[PATCH 4.9 02/22] mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>

commit 02390b87a9459937cdb299e6b34ff33992512ec7 upstream

With boot-time switching between paging mode we will have variable
MAX_PHYSMEM_BITS.

Let's use the maximum variable possible for CONFIG_X86_5LEVEL=y
configuration to define zsmalloc data structures.

The patch introduces MAX_POSSIBLE_PHYSMEM_BITS to cover such case.
It also suits well to handle PAE special case.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214111656.88514-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[florian: drop arch/x86/include/asm/pgtable_64_types.h changes since
there is no CONFIG_X86_5LEVEL]
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/include/asm/pgtable-3level_types.h |    1 +
 mm/zsmalloc.c                               |   13 +++++++------
 2 files changed, 8 insertions(+), 6 deletions(-)

--- a/arch/x86/include/asm/pgtable-3level_types.h
+++ b/arch/x86/include/asm/pgtable-3level_types.h
@@ -42,5 +42,6 @@ typedef union {
  */
 #define PTRS_PER_PTE	512
 
+#define MAX_POSSIBLE_PHYSMEM_BITS	36
 
 #endif /* _ASM_X86_PGTABLE_3LEVEL_DEFS_H */
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -83,18 +83,19 @@
  * This is made more complicated by various memory models and PAE.
  */
 
-#ifndef MAX_PHYSMEM_BITS
-#ifdef CONFIG_HIGHMEM64G
-#define MAX_PHYSMEM_BITS 36
-#else /* !CONFIG_HIGHMEM64G */
+#ifndef MAX_POSSIBLE_PHYSMEM_BITS
+#ifdef MAX_PHYSMEM_BITS
+#define MAX_POSSIBLE_PHYSMEM_BITS MAX_PHYSMEM_BITS
+#else
 /*
  * If this definition of MAX_PHYSMEM_BITS is used, OBJ_INDEX_BITS will just
  * be PAGE_SHIFT
  */
-#define MAX_PHYSMEM_BITS BITS_PER_LONG
+#define MAX_POSSIBLE_PHYSMEM_BITS BITS_PER_LONG
 #endif
 #endif
-#define _PFN_BITS		(MAX_PHYSMEM_BITS - PAGE_SHIFT)
+
+#define _PFN_BITS		(MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT)
 
 /*
  * Memory for allocating for handle keeps object position by