Merge branch 'upstream-fixes' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik...

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 7ddd5a6..5f1d758 100644 (file)
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2514,7 +2514,7 @@ static void ata_sg_clean(struct ata_queued_cmd *qc)
        assert(sg != NULL);
 
        if (qc->flags & ATA_QCFLAG_SINGLE)
-               assert(qc->n_elem == 1);
+               assert(qc->n_elem <= 1);
 
        VPRINTK("unmapping %u sg elements\n", qc->n_elem);
 
@@ -2537,7 +2537,7 @@ static void ata_sg_clean(struct ata_queued_cmd *qc)
                        kunmap_atomic(addr, KM_IRQ0);
                }
        } else {
-               if (sg_dma_len(&sg[0]) > 0)
+               if (qc->n_elem)
                        dma_unmap_single(ap->host_set->dev,
                                sg_dma_address(&sg[0]), sg_dma_len(&sg[0]),
                                dir);
@@ -2570,7 +2570,7 @@ static void ata_fill_sg(struct ata_queued_cmd *qc)
        unsigned int idx;
 
        assert(qc->__sg != NULL);
-       assert(qc->n_elem > 0);
+       assert(qc->n_elem > 0 || qc->pad_len > 0);
 
        idx = 0;
        ata_for_each_sg(sg, qc) {
@@ -2715,6 +2715,7 @@ static int ata_sg_setup_one(struct ata_queued_cmd *qc)
        int dir = qc->dma_dir;
        struct scatterlist *sg = qc->__sg;
        dma_addr_t dma_address;
+       int trim_sg = 0;
 
        /* we must lengthen transfers to end on a 32-bit boundary */
        qc->pad_len = sg->length & 3;
@@ -2734,13 +2735,15 @@ static int ata_sg_setup_one(struct ata_queued_cmd *qc)
                sg_dma_len(psg) = ATA_DMA_PAD_SZ;
                /* trim sg */
                sg->length -= qc->pad_len;
+               if (sg->length == 0)
+                       trim_sg = 1;
 
                DPRINTK("padding done, sg->length=%u pad_len=%u\n",
                        sg->length, qc->pad_len);
        }
 
-       if (!sg->length) {
-               sg_dma_address(sg) = 0;
+       if (trim_sg) {
+               qc->n_elem--;
                goto skip_map;
        }
 
@@ -2753,9 +2756,9 @@ static int ata_sg_setup_one(struct ata_queued_cmd *qc)
        }
 
        sg_dma_address(sg) = dma_address;
-skip_map:
        sg_dma_len(sg) = sg->length;
 
+skip_map:
        DPRINTK("mapped buffer of %d bytes for %s\n", sg_dma_len(sg),
                qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read");
 

diff --git a/drivers/scsi/sata_qstor.c b/drivers/scsi/sata_qstor.c
index de05e28..80480f0 100644 (file)
--- a/drivers/scsi/sata_qstor.c
+++ b/drivers/scsi/sata_qstor.c
@@ -277,7 +277,7 @@ static unsigned int qs_fill_sg(struct ata_queued_cmd *qc)
        u8 *prd = pp->pkt + QS_CPB_BYTES;
 
        assert(qc->__sg != NULL);
-       assert(qc->n_elem > 0);
+       assert(qc->n_elem > 0 || qc->pad_len > 0);
 
        nelem = 0;
        ata_for_each_sg(sg, qc) {

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 9e5db29..c91be5e 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -557,17 +557,29 @@ ata_sg_is_last(struct scatterlist *sg, struct ata_queued_cmd *qc)
 }
 
 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)
 {
        if (sg == &qc->pad_sgent)
                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)
 {