Commit 70044d71 authored by Tejun Heo's avatar Tejun Heo
Browse files

firewire: don't use PREPARE_DELAYED_WORK 



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 a2c1c57b
"workqueue: consider work function when searching for busy work items"
due to which fw_workqueue lost its required non-reentrancy property.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarStefan 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+
parent 5bdfff96

drivers/firewire/core-device.c

+15 −7
Original line number Diff line number Diff line
@@ -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)
@@ -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",
@@ -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;
@@ -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;
@@ -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);

		}
@@ -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;
@@ -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);

		}

drivers/firewire/sbp2.c

+13 −4
Original line number Diff line number Diff line
@@ -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_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. */
@@ -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)
@@ -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));
@@ -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;
@@ -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;

include/linux/firewire.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

};

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