[PATCH 3.10 47/85] firewire: dont use PREPARE_DELAYED_WORK

Greg Kroah-Hartman
2014-03-21T00:37:32Z

From: Tejun Heo <tj@kernel.org>

commit 70044d71d31d6973665ced5be04ef39ac1c09a48 upstream.

PREPARE_[DELAYED_]WORK() are being phased out. They have few users
and a nasty surprise in terms of reentrancy guarantee as workqueue
considers work items to be different if they don't have the same work
function.

firewire core-device and sbp2 have been been multiplexing work items
with multiple work functions. Introduce fw_device_workfn() and
sbp2_lu_workfn() which invoke fw_device->workfn and
sbp2_logical_unit->workfn respectively and always use the two
functions as the work functions and update the users to set the
->workfn fields instead of overriding work functions using
PREPARE_DELAYED_WORK().

This fixes a variety of possible regressions since a2c1c57be8d9
"workqueue: consider work function when searching for busy work items"
due to which fw_workqueue lost its required non-reentrancy property.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: linux1394-devel@lists.sourceforge.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/firewire/core-device.c | 22 +++++++++++++++-------
drivers/firewire/sbp2.c | 17 +++++++++++++----
include/linux/firewire.h | 1 +
3 files changed, 29 insertions(+), 11 deletions(-)

--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -895,7 +895,7 @@ static int lookup_existing_device(struct
old->config_rom_retries = 0;
fw_notice(card, "rediscovered device %s\n", dev_name(dev));

- PREPARE_DELAYED_WORK(&old->work, fw_device_update);
+ old->workfn = fw_device_update;
fw_schedule_device_work(old, 0);

if (current_node == card->root_node)
@@ -1054,7 +1054,7 @@ static void fw_device_init(struct work_s
if (atomic_cmpxchg(&device->state,
FW_DEVICE_INITIALIZING,
FW_DEVICE_RUNNING) == FW_DEVICE_GONE) {
- PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
+ device->workfn = fw_device_shutdown;
fw_schedule_device_work(device, SHUTDOWN_DELAY);
} else {
fw_notice(card, "created device %s: GUID %08x%08x, S%d00\n",
@@ -1175,13 +1175,20 @@ static void fw_device_refresh(struct wor
dev_name(&device->device), fw_rcode_string(ret));
gone:
atomic_set(&device->state, FW_DEVICE_GONE);
- PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
+ device->workfn = fw_device_shutdown;
fw_schedule_device_work(device, SHUTDOWN_DELAY);
out:
if (node_id == card->root_node->node_id)
fw_schedule_bm_work(card, 0);
}

+static void fw_device_workfn(struct work_struct *work)
+{
+ struct fw_device *device = container_of(to_delayed_work(work),
+ struct fw_device, work);
+ device->workfn(work);
+}
+
void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
{
struct fw_device *device;
@@ -1231,7 +1238,8 @@ void fw_node_event(struct fw_card *card,
* power-up after getting plugged in. We schedule the
* first config rom scan half a second after bus reset.
*/
- INIT_DELAYED_WORK(&device->work, fw_device_init);
+ device->workfn = fw_device_init;
+ INIT_DELAYED_WORK(&device->work, fw_device_workfn);
fw_schedule_device_work(device, INITIAL_DELAY);
break;

@@ -1247,7 +1255,7 @@ void fw_node_event(struct fw_card *card,
if (atomic_cmpxchg(&device->state,
FW_DEVICE_RUNNING,
FW_DEVICE_INITIALIZING) == FW_DEVICE_RUNNING) {
- PREPARE_DELAYED_WORK(&device->work, fw_device_refresh);
+ device->workfn = fw_device_refresh;
fw_schedule_device_work(device,
device->is_local ? 0 : INITIAL_DELAY);
}
@@ -1262,7 +1270,7 @@ void fw_node_event(struct fw_card *card,
smp_wmb(); /* update node_id before generation */
device->generation = card->generation;
if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
- PREPARE_DELAYED_WORK(&device->work, fw_device_update);
+ device->workfn = fw_device_update;
fw_schedule_device_work(device, 0);
}
break;
@@ -1287,7 +1295,7 @@ void fw_node_event(struct fw_card *card,
device = node->data;
if (atomic_xchg(&device->state,
FW_DEVICE_GONE) == FW_DEVICE_RUNNING) {
- PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
+ device->workfn = fw_device_shutdown;
fw_schedule_device_work(device,
list_empty(&card->link) ? 0 : SHUTDOWN_DELAY);
}
--- a/drivers/firewire/sbp2.c
+++ b/drivers/firewire/sbp2.c
@@ -146,6 +146,7 @@ struct sbp2_logical_unit {
*/
int generation;
int retries;
+ work_func_t workfn;
struct delayed_work work;
bool has_sdev;
bool blocked;
@@ -864,7 +865,7 @@ static void sbp2_login(struct work_struc
/* set appropriate retry limit(s) in BUSY_TIMEOUT register */
sbp2_set_busy_timeout(lu);

- PREPARE_DELAYED_WORK(&lu->work, sbp2_reconnect);
+ lu->workfn = sbp2_reconnect;
sbp2_agent_reset(lu);

/* This was a re-login. */
@@ -918,7 +919,7 @@ static void sbp2_login(struct work_struc
* If a bus reset happened, sbp2_update will have requeued
* lu->work already. Reset the work from reconnect to login.
*/
- PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
+ lu->workfn = sbp2_login;
}

static void sbp2_reconnect(struct work_struct *work)
@@ -952,7 +953,7 @@ static void sbp2_reconnect(struct work_s
lu->retries++ >= 5) {
dev_err(tgt_dev(tgt), "failed to reconnect\n");
lu->retries = 0;
- PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
+ lu->workfn = sbp2_login;
}
sbp2_queue_work(lu, DIV_ROUND_UP(HZ, 5));

@@ -972,6 +973,13 @@ static void sbp2_reconnect(struct work_s
sbp2_conditionally_unblock(lu);
}

+static void sbp2_lu_workfn(struct work_struct *work)
+{
+ struct sbp2_logical_unit *lu = container_of(to_delayed_work(work),
+ struct sbp2_logical_unit, work);
+ lu->workfn(work);
+}
+
static int sbp2_add_logical_unit(struct sbp2_target *tgt, int lun_entry)
{
struct sbp2_logical_unit *lu;
@@ -998,7 +1006,8 @@ static int sbp2_add_logical_unit(struct
lu->blocked = false;
++tgt->dont_block;
INIT_LIST_HEAD(&lu->orb_list);
- INIT_DELAYED_WORK(&lu->work, sbp2_login);
+ lu->workfn = sbp2_login;
+ INIT_DELAYED_WORK(&lu->work, sbp2_lu_workfn);

list_add_tail(&lu->link, &tgt->lu_list);
return 0;
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -200,6 +200,7 @@ struct fw_device {
unsigned irmc:1;
unsigned bc_implemented:2;

+ work_func_t workfn;
struct delayed_work work;
struct fw_attribute_group attribute_group;
};