[Xen-devel] [PATCH v2] xen: avoid type warning in xchg_xen_ulong

[Arnd Bergmann <arnd@xxxxxxxx>]

The improved type-checking version of container_of() triggers a warning for
xchg_xen_ulong, pointing out that 'xen_ulong_t' is unsigned, but atomic64_t
contains a signed value:

drivers/xen/events/events_2l.c: In function 'evtchn_2l_handle_events':
drivers/xen/events/events_2l.c:187:1020: error: call to 
'__compiletime_assert_187' declared with attribute error: pointer type mismatch 
in container_of()

This adds a cast to work around the warning.

Cc: Ian Abbott <abbotti@xxxxxxxxx>
Fixes: 85323a991d40 ("xen: arm: mandate EABI and use generic atomic 
operations.")
Fixes: daa2ac80834d ("kernel.h: handle pointers to arrays better in 
container_of()")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
v2: found the correct warning message and updated the changelog
---
 arch/arm/include/asm/xen/events.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/xen/events.h 
b/arch/arm/include/asm/xen/events.h
index 71e473d05fcc..620dc75362e5 100644
--- a/arch/arm/include/asm/xen/events.h
+++ b/arch/arm/include/asm/xen/events.h
@@ -16,7 +16,7 @@ static inline int xen_irqs_disabled(struct pt_regs *regs)
        return raw_irqs_disabled_flags(regs->ARM_cpsr);
 }
 
-#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((ptr),     \
+#define xchg_xen_ulong(ptr, val) atomic64_xchg(container_of((long long*)(ptr),\
                                                            atomic64_t, \
                                                            counter), (val))
 
-- 
2.9.0


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