Patch "mm/cma: silence warnings due to max() usage" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

mm/cma: silence warnings due to max() usage

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mm-cma-silence-warnings-due-to-max-usage.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Stephen Rothwell <[email protected]>
Date: Fri, 27 May 2016 14:27:41 -0700
Subject: mm/cma: silence warnings due to max() usage

From: Stephen Rothwell <[email protected]>

commit badbda53e505089062e194c614e6f23450bc98b2 upstream.

pageblock_order can be (at least) an unsigned int or an unsigned long depending on the kernel config and architecture, so use max_t(unsigned long, ...) when comparing it.

fixes these warnings:

In file included from include/asm-generic/bug.h:13:0,

                 from arch/powerpc/include/asm/bug.h:127,
                 from include/linux/bug.h:4,
                 from include/linux/mmdebug.h:4,
                 from include/linux/mm.h:8,
                 from include/linux/memblock.h:18,
                 from mm/cma.c:28:

mm/cma.c: In function 'cma_init_reserved_mem':
include/linux/kernel.h:748:17: warning: comparison of distinct pointer types lacks a cast
(void) (&_max1 == &_max2); ^
mm/cma.c:186:27: note: in expansion of macro 'max'

  alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
                           ^

mm/cma.c: In function 'cma_declare_contiguous':
include/linux/kernel.h:748:17: warning: comparison of distinct pointer types lacks a cast
(void) (&_max1 == &_max2); ^
include/linux/kernel.h:747:9: note: in definition of macro 'max'
typeof(y) _max2 = (y); ^
mm/cma.c:270:29: note: in expansion of macro 'max'

   (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
                             ^

include/linux/kernel.h:748:17: warning: comparison of distinct pointer types lacks a cast
(void) (&_max1 == &_max2); ^
include/linux/kernel.h:747:21: note: in definition of macro 'max'
typeof(y) _max2 = (y); ^
mm/cma.c:270:29: note: in expansion of macro 'max'

   (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
                             ^

---
 mm/cma.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

@@ -183,7 +183,8 @@ int __init cma_init_reserved_mem(phys_ad
 		return -EINVAL;
 
 	/* ensure minimal alignment required by mm core */
-	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+	alignment = PAGE_SIZE <<
+			max_t(unsigned long, MAX_ORDER - 1, pageblock_order);
 
 	/* alignment should be aligned with order_per_bit */
 	if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))

@@ -266,8 +267,8 @@ int __init cma_declare_contiguous(phys_a
 	 * migratetype page by page allocator's buddy algorithm. In the case,
 	 * you couldn't get a contiguous memory, which is not what we want.
 	 */
-	alignment = max(alignment,
-		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
+	alignment = max(alignment,  (phys_addr_t)PAGE_SIZE <<
+			  max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
 	base = ALIGN(base, alignment);
 	size = ALIGN(size, alignment);
 	limit &= ~(alignment - 1);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/mm-cma-silence-warnings-due-to-max-usage.patch