X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Flinux%2Flibata.h;h=66b6847225df10bdead7a9f02bef8e710d1d1b52;hb=f131883e73a8662dc92c3ea371ae9ded0c8f2c37;hp=0d6bf50ad02958ca598aaf5bb4ba263e9cb93e64;hpb=ccbe6d5ee0eb3182675ef1c84322810fd884586d;p=firefly-linux-kernel-4.4.55.git

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 0d6bf50ad029..66b6847225df 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -615,6 +615,16 @@ ata_sg_is_last(struct scatterlist *sg, struct ata_queued_cmd *qc)
 	return 0;
 }
 
+static inline struct scatterlist *
+ata_qc_first_sg(struct ata_queued_cmd *qc)
+{
+	if (qc->n_elem)
+		return qc->__sg;
+	if (qc->pad_len)
+		return &qc->pad_sgent;
+	return NULL;
+}
+
 static inline struct scatterlist *
 ata_qc_next_sg(struct scatterlist *sg, struct ata_queued_cmd *qc)
 {
@@ -622,11 +632,13 @@ ata_qc_next_sg(struct scatterlist *sg, struct ata_queued_cmd *qc)
 		return NULL;
 	if (++sg - qc->__sg < qc->n_elem)
 		return sg;
-	return qc->pad_len ? &qc->pad_sgent : NULL;
+	if (qc->pad_len)
+		return &qc->pad_sgent;
+	return NULL;
 }
 
 #define ata_for_each_sg(sg, qc) \
-	for (sg = qc->__sg; sg; sg = ata_qc_next_sg(sg, qc))
+	for (sg = ata_qc_first_sg(qc); sg; sg = ata_qc_next_sg(sg, qc))
 
 static inline unsigned int ata_tag_valid(unsigned int tag)
 {