[SCSI] qla2xxx: use kthread_ API

Use the kthread_ API instead of opencoding lots of hairy code for kernel
thread creation and teardown.

Also switch from semaphore-based thread wakeup to wake_up_process.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-By: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index b31a03b..2e16f32 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -2414,11 +2414,7 @@
 	struct sns_cmd_pkt	*sns_cmd;
 	dma_addr_t		sns_cmd_dma;
 
-	pid_t			dpc_pid;
-	int			dpc_should_die;
-	struct completion	dpc_inited;
-	struct completion	dpc_exited;
-	struct semaphore	*dpc_wait;
+	struct task_struct	*dpc_thread;
 	uint8_t dpc_active;                  /* DPC routine is active */
 
 	/* Timeout timers. */