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 <stefanr@s5r6.in-berlin.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index f05fc7b..bb8c4d2 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -228,8 +228,8 @@
/* Use an arbitrary short delay to combine multiple reset requests. */
fw_card_get(card);
- if (!schedule_delayed_work(&card->br_work,
- delayed ? DIV_ROUND_UP(HZ, 100) : 0))
+ if (!queue_delayed_work(fw_wq, &card->br_work,
+ delayed ? DIV_ROUND_UP(HZ, 100) : 0))
fw_card_put(card);
}
EXPORT_SYMBOL(fw_schedule_bus_reset);
@@ -241,7 +241,7 @@
/* Delay for 2s after last reset per IEEE 1394 clause 8.2.1. */
if (card->reset_jiffies != 0 &&
time_before64(get_jiffies_64(), card->reset_jiffies + 2 * HZ)) {
- if (!schedule_delayed_work(&card->br_work, 2 * HZ))
+ if (!queue_delayed_work(fw_wq, &card->br_work, 2 * HZ))
fw_card_put(card);
return;
}