When deleting an edac device, we have to wait for its edac_dev.work to be
completed before deleting the whole edac_dev structure. Since we have no
idea which work in current edac_poller's workqueue is the work we are
conerned about, we wait for all work in the edac_poller's workqueue to be
proceseed. This is done via flush_cpu_workqueue() which inserts a
wq_barrier into the tail of the workqueue and then sleeping on the
completion of this wq_barrier. The edac_poller will wake up sleepers when
it is found.
EDAC core creates only one kernel worker thread, edac_poller, to run the
works of all current edac devices. They share the same callback function
of edac_device_workq_function(), which would grab the mutex of
device_ctls_mutex first before it checks the device. This is exactly
where edac_poller and rmmod would have a great chance to deadlock.
In below call trace of rmmod > ... >
edac_device_del_device >
edac_device_workq_teardown > flush_workqueue > flush_cpu_workqueue,
device_ctls_mutex would have already been grabbed by
edac_device_del_device(). So, on one hand rmmod would sleep on the
completion of a wq_barrier, holding device_ctls_mutex; on the other hand
edac_poller would be blocked on the same mutex when it's running any one
of works of existing edac evices(Note, this edac_dev.work is likely to be
totally irrelevant to the one that is being removed right now)and never
would have a chance to run the work of above wq_barrier to wake rmmod up.
edac_device_workq_teardown() should not be called within the critical
region of device_ctls_mutex. Just like is done in edac_pci_del_device()
and edac_mc_del_mc(), where edac_pci_workq_teardown() and
edac_mc_workq_teardown() are called after related mutex are released.
Moreover, an edac_dev.work should check first if it is being removed. If
this is the case, then it should bail out immediately. Since not all of
existing edac devices are to be removed, this "shutting flag" should be
contained to edac device being removed. The current edac_dev.op_state can
be used to serve this purpose.
The original deadlock problem and the solution have been witnessed and
tested on actual hardware. Without the solution, rmmod an edac driver
would result in below deadlock:
root@localhost:/root> rmmod mv64x60_edac
EDAC DEBUG: mv64x60_dma_err_remove()
EDAC DEBUG: edac_device_del_device()
EDAC DEBUG: find_edac_device_by_dev()
(hang for a moment)
INFO: task edac-poller:2030 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
edac-poller D 00000000 0 2030 2
Call Trace:
[df159dc0] [c0071e3c] free_hot_cold_page+0x17c/0x304 (unreliable)
[df159e80] [c000a024] __switch_to+0x6c/0xa0
[df159ea0] [c03587d8] schedule+0x2f4/0x4d8
[df159f00] [c03598a8] __mutex_lock_slowpath+0xa0/0x174
[df159f40] [e1030434] edac_device_workq_function+0x28/0xd8 [edac_core]
[df159f60] [c003beb4] run_workqueue+0x114/0x218
[df159f90] [c003c674] worker_thread+0x5c/0xc8
[df159fd0] [c004106c] kthread+0x5c/0xa0
[df159ff0] [c0013538] original_kernel_thread+0x44/0x60
INFO: task rmmod:2062 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
rmmod D 0ff2c9fc 0 2062 1839
Call Trace:
[df119c00] [c0437a74] 0xc0437a74 (unreliable)
[df119cc0] [c000a024] __switch_to+0x6c/0xa0
[df119ce0] [c03587d8] schedule+0x2f4/0x4d8
[df119d40] [c03591dc] schedule_timeout+0xb0/0xf4
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 06916639e2 ("driver-core: add
dev_name() to help transition away from using bus_id") added a static
inline dev_name() and used it in dev_printk.
Unfortunately, drivers/edac/edac_core.h defines a macro called
dev_name(). Rename the latter.
Diagnosis by Tony Breeds and Michael Ellerman.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Collection of patches, merged into one, from Adrian that do the following:
1) This patch makes the following needlessly global functions static:
- edac_pci_get_log_pe()
- edac_pci_get_log_npe()
- edac_pci_get_panic_on_pe()
- edac_pci_unregister_sysfs_instance_kobj()
- edac_pci_main_kobj_setup()
2) Remove unneeded function edac_device_find()
3) Added #if 0 around function edac_pci_find()
4) make the needlessly global edac_pci_generic_check() static
5) Removed function edac_check_mc_devices()
Doug Thompson modified Adrian's patches, to bettern represent
the direction of EDAC, and make them one patch.
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: Doug Thompson <norsk5@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When rounding a relative timeout we need to use round_jiffies_relative().
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ENABLE the 'logging' of CE and UE events for the EDAC_DEVICE class of error
harvester in EDAC
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some simple fixes to properly reference counter values from the block
attribute level of edac_device objects. Properly sequencing the array pointer
was added, resulting in correct identification of block level attributes from
their base class functions.
Added more verbose debug statement for event tracking.
Also during some corner testing, found a bug in the store/show sequence
of operations for the block attribute/controls management.
An old intermediate structure for 'blocks' was still in the processing
pipeline. This patch removes that old structure and correctly utilizes the
new struct edac_dev_sysfs_block_attribute for passing control from the sysfs
to the low level store/show function of the edac driver.
Now the proper kobj pointer to passed downward to the store/show
functions.
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Cc: Greg KH <greg@kroah.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix mutex locking deadlock on the device controller linked list. Was calling
a lock then a function that could call the same lock. Moved the cancel workq
function to outside the lock
Added some short circuit logic in the workq code
Added comments of description
Code tidying
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Cc: Greg KH <greg@kroah.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With feedback, this patch corrects operation of the kobject release operation
on kobjects, attributes and controls for the edac_device.
Cc: Alan Cox alan@lxorguk.ukuu.org.uk
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Acked-by: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Refactoring of sysfs code necessitated the refactoring of the
edac_device_alloc() and edac_device_add_device() apis, of moving the index
value to the alloc() function. This patch alters the in tree drivers to
utilize this new api signature.
Having the index value performed later created a chicken-and-the-egg issue.
Moving it to the alloc() function allows for creating the necessary sysfs
entries with the proper index number
Cc: Alan Cox alan@lxorguk.ukuu.org.uk
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes and enhances the driver level set of sysfs attributes that
can be added to the 'block' level of an edac_device type of driver.
There is a controller information structure, which contains one or more
instances of device. Each instance will have one or more blocks of device
specific counters. This patch fixes the ability to have more detailed
attributes/controls for each of the 'blocks', providing for the addition of
controls/attributes from the low level driver to user space via sysfs.
Cc: Alan Cox alan@lxorguk.ukuu.org.uk
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A previous patch changed the edac_mc src file from semaphore usage to mutex
This patch changes the edac_device src file as well, from semaphore use to
mutex operation.
Use a mutex primitive for mutex operations, as it does not require a
semaphore
Cc: Alan Cox alan@lxorguk.ukuu.org.uk
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Refactored the function edac_op_state_toString() to be edac_op_state_to_string()
for consistent style, and its callers
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Refactor the edac_align_ptr() function to reduce the noise of casting the
aligned pointer to the various types of data objects and modified its callers
to its new signature
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For the file edac_device.c perform some coding style enhancements
Add some function header comments
Made for better readability commands
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes some remnant spaces inserted by the use of Lindent.
Seems Lindent adds some spaces when it shoulded. These have been fixed.
In addition, goto targets have issues, these have been fixed
in this patch.
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The error handling output strings needed to be refactored for better
displaying of the error informaton.
Also needed to added offset_value for output as well
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The origin of this code comes from patches at sourceforge, that
allow EDAC to be updated to various kernels. With kernel version 2.6.20 a
new workq system was installed, thus the patches needed to be modified
based on the kernel version. For submitting to the latest kernel.org
those #ifdefs are removed
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Run the EDAC CORE files through Lindent for cleanup
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Dave Jiang <djiang@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Moving PCI to a per-instance device model
This should include the correct sysfs setup as well. Please review.
Signed-off-by: Dave Jiang <djiang@mvista.com>
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the memory controller object to work queue based implementation from the
kernel thread based.
Signed-off-by: Dave Jiang <djiang@mvista.com>
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move dev_name() macro to a more generic interface since it's not possible
to determine whether a device is pci, platform, or of_device easily.
Now each low level driver sets the name into the control structure, and
the EDAC core references the control structure for the information.
Better abstraction.
Signed-off-by: Dave Jiang <djiang@mvista.com>
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds the new 'class' of object to be managed, named: 'edac_device'.
As a peer of the 'edac_mc' class of object, it provides a non-memory centric
view of an ERROR DETECTING device in hardware. It provides a sysfs interface
and an abstraction for varioius EDAC type devices.
Multiple 'instances' within the class are possible, with each 'instance'
able to have multiple 'blocks', and each 'block' having 'attributes'.
At the 'block' level there are the 'ce_count' and 'ue_count' fields
which the device driver can update and/or call edac_device_handle_XX()
functions. At each higher level are additional 'total' count fields,
which are a summation of counts below that level.
This 'edac_device' has been used to capture and present ECC errors
which are found in a a L1 and L2 system on a per CORE/CPU basis.
Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
