dma-mapping: remove leftover NULL device support

Most dma_map_ops implementations already had some issues with a NULL
device, or did simply crash if one was fed to them.  Now that we have
cleaned up all the obvious offenders we can stop to pretend we
support this mode.

Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 6 insertions, 7 deletions

diff --git a/Documentation/DMA-API-HOWTO.txt b/Documentation/DMA-API-HOWTO.txt
index 1a721d0f35c85..0e98cf7466dd0 100644
--- a/Documentation/DMA-API-HOWTO.txt
+++ b/Documentation/DMA-API-HOWTO.txt
@@ -365,13 +365,12 @@ __get_free_pages() (but takes size instead of a page order).  If your
 driver needs regions sized smaller than a page, you may prefer using
 the dma_pool interface, described below.
 
-The consistent DMA mapping interfaces, for non-NULL dev, will by
-default return a DMA address which is 32-bit addressable.  Even if the
-device indicates (via DMA mask) that it may address the upper 32-bits,
-consistent allocation will only return > 32-bit addresses for DMA if
-the consistent DMA mask has been explicitly changed via
-dma_set_coherent_mask().  This is true of the dma_pool interface as
-well.
+The consistent DMA mapping interfaces, will by default return a DMA address
+which is 32-bit addressable.  Even if the device indicates (via the DMA mask)
+that it may address the upper 32-bits, consistent allocation will only
+return > 32-bit addresses for DMA if the consistent DMA mask has been
+explicitly changed via dma_set_coherent_mask().  This is true of the
+dma_pool interface as well.
 
 dma_alloc_coherent() returns two values: the virtual address which you
 can use to access it from the CPU and dma_handle which you pass to the