Adds SRCU operations to rcutorture and updates rcutorture documentation.
Also increases the stress imposed by the rcutorture test.
[bunk@stusta.de: make needlessly global code static] Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Cc: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Updated patch adding a variant of RCU that permits sleeping in read-side
critical sections. SRCU is as follows:
o Each use of SRCU creates its own srcu_struct, and each
srcu_struct has its own set of grace periods. This is
critical, as it prevents one subsystem with a blocking
reader from holding up SRCU grace periods for other
subsystems.
o The SRCU primitives (srcu_read_lock(), srcu_read_unlock(),
and synchronize_srcu()) all take a pointer to a srcu_struct.
o The SRCU primitives must be called from process context.
o srcu_read_lock() returns an int that must be passed to
the matching srcu_read_unlock(). Realtime RCU avoids the
need for this by storing the state in the task struct,
but SRCU needs to allow a given code path to pass through
multiple SRCU domains -- storing state in the task struct
would therefore require either arbitrary space in the
task struct or arbitrary limits on SRCU nesting. So I
kicked the state-storage problem up to the caller.
Of course, it is not permitted to call synchronize_srcu()
while in an SRCU read-side critical section.
o There is no call_srcu(). It would not be hard to implement
one, but it seems like too easy a way to OOM the system.
(Hey, we have enough trouble with call_rcu(), which does
-not- permit readers to sleep!!!) So, if you want it,
please tell me why...
[josht@us.ibm.com: sparse notation] Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Josh Triplett <josh@freedesktop.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This moves the declarations for the architecture helpers into
include/linux/htirq.h from the generic include/linux/pci.h. Hopefully this
will make this distinction clearer.
htirq.h is included where it is needed.
The dependency on the msi code is fixed and removed.
The Makefile is tidied up.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tony Luck <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] msi: refactor and move the msi irq_chip into the arch code
It turns out msi_ops was simply not enough to abstract the architecture
specific details of msi. So I have moved the resposibility of constructing
the struct irq_chip to the architectures, and have two architecture specific
functions arch_setup_msi_irq, and arch_teardown_msi_irq.
For simple architectures those functions can do all of the work. For
architectures with platform dependencies they can call into the appropriate
platform code.
With this msi.c is finally free of assuming you have an apic, and this
actually takes less code.
The helpers for the architecture specific code are declared in the linux/msi.h
to keep them separate from the msi functions used by drivers in linux/pci.h
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tony Luck <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] msi: only use a single irq_chip for msi interrupts
The logic works like this.
Since we no longer track the state logic by hand in msi.c startup and shutdown
are no longer needed.
By updating msi_set_mask_bit to work on msi devices that do not implement a
mask bit we can always call the mask/unmask functions.
What we really have are mask and unmask so we use them to implement the .mask
and .unmask functions instead of .enable and .disable.
By switching to the handle_edge_irq handler we only need an ack function that
moves the irq if necessary. Which removes the old end and ack functions and
their peculiar logic of sometimes disabling an irq.
This removes the reliance on pre genirq irq handling methods.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tony Luck <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] msi: simplify msi sanity checks by adding with generic irq code
Currently msi.c is doing sanity checks that make certain before an irq is
destroyed it has no more users.
By adding irq_has_action I can perform the test is a generic way, instead of
relying on a msi specific data structure.
By performing the core check in dynamic_irq_cleanup I ensure every user of
dynamic irqs has a test present and we don't free resources that are in use.
In msi.c this allows me to kill the attrib.state member of msi_desc and all of
the assciated code to maintain it.
To keep from freeing data structures when irq cleanup code is called to soon
changing dyanamic_irq_cleanup is insufficient because there are msi specific
data structures that are also not safe to free.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tony Luck <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg KH <greg@kroah.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] Initial generic hypertransport interrupt support
This patch implements two functions ht_create_irq and ht_destroy_irq for
use by drivers. Several other functions are implemented as helpers for
arch specific irq_chip handlers.
The driver for the card I tested this on isn't yet ready to be merged.
However this code is and hypertransport irqs are in use in a few other
places in the kernel. Not that any of this will get merged before 2.6.19
Because the ipath-ht400 is slightly out of spec this code will need to be
generalized to work there.
I think all of the powerpc uses are for a plain interrupt controller in a
chipset so support for native hypertransport devices is a little less
interesting.
However I think this is a half way decent model on how to separate arch
specific and generic helper code, and I think this is a functional model of
how to get the architecture dependencies out of the msi code.
[akpm@osdl.org: Kconfig fix] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg KH <greg@kroah.com> Cc: Andi Kleen <ak@muc.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: x86_64 irq: make vector_irq per cpu
This refactors the irq handling code to make the vectors a per cpu resource so
the same vector number can be simultaneously used on multiple cpus for
different irqs.
This should make systems that were hitting limits on the total number of irqs
much more livable.
[akpm@osdl.org: build fix]
[akpm@osdl.org: __target_IO_APIC_irq is unneeded on UP] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: x86_64 irq: Make the external irq handlers report their vector, not the irq number
This is a small pessimization but it paves the way for making this information
per cpu. Which allows the the maximum number of IRQS to become NR_CPUS*224.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: irq: generalize the check for HARDIRQ_BITS
This patch adds support for systems that cannot receive every interrupt on a
single cpu simultaneously, in the check to see if we have enough HARDIRQ_BITS.
MAX_HARDIRQS_PER_CPU becomes the count of the maximum number of hardare
generated interrupts per cpu.
On architectures that support per cpu interrupt delivery this can be a
significant space savings and scalability bonus.
This patch adds support for systems that cannot receive every interrupt on
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Because of the nasty way that CONFIG_PCI_MSI was implemented we wound up with
set_irq_info and set_native_irq_info, with move_irq and move_native_irq. Both
functions did the same thing but they were built and called under different
circumstances. Now that the msi hacks are gone we can kill move_irq and
set_irq_info.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: i386 irq: Remove the msi assumption that irq == vector
This patch removes the change in behavior of the irq allocation code when
CONFIG_PCI_MSI is defined. Removing all instances of the assumption that irq
== vector.
create_irq is rewritten to first allocate a free irq and then to assign that
irq a vector.
assign_irq_vector is made static and the AUTO_ASSIGN case which allocates an
vector not bound to an irq is removed.
The ioapic vector methods are removed, and everything now works with irqs.
The definition of NR_IRQS no longer depends on CONFIG_PCI_MSI
[akpm@osdl.org: cleanup] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: x86_64 irq: Remove the msi assumption that irq == vector
This patch removes the change in behavior of the irq allocation code when
CONFIG_PCI_MSI is defined. Removing all instances of the assumption that irq
== vector.
create_irq is rewritten to first allocate a free irq and then to assign that
irq a vector.
assign_irq_vector is made static and the AUTO_ASSIGN case which allocates an
vector not bound to an irq is removed.
The ioapic vector methods are removed, and everything now works with irqs.
The definition of NR_IRQS no longer depends on CONFIG_PCI_MSI
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: i386 irq: Move msi message composition into io_apic.c
This removes the hardcoded assumption that irq == vector in the msi
composition code, and it allows the msi message composition to setup logical
mode, or lowest priorirty delivery mode as we do for other apic interrupts,
and with the same selection criteria.
Basically this moves the problem of what is in the msi message into the
architecture irq management code where it belongs. Not in a generic layer
that doesn't have enough information to compose msi messages properly.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: x86_64 irq: Move msi message composition into io_apic.c
This removes the hardcoded assumption that irq == vector in the msi
composition code, and it allows the msi message composition to setup logical
mode, or lowest priorirty delivery mode as we do for other apic interrupts,
and with the same selection criteria.
Basically this moves the problem of what is in the msi message into the
architecture irq management code where it belongs. Not in a generic layer
that doesn't have enough information to compose msi messages properly.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: msi: make the msi code irq based and not vector based
The msi currently allocates irqs backwards. First it allocates a platform
dependent routing value for an interrupt the ``vector'' and then it figures
out from the vector which irq you are on.
For ia64 this is fine. For x86 and x86_64 this is complete nonsense and makes
an enourmous mess of the irq handling code and prevents some pretty
significant cleanups in the code for handling large numbers of irqs.
This patch refactors msi.c to work in terms of irqs and create_irq/destroy_irq
for dynamically managing irqs.
Hopefully this is finally a version of msi.c that is useful on more than just
x86 derivatives.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The current implementation of create_irq() is a hack but it is the current
hack that msi.c uses, and unfortunately the ``generic'' apic msi ops depend on
this hack. Thus we are this hack of assuming irq == vector until the
depencencies in the generic irq code are removed.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The current implementation of create_irq() is a hack but it is the current
hack that msi.c uses, and unfortunately the ``generic'' apic msi ops depend on
this hack. Thus we are stuck this hack of assuming irq == vector until the
depencencies in the generic msi code are removed.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: irq: add a dynamic irq creation API
With the msi support comes a new concept in irq handling, irqs that are
created dynamically at run time.
Currently the msi code allocates irqs backwards. First it allocates a
platform dependent routing value for an interrupt the ``vector'' and then it
figures out from the vector which irq you are on.
This msi backwards allocator suffers from two basic problems. The allocator
suffers because it is trying to do something that is architecture specific in
a generic way making it brittle, inflexible, and tied to tightly to the
architecture implementation. The alloctor also suffers from it's very
backwards nature as it has tied things together that should have no
dependencies.
To solve the basic dynamic irq allocation problem two new architecture
specific functions are added: create_irq and destroy_irq.
create_irq takes no input and returns an unused irq number, that won't be
reused until it is returned to the free poll with destroy_irq. The irq then
can be used for any purpose although the only initial consumer is the msi
code.
destroy_irq takes an irq number allocated with create_irq and returns it to
the free pool.
Making this functionality per architecture increases the simplicity of the irq
allocation code and increases it's flexibility.
dynamic_irq_init() and dynamic_irq_cleanup() are added to automate the
irq_desc initializtion that should happen for dynamic irqs.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: msi: simplify the msi irq limit policy
Currently we attempt to predict how many irqs we will be able to allocate with
msi using pci_vector_resources and some complicated accounting, and then we
only allow each device as many irqs as we think are available on average.
Only the s2io driver even takes advantage of this feature all other drivers
have a fixed number of irqs they need and bail if they can't get them.
pci_vector_resources is inaccurate if anyone ever frees an irq. The whole
implmentation is racy. The current irq limit policy does not appear to make
sense with current drivers. So I have simplified things. We can revisit this
we we need a more sophisticated policy.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The current msi_ops are short sighted in a number of ways, this patch attempts
to fix the glaring deficiences.
- Report in msi_ops if a 64bit address is needed in the msi message, so we
can fail 32bit only msi structures.
- Send and receive a full struct msi_msg in both setup and target. This is
a little cleaner and allows for architectures that need to modify the data
to retarget the msi interrupt to a different cpu.
- In target pass in the full cpu mask instead of just the first cpu in case
we can make use of the full cpu mask.
- Operate in terms of irqs and not vectors, currently there is still a 1-1
relationship but on architectures other than ia64 I expect this will change.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: msi: implement helper functions read_msi_msg and write_msi_msg
In support of this I also add a struct msi_msg that captures the the two
address and one data field ina typical msi message, and I remember the pos and
if the address is 64bit in struct msi_desc.
This makes the code a little more readable and easier to maintain, and paves
the way to further simplfications.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: msi: make the msi boolean tests return either 0 or 1
This allows the output of the msi tests to be stored directly in a bit field.
If you don't do this a value greater than one will be truncated and become 0.
Changing true to false with bizare consequences.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: msi: simplify msi enable and disable
The problem. Because the disable routines leave the msi interrupts in all
sorts of half enabled states the enable routines become impossible to
implement correctly, and almost impossible to understand.
Simplifing this allows me to simply kill the buggy reroute_msix_table, and
generally makes the code more maintainable.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Rajesh Shah <rajesh.shah@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: x86_64 irq: Reenable migrating irqs to other cpus
In the latest changes the code for migrating x86_64 irqs was dropped. This
reads it in a fashion that will work even if we change the vector on level
triggered irqs when we migrate them.
[akpm@osdl.org: build fix] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently move_native_irq disables and renables the irq we are migrating to
ensure we don't take that irq when we are actually doing the migration
operation. Disabling the irq needs to happen but sometimes doing the work is
move_native_irq is too late.
On x86 with ioapics the irq move sequences needs to be:
edge_triggered:
mask irq.
move irq.
unmask irq.
ack irq.
level_triggered:
mask irq.
ack irq.
move irq.
unmask irq.
We can easily perform the edge triggered sequence, with the current defintion
of move_native_irq. However the level triggered case does not map well. For
that I have added move_masked_irq, to allow me to disable the irqs around both
the ack and the move.
Q: Why have we not seen this problem earlier?
A: The only symptom I have been able to reproduce is that if we change
the vector before acknowleding an irq the wrong irq is acknowledged.
Since we currently are not reprogramming the irq vector during
migration no problems show up.
We have to mask the irq before we acknowledge the irq or else we could
hit a window where an irq is asserted just before we acknowledge it.
Edge triggered irqs do not have this problem because acknowledgements
do not propogate in the same way.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] genirq: irq: convert the move_irq flag from a 32bit word to a single bit
The primary aim of this patchset is to remove maintenances problems caused by
the irq infrastructure. The two big issues I address are an artificially
small cap on the number of irqs, and that MSI assumes vector == irq. My
primary focus is on x86_64 but I have touched other architectures where
necessary to keep them from breaking.
- To increase the number of irqs I modify the code to look at the (cpu,
vector) pair instead of just looking at the vector.
With a large number of irqs available systems with a large irq count no
longer need to compress their irq numbers to fit. Removing a lot of brittle
special cases.
For acpi guys the result is that irq == gsi.
- Addressing the fact that MSI assumes irq == vector takes a few more
patches. But suffice it to say when I am done none of the generic irq code
even knows what a vector is.
In quick testing on a large Unisys x86_64 machine we stumbled over at least
one driver that assumed that NR_IRQS could always fit into an 8 bit number.
This driver is clearly buggy today. But this has become a class of bugs that
it is now much easier to hit.
This patch:
This is a minor space optimization. In practice I don't think this has any
affect because of our alignment constraints and the other fields but there is
not point in chewing up an uncessary word and since we already read the flag
field this should improve the cache hit ratio of the irq handler.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Rajesh Shah <rajesh.shah@intel.com> Cc: Andi Kleen <ak@muc.de> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ingo Molnar [Wed, 4 Oct 2006 09:16:26 +0000 (02:16 -0700)]
[PATCH] genirq: convert the i386 architecture to irq-chips
This patch converts all the i386 PIC controllers (except VisWS and Voyager,
which I could not test - but which should still work as old-style IRQ layers)
to the new and simpler irq-chip interrupt handling layer.
[akpm@osdl.org: build fix]
[mingo@elte.hu: enable fasteoi handler for i386 level-triggered IO-APIC irqs] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ingo Molnar [Wed, 4 Oct 2006 09:16:25 +0000 (02:16 -0700)]
[PATCH] genirq: convert the x86_64 architecture to irq-chips
This patch converts all the x86_64 PIC controllers layers to the new and
simpler irq-chip interrupt handling layer.
[mingo@elte.hu: The patch also enables the fasteoi handler for x86_64] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Roland Dreier <rolandd@cisco.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Andrew Morton [Wed, 4 Oct 2006 09:16:24 +0000 (02:16 -0700)]
[PATCH] fbdev: riva warning fix
drivers/video/riva/fbdev.c: In function `riva_get_EDID_OF':
drivers/video/riva/fbdev.c:1846: warning: assignment discards qualifiers from pointer target type
This code is being bad: copying a pointer to read-only OF data into a
non-const pointer.
Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Michael Halcrow [Wed, 4 Oct 2006 09:16:22 +0000 (02:16 -0700)]
[PATCH] ecryptfs: fs/Makefile and fs/Kconfig
eCryptfs is a stacked cryptographic filesystem for Linux. It is derived from
Erez Zadok's Cryptfs, implemented through the FiST framework for generating
stacked filesystems. eCryptfs extends Cryptfs to provide advanced key
management and policy features. eCryptfs stores cryptographic metadata in the
header of each file written, so that encrypted files can be copied between
hosts; the file will be decryptable with the proper key, and there is no need
to keep track of any additional information aside from what is already in the
encrypted file itself.
[akpm@osdl.org: updates for ongoing API changes]
[bunk@stusta.de: cleanups]
[akpm@osdl.org: alpha build fix]
[akpm@osdl.org: cleanups]
[tytso@mit.edu: inode-diet updates]
[pbadari@us.ibm.com: generic_file_*_read/write() interface updates]
[rdunlap@xenotime.net: printk format fixes]
[akpm@osdl.org: make slab creation and teardown table-driven] Signed-off-by: Phillip Hellewell <phillip@hellewell.homeip.net> Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] Fix linux/nfsd/const.h for make headers_check
make headers_check fails on linux/nfsd/const.h.
Since linux/sunrpc/msg_prot.h does not seem to export anything interesting
for userspace, this patch moves it in the __KERNEL__ protected section.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:20 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd4: actually use all the pieces to implement referrals
Use all the pieces set up so far to implement referral support, allowing
return of NFS4ERR_MOVED and fs_locations attribute.
Signed-off-by: Manoj Naik <manoj@almaden.ibm.com> Signed-off-by: Fred Isaman <iisaman@citi.umich.edu> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:19 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd4: xdr encoding for fs_locations
Encode fs_locations attribute.
Signed-off-by: Manoj Naik <manoj@almaden.ibm.com> Signed-off-by: Fred Isaman <iisaman@citi.umich.edu> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Manoj Naik [Wed, 4 Oct 2006 09:16:18 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd4: fslocations data structures
Define FS locations structures, some functions to manipulate them, and add
code to parse FS locations in downcall and add to the exports structure.
[bfields@fieldses.org: bunch of fixes and cleanups] Signed-off-by: Manoj Naik <manoj@almaden.ibm.com> Signed-off-by: Fred Isaman <iisaman@citi.umich.edu> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:17 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd: store export path in export
Store the export path in the svc_export structure instead of storing only the
dentry. This will prevent the need for additional d_path calls to provide
NFSv4 fs_locations support.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Wed, 4 Oct 2006 09:16:16 +0000 (02:16 -0700)]
[PATCH] knfsd: close a race-opportunity in d_splice_alias
There is a possible race in d_splice_alias. Though __d_find_alias(inode, 1)
will only return a dentry with DCACHE_DISCONNECTED set, it is possible for it
to get cleared before the BUG_ON, and it is is not possible to lock against
that.
There are a couple of problems here. Firstly, the code doesn't match the
comment. The comment describes a 'disconnected' dentry as being IS_ROOT as
well as DCACHE_DISCONNECTED, however there is not testing of IS_ROOT anythere.
A dentry is marked DCACHE_DISCONNECTED when allocated with d_alloc_anon, and
remains DCACHE_DISCONNECTED while a path is built up towards the root. So a
dentry can have a valid name and a valid parent and even grandparent, but will
still be DCACHE_DISCONNECTED until a path to the root is created. Once the
path to the root is complete, everything in the path gets DCACHE_DISCONNECTED
cleared. So the fact that DCACHE_DISCONNECTED isn't enough to say that a
dentry is free to be spliced in with a given name. This can only be allowed
if the dentry does not yet have a name, so the IS_ROOT test is needed too.
However even adding that test to __d_find_alias isn't enough. As
d_splice_alias drops dcache_lock before calling d_move to perform the splice,
it could race with another thread calling d_splice_alias to splice the inode
in with a different name in a different part of the tree (in the case where a
file has hard links). So that splicing code is only really safe for
directories (as we know that directories only have one link). For
directories, the caller of d_splice_alias will be holding i_mutex on the
(unique) parent so there is no room for a race.
A consequence of this is that a non-directory will never benefit from being
spliced into a pre-exisiting dentry, but that isn't a problem. It is
perfectly OK for a non-directory to have multiple dentries, some anonymous,
some not. And the comment for d_splice_alias says that it only happens for
directories anyway.
Signed-off-by: Neil Brown <neilb@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Wed, 4 Oct 2006 09:16:15 +0000 (02:16 -0700)]
[PATCH] knfsd: fix auto-sizing of nfsd request/reply buffers
totalram is measured in pages, not bytes, so PAGE_SHIFT must be used when
trying to find 1/4096 of RAM.
Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:14 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd4: acls: fix handling of zero-length acls
It is legal to have zero-length NFSv4 acls; they just deny everything.
Also, nfs4_acl_nfsv4_to_posix will always return with pacl and dpacl set on
success, so the caller doesn't need to check this.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There's no need to handle the case where the caller passes in null for pacl or
dpacl; no caller does that, because it would be a dumb thing to do.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:12 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd4: acls: fix inheritance
We can be a little more flexible about the flags allowed for inheritance (in
particular, we can deal with either the presence or the absence of
INHERIT_ONLY), but we should probably reject other combinations that we don't
understand.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:11 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd4: acls: relax the nfsv4->posix mapping
Use a different nfsv4->(draft posix) acl mapping which is
1. completely backwards compatible,
2. accepts any nfsv4 acl, and
3. errs on the side of restricting permissions.
In detail:
1. completely backwards compatible: The new mapping produces the
same result on any acl produced by the existing (draft
posix)->nfsv4 mapping; the one exception is that we no longer
attempt to guess the value of the mask by assuming certain denies
represent the mask. Since the server still keeps track of the mask
locally, sequences of chmod's will still be handled fine; the only
thing this will change is sequences of chmod's with intervening
read-modify-writes of the acl. That last case just isn't worth the
trouble and the possible misrepresentations of the user's intent
(if we guess that a certain deny indicates masking is in effect
when it really isn't).
2. accepts any nfsv4 acl: That's not quite true: we still reject
acls that use combinations of inheritance flags that we don't
support. We also reject acls that attempt to explicitly deny
read_acl or read_attributes permissions, or that attempt to deny
write_acl or write_attributes permissions to the owner of the file.
3. errs on the side of restricting permissions: one exception to
this last rule: we totally ignore some bits (write_owner,
synchronize, read_named_attributes, etc.) that are completely alien
to our filesystem semantics, in some cases even if that would mean
ignoring an explicit deny that we have no intention of enforcing.
Excepting that, the posix acl produced should be the most
permissive acl that is not more permissive than the given nfsv4
acl.
And the new code's shorter, too. Neato.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:10 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd4: clean up exp_pseudoroot
The previous patch enables some minor simplification here.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:09 +0000 (02:16 -0700)]
[PATCH] knfsd: nfsd4: refactor exp_pseudoroot
We could be using more common code in exp_pseudoroot(). This will also
simplify some changes we need to make later.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:08 +0000 (02:16 -0700)]
[PATCH] knfsd: svcrpc: use consistent variable name for the reply state
The rpc reply has multiple levels of error returns. The code here contributes
to the confusion by using "accept_statp" for a pointer to what the rfc (and
wireshark, etc.) refer to as the "reply_stat". (The confusion is compounded
by the fact that the rfc also has an "accept_stat" which follows the
reply_stat in the succesful case.)
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:07 +0000 (02:16 -0700)]
[PATCH] knfsd: svcrpc: gss: fix failure on SVC_DENIED in integrity case
If the request is denied after gss_accept was called, we shouldn't try to wrap
the reply. We were checking the accept_stat but not the reply_stat.
To check the reply_stat in _release, we need a pointer to before (rather than
after) the verifier, so modify body_start appropriately.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
J.Bruce Fields [Wed, 4 Oct 2006 09:16:06 +0000 (02:16 -0700)]
[PATCH] knfsd: svcrpc: gss: factor out some common wrapping code
Factor out some common code from the integrity and privacy cases.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Neil Brown [Wed, 4 Oct 2006 09:16:06 +0000 (02:16 -0700)]
[PATCH] Convert lockd to use the newer mutex instead of the older semaphore
Both the (recently introduces) nsm_sema and the older f_sema are converted
over.
Cc: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:16:05 +0000 (02:16 -0700)]
[PATCH] knfsd: register all RPC programs with portmapper by default
The NFSACL patches introduced support for multiple RPC services listening on
the same transport. However, only the first of these services was registered
with portmapper. This was perfectly fine for nfsacl, as you traditionally do
not want these to show up in a portmapper listing.
The patch below changes the default behavior to always register all services
listening on a given transport, but retains the old behavior for nfsacl
services.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:16:04 +0000 (02:16 -0700)]
[PATCH] knfsd: lockd: fix use of h_nextrebind
nlmclnt_recovery would try to force a portmap rebind by setting
host->h_nextrebind to 0. The right thing to do here is to set it to the
current time.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:16:03 +0000 (02:16 -0700)]
[PATCH] knfsd: export nsm_local_state to user space via sysctl
Every NLM call includes the client's NSM state. Currently, the Linux client
always reports 0 - which seems not to cause any problems, but is not what the
protocol says.
This patch exposes the kernel's internal variable to user space via a sysctl,
which can be set at system boot time by statd.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:16:03 +0000 (02:16 -0700)]
[PATCH] knfsd: match GRANTED_RES replies using cookies
When we send a GRANTED_MSG call, we current copy the NLM cookie provided in
the original LOCK call - because in 1996, some broken clients seemed to rely
on this bug. However, this means the cookies are not unique, so that when the
client's GRANTED_RES message comes back, we cannot simply match it based on
the cookie, but have to use the client's IP address in addition. Which breaks
when you have a multi-homed NFS client.
The X/Open spec explicitly mentions that clients should not expect the same
cookie; so one may hope that any clients that were broken in 1996 have either
been fixed or rendered obsolete.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:16:02 +0000 (02:16 -0700)]
[PATCH] knfsd: make nlmclnt_next_cookie SMP safe
The way we incremented the NLM cookie in nlmclnt_next_cookie was not thread
safe. This patch changes the counter to an atomic_t
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:16:01 +0000 (02:16 -0700)]
[PATCH] knfsd: lockd: optionally use hostnames for identifying peers
This patch adds the nsm_use_hostnames sysctl and module param. If set, lockd
will use the client's name (as given in the NLM arguments) to find the NSM
handle. This makes recovery work when the NFS peer is multi-homed, and the
reboot notification arrives from a different IP than the original lock calls.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Wed, 4 Oct 2006 09:16:00 +0000 (02:16 -0700)]
[PATCH] knfsd: simplify nlmsvc_invalidate_all
As a result of previous patches, the loop in nlmsvc_invalidate_all just sets
h_expires for all client/hosts to 0 (though does it in a very complicated
way).
This was possibly meant to trigger early garbage collection but half the time
'0' is in the future and so it infact delays garbage collection.
Pre-aging the 'hosts' is not really needed at this point anyway so we throw
out the loop and nlm_find_client which is no longer needed.
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:16:00 +0000 (02:16 -0700)]
[PATCH] knfsd: lockd: Add nlm_destroy_host
This patch moves the host destruction code out of nlm_host_gc into a function
of its own.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:59 +0000 (02:15 -0700)]
[PATCH] knfsd: lockd: make nlm_traverse_* more flexible
This patch makes nlm_traverse{locks,blocks,shares} and friends use a function
pointer rather than a "action" enum.
This function pointer is given two nlm_hosts (one given by the caller, the
other taken from the lock/block/share currently visited), and is free to do
with them as it wants. If it returns a non-zero value, the lockd/block/share
is released.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:58 +0000 (02:15 -0700)]
[PATCH] knfsd: change nlm_file to use a hlist
This changes struct nlm_file and the nlm_files hash table to use a hlist
instead of the home-grown lists.
This allows us to remove f_hash which was only used to find the right hash
chain to delete an entry from.
It also increases the size of the nlm_files hash table from 32 to 128.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:57 +0000 (02:15 -0700)]
[PATCH] knfsd: lockd: Change list of blocked list to list_node
This patch changes the nlm_blocked list to use a list_node instead of
homegrown linked list handling.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:56 +0000 (02:15 -0700)]
[PATCH] knfsd: lockd: make the hash chains use a hlist_node
Get rid of the home-grown singly linked lists for the nlm_host hash table.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:56 +0000 (02:15 -0700)]
[PATCH] knfsd: lockd: make the nsm upcalls use the nsm_handle
This converts the statd upcalls to use the nsm_handle
This means that we only register each host once with statd, rather than
registering each host/vers/protocol triple.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:55 +0000 (02:15 -0700)]
[PATCH] knfsd: lockd: Make nlm_host_rebooted use the nsm_handle
This patch makes the SM_NOTIFY handling understand and use the nsm_handle.
To make it a bit clear what is happening:
nlmclent_prepare_reclaim and nlmclnt_finish_reclaim
get open-coded into 'reclaimer'
The result is tidied up.
Then some of that functionality is moved out into nlm_host_rebooted (which
calls nlmclnt_recovery which starts a thread which runs reclaimer).
Also host_rebooted now finds an nsm_handle rather than a host, then then
iterates over all hosts and deals with each host that shares that nsm_handle.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:54 +0000 (02:15 -0700)]
[PATCH] knfsd: misc minor fixes, indentation changes
cleans up some code in lockd/host.c, fixes an error printk and makes it a
fatal BUG if nlmsvc_free_host_resources fails.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:53 +0000 (02:15 -0700)]
[PATCH] knfsd: lockd: introduce nsm_handle
This patch introduces the nsm_handle, which is shared by all nlm_host objects
referring to the same client.
With this patch applied, all nlm_hosts from the same address will share the
same nsm_handle. A future patch will add sharing by name.
Note: this patch changes h_name so that it is no longer guaranteed to be an IP
address of the host. When the host represents an NFS server, h_name will be
the name passed in the mount call. When the host represents a client, h_name
will be the name presented in the lock request received from the client. A
h_name is only used for printing informational messages, this change should
not be significant.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:52 +0000 (02:15 -0700)]
[PATCH] knfsd: when looking up a lockd host, pass hostname & length
This patch adds the peer's hostname (and name length) to all calls to
nlm*_lookup_host functions. A subsequent patch will make use of these (is
requested by a sysctl).
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:52 +0000 (02:15 -0700)]
[PATCH] knfsd: consolidate common code for statd->lockd notification
Common code from nlm4svc_proc_sm_notify and nlmsvc_proc_sm_notify is moved
into a new nlm_host_rebooted.
This is in preparation of a patch that will change the reboot notification
handling entirely.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Olaf Kirch [Wed, 4 Oct 2006 09:15:51 +0000 (02:15 -0700)]
[PATCH] knfsd: hide use of lockd's h_monitored flag
This patch moves all checks of the h_monitored flag into the
nsm_monitor/unmonitor functions. A subsequent patch will replace the
mechanism by which we mark a host as being monitored.
There is still one occurence of h_monitored outside of mon.c and that is in
clntlock.c where we respond to a reboot. The subsequent patch will modify
this too.
Signed-off-by: Olaf Kirch <okir@suse.de> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Greg Banks [Wed, 4 Oct 2006 09:15:50 +0000 (02:15 -0700)]
[PATCH] knfsd: knfsd: cache ipmap per TCP socket
Speed up high call-rate workloads by caching the struct ip_map for the peer on
the connected struct svc_sock instead of looking it up in the ip_map cache
hashtable on every call. This helps workloads using AUTH_SYS authentication
over TCP.
Testing was on a 4 CPU 4 NIC Altix using 4 IRIX clients, each with 16
synthetic client threads simulating an rsync (i.e. recursive directory
listing) workload reading from an i386 RH9 install image (161480 regular files
in 10841 directories) on the server. That tree is small enough to fill in the
server's RAM so no disk traffic was involved. This setup gives a sustained
call rate in excess of 60000 calls/sec before being CPU-bound on the server.
Profiling showed strcmp(), called from ip_map_match(), was taking 4.8% of each
CPU, and ip_map_lookup() was taking 2.9%. This patch drops both contribution
into the profile noise.
Note that the above result overstates this value of this patch for most
workloads. The synthetic clients are all using separate IP addresses, so
there are 64 entries in the ip_map cache hash. Because the kernel measured
contained the bug fixed in commit
and was running on 64bit little-endian machine, probably all of those 64
entries were on a single chain, thus increasing the cost of ip_map_lookup().
With a modern kernel you would need more clients to see the same amount of
performance improvement. This patch has helped to scale knfsd to handle a
deployment with 2000 NFS clients.
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Greg Banks [Wed, 4 Oct 2006 09:15:49 +0000 (02:15 -0700)]
[PATCH] knfsd: make nfsd readahead params cache SMP-friendly
Make the nfsd read-ahead params cache more SMP-friendly by changing the single
global list and lock into a fixed 16-bucket hashtable with per-bucket locks.
This reduces spinlock contention in nfsd_read() on read-heavy workloads on
multiprocessor servers.
Testing was on a 4 CPU 4 NIC Altix using 4 IRIX clients each doing 1K
streaming reads at full line rate. The server had 128 nfsd threads, which
sizes the RA cache at 256 entries, of which only a handful were used. Flat
profiling shows nfsd_read(), including the inlined nfsd_get_raparms(), taking
10.4% of each CPU. This patch drops the contribution from nfsd() to 1.71% for
each CPU.
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Wed, 4 Oct 2006 09:15:48 +0000 (02:15 -0700)]
[PATCH] knfsd: Allow max size of NFSd payload to be configured
The max possible is the maximum RPC payload. The default depends on amount of
total memory.
The value can be set within reason as long as no nfsd threads are currently
running. The value can also be ready, allowing the default to be determined
after nfsd has started.
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Greg Banks [Wed, 4 Oct 2006 09:15:47 +0000 (02:15 -0700)]
[PATCH] knfsd: Prepare knfsd for support of rsize/wsize of up to 1MB, over TCP
The limit over UDP remains at 32K. Also, make some of the apparently
arbitrary sizing constants clearer.
The biggest change here involves replacing NFSSVC_MAXBLKSIZE by a function of
the rqstp. This allows it to be different for different protocols (udp/tcp)
and also allows it to depend on the servers declared sv_bufsiz.
Note that we don't actually increase sv_bufsz for nfs yet. That comes next.
Signed-off-by: Greg Banks <gnb@melbourne.sgi.com> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Wed, 4 Oct 2006 09:15:47 +0000 (02:15 -0700)]
[PATCH] knfsd: Avoid excess stack usage in svc_tcp_recvfrom
.. by allocating the array of 'kvec' in 'struct svc_rqst'.
As we plan to increase RPCSVC_MAXPAGES from 8 upto 256, we can no longer
allocate an array of this size on the stack. So we allocate it in 'struct
svc_rqst'.
However svc_rqst contains (indirectly) an array of the same type and size
(actually several, but they are in a union). So rather than waste space, we
move those arrays out of the separately allocated union and into svc_rqst to
share with the kvec moved out of svc_tcp_recvfrom (various arrays are used at
different times, so there is no conflict).
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Wed, 4 Oct 2006 09:15:46 +0000 (02:15 -0700)]
[PATCH] knfsd: Replace two page lists in struct svc_rqst with one
We are planning to increase RPCSVC_MAXPAGES from about 8 to about 256. This
means we need to be a bit careful about arrays of size RPCSVC_MAXPAGES.
struct svc_rqst contains two such arrays. However the there are never more
that RPCSVC_MAXPAGES pages in the two arrays together, so only one array is
needed.
The two arrays are for the pages holding the request, and the pages holding
the reply. Instead of two arrays, we can simply keep an index into where the
first reply page is.
This patch also removes a number of small inline functions that probably
server to obscure what is going on rather than clarify it, and opencode the
needed functionality.
Also remove the 'rq_restailpage' variable as it is *always* 0. i.e. if the
response 'xdr' structure has a non-empty tail it is always in the same pages
as the head.
check counters are initilised and incr properly
check for consistant usage of ++ etc
maybe extra some inlines for common approach
general review
Signed-off-by: Neil Brown <neilb@suse.de> Cc: Magnus Maatta <novell@kiruna.se> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Wed, 4 Oct 2006 09:15:45 +0000 (02:15 -0700)]
[PATCH] knfsd: Fixed handling of lockd fail when adding nfsd socket
Arrgg.. We cannot 'lockd_up' before 'svc_addsock' as we don't know the
protocol yet.... So switch it around again and save the name of the created
sockets so that it can be closed if lock_up fails.
Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
NeilBrown [Wed, 4 Oct 2006 09:15:44 +0000 (02:15 -0700)]
[PATCH] knfsd: call lockd_down when closing a socket via a write to nfsd/portlist
The refcount that nfsd holds on lockd is based on the number of open sockets.
So when we close a socket, we should decrement the ref (with lockd_down).
Currently when a socket is closed via writing to the portlist file, that
doesn't happen.
So: make sure we get an error return if the socket that was requested does is
not found, and call lockd_down if it was.
Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Pierre Ossman [Wed, 4 Oct 2006 09:15:41 +0000 (02:15 -0700)]
[PATCH] mmc: properly use the new multi block-write error handling
Use the new multi block-write error reporting flag and properly tell the block
layer how much data was transferred before the error.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Pierre Ossman [Wed, 4 Oct 2006 09:15:41 +0000 (02:15 -0700)]
[PATCH] mmc: use own work queue
The MMC layer uses the standard work queue for doing card detection. As this
queue is shared with other crucial subsystems, the effects of a long (and
perhaps buggy) detection can cause the system to be unusable. E.g. the
keyboard stops working while the detection routine is running.
The solution is to add a specific mmc work queue to run the detection code in.
This is similar to how other subsystems handle detection (a full kernel
thread is the most common theme).
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Pierre Ossman [Wed, 4 Oct 2006 09:15:40 +0000 (02:15 -0700)]
[PATCH] mmc: avoid some resets without card
Some Ricoh controllers only respect a full reset when there is no card in the
slot. As we wait for the reset to complete, we must avoid even requesting
those resets on the buggy controllers.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Pierre Ossman [Wed, 4 Oct 2006 09:15:39 +0000 (02:15 -0700)]
[PATCH] mmc: fix MMIO vs memory races in sdhci
Sprinkle some mmiowb() where needed (writeX() before unlock()).
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Alex Dubov [Wed, 4 Oct 2006 09:15:38 +0000 (02:15 -0700)]
[PATCH] mmc: driver for TI FlashMedia card reader - Kconfig/Makefile
Signed-off-by: Alex Dubov <oakad@yahoo.com> Cc: Daniel Qarras <dqarras@yahoo.com> Acked-by: Pierre Ossman <drzeus@drzeus.cx> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Alex Dubov [Wed, 4 Oct 2006 09:15:37 +0000 (02:15 -0700)]
[PATCH] mmc: driver for TI FlashMedia card reader - source
Driver for TI Flash Media card reader. At present, only MMC/SD cards are
supported.
[akpm@osdl.org: cleanups, build fixes] Signed-off-by: Alex Dubov <oakad@yahoo.com> Cc: Daniel Qarras <dqarras@yahoo.com> Acked-by: Pierre Ossman <drzeus@drzeus.cx> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Thanks alexander.krause@erazor-zone.de, dzpost@dedekind.net, for the
reports and patch test, and phelps@mantara.com for the independent patch
and verification.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Cc: <alexander.krause@erazor-zone.de> Cc: <dzpost@dedekind.net> Cc: <phelps@mantara.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Kenji Kaneshige [Wed, 4 Oct 2006 09:15:34 +0000 (02:15 -0700)]
[PATCH] fix "PCI: assign ioapic resource at hotplug"
Roland Dreier wrote:
> The change "PCI: assign ioapic resource at hotplug" (commit
> 23186279658cea6d42a050400d3e79c56cb459b4 in Linus's tree) makes
> networking stop working on my system (SuperMicro H8QC8 with four
> dual-core Opteron 885 CPUs). In particular, the on-board NIC stops
> working, probably because it gets assigned the wrong IRQ (225 in the
> non-working case, 217 in the working case)
>
> With that patch applied, e1000 doesn't work. Reverting just that
> patch (shown below) from Linus's latest tree fixes things for me.
>
The cause of this problem might be an wrong assumption that the 'start'
member of resource structure for ioapic device has non-zero value if the
resources are assigned by firmware. The 'start' member of ioapic device
seems not to be set even though the resources were actually assigned to
ioapic devices by firmware.
David Gibson [Wed, 4 Oct 2006 09:15:32 +0000 (02:15 -0700)]
[PATCH] Fix spurious error on TAGS target when missing defconfig
Not all architectures have a file named 'defconfig' (e.g. powerpc).
However the make TAGS and make tags targets search such files for tags,
causing an error message when they don't exist. This patch addresses the
problem by instructing xargs not to run the tags program if there are no
matching files.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[PATCH] slab: clean up leak tracking ifdefs a little bit
- rename ____kmalloc to kmalloc_track_caller so that people have a chance
to guess what it does just from it's name. Add a comment describing it
for those who don't. Also move it after kmalloc in slab.h so people get
less confused when they are just looking for kmalloc - move things around
in slab.c a little to reduce the ifdef mess.
[penberg@cs.helsinki.fi: Fix up reversed #ifdef] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>