From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
libata passes the returned value of dma_map_sg() to dma_unmap_sg(),which
is the misuse of dma_unmap_sg().
DMA-mapping.txt says:
To unmap a scatterlist, just call:
pci_unmap_sg(pdev, sglist, nents, direction);
Again, make sure DMA activity has already finished.
PLEASE NOTE: The 'nents' argument to the pci_unmap_sg call must be
the _same_ one you passed into the pci_map_sg call,
it should _NOT_ be the 'count' value _returned_ from the
pci_map_sg call.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Jeff Garzik <jeff@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/ata/libata-core.c | 4 ++--
include/linux/libata.h | 1 +
2 files changed, 3 insertions(+), 2 deletions(-)
diff -puN drivers/ata/libata-core.c~libata-fix-dma_unmap_sg-misuse drivers/ata/libata-core.c
--- a/drivers/ata/libata-core.c~libata-fix-dma_unmap_sg-misuse
+++ a/drivers/ata/libata-core.c
@@ -4612,7 +4612,7 @@ void ata_sg_clean(struct ata_queued_cmd
VPRINTK("unmapping %u sg elements\n", qc->n_elem);
if (qc->n_elem)
- dma_unmap_sg(ap->dev, sg, qc->n_elem, dir);
+ dma_unmap_sg(ap->dev, sg, qc->orig_n_elem, dir);
qc->flags &= ~ATA_QCFLAG_DMAMAP;
qc->sg = NULL;
@@ -4727,7 +4727,7 @@ static int ata_sg_setup(struct ata_queue
return -1;
DPRINTK("%d sg elements mapped\n", n_elem);
-
+ qc->orig_n_elem = qc->n_elem;
qc->n_elem = n_elem;
qc->flags |= ATA_QCFLAG_DMAMAP;
diff -puN include/linux/libata.h~libata-fix-dma_unmap_sg-misuse include/linux/libata.h
--- a/include/linux/libata.h~libata-fix-dma_unmap_sg-misuse
+++ a/include/linux/libata.h
@@ -530,6 +530,7 @@ struct ata_queued_cmd {
unsigned long flags; /* ATA_QCFLAG_xxx */
unsigned int tag;
unsigned int n_elem;
+ unsigned int orig_n_elem;
int dma_dir;
_
--
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