[PATCH] powerpc: don't re-issue spinlock typedef that breaks older gcc

Paul Gortmaker paul.gortmaker at windriver.com
Wed Jan 29 03:16:57 EST 2014

Commit b3084f4db3aeb991c507ca774337c7e7893ed04f ("powerpc/thp: Fix
crash on mremap") added a "typedef struct spinlock spinlock_t;"
which on gcc 4.5.2 (and possibly other versions) causes many of:

include/linux/spinlock_types.h:76:3: error: redefinition of typedef 'spinlock_t'
arch/powerpc/include/asm/pgtable-ppc64.h:563:25: note: previous declaration of 'spinlock_t' was here
In file included from include/linux/mutex.h:15:0,
                 from include/linux/notifier.h:13,
                 from include/linux/pm_qos.h:8,
                 from include/linux/netdevice.h:28,
                 from drivers/net/wireless/ath/wil6210/wil6210.h:20,
                 from drivers/net/wireless/ath/wil6210/debug.c:17:

It appears that somewhere between gcc 4.5.2 and 4.6.3 this
redefinition restriction was lifted.  Using the proper header
from within !ASSEMBLY seems to fix it up in an acceptable way.

Cc: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill.shutemov at linux.intel.com>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker at windriver.com>

[ Note that b3084f4db3 isn't mainline yet, it is currently in
  benh/powerpc.git #merge -- but is headed there soon via:
             https://lkml.org/lkml/2014/1/27/599           ]

 arch/powerpc/include/asm/pgtable-ppc64.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h
index d27960c89a71..3b638411646a 100644
--- a/arch/powerpc/include/asm/pgtable-ppc64.h
+++ b/arch/powerpc/include/asm/pgtable-ppc64.h
@@ -111,6 +111,8 @@
 #ifndef __ASSEMBLY__
+#include <linux/spinlock_types.h>
  * This is the default implementation of various PTE accessors, it's
  * used in all cases except Book3S with 64K pages where we have a
@@ -560,7 +562,6 @@ extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 			    pmd_t *pmdp);
 #define pmd_move_must_withdraw pmd_move_must_withdraw
-typedef struct spinlock spinlock_t;
 static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl,
 					 spinlock_t *old_pmd_ptl)

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