1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index f3c115b55681..1514cb5e35f7 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -252,6 +252,29 @@ static unsigned int ata_pack_xfermask(unsigned int pio_mask,
                 ((udma_mask << ATA_SHIFT_UDMA) & ATA_MASK_UDMA);
 }
 
+/**
+ *      ata_unpack_xfermask - Unpack xfer_mask into pio, mwdma and udma masks
+ *      @xfer_mask: xfer_mask to unpack
+ *      @pio_mask: resulting pio_mask
+ *      @mwdma_mask: resulting mwdma_mask
+ *      @udma_mask: resulting udma_mask
+ *
+ *      Unpack @xfer_mask into @pio_mask, @mwdma_mask and @udma_mask.
+ *      Any NULL distination masks will be ignored.
+ */
+static void ata_unpack_xfermask(unsigned int xfer_mask,
+                                unsigned int *pio_mask,
+                                unsigned int *mwdma_mask,
+                                unsigned int *udma_mask)
+{
+        if (pio_mask)
+                *pio_mask = (xfer_mask & ATA_MASK_PIO) >> ATA_SHIFT_PIO;
+        if (mwdma_mask)
+                *mwdma_mask = (xfer_mask & ATA_MASK_MWDMA) >> ATA_SHIFT_MWDMA;
+        if (udma_mask)
+                *udma_mask = (xfer_mask & ATA_MASK_UDMA) >> ATA_SHIFT_UDMA;
+}
+
 static const struct ata_xfer_ent {
         unsigned int shift, bits;
         u8 base;