From 6ea9e7bbfc389a12d52646449a201fe933ccd663 Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Wed, 13 Oct 2010 13:39:46 +0200 Subject: firewire: core: use non-reentrant workqueue with rescuer firewire-core manages the following types of work items: fw_card.br_work: - resets the bus on a card and possibly sends a PHY packet before that - does not sleep for long or not at all - is scheduled via fw_schedule_bus_reset() by - firewire-ohci's pci_probe method - firewire-ohci's set_config_rom method, called by kernelspace protocol drivers and userspace drivers which add/remove Configuration ROM descriptors - userspace drivers which use the bus reset ioctl - itself if the last reset happened less than 2 seconds ago fw_card.bm_work: - performs bus management duties - usually does not (but may in corner cases) sleep for long - is scheduled via fw_schedule_bm_work() by - firewire-ohci's self-ID-complete IRQ handler tasklet - firewire-core's fw_device.work instances whenever the root node device was (successfully or unsuccessfully) discovered, refreshed, or rediscovered - itself in case of resource allocation failures or in order to obey the 125ms bus manager arbitration interval fw_device.work: - performs node probe, update, shutdown, revival, removal; including kernel driver probe, update, shutdown and bus reset notification to userspace drivers - usually sleeps moderately long, in corner cases very long - is scheduled by - firewire-ohci's self-ID-complete IRQ handler tasklet via the core's fw_node_event - firewire-ohci's pci_remove method via core's fw_destroy_nodes/ fw_node_event - itself during retries, e.g. while a node is powering up iso_resource.work: - accesses registers at the Isochronous Resource Manager node - usually does not (but may in corner cases) sleep for long - is scheduled via schedule_iso_resource() by - the owning userspace driver at addition and removal of the resource - firewire-core's fw_device.work instances after bus reset - itself in case of resource allocation if necessary to obey the 1000ms reallocation period after bus reset fw_card.br_work instances should not, and instances of the others must not, be executed in parallel by multiple CPUs -- but were not protected against that. Hence allocate a non-reentrant workqueue for them. fw_device.work may be used in the memory reclaim path in case of SBP-2 device updates. Hence we need a workqueue with rescuer and cannot use system_nrt_wq. Signed-off-by: Stefan Richter Reviewed-by: Tejun Heo --- drivers/firewire/core.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/firewire/core.h') diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h index 0fe4e4e6eda7..00ea7730c6a7 100644 --- a/drivers/firewire/core.h +++ b/drivers/firewire/core.h @@ -140,6 +140,8 @@ void fw_cdev_handle_phy_packet(struct fw_card *card, struct fw_packet *p); extern struct rw_semaphore fw_device_rwsem; extern struct idr fw_device_idr; extern int fw_cdev_major; +struct workqueue_struct; +extern struct workqueue_struct *fw_wq; struct fw_device *fw_device_get_by_devt(dev_t devt); int fw_device_set_broadcast_channel(struct device *dev, void *gen); -- cgit v1.2.3