[SCSI] libsas: add sas_eh_abort_handler

When recovering failed eh-cmnds let the lldd attempt an abort via
scsi_abort_eh_cmnd before escalating.
Reviewed-by: NJacek Danecki <jacek.danecki@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

drivers/scsi/libsas/sas_scsi_host.c

@@ -531,6 +531,27 @@ static int sas_queue_reset(struct domain_device *dev, int reset_type, int lun, i
 	return FAILED;
 }
 
+int sas_eh_abort_handler(struct scsi_cmnd *cmd)
+{
+	int res;
+	struct sas_task *task = TO_SAS_TASK(cmd);
+	struct Scsi_Host *host = cmd->device->host;
+	struct sas_internal *i = to_sas_internal(host->transportt);
+
+	if (current != host->ehandler)
+		return FAILED;
+
+	if (!i->dft->lldd_abort_task)
+		return FAILED;
+
+	res = i->dft->lldd_abort_task(task);
+	if (res == TMF_RESP_FUNC_SUCC || res == TMF_RESP_FUNC_COMPLETE)
+		return SUCCESS;
+
+	return FAILED;
+}
+EXPORT_SYMBOL_GPL(sas_eh_abort_handler);
+
 /* Attempt to send a LUN reset message to a device */
 int sas_eh_device_reset_handler(struct scsi_cmnd *cmd)
 {

include/scsi/libsas.h

@@ -720,6 +720,7 @@ void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *);
 void sas_init_dev(struct domain_device *);
 
 void sas_task_abort(struct sas_task *);
+int sas_eh_abort_handler(struct scsi_cmnd *cmd);
 int sas_eh_device_reset_handler(struct scsi_cmnd *cmd);
 int sas_eh_bus_reset_handler(struct scsi_cmnd *cmd);