staging/fwserial: don't use PREPARE_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.

fwtty_peer->work is multiplexed with multiple work functions.
Introduce fwserial_peer_workfn() which invokes fwtty_peer->workfn and
always use it as the work function and update the users to set the
->workfn field instead of overriding the work function using
PREPARE_WORK().

It would probably be best to route this with other related updates
through the workqueue tree.

Compile tested.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Hurley <peter@hurleysoftware.com>

2 files changed, 11 insertions, 3 deletions

diff --git a/drivers/staging/fwserial/fwserial.c b/drivers/staging/fwserial/fwserial.c
index 8af136e9c9dc..b22142ee5262 100644
--- a/drivers/staging/fwserial/fwserial.c
+++ b/drivers/staging/fwserial/fwserial.c
@@ -2036,6 +2036,13 @@ static void fwserial_auto_connect(struct work_struct *work)
                 schedule_delayed_work(&peer->connect, CONNECT_RETRY_DELAY);
 }
 
+static void fwserial_peer_workfn(struct work_struct *work)
+{
+        struct fwtty_peer *peer = to_peer(work, work);
+
+        peer->workfn(work);
+}
+
 /**
  * fwserial_add_peer - add a newly probed 'serial' unit device as a 'peer'
  * @serial: aggregate representing the specific fw_card to add the peer to
@@ -2100,7 +2107,7 @@ static int fwserial_add_peer(struct fw_serial *serial, struct fw_unit *unit)
         peer->port = NULL;
 
         init_timer(&peer->timer);
-        INIT_WORK(&peer->work, NULL);
+        INIT_WORK(&peer->work, fwserial_peer_workfn);
         INIT_DELAYED_WORK(&peer->connect, fwserial_auto_connect);
 
         /* associate peer with specific fw_card */
@@ -2702,7 +2709,7 @@ static int fwserial_parse_mgmt_write(struct fwtty_peer *peer,
 
                 } else {
                         peer->work_params.plug_req = pkt->plug_req;
-                        PREPARE_WORK(&peer->work, fwserial_handle_plug_req);
+                        peer->workfn = fwserial_handle_plug_req;
                         queue_work(system_unbound_wq, &peer->work);
                 }
                 break;
@@ -2731,7 +2738,7 @@ static int fwserial_parse_mgmt_write(struct fwtty_peer *peer,
                         fwtty_err(&peer->unit, "unplug req: busy\n");
                         rcode = RCODE_CONFLICT_ERROR;
                 } else {
-                        PREPARE_WORK(&peer->work, fwserial_handle_unplug_req);
+                        peer->workfn = fwserial_handle_unplug_req;
                         queue_work(system_unbound_wq, &peer->work);
                 }
                 break;
diff --git a/drivers/staging/fwserial/fwserial.h b/drivers/staging/fwserial/fwserial.h
index 54f7f9b9b212..98b853d4acbc 100644
--- a/drivers/staging/fwserial/fwserial.h
+++ b/drivers/staging/fwserial/fwserial.h
@@ -91,6 +91,7 @@ struct fwtty_peer {
         struct rcu_head         rcu;
 
         spinlock_t              lock;
+        work_func_t             workfn;
         struct work_struct      work;
         struct peer_work_params work_params;
         struct timer_list       timer;