Commit 5825627c authored Feb 27, 2009 by FUJITA Tomonori Committed by Jeff Garzik Mar 05, 2009

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>

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;

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