Use asm offsets to make sure the offset defines to struct _lowcore and
its layout don't get out of sync.
Also add a BUILD_BUG_ON() which checks that the size of the structure
is sane.
And while being at it change those sites which use odd casts to access
the current lowcore. These should use S390_lowcore instead.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Introduce the MACHINE_IS_LPAR flag for code that should only be
executed if Linux is running in an LPAR.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove a memset hack that relied on the internal layout of the
qdio_irq struct and move the per device statistics data into an own
cache line to avoid cache line bashing between the inbound and the
outbound queue tasklets. Also reduce the number of allocated queues
from 32 to 4 which is the current maximum. That saves a cache line
in struct qdio_irq.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Add counters for the number of processed SBALs. The numbers summarize
how many SBALs were processed at each queue scan and indicate the
utilization of the queue. Furthermore the number of unsuccessfull
queue scans, SBAL errors and the total number of processed
SBALs are accounted.
Also regroup struct qdio_q to move read-mostly and write-mostly data
into different cachelines.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Some parts of cio do not shift PAGE_DEFAULT_KEY correctly and end up
with an incorrect key in their data structures.
Since the default key is zero this doesn't really matter. However if
somebody would use key-controlled protection for debugging purposes
it would be quite helpful if all of this would work as expected.
Also remove a stale declaration.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
ccw_device_pm_restore: trigger subchannel event to better handle
changes to the subchannel device.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Callers of ccw_device_notify could not distinguish between a driver
who has no notifier registered and a driver who doesn't want to keep
a device after a certain event. Change this by adding proper return
codes.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Make the potentially long blocking wait_event's used by the cio
settle mechanism interruptible.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
To fetch a pending channel report word (crw) we use a kernel
thread which triggers stcrw and sleeps on a semaphore. The s390
machine check handler uses crw_handle_channel_report to handle
one crw if needed.
This patch replaces the semaphore with a waitqueue (to block the
kernel thread) and an atomic_t (to count the number of pending
requests).
By this we achieve the ability to force this thread to check for
a pending crw (independent on when it is triggered by the machine
check handler) and wait for this action to finish.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This patch introduces a proc file cio_settle. A write request to
this file is blocked until all queued cio actions are handled.
This will allow userspace to wait for pending work affecting
device availability after changing cio_ignore or the hardware
configuration.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
We used to maintain 2 singlethreaded workqueues for synchronization
and to trigger work from interrupt context. Since our latest cio
changes we only use one of these workqueues. So get rid of the
unused workqueue, rename the remaining one to "cio_work_q" and move
its ownership to the channel subsystem driver.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
If a CHPID is offline during a device shutdown the ccw_device_halt|clear
may fail and the qdio device stays in state STOPPED until the shutdown is
finished. If an interrupt occurs before the device is set to INACTIVE
the STOPPED state triggers a WARN_ON in the interrupt handler.
Prevent this WARN_ON by catching the STOPPED state in the interrupt
handler.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Inbound traffic handling may hang if next buffer to check is in
state ERROR, polling is stopped and the final check for further
available inbound buffers disregards buffers in state ERROR.
This patch includes state ERROR when checking availability of
more inbound buffers.
Cc: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Revamp the qdio performance statistics and move them from procfs to
debugfs using the seq_file interface. Since the statistics are not
intended for the general user the removal of /proc/qdio_perf should
not surprise anyone.
The per device statistics are disabled by default, writing 1 to
/<debugfs mountpoint>/qdio/<device bus ID>/statistics enables the
statistics for the given device.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Add a counter to the qdio performance statistics that indicates that no
free buffers were left in the input queue. If the counter gets increased
it means that the qdio adapter filled all available buffers and possibly
had more buffers ready but could not transmit them.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Don't write debug feature log entries for sl, slsb and sbal since these
elements can be located from the qdio_q pointer which is also logged.
* Convert WARN_ON for wrong alignment of sbal to BUG_ON.
* Remove WARN_ON's for wrong alignment of q / qib / slib since these
alignments should be guaranteed by kmem_cache_alloc alignment /
struct aligned attribute / __get_free_page.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Channel path vary is currently broken: channel paths which are varied
offline are still used by Linux. The reason for this is that:
* the path mask indicating which paths of an I/O device can be used
is reset by each internal I/O request
* the logic that checks if a path group is already in its designated
target state incorrectly interprets the result "is correctly set"
as "is correctly set and available"
Fix this by resetting the path mask only for internal I/O requests
which affect the path mask and by correcting the pgid check logic.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Memset should be given the size of the structure, not the size of the pointer.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
type T;
T *x;
expression E;
@@
memset(x, E, sizeof(
+ *
x))
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Using dev_set_drvdata prior to device_register will force the driver core
to kmalloc its private data. Since we use this for the console subchannel
lets set the drvdata before taking the subchannels spinlock.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
If we detect a busy subchannel after the driver's set_offline
callback returned in ccw_device_set_offline, the current behavior
is to unregister the device, which may lead to undesired
consequences. Change this to just quiesce the subchannel and go on
with the offline processing.
Note: This is no excuse for not fixing these drivers -
after the set_offline callback they should have no running IO!
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Improve error recovery for internal I/Os by repeating each I/O
256 times per path to cope with long-running non-permanent error
conditions. Also retry each path twice to cope with link flapping,
i.e. single paths becoming unavailable in the order in which they
are tried.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
IO subchannels are always unregistered in process context, so use
spin_lock_irq in the corresponding remove callback.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Ensure that there will be no more interrupts for an
unregistered device by using the same quiesce and disable loop
as in io_subchannel_shutdown.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Try to disable the old subchannel before we ask the driver core
to move the attached device to a new parent. This way we can use
the QUIESCE state during shutdown which prevents a possible use
after free situation in some error cases.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Handle a failing cio_disable_subchannel at the end of our device
recognition as if the recognition itself failed. This way
subsequent registration steps do not need to handle enabled
subchannels.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
DEV_STATE_QUIESCE is used to stop all IO on a busy subchannel.
This patch fixes the following problems related to the QUIESCE
state:
* Fix a potential race condition which could occur when the
resulting state was DEV_STATE_OFFLINE.
* Add missing locking around cio_disable_subchannel,
ccw_device_cancel_halt_clear and the cdev's handler.
* Loop until we know for sure that the subchannel is disabled.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
The function ccw_device_unregister has to ensure to remove
all references obtained by device_add and device_initialize.
Unfortunately it gets called for devices which are
1) uninitialized, 2) initialized but unregistered, and
3) registered devices. To distinguish 1) and 2) this patch
introduces a new flag "initialized", which is 1 as long as we
hold the initial device reference.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
We used to maintain a "registered" flag in our ccw_device_private
structure. This patch removes the "registered" flag and converts
all users of it to device_is_registered which has the exact same
meaning.
Note: The usage the atomic operation test_and_clear_bit is replaced
by the non-atomic if (device_is_registered()) device_del(). This
will not do harm, since we serialize calls to ccw_device_unregister
with a single-threaded workqueue.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
An Unconditional Reserve + Release operation (steal lock) for a
boxed device may fail when encountering special error cases
(e.g. unit checks or path errors). Fix this by using the more
robust ccw_request infrastructure for performing the steal lock
CCW program.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Set-pgid operations fail for some device types under z/VM for which
the hypervisor has already set the pgid. Also reserved devices or
changed pgids are not correctly recognized. Fix these problems by
using a combination of sense-pgid and set-pgid and by also accepting
pre-defined pgid settings.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Split setting (driver wants feature enabled) and status (feature
setup was successful) for PGID related ccw device features so that
setup errors can be detected. Previously, incorrectly handled setup
errors could in rare cases lead to erratic I/O behavior and
permanently unusuable devices.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
After changing all internal I/O functions to use the newly introduced
ccw request infrastructure, retries are handled automatically after a
clear operation. Therefore remove the internal retry flag and
associated code.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Accept a request for setting a not-operational device offline.
This way, users can remove devices from Linux which would otherwise
remain unusable until reboot.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Use the newly introduced ccw request infrastructure to implement
pgid related operations: sense pgid, set pgid and disband pg.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Use the newly introduced ccw request infrastructure to implement
the sense id operation.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Reduce code duplication by introducing a central infrastructure to
perform an internal I/O operation on a CCW device.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove the call to BUG() for situations which are unexpected
but do not cause actual problems.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Device recognition needs to be started with the ccw device lock
held to prevent race conditions between I/O starting and interrupt
reception.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Handle verification errors consistently through the existing
callback ccw_device_done to reduce cleanup code duplication.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Remove the return code from ccw_device_recognition and handle
recognition errors through the existing callback
ccw_device_recog_done to reduce cleanup code duplication.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Print a warning message in case a ccw device enters boxed or
not operational state during online/offline processing.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Introduce a central mechanism for performing delayed ccw device work
to ensure that different types of work do not overwrite each other.
Prioritization ensures that the most important work is always
performed while less important tasks are either obsoleted or repeated
later.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Ensure that current and future users of sch->work do not overwrite
each other by introducing a single mechanism for delayed subchannel
work.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Change the initiative to update subchannel-ccw device associations
to the subchannel: when there is an indication that the internal
association no longer reflects the current hardware state, mark
each affected subchannel as requiring attention. Once processing
reaches a subchannel, determine the correct association for that
subchannel at that time and perform the necessary device_move
operations.
This change fixes problems with the previous approach which would
leave devices in an inconsistent state when a new hardware change
occurred while a device_move was already scheduled.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
sch_create_and_recog_new_device() associates a parent subchannel
with its ccw device child even though this is already done by
the subsequently called io_subchannel_recog(). Also make sure
io_subchannel_recog() sets the association under lock.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
io_subchannel_probe() frees memory for sch->private which is later
freed again when io_subchannel_remove() is called. Fix this problem
by removing the cleanup in io_subchannel_probe().
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Allow the architecture to request a normal jiffy tick when the system
goes idle and tick_nohz_stop_sched_tick is called . On s390 the hook is
used to prevent the system going fully idle if there has been an
interrupt other than a clock comparator interrupt since the last wakeup.
On s390 the HiperSockets response time for 1 connection ping-pong goes
down from 42 to 34 microseconds. The CPU cost decreases by 27%.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
LKML-Reference: <20090929122533.402715150@de.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Heiko Carstens