drivers/scsi/scsi_debug.c: resolve sg buffer const-ness issue

do_device_access() takes a separate parameter to indicate the direction of
data transfer, which it used to use to select the appropriate function out
of sg_pcopy_{to,from}_buffer().  However these two functions now have

So this patch makes it bypass these wrappers and call the underlying
function sg_copy_buffer() directly; this has the same calling style as
do_device_access() i.e.  a separate direction-of-transfer parameter and no
pointers-to-const, so skipping the wrappers not only eliminates the
warning, it also make the code simpler :)

[akpm@linux-foundation.org: fix very broken build]
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 317b62c..d105a9f 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -650,9 +650,8 @@
  * Returns the number of copied bytes.
  *
  **/
-static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
-			     void *buf, size_t buflen, off_t skip,
-			     bool to_buffer)
+size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf,
+		      size_t buflen, off_t skip, bool to_buffer)
 {
 	unsigned int offset = 0;
 	struct sg_mapping_iter miter;
@@ -689,6 +688,7 @@
 	local_irq_restore(flags);
 	return offset;
 }
+EXPORT_SYMBOL(sg_copy_buffer);
 
 /**
  * sg_copy_from_buffer - Copy from a linear buffer to an SG list