.h:142: warning: return makes pointer from integer without a cast
In file included from linux/include/linux/sh_clk.h:10,
from linux/drivers/sh/pm_runtime.c:19:
linux/include/linux/err.h: At top level:
linux/include/linux/err.h:22: error: conflicting types for 'ERR_PTR'
linux/include/linux/pm_domain.h:142: note: previous implicit declaration of 'ERR_PTR' was here
make[3]: *** [drivers/sh/pm_runtime.o] Error 1
Reported-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Measure the time of execution of the .stop(), .start(), .save_state()
and .restore_state() PM domain device callbacks and if the result
is greater than the corresponding latency value stored in the
device's struct generic_pm_domain_data object, replace the inaccurate
value with the measured time.
Do analogously for the PM domains' .power_off() and .power_off()
callbacks.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Add a function deciding whether or not a given PM domain should
be powered off on the basis of the PM QoS constraints of devices
belonging to it and their PM QoS timing data.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Add a function deciding whether or not devices should be stopped in
pm_genpd_runtime_suspend() depending on their PM QoS constraints
and stop/start timing values. Make it possible to add information
used by this function to device objects.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@opensource.se>
The current generic PM domains code attempts to use the generic
system suspend operations along with the domains' device stop/start
routines, which requires device drivers to assume that their
system suspend/resume (and hibernation/restore) callbacks will always
be used with generic PM domains. However, in theory, the same
hardware may be used in devices that don't belong to any PM domain,
in which case it would be necessary to add "fake" PM domains to
satisfy the above assumption. Also, the domain the hardware belongs
to may not be handled with the help of the generic code.
To allow device drivers that may be used along with the generic PM
domains code of more flexibility, add new device callbacks,
.suspend(), .suspend_late(), .resume_early(), .resume(), .freeze(),
.freeze_late(), .thaw_early(), and .thaw(), that can be supplied by
the drivers in addition to their "standard" system suspend and
hibernation callbacks. These new callbacks, if defined, will be used
by the generic PM domains code for the handling of system suspend and
hibernation instead of the "standard" ones. This will allow drivers
to be designed to work with generic PM domains as well as without
them.
For backwards compatibility, introduce default implementations of the
new callbacks for PM domains that will execute pm_generic_suspend(),
pm_generic_suspend_noirq(), pm_generic_resume_noirq(),
pm_generic_resume(), pm_generic_freeze(), pm_generic_freeze_noirq(),
pm_generic_thaw_noirq(), and pm_generic_thaw(), respectively, for the
given device if its driver doesn't define those callbacks.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The current PM domains code uses device drivers' .runtime_suspend()
and .runtime_resume() callbacks as the "save device state" and
"restore device state" operations, which may not be appropriate in
general, because it forces drivers to assume that they always will
be used with generic PM domains. However, in theory, the same
hardware may be used in devices that don't belong to any PM
domain, in which case it would be necessary to add "fake" PM
domains to satisfy the above assumption. It also may be located in
a PM domain that's not handled with the help of the generic code.
To allow device drivers that may be used along with the generic PM
domains code of more flexibility, introduce new device callbacks,
.save_state() and .restore_state(), that can be supplied by the
drivers in addition to their "standard" runtime PM callbacks. This
will allow the drivers to be designed to work with generic PM domains
as well as without them.
For backwards compatibility, introduce default .save_state() and
.restore_state() callback routines for PM domains that will execute
a device driver's .runtime_suspend() and .runtime_resume() callbacks,
respectively, for the given device if the driver doesn't provide its
own implementations of .save_state() and .restore_state().
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The current generic PM domains code requires that the same .stop(),
.start() and .active_wakeup() device callback routines be used for
all devices in the given domain, which is inflexible and may not
cover some specific use cases. For this reason, make it possible to
use device specific .start()/.stop() and .active_wakeup() callback
routines by adding corresponding callback pointers to struct
generic_pm_domain_data. Add a new helper routine,
pm_genpd_register_callbacks(), that can be used to populate
the new per-device callback pointers.
Modify the shmobile's power domains code to allow drivers to add
their own code to be run during the device stop and start operations
with the help of the new callback pointers.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@opensource.se>
Make the runtime PM core use device PM QoS constraints to check if
it is allowed to suspend a given device, so that an error code is
returned if the device's own PM QoS constraint is negative or one of
its children has already been suspended for too long. If this is
not the case, the maximum estimated time the device is allowed to be
suspended, computed as the minimum of the device's PM QoS constraint
and the PM QoS constraints of its children (reduced by the difference
between the current time and their suspend times) is stored in a new
device's PM field power.max_time_suspended_ns that can be used by
the device's subsystem or PM domain to decide whether or not to put
the device into lower-power (and presumably higher-latency) states
later (if the constraint is 0, which means "no constraint", the
power.max_time_suspended_ns is set to -1).
Additionally, the time of execution of the subsystem-level
.runtime_suspend() callback for the device is recorded in the new
power.suspend_time field for later use by the device's subsystem or
PM domain along with power.max_time_suspended_ns (it also is used
by the core code when the device's parent is suspended).
Introduce a new helper function,
pm_runtime_update_max_time_suspended(), allowing subsystems and PM
domains (or device drivers) to update the power.max_time_suspended_ns
field, for example after changing the power state of a suspended
device.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
We need to properly add the hid device to correctly initialize the sysfs state.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reported-by: Fuzhou Chen <fuzhouch@microsoft.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* 'fixes' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm:
ARM: 7182/1: ARM cpu topology: fix warning
ARM: 7181/1: Restrict kprobes probing SWP instructions to ARMv5 and below
ARM: 7180/1: Change kprobes testcase with unpredictable STRD instruction
ARM: 7177/1: GIC: avoid skipping non-existent PPIs in irq_start calculation
ARM: 7176/1: cpu_pm: register GIC PM notifier only once
ARM: 7175/1: add subname parameter to mfp_set_groupg callers
ARM: 7174/1: Fix build error in kprobes test code on Thumb2 kernels
ARM: 7172/1: dma: Drop GFP_COMP for DMA memory allocations
ARM: 7171/1: unwind: add unwind directives to bitops assembly macros
ARM: 7170/2: fix compilation breakage in entry-armv.S
ARM: 7168/1: use cache type functions for arch_get_unmapped_area
ARM: perf: check that we have a platform device when reserving PMU
ARM: 7166/1: Use PMD_SHIFT instead of PGDIR_SHIFT in dma-consistent.c
ARM: 7165/2: PL330: Fix typo in _prepare_ccr()
ARM: 7163/2: PL330: Only register usable channels
ARM: 7162/1: errata: tidy up Kconfig options for PL310 errata workarounds
ARM: 7161/1: errata: no automatic store buffer drain
ARM: perf: initialise used_mask for fake PMU during validation
ARM: PMU: remove pmu_init declaration
ARM: PMU: re-export release_pmu symbol to modules
Commit 1386be55e3 ("dccp: fix
auto-loading of dccp(_probe)") fixed a bug but created a new
compiler warning:
net/dccp/probe.c: In function ‘dccpprobe_init’:
net/dccp/probe.c:166:2: warning: the omitted middle operand in ?: will always be ‘true’, suggest explicit middle operand [-Wparentheses]
try_then_request_module() is built for situations where the
"existence" test is some lookup function that returns a non-NULL
object on success, and with a reference count of some kind held.
Here we're looking for a success return of zero from the jprobe
registry.
Instead of fighting the way try_then_request_module() works, simply
open code what we want to happen in a local helper function.
Signed-off-by: David S. Miller <davem@davemloft.net>
Whenever we free a slot, we know that the resulting xprt->num_reqs will
be less than xprt->max_reqs, so we know that we can release at least one
backlogged rpc_task.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>=3.1]
This reverts commit 81d54ec847.
If we take the "try_again" goto, due to a checksum error,
the 'len' has already been truncated. So we won't compute
the same values as the original code did.
Reported-by: paul bilke <fsmail@conspiracy.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'for-usb-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sarah/xhci:
Revert "xHCI: reset-on-resume quirk for NEC uPD720200"
xHCI: fix bug in xhci_clear_command_ring()
When in user-stp mode, bridge master do not follow state of its slaves, so
after the following sequence of events it can stuck forever in no-carrier
state:
1) turn stp off
2) put all slaves down - master device will follow their state and also go in
no-carrier state
3) turn stp on with bridge-stp script returning 0 (go to the user-stp mode)
Now bridge master won't follow slaves' state and will never reach running
state.
This patch solves the problem by making user-stp and kernel-stp behavior
similar regarding master following slaves' states.
Signed-off-by: Vitalii Demianets <vitas@nppfactor.kiev.ua>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If the rpc_task gets restarted, then we want to ensure that we don't
double-count the execution time statistics, timeout data, etc.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This reverts commit df711fc996.
The commit added a reset-on-resume quirk because the NEC chipset stopped
responding to commands about 30 minutes after a system resume from
suspend. We thought it was a chipset issue, but it turns out that the
xHCI driver was zeroing out the link TRB after a successful context
restore during resume. The host controller would fall off the command
ring sometime later, causing it to not respond to new commands.
The link TRB issue has been fixed with commit
158886cd2c "xHCI: fix bug in
xhci_clear_command_ring()", so revert the reset-on-resume quirk, as it's
not necessary.
Commit df711fc996 was marked for stable
trees back to 2.6.37, but according to my mail, it has not made it into
Linus' tree or the stable trees yet.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Tested-by: Julian Sikorski <belegdol@gmail.com>
Cc: Andiry Xu <andiry.xu@amd.com>
Otherwise we won't notice the peer GENID change.
Reported-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Hank is no longer at Microsoft, so remove his email address as it
bounces.
Cc: KY Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When system enters suspend, xHCI driver clears command ring by writing zero
to all the TRBs. However, this also writes zero to the Link TRB, and the ring
is mangled. This may cause driver accesses wrong memory address and the
result is unpredicted.
When clear the command ring, keep the last Link TRB intact, only clear its
cycle bit. This should fix the "command ring full" issue reported by Oliver
Neukum.
This should be backported to stable kernels as old as 2.6.37, since the
commit 89821320 "xhci: Fix command ring replay after resume" is merged.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Reported-by: Oliver Neukum <oneukum@suse.de>
This removes the hv_mouse driver as it's now in Jiri's HID tree in the
"proper" place.
Cc: KY Srinivasan <kys@microsoft.com>
Cc: Jiri Kosina <jikos@jikos.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
gcc compiler is smart enough to use a single load/store if we
memcpy(dptr, sptr, 8) on x86_64, regardless of
CONFIG_CC_OPTIMIZE_FOR_SIZE
In IP header, daddr immediately follows saddr, this wont change in the
future. We only need to make sure our flowi4 (saddr,daddr) fields wont
break the rule.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This also works around a bogus gcc warning generated by an
upcoming patch from Eric Dumazet that rearranges the layout
of struct flowi4.
Signed-off-by: David S. Miller <davem@davemloft.net>
The current code implemented a per-HBA memory pool mechanism. For IDE disks
managed by this driver, there is a one to one correspondance between the
block device and the associated virtual HBA and since currently only IDE devices
can be the boot device, this addressed the deadlock issues that were raised during
the review process. This patch implements a per-lun memory pool mechanism.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix a bug in copy_from_bounce_buffer().
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix a bug in storvsc_command_completion() that leaks memory when scatter/gather
lists are used on the "write" side.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The code in storvsc_device_alloc() is not needed as this would be
done by default. Get rid of it. We still keep the function as we use
this hook to allocate per-LUN memory pools in a later patch.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Disable clustering, since the host side on Hyper-V requires that
each I/O element not exceed the page size. As part of this
cleanup, get rid of the function to merge bvecs, as the primary
reason for this function was to avoid having an element exceed
the page size.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add code to accept promiscuous mode setting, and pass it to
RNDIS filter.
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch enables or updates support for the CC770 and AN82527
CAN controller on the TQM8548 and TQM8xx boards.
CC: devicetree-discuss@lists.ozlabs.org
CC: linuxppc-dev@ozlabs.org
CC: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This driver works with both, static platform data and device tree
bindings. It has been tested on a TQM855L board with two AN82527
CAN controllers on the local bus.
CC: Devicetree-discuss@lists.ozlabs.org
CC: linuxppc-dev@ozlabs.org
CC: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds support for legacy Bosch CC770 and Intel AN82527 CAN
controllers on the ISA or PC-104 bus. The I/O port or memory address
and the IRQ number must be specified via module parameters:
insmod cc770_isa.ko port=0x310,0x380 irq=7,11
for ISA devices using I/O ports or:
insmod cc770_isa.ko mem=0xd1000,0xd1000 irq=7,11
for memory mapped ISA devices.
Indirect access via address and data port is supported as well:
insmod cc770_isa.ko port=0x310,0x380 indirect=1 irq=7,11
Furthermore, the following mode parameter can be defined:
clk: External oscillator clock frequency (default=16000000 [16 MHz])
cir: CPU interface register (default=0x40 [DSC])
bcr: Bus configuration register (default=0x40 [CBY])
cor: Clockout register (default=0x00)
Note: for clk, cir, bcr and cor, the first argument re-defines the
default for all other devices, e.g.:
insmod cc770_isa.ko mem=0xd1000,0xd1000 irq=7,11 clk=24000000
is equivalent to
insmod cc770_isa.ko mem=0xd1000,0xd1000 irq=7,11 clk=24000000,24000000
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
"line6" hasn't been set at this point and we should be using
&interface->dev instead.
Gcc would have complained about this if it weren't for the fact that we
initialized line6 to NULL. I removed the initialization.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We need to properly add the hid device to correctly initialize the
sysfs state. While this patch is against the staging tree; Jiri,
please pick up this patch as you merge the Hyper-V mouse driver.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reported-by: Fuzhou Chen <fuzhouch@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Dan Carpenter <dan.carpenter@oracle.com> wrote:
> Sparse complains that these signed bitfields look "dubious". The
> problem is that instead of being either 0 or 1 like people would expect,
> signed one bit variables like this are either 0 or -1. It doesn't cause
> a problem in this case but it's ugly so lets fix them.
* walter harms (wharms@bfs.de) wrote:
> hi,
> This patch looks ok to me but this design is ugly by itself.
> It should be replaced by an uchar uint whatever or use a
> real bool (obviously not preferred by this programmes).
bool :1, uchar :1 or uint :1 could make sense. uchar:1/bool:1 won't save
any space here, because the surrounding fields are either uint or
pointers, so alignment will just add padding.
I try to use int/uint whenever possible because x86 CPUs tend to get
less register false-dependencies when using instructions modifying the
whole register (generated by using int/uint types) rather than only part
of it (uchar/char/bool). I only use char/uchar/bool when there is a
clear wanted space gain.
The reason why I never use the bool type within a structure when I want
a compact representation is that bool takes a whole byte just to
represent one bit:
struct usebitfield {
int a;
unsigned int f:1, g:1, h:1, i:1, j:1;
int b;
};
struct usebool {
int a;
bool f, g, h, i, j;
int b;
};
struct useboolbf {
int a;
bool f:1, g:1, h:1, i:1, j:1;
int b;
};
int main()
{
printf("bitfield %d bytes, bool %d bytes, boolbitfield %d bytes\n",
sizeof(struct usebitfield), sizeof(struct usebool),
sizeof(struct useboolbf));
}
result:
bitfield 12 bytes, bool 16 bytes, boolbitfield 12 bytes
This is because each bool takes one byte, while the bitfields are put in
units of "unsigned int" (or bool for the 3rd struct). So in this
example, we need 5 bytes + 3 bytes alignment for the bool, but only 4
bytes to hold the "unsigned int" unit for the bitfields.
The choice between bool and bitfields must also take into account the
frequency of access to the variable, because bitfields require mask
operations to access the selected bit(s). You will notice that none of
these bitfields are accessed on the tracing fast-path: only in
slow-paths. Therefore, space gain is more important than speed here.
One might argue that I have so few of these fields here that it does not
make an actual difference to go for bitfield or bool. I am just trying
to choose types best suited for their intended purpose, ensuring they
are future-proof and will allow simply adding more fields using the same
type, as needed.
So I guess I'll go for uint :1.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
At this point the variable j is always set to 7 and the code within
the loop has to run only once anyway.
As suggested by David Miller:
"You can simply this even further since p[7] is what is used here,
and this means len is one, the inner loop therefore executes only
once, and the p[7].field value is not used (it's zero in the table)
and the write to it is completely thrown away."
Signed-off-by: Patrick Kelle <patrick.kelle81@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* Dan Carpenter <dan.carpenter@oracle.com> wrote:
> The patch c844b2f5cf: "lttng lib: ring buffer" from Nov 28, 2011,
> leads to the following Smatch complaint:
>
> drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c +86
> +lib_ring_buffer_mmap_buf()
> warn: variable dereferenced before check 'buf' (see line 79)
>
> drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c
> 78 unsigned long length = vma->vm_end - vma->vm_start;
> 79 struct channel *chan = buf->backend.chan;
> ^^^^^^^^^^^^^^^^^
> Dereference.
>
> 80 const struct lib_ring_buffer_config *config = chan->backend.config;
> 81 unsigned long mmap_buf_len;
> 82
> 83 if (config->output != RING_BUFFER_MMAP)
> 84 return -EINVAL;
> 85
> 86 if (!buf)
> ^^^^
> Check.
>
> 87 return -EBADF;
> 88
Let's move the NULL buf check to the file "open", where it belongs. The
"open" file operation is the actual interface between lib ring buffer
and the modules using it.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
