2 files changed, 12 insertions, 5 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index e998028302da..ee72994500a3 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4763,13 +4763,15 @@ void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
 }
 
 static unsigned int ata_sg_setup_extra(struct ata_queued_cmd *qc,
-                                       unsigned int *n_elem_extra)
+                                       unsigned int *n_elem_extra,
+                                       unsigned int *nbytes_extra)
 {
         struct ata_port *ap = qc->ap;
         unsigned int n_elem = qc->n_elem;
         struct scatterlist *lsg, *copy_lsg = NULL, *tsg = NULL, *esg = NULL;
 
         *n_elem_extra = 0;
+        *nbytes_extra = 0;
 
         /* needs padding? */
         qc->pad_len = qc->nbytes & 3;
@@ -4833,6 +4835,7 @@ static unsigned int ata_sg_setup_extra(struct ata_queued_cmd *qc,
                 esg = &qc->extra_sg[1];
 
                 (*n_elem_extra)++;
+                (*nbytes_extra) += 4 - qc->pad_len;
         }
 
         if (copy_lsg)
@@ -4866,11 +4869,11 @@ static unsigned int ata_sg_setup_extra(struct ata_queued_cmd *qc,
 static int ata_sg_setup(struct ata_queued_cmd *qc)
 {
         struct ata_port *ap = qc->ap;
-        unsigned int n_elem, n_elem_extra;
+        unsigned int n_elem, n_elem_extra, nbytes_extra;
 
         VPRINTK("ENTER, ata%u\n", ap->print_id);
 
-        n_elem = ata_sg_setup_extra(qc, &n_elem_extra);
+        n_elem = ata_sg_setup_extra(qc, &n_elem_extra, &nbytes_extra);
 
         if (n_elem) {
                 n_elem = dma_map_sg(ap->dev, qc->sg, n_elem, qc->dma_dir);
@@ -4885,7 +4888,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
 
         qc->n_elem = qc->mapped_n_elem = n_elem;
         qc->n_elem += n_elem_extra;
-
+        qc->nbytes += nbytes_extra;
         qc->flags |= ATA_QCFLAG_DMAMAP;
 
         return 0;
@@ -5949,6 +5952,9 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
          */
         BUG_ON(ata_is_data(prot) && (!qc->sg || !qc->n_elem || !qc->nbytes));
 
+        /* ata_sg_setup() may update nbytes */
+        qc->raw_nbytes = qc->nbytes;
+
         if (ata_is_dma(prot) || (ata_is_pio(prot) &&
                                  (ap->flags & ATA_FLAG_PIO_DMA)))
                 if (ata_sg_setup(qc))
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 162f8b5509ac..7b7c78e42077 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -466,6 +466,7 @@ struct ata_queued_cmd {
         unsigned int            sect_size;
 
         unsigned int            nbytes;
+        unsigned int            raw_nbytes;
         unsigned int            curbytes;
 
         struct scatterlist      *cursg;
@@ -1362,7 +1363,7 @@ static inline void ata_qc_reinit(struct ata_queued_cmd *qc)
         qc->flags = 0;
         qc->cursg = NULL;
         qc->cursg_ofs = 0;
-        qc->nbytes = qc->curbytes = 0;
+        qc->nbytes = qc->raw_nbytes = qc->curbytes = 0;
         qc->n_elem = 0;
         qc->mapped_n_elem = 0;
         qc->n_iter = 0;