[SCSI] libsas: add sas_abort_task

This patch adds an external function, sas_abort_task, to enable LLDDs
to abort sas_tasks.  It also adds a work_struct so that the actual
work of aborting a task can be shifted from tasklet context (in the
LLDD) onto the scsi_host's workqueue.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 64 insertions, 0 deletions

diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c
index 6a97b07849b4..c5fd37522728 100644
--- a/drivers/scsi/libsas/sas_scsi_host.c
+++ b/drivers/scsi/libsas/sas_scsi_host.c
@@ -33,6 +33,7 @@
 #include <scsi/scsi_transport.h>
 #include <scsi/scsi_transport_sas.h>
 #include "../scsi_sas_internal.h"
+#include "../scsi_transport_api.h"
 
 #include <linux/err.h>
 #include <linux/blkdev.h>
@@ -798,6 +799,64 @@ void sas_shutdown_queue(struct sas_ha_struct *sas_ha)
         spin_unlock_irqrestore(&core->task_queue_lock, flags);
 }
 
+static int do_sas_task_abort(struct sas_task *task)
+{
+        struct scsi_cmnd *sc = task->uldd_task;
+        struct sas_internal *si =
+                to_sas_internal(task->dev->port->ha->core.shost->transportt);
+        unsigned long flags;
+        int res;
+
+        spin_lock_irqsave(&task->task_state_lock, flags);
+        if (task->task_state_flags & SAS_TASK_STATE_ABORTED) {
+                spin_unlock_irqrestore(&task->task_state_lock, flags);
+                SAS_DPRINTK("%s: Task %p already aborted.\n", __FUNCTION__,
+                            task);
+                return 0;
+        }
+
+        task->task_state_flags |= SAS_TASK_INITIATOR_ABORTED;
+        if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
+                task->task_state_flags |= SAS_TASK_STATE_ABORTED;
+        spin_unlock_irqrestore(&task->task_state_lock, flags);
+
+        if (!si->dft->lldd_abort_task)
+                return -ENODEV;
+
+        res = si->dft->lldd_abort_task(task);
+        if ((task->task_state_flags & SAS_TASK_STATE_DONE) ||
+            (res == TMF_RESP_FUNC_COMPLETE))
+        {
+                /* SMP commands don't have scsi_cmds(?) */
+                if (!sc) {
+                        task->task_done(task);
+                        return 0;
+                }
+                scsi_req_abort_cmd(sc);
+                scsi_schedule_eh(sc->device->host);
+                return 0;
+        }
+
+        spin_lock_irqsave(&task->task_state_lock, flags);
+        task->task_state_flags &= ~SAS_TASK_INITIATOR_ABORTED;
+        if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
+                task->task_state_flags &= ~SAS_TASK_STATE_ABORTED;
+        spin_unlock_irqrestore(&task->task_state_lock, flags);
+
+        return -EAGAIN;
+}
+
+void sas_task_abort(struct sas_task *task)
+{
+        int i;
+
+        for (i = 0; i < 5; i++)
+                if (!do_sas_task_abort(task))
+                        return;
+
+        SAS_DPRINTK("%s: Could not kill task!\n", __FUNCTION__);
+}
+
 EXPORT_SYMBOL_GPL(sas_queuecommand);
 EXPORT_SYMBOL_GPL(sas_target_alloc);
 EXPORT_SYMBOL_GPL(sas_slave_configure);
@@ -805,3 +864,4 @@ EXPORT_SYMBOL_GPL(sas_slave_destroy);
 EXPORT_SYMBOL_GPL(sas_change_queue_depth);
 EXPORT_SYMBOL_GPL(sas_change_queue_type);
 EXPORT_SYMBOL_GPL(sas_bios_param);
+EXPORT_SYMBOL_GPL(sas_task_abort);
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 7bf2e8b9903c..a1fc20a47c50 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -528,6 +528,8 @@ struct sas_task {
 
         void   *lldd_task;        /* for use by LLDDs */
         void   *uldd_task;
+
+        struct work_struct abort_work;
 };
 
 
@@ -627,4 +629,6 @@ void sas_unregister_dev(struct domain_device *);
 
 void sas_init_dev(struct domain_device *);
 
+void sas_task_abort(struct sas_task *task);
+
 #endif /* _SASLIB_H_ */