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firewire: core: use non-reentrant workqueue with rescuer

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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>
This commit is contained in:
Stefan Richter
2010-10-13 13:39:46 +02:00
parent 13882a82ee
commit 6ea9e7bbfc
5 changed files with 36 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/firewire/core-device.c
View File

@ -725,6 +725,14 @@ struct fw_device *fw_device_get_by_devt(dev_t devt)
return device;
}
struct workqueue_struct *fw_wq;
static void fw_schedule_device_work(struct fw_device *device,
unsigned long delay)
{
queue_delayed_work(fw_wq, &device->work, delay);
}
/*
* These defines control the retry behavior for reading the config
* rom. It shouldn't be necessary to tweak these; if the device
@ -750,7 +758,7 @@ static void fw_device_shutdown(struct work_struct *work)
if (time_before64(get_jiffies_64(),
device->card->reset_jiffies + SHUTDOWN_DELAY)
&& !list_empty(&device->card->link)) {
schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
fw_schedule_device_work(device, SHUTDOWN_DELAY);
return;
}
@ -862,7 +870,7 @@ static int lookup_existing_device(struct device *dev, void *data)
fw_notify("rediscovered device %s\n", dev_name(dev));
PREPARE_DELAYED_WORK(&old->work, fw_device_update);
schedule_delayed_work(&old->work, 0);
fw_schedule_device_work(old, 0);
if (current_node == card->root_node)
fw_schedule_bm_work(card, 0);
@ -953,7 +961,7 @@ static void fw_device_init(struct work_struct *work)
if (device->config_rom_retries < MAX_RETRIES &&
atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
device->config_rom_retries++;
schedule_delayed_work(&device->work, RETRY_DELAY);
fw_schedule_device_work(device, RETRY_DELAY);
} else {
if (device->node->link_on)
fw_notify("giving up on config rom for node id %x\n",
@ -1019,7 +1027,7 @@ static void fw_device_init(struct work_struct *work)
FW_DEVICE_INITIALIZING,
FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
fw_schedule_device_work(device, SHUTDOWN_DELAY);
} else {
if (device->config_rom_retries)
fw_notify("created device %s: GUID %08x%08x, S%d00, "
@ -1098,7 +1106,7 @@ static void fw_device_refresh(struct work_struct *work)
if (device->config_rom_retries < MAX_RETRIES / 2 &&
atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
device->config_rom_retries++;
schedule_delayed_work(&device->work, RETRY_DELAY / 2);
fw_schedule_device_work(device, RETRY_DELAY / 2);
return;
}
@ -1131,7 +1139,7 @@ static void fw_device_refresh(struct work_struct *work)
if (device->config_rom_retries < MAX_RETRIES &&
atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
device->config_rom_retries++;
schedule_delayed_work(&device->work, RETRY_DELAY);
fw_schedule_device_work(device, RETRY_DELAY);
return;
}
@ -1158,7 +1166,7 @@ static void fw_device_refresh(struct work_struct *work)
gone:
atomic_set(&device->state, FW_DEVICE_GONE);
PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
schedule_delayed_work(&device->work, SHUTDOWN_DELAY);
fw_schedule_device_work(device, SHUTDOWN_DELAY);
out:
if (node_id == card->root_node->node_id)
fw_schedule_bm_work(card, 0);
@ -1214,7 +1222,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
* first config rom scan half a second after bus reset.
*/
INIT_DELAYED_WORK(&device->work, fw_device_init);
schedule_delayed_work(&device->work, INITIAL_DELAY);
fw_schedule_device_work(device, INITIAL_DELAY);
break;
case FW_NODE_INITIATED_RESET:
@ -1230,7 +1238,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
FW_DEVICE_RUNNING,
FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
schedule_delayed_work(&device->work,
fw_schedule_device_work(device,
device->is_local ? 0 : INITIAL_DELAY);
}
break;
@ -1245,7 +1253,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
device->generation = card->generation;
if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
PREPARE_DELAYED_WORK(&device->work, fw_device_update);
schedule_delayed_work(&device->work, 0);
fw_schedule_device_work(device, 0);
}
break;
@ -1270,7 +1278,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
if (atomic_xchg(&device->state,
FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
schedule_delayed_work(&device->work,
fw_schedule_device_work(device,
list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
}
break;