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firewire: don't use PREPARE_DELAYED_WORK
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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 a2c1c57
"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
Cc: stable@vger.kernel.org # v3.9+
Cc: stable@vger.kernel.org # v3.8.2+
Cc: stable@vger.kernel.org # v3.4.60+
Cc: stable@vger.kernel.org # v3.2.40+
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Tejun Heo committed Mar 7, 2014
1 parent 5bdfff9 commit 70044d7
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Showing 3 changed files with 29 additions and 11 deletions.
22 changes: 15 additions & 7 deletions drivers/firewire/core-device.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -916,7 +916,7 @@ static int lookup_existing_device(struct device *dev, void *data)
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)
Expand Down Expand Up @@ -1075,7 +1075,7 @@ static void fw_device_init(struct work_struct *work)
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",
Expand Down Expand Up @@ -1196,13 +1196,20 @@ static void fw_device_refresh(struct work_struct *work)
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;
Expand Down Expand Up @@ -1252,7 +1259,8 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
* 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;

Expand All @@ -1268,7 +1276,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
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);
}
Expand All @@ -1283,7 +1291,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
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;
Expand All @@ -1308,7 +1316,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
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);
}
Expand Down
17 changes: 13 additions & 4 deletions drivers/firewire/sbp2.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -864,7 +865,7 @@ static void sbp2_login(struct work_struct *work)
/* 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. */
Expand Down Expand Up @@ -918,7 +919,7 @@ static void sbp2_login(struct work_struct *work)
* 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)
Expand Down Expand Up @@ -952,7 +953,7 @@ static void sbp2_reconnect(struct work_struct *work)
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));

Expand All @@ -972,6 +973,13 @@ static void sbp2_reconnect(struct work_struct *work)
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;
Expand All @@ -998,7 +1006,8 @@ static int sbp2_add_logical_unit(struct sbp2_target *tgt, int lun_entry)
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;
Expand Down
1 change: 1 addition & 0 deletions include/linux/firewire.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
};
Expand Down

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