libata: Add helper ata_shost_to_port()
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 2564bc5..fe0a1dc 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -33,6 +33,7 @@
 #include <asm/io.h>
 #include <linux/ata.h>
 #include <linux/workqueue.h>
+#include <scsi/scsi_host.h>
 
 /*
  * compile-time options: to be removed as soon as all the drivers are
@@ -977,4 +978,9 @@
 	dma_free_coherent(dev, ATA_DMA_PAD_BUF_SZ, ap->pad, ap->pad_dma);
 }
 
+static inline struct ata_port *ata_shost_to_port(struct Scsi_Host *host)
+{
+	return (struct ata_port *) &host->hostdata[0];
+}
+
 #endif /* __LINUX_LIBATA_H__ */