From cc1887f3d8ae8ea61efa1a75af8ec0467b9dd546 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 20 Feb 2006 23:48:38 +0900 Subject: [PATCH] [PATCH] libata: fix qc->n_elem == 0 case handling in ata_qc_next_sg This patch makes ata_for_each_sg() start with pad_sgent when qc->n_elem is zero. Previously, ata_for_each_sg() unconditionally started with qc->__sg, handling the first sg to fill_sg() routines even when the entry was invalid. And while at it, unwind ?: in ata_qc_next_sg() into if statement. Signed-off-by: Tejun Heo Signed-off-by: Jeff Garzik --- include/linux/libata.h | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/include/linux/libata.h b/include/linux/libata.h index 9e5db2949c58..c91be5e64ede 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -556,6 +556,16 @@ 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) { @@ -563,11 +573,13 @@ 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) { -- 2.20.1