uml: speed page fault path

Give the page fault code a specialized path.  There is only one page to look
at, so there's no point in going into the general page table walking code.
There's only going to be one host operation, so there are no opportunities for
merging.  So, we go straight to the pte we want, figure out what needs doing,
and do it.

While I was in here, I fixed the wart where the address passed to unmap was a
void *, but an unsigned long to map and protect.

This gives me just under 10% on a kernel build.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 6cdfda807b65..af0790719b77 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -219,8 +219,8 @@ int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
         return ret;
 }
 
-int unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
-          void **data)
+int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
+          int done, void **data)
 {
         int ret;