[SCSI] libsas: introduce sas_work to fix sas_drain_work vs sas_queue_work
When requeuing work to a draining workqueue the last work instance may
not be idle, so sas_queue_work() must not touch work->entry. Introduce
sas_work with a drain_node list_head to have a private list for
collecting work deferred due to drain collision.
Fixes reports like:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff810410d4>] process_one_work+0x2e/0x338
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 5f5ed1b..f4f1c96 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -217,11 +217,29 @@
struct kref kref;
};
-struct sas_discovery_event {
+struct sas_work {
+ struct list_head drain_node;
struct work_struct work;
+};
+
+static inline void INIT_SAS_WORK(struct sas_work *sw, void (*fn)(struct work_struct *))
+{
+ INIT_WORK(&sw->work, fn);
+ INIT_LIST_HEAD(&sw->drain_node);
+}
+
+struct sas_discovery_event {
+ struct sas_work work;
struct asd_sas_port *port;
};
+static inline struct sas_discovery_event *to_sas_discovery_event(struct work_struct *work)
+{
+ struct sas_discovery_event *ev = container_of(work, typeof(*ev), work.work);
+
+ return ev;
+}
+
struct sas_discovery {
struct sas_discovery_event disc_work[DISC_NUM_EVENTS];
unsigned long pending;
@@ -244,7 +262,7 @@
struct list_head destroy_list;
enum sas_linkrate linkrate;
- struct work_struct work;
+ struct sas_work work;
/* public: */
int id;
@@ -270,10 +288,17 @@
};
struct asd_sas_event {
- struct work_struct work;
+ struct sas_work work;
struct asd_sas_phy *phy;
};
+static inline struct asd_sas_event *to_asd_sas_event(struct work_struct *work)
+{
+ struct asd_sas_event *ev = container_of(work, typeof(*ev), work.work);
+
+ return ev;
+}
+
/* The phy pretty much is controlled by the LLDD.
* The class only reads those fields.
*/
@@ -333,10 +358,17 @@
};
struct sas_ha_event {
- struct work_struct work;
+ struct sas_work work;
struct sas_ha_struct *ha;
};
+static inline struct sas_ha_event *to_sas_ha_event(struct work_struct *work)
+{
+ struct sas_ha_event *ev = container_of(work, typeof(*ev), work.work);
+
+ return ev;
+}
+
enum sas_ha_state {
SAS_HA_REGISTERED,
SAS_HA_DRAINING,