On Tuesday 17 February 2009, FUJITA Tomonori wrote: > Looks like that libata misuses dma_unmap_sg though I'm not familiar > with libata so I might completely misunderstand something. > > = > From: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> > Subject: [PATCH] fix dma_unmap_sg misuse > > 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. This is correct and other subsystems (SCSI, IDE) are compliant with it. > Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@xxxxxxxxx> > --- > drivers/ata/libata-core.c | 4 ++-- > include/linux/libata.h | 1 + > 2 files changed, 3 insertions(+), 2 deletions(-) > > 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 @@ void ata_sg_clean(struct ata_queued_cmd *qc) > 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_queued_cmd *qc) > 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 --git a/include/linux/libata.h b/include/linux/libata.h > index 5577ea8..2de827d 100644 > --- a/include/linux/libata.h > +++ b/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; -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html