linux/drivers/edac/edac_device.c, branch v2.6.39-rc2

edac: core: remove completion-wait for complete with rcu_barrier

2009-09-24T14:21:05Z

Module edac_core.ko uses call_rcu() callbacks in edac_device.c, edac_mc.c and edac_pci.c. They all use a wait_for_completion() scheme, but this scheme it not 100% safe on multiple CPUs. See the _rcu_barrier() implementation which explains why extra precausion is needed. The patch adds a comment about rcu_barrier() and as a precausion calls rcu_barrier(). A maintainer needs to look at removing the wait_for_completion code. [dougthompson@xmission.com: remove the wait_for_completion code] Signed-off-by Jesper Dangaard Brouer Signed-off-by: Doug Thompson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

edac: add edac_device_alloc_index()

2009-06-18T20:03:56Z

Add edac_device_alloc_index(), because for MAPLE platform there may exist several EDAC driver modules that could make use of edac_device_ctl_info structure at the same time. The index allocation for these structures should be taken care of by EDAC core. [akpm@linux-foundation.org: cleanups] Signed-off-by: Harry Ciao Cc: Doug Thompson Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Kumar Gala Cc: Paul Mackerras Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

edac: use to_delayed_work()

2009-04-13T22:04:34Z

The edac-core driver includes code which assumes that the work_struct which is included in every delayed_work is the first member of that structure. This is currently the case but might change in the future, so use to_delayed_work() instead, which doesn't make such an assumption. linux-2.6.30-rc1 has the to_delayed_work() function that will allow this patch to work Signed-off-by: Jean Delvare Signed-off-by: Doug Thompson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

edac: struct device: replace bus_id with dev_name(), dev_set_name()

2009-01-06T23:59:30Z

This patch is part of a larger patch series which will remove the "char bus_id[20]" name string from struct device. The device name is managed in the kobject anyway, and without any size limitation, and just needlessly copied into "struct device". [akpm@linux-foundation.org: coding-style fixes] Acked-by: Greg Kroah-Hartman Acked-by: Doug Thompson Signed-off-by: Kay Sievers Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

edac: fix edac core deadlock when removing a device

2008-12-23T23:58:21Z

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

dev_name introduction fall out fix

2008-05-05T22:08:38Z

Commit 06916639e2fed9ee475efef2747a1b7429f8fe76 ("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 Acked-by: Doug Thompson Signed-off-by: Linus Torvalds

edac: remove unneeded functions and add static accessor

2008-04-29T15:06:26Z

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 Signed-off-by: Adrian Bunk Signed-off-by: Doug Thompson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

edac: use the shorter LIST_HEAD for brevity

2008-04-29T15:06:26Z

Signed-off-by: Robert P. J. Day Acked-by: Doug Thompson Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

drivers-edac: use round_jiffies_relative

2008-02-07T16:42:23Z

When rounding a relative timeout we need to use round_jiffies_relative(). Signed-off-by: Anton Blanchard Acked-by: Arjan van de Ven Cc: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

drivers-edac: turn on edac device error logging

2008-02-07T16:42:23Z

ENABLE the 'logging' of CE and UE events for the EDAC_DEVICE class of error harvester in EDAC Cc: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds