libata: fix dma_unmap_sg misuse
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@lab.ntt.co.jp>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 9fbf059..5e324ce 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4612,7 +4612,7 @@
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 @@
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;