X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=Documentation%2FDMA-API.txt;h=b462bb1495438b4854564151cdddb9b3c98e91a2;hb=refs%2Fheads%2Fv2.6.28-omap1-h63xx;hp=b8e86460046e7ee3dba003c12de57ae2d6f7fb36;hpb=24924f884cd36603615ea5496244e542b0b513c6;p=linux-2.6-omap-h63xx.git diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index b8e86460046..b462bb14954 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -316,12 +316,10 @@ reduce current DMA mapping usage or delay and try again later). pci_map_sg(struct pci_dev *hwdev, struct scatterlist *sg, int nents, int direction) -Maps a scatter gather list from the block layer. - Returns: the number of physical segments mapped (this may be shorter -than passed in if the block layer determines that some -elements of the scatter/gather list are physically adjacent and thus -may be mapped with a single entry). +than passed in if some elements of the scatter/gather list are +physically or virtually adjacent and an IOMMU maps them with a single +entry). Please note that the sg cannot be mapped again if it has been mapped once. The mapping process is allowed to destroy information in the sg.