Date: Wed Oct 13 13:39:46 CEST 2010
From: Stefan Richter <[email protected]>
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 <[email protected]>
Reviewed-by: Tejun Heo <[email protected]>
---
drivers/firewire/core-card.c | 6 +++---
drivers/firewire/core-cdev.c | 2 +-
drivers/firewire/core-device.c | 30 ++++++++++++++++++----------
drivers/firewire/core-transaction.c | 12 ++++++++++-
drivers/firewire/core.h | 2 ++
5 files changed, 36 insertions(+), 16 deletions(-)
Index: b/drivers/firewire/core-card.c
===================================================================
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -228,8 +228,8 @@ void fw_schedule_bus_reset(struct fw_car
/* 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 @@ static void br_work(struct work_struct *
/* 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;
}
Index: b/drivers/firewire/core-cdev.c
===================================================================
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -149,7 +149,7 @@ static void release_iso_resource(struct
static void schedule_iso_resource(struct iso_resource *r, unsigned long delay)
{
client_get(r->client);
- if (!schedule_delayed_work(&r->work, delay))
+ if (!queue_delayed_work(fw_wq, &r->work, delay))
client_put(r->client);
}
Index: b/drivers/firewire/core-device.c
===================================================================
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -725,6 +725,14 @@ struct fw_device *fw_device_get_by_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 wo
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
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_s
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_s
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 wor
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 wor
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 wor
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,
* 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,
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,
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,
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;
Index: b/drivers/firewire/core-transaction.c
===================================================================
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -36,6 +36,7 @@
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/types.h>
+#include <linux/workqueue.h>
#include <asm/byteorder.h>
@@ -1213,13 +1214,21 @@ static int __init fw_core_init(void)
{
int ret;
+ fw_wq = alloc_workqueue(KBUILD_MODNAME,
+ WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
+ if (!fw_wq)
+ return -ENOMEM;
+
ret = bus_register(&fw_bus_type);
- if (ret < 0)
+ if (ret < 0) {
+ destroy_workqueue(fw_wq);
return ret;
+ }
fw_cdev_major = register_chrdev(0, "firewire", &fw_device_ops);
if (fw_cdev_major < 0) {
bus_unregister(&fw_bus_type);
+ destroy_workqueue(fw_wq);
return fw_cdev_major;
}
@@ -1235,6 +1244,7 @@ static void __exit fw_core_cleanup(void)
{
unregister_chrdev(fw_cdev_major, "firewire");
bus_unregister(&fw_bus_type);
+ destroy_workqueue(fw_wq);
idr_destroy(&fw_device_idr);
}
Index: b/drivers/firewire/core.h
===================================================================
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -138,6 +138,8 @@ void fw_cdev_handle_phy_packet(struct fw
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);
--
Stefan Richter
-=====-==-== -=-= ----=
http://arcgraph.de/sr/
The struct sbp2_logical_unit.work items can all be executed in parallel
but are not reentrant. Furthermore, reconnect or re-login work must be
executed in a WQ_MEM_RECLAIM workqueue.
Hence replace the old single-threaded firewire-sbp2 workqueue by a
concurrency-managed but non-reentrant workqueue with rescuer.
firewire-core already maintains one, hence use this one.
In earlier versions of this change, I observed occasional failures of
parallel INQUIRY to an Initio INIC-2430 FireWire 800 to dual IDE bridge.
More testing indicates that parallel INQUIRY is not actually a problem,
but too quick successions of logout and login + INQUIRY, e.g. a quick
sequence of cable plugout and plugin, can result in failed INQUIRY.
This does not seem to be something that should or could be addressed by
serialization.
Another dual-LU device to which I currently have access to, an
OXUF924DSB FireWire 800 to dual SATA bridge with firmware from MacPower,
has been successfully tested with this too.
This change is beneficial to environments with two or more FireWire
storage devices, especially if they are located on the same bus.
Management tasks that should be performed as soon and as quickly as
possible, especially reconnect, are no longer held up by tasks on other
devices that may take a long time, especially login with INQUIRY and sd
or sr driver probe.
Signed-off-by: Stefan Richter <[email protected]>
---
drivers/firewire/core-card.c | 4 ++--
drivers/firewire/core-cdev.c | 2 +-
drivers/firewire/core-device.c | 5 +++--
drivers/firewire/core-transaction.c | 12 ++++++------
drivers/firewire/core.h | 2 --
drivers/firewire/sbp2.c | 9 +--------
include/linux/firewire.h | 2 ++
7 files changed, 15 insertions(+), 21 deletions(-)
Index: b/drivers/firewire/core-card.c
===================================================================
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -228,7 +228,7 @@ void fw_schedule_bus_reset(struct fw_car
/* Use an arbitrary short delay to combine multiple reset requests. */
fw_card_get(card);
- if (!queue_delayed_work(fw_wq, &card->br_work,
+ if (!queue_delayed_work(fw_workqueue, &card->br_work,
delayed ? DIV_ROUND_UP(HZ, 100) : 0))
fw_card_put(card);
}
@@ -241,7 +241,7 @@ static void br_work(struct work_struct *
/* 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 (!queue_delayed_work(fw_wq, &card->br_work, 2 * HZ))
+ if (!queue_delayed_work(fw_workqueue, &card->br_work, 2 * HZ))
fw_card_put(card);
return;
}
Index: b/drivers/firewire/core-cdev.c
===================================================================
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -149,7 +149,7 @@ static void release_iso_resource(struct
static void schedule_iso_resource(struct iso_resource *r, unsigned long delay)
{
client_get(r->client);
- if (!queue_delayed_work(fw_wq, &r->work, delay))
+ if (!queue_delayed_work(fw_workqueue, &r->work, delay))
client_put(r->client);
}
Index: b/drivers/firewire/core-device.c
===================================================================
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -725,12 +725,13 @@ struct fw_device *fw_device_get_by_devt(
return device;
}
-struct workqueue_struct *fw_wq;
+struct workqueue_struct *fw_workqueue;
+EXPORT_SYMBOL(fw_workqueue);
static void fw_schedule_device_work(struct fw_device *device,
unsigned long delay)
{
- queue_delayed_work(fw_wq, &device->work, delay);
+ queue_delayed_work(fw_workqueue, &device->work, delay);
}
/*
Index: b/drivers/firewire/core-transaction.c
===================================================================
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -1214,21 +1214,21 @@ static int __init fw_core_init(void)
{
int ret;
- fw_wq = alloc_workqueue(KBUILD_MODNAME,
- WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
- if (!fw_wq)
+ fw_workqueue = alloc_workqueue("firewire",
+ WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
+ if (!fw_workqueue)
return -ENOMEM;
ret = bus_register(&fw_bus_type);
if (ret < 0) {
- destroy_workqueue(fw_wq);
+ destroy_workqueue(fw_workqueue);
return ret;
}
fw_cdev_major = register_chrdev(0, "firewire", &fw_device_ops);
if (fw_cdev_major < 0) {
bus_unregister(&fw_bus_type);
- destroy_workqueue(fw_wq);
+ destroy_workqueue(fw_workqueue);
return fw_cdev_major;
}
@@ -1244,7 +1244,7 @@ static void __exit fw_core_cleanup(void)
{
unregister_chrdev(fw_cdev_major, "firewire");
bus_unregister(&fw_bus_type);
- destroy_workqueue(fw_wq);
+ destroy_workqueue(fw_workqueue);
idr_destroy(&fw_device_idr);
}
Index: b/drivers/firewire/core.h
===================================================================
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -138,8 +138,6 @@ void fw_cdev_handle_phy_packet(struct fw
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);
Index: b/drivers/firewire/sbp2.c
===================================================================
--- a/drivers/firewire/sbp2.c
+++ b/drivers/firewire/sbp2.c
@@ -826,8 +826,6 @@ static void sbp2_target_put(struct sbp2_
kref_put(&tgt->kref, sbp2_release_target);
}
-static struct workqueue_struct *sbp2_wq;
-
/*
* Always get the target's kref when scheduling work on one its units.
* Each workqueue job is responsible to call sbp2_target_put() upon return.
@@ -835,7 +833,7 @@ static struct workqueue_struct *sbp2_wq;
static void sbp2_queue_work(struct sbp2_logical_unit *lu, unsigned long delay)
{
sbp2_target_get(lu->tgt);
- if (!queue_delayed_work(sbp2_wq, &lu->work, delay))
+ if (!queue_delayed_work(fw_workqueue, &lu->work, delay))
sbp2_target_put(lu->tgt);
}
@@ -1645,17 +1643,12 @@ MODULE_ALIAS("sbp2");
static int __init sbp2_init(void)
{
- sbp2_wq = create_singlethread_workqueue(KBUILD_MODNAME);
- if (!sbp2_wq)
- return -ENOMEM;
-
return driver_register(&sbp2_driver.driver);
}
static void __exit sbp2_cleanup(void)
{
driver_unregister(&sbp2_driver.driver);
- destroy_workqueue(sbp2_wq);
}
module_init(sbp2_init);
Index: b/include/linux/firewire.h
===================================================================
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -448,4 +448,6 @@ void fw_iso_resource_manage(struct fw_ca
u64 channels_mask, int *channel, int *bandwidth,
bool allocate);
+extern struct workqueue_struct *fw_workqueue;
+
#endif /* _LINUX_FIREWIRE_H */
--
Stefan Richter
-=====-==-== -=-= ----=
http://arcgraph.de/sr/