firewire: Add ref-counting for sbp2_device and hold a ref while we have work scheduled.

Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 30 insertions, 12 deletions

diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c
index 0c87724cec3f..d7940db30a5b 100644
--- a/drivers/firewire/fw-sbp2.c
+++ b/drivers/firewire/fw-sbp2.c
@@ -51,6 +51,7 @@ typedef void (*scsi_done_fn_t) (struct scsi_cmnd *);
 static const char sbp2_driver_name[] = "sbp2";
 
 struct sbp2_device {
+        struct kref kref;
         struct fw_unit *unit;
         struct fw_address_handler address_handler;
         struct list_head orb_list;
@@ -513,6 +514,22 @@ static int add_scsi_devices(struct fw_unit *unit);
 static void remove_scsi_devices(struct fw_unit *unit);
 static void sbp2_reconnect(struct work_struct *work);
 
+static void
+release_sbp2_device(struct kref *kref)
+{
+        struct sbp2_device *sd = container_of(kref, struct sbp2_device, kref);
+
+        sbp2_send_management_orb(sd->unit, sd->node_id, sd->generation,
+                                 SBP2_LOGOUT_REQUEST, sd->login_id, NULL);
+
+        remove_scsi_devices(sd->unit);
+
+        fw_core_remove_address_handler(&sd->address_handler);
+        fw_notify("removed sbp2 unit %s\n", sd->unit->device.bus_id);
+        put_device(&sd->unit->device);
+        kfree(sd);
+}
+
 static void sbp2_login(struct work_struct *work)
 {
         struct sbp2_device *sd =
@@ -537,6 +554,7 @@ static void sbp2_login(struct work_struct *work)
                         fw_error("failed to login to %s\n",
                                  unit->device.bus_id);
                         remove_scsi_devices(unit);
+                        kref_put(&sd->kref, release_sbp2_device);
                 }
                 return;
         }
@@ -577,6 +595,7 @@ static void sbp2_login(struct work_struct *work)
                  * retry login on bus reset. */
                 PREPARE_DELAYED_WORK(&sd->work, sbp2_login);
         }
+        kref_put(&sd->kref, release_sbp2_device);
 }
 
 static int sbp2_probe(struct device *dev)
@@ -595,6 +614,7 @@ static int sbp2_probe(struct device *dev)
         unit->device.driver_data = sd;
         sd->unit = unit;
         INIT_LIST_HEAD(&sd->orb_list);
+        kref_init(&sd->kref);
 
         sd->address_handler.length = 0x100;
         sd->address_handler.address_callback = sbp2_status_write;
@@ -650,10 +670,14 @@ static int sbp2_probe(struct device *dev)
                           unit->device.bus_id,
                           sd->workarounds, firmware_revision, model);
 
+        get_device(&unit->device);
+
         /* We schedule work to do the login so we can easily
-         * reschedule retries. */
+         * reschedule retries. Always get the ref before scheduling
+         * work.*/
         INIT_DELAYED_WORK(&sd->work, sbp2_login);
-        schedule_delayed_work(&sd->work, 0);
+        if (schedule_delayed_work(&sd->work, 0))
+                kref_get(&sd->kref);
 
         return 0;
 }
@@ -663,15 +687,7 @@ static int sbp2_remove(struct device *dev)
         struct fw_unit *unit = fw_unit(dev);
         struct sbp2_device *sd = unit->device.driver_data;
 
-        sbp2_send_management_orb(unit, sd->node_id, sd->generation,
-                                 SBP2_LOGOUT_REQUEST, sd->login_id, NULL);
-
-        remove_scsi_devices(unit);
-
-        fw_core_remove_address_handler(&sd->address_handler);
-        kfree(sd);
-
-        fw_notify("removed sbp2 unit %s\n", dev->bus_id);
+        kref_put(&sd->kref, release_sbp2_device);
 
         return 0;
 }
@@ -710,6 +726,7 @@ static void sbp2_reconnect(struct work_struct *work)
                   unit->device.bus_id, sd->retries);
         sbp2_agent_reset(unit);
         sbp2_cancel_orbs(unit);
+        kref_put(&sd->kref, release_sbp2_device);
 }
 
 static void sbp2_update(struct fw_unit *unit)
@@ -719,7 +736,8 @@ static void sbp2_update(struct fw_unit *unit)
 
         sd->retries = 0;
         fw_device_enable_phys_dma(device);
-        schedule_delayed_work(&sd->work, 0);
+        if (schedule_delayed_work(&sd->work, 0))
+                kref_get(&sd->kref);
 }
 
 #define SBP2_UNIT_SPEC_ID_ENTRY 0x0000609e