Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5825627c authored by FUJITA Tomonori's avatar FUJITA Tomonori Committed by Jeff Garzik
Browse files

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: default avatarFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: default avatarBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent e7d3ef13

drivers/ata/libata-core.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

include/linux/libata.h

+1 −0
Original line number Diff line number Diff line
@@ -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;