gpu/drm: remove the powerpc hack in drm_legacy_sg_alloc

The non-cached vmalloc mapping was initially added as a hack for the
first-gen amigaone platform (6xx/book32s), isn't fully supported upstream,
and which used the legacy radeon driver together with non-coherent DMA.
However this only ever worked reliably for DRI .

Remove the hack as it is the last user of __vmalloc passing a page
protection flag other than PAGE_KERNEL and didn't do anything for other
platforms with non-coherent DMA.

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Daniel Vetter <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Gao Xiang <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Haiyang Zhang <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: "K. Y. Srinivasan" <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Michael Kelley <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Nitin Gupta <[email protected]>
Cc: Robin Murphy <[email protected]>
Cc: Sakari Ailus <[email protected]>
Cc: Stephen Hemminger <[email protected]>
Cc: Sumit Semwal <[email protected]>
Cc: Wei Liu <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Will Deacon <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

Author: Christoph Hellwig

drivers/gpu/drm/drm_scatter.c

@@ -43,15 +43,6 @@
 
 #define DEBUG_SCATTER 0
 
-static inline void *drm_vmalloc_dma(unsigned long size)
-{
-#if defined(__powerpc__) && defined(CONFIG_NOT_COHERENT_CACHE)
-	return __vmalloc(size, GFP_KERNEL, pgprot_noncached_wc(PAGE_KERNEL));
-#else
-	return vmalloc_32(size);
-#endif
-}
-
 static void drm_sg_cleanup(struct drm_sg_mem * entry)
 {
 	struct page *page;
@@ -126,7 +117,7 @@ int drm_legacy_sg_alloc(struct drm_device *dev, void *data,
 		return -ENOMEM;
 	}
 
-	entry->virtual = drm_vmalloc_dma(pages << PAGE_SHIFT);
+	entry->virtual = vmalloc_32(pages << PAGE_SHIFT);
 	if (!entry->virtual) {
 		kfree(entry->busaddr);
 		kfree(entry->pagelist);