dmaengine: add DMA_COMPL_SKIP_{SRC,DEST}_UNMAP flags to control dma unmap

In some cases client code may need the dma-driver to skip the unmap of source
and/or destination buffers.  Setting these flags indicates to the driver to
skip the unmap step.  In this regard async_xor is currently broken in that it
allows the destination buffer to be unmapped while an operation is still in
progress, i.e. when the number of sources exceeds the hardware channel's
maximum (fixed in a subsequent patch).

Acked-by: Saeed Bishara <saeed@marvell.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 23 insertions, 25 deletions

diff --git a/drivers/dma/ioat_dma.c b/drivers/dma/ioat_dma.c
index 90e5b0a28cbf..171cad69f318 100644
--- a/drivers/dma/ioat_dma.c
+++ b/drivers/dma/ioat_dma.c
@@ -757,6 +757,27 @@ static void ioat_dma_cleanup_tasklet(unsigned long data)
                chan->reg_base + IOAT_CHANCTRL_OFFSET);
 }
 
+static void
+ioat_dma_unmap(struct ioat_dma_chan *ioat_chan, struct ioat_desc_sw *desc)
+{
+        /*
+         * yes we are unmapping both _page and _single
+         * alloc'd regions with unmap_page. Is this
+         * *really* that bad?
+         */
+        if (!(desc->async_tx.flags & DMA_COMPL_SKIP_DEST_UNMAP))
+                pci_unmap_page(ioat_chan->device->pdev,
+                                pci_unmap_addr(desc, dst),
+                                pci_unmap_len(desc, len),
+                                PCI_DMA_FROMDEVICE);
+
+        if (!(desc->async_tx.flags & DMA_COMPL_SKIP_SRC_UNMAP))
+                pci_unmap_page(ioat_chan->device->pdev,
+                                pci_unmap_addr(desc, src),
+                                pci_unmap_len(desc, len),
+                                PCI_DMA_TODEVICE);
+}
+
 /**
  * ioat_dma_memcpy_cleanup - cleanup up finished descriptors
  * @chan: ioat channel to be cleaned up
@@ -817,21 +838,7 @@ static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *ioat_chan)
                          */
                         if (desc->async_tx.cookie) {
                                 cookie = desc->async_tx.cookie;
-
-                                /*
-                                 * yes we are unmapping both _page and _single
-                                 * alloc'd regions with unmap_page. Is this
-                                 * *really* that bad?
-                                 */
-                                pci_unmap_page(ioat_chan->device->pdev,
-                                                pci_unmap_addr(desc, dst),
-                                                pci_unmap_len(desc, len),
-                                                PCI_DMA_FROMDEVICE);
-                                pci_unmap_page(ioat_chan->device->pdev,
-                                                pci_unmap_addr(desc, src),
-                                                pci_unmap_len(desc, len),
-                                                PCI_DMA_TODEVICE);
-
+                                ioat_dma_unmap(ioat_chan, desc);
                                 if (desc->async_tx.callback) {
                                         desc->async_tx.callback(desc->async_tx.callback_param);
                                         desc->async_tx.callback = NULL;
@@ -890,16 +897,7 @@ static void ioat_dma_memcpy_cleanup(struct ioat_dma_chan *ioat_chan)
                                 if (desc->async_tx.cookie) {
                                         cookie = desc->async_tx.cookie;
                                         desc->async_tx.cookie = 0;
-
-                                        pci_unmap_page(ioat_chan->device->pdev,
-                                                      pci_unmap_addr(desc, dst),
-                                                      pci_unmap_len(desc, len),
-                                                      PCI_DMA_FROMDEVICE);
-                                        pci_unmap_page(ioat_chan->device->pdev,
-                                                      pci_unmap_addr(desc, src),
-                                                      pci_unmap_len(desc, len),
-                                                      PCI_DMA_TODEVICE);
-
+                                        ioat_dma_unmap(ioat_chan, desc);
                                         if (desc->async_tx.callback) {
                                                 desc->async_tx.callback(desc->async_tx.callback_param);
                                                 desc->async_tx.callback = NULL;