When we use a DECLARE_HYPERCALL_BUFFER_SHADOW define a user
pointer '_name' and a shadow xc_hypercall_buffer_t.
then call xc_hypercall_buffer_free_pages(_xch, _name, _nr),
the complier will report '_name' unused error, it's because
xc_hypercall_buffer_free_pages() is a MACRO and '_name'
transparently converted to the hypercall buffer. it confused
the caller because xc_hypercall_buffer_free_pages() do look
like a function and take '_name' as an arg.
Add an if check to let the compiler think we are actually
using the argument '_name'.
Signed-off-by: Yang Hongyang <yan...@cn.fujitsu.com>
CC: Ian Campbell <ian.campb...@citrix.com>
CC: Ian Jackson <ian.jack...@eu.citrix.com>
CC: Wei Liu <wei.l...@citrix.com>
CC: Andrew Cooper <andrew.coop...@citrix.com>
---
tools/libxc/include/xenctrl.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 43fc31c..448063c 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -350,7 +350,12 @@ void xc__hypercall_buffer_free(xc_interface *xch,
xc_hypercall_buffer_t *b);
void *xc__hypercall_buffer_alloc_pages(xc_interface *xch,
xc_hypercall_buffer_t *b, int nr_pages);
#define xc_hypercall_buffer_alloc_pages(_xch, _name, _nr)
xc__hypercall_buffer_alloc_pages(_xch, HYPERCALL_BUFFER(_name), _nr)
void xc__hypercall_buffer_free_pages(xc_interface *xch, xc_hypercall_buffer_t
*b, int nr_pages);
-#define xc_hypercall_buffer_free_pages(_xch, _name, _nr)
xc__hypercall_buffer_free_pages(_xch, HYPERCALL_BUFFER(_name), _nr)
+#define xc_hypercall_buffer_free_pages(_xch, _name, _nr) \
+ do { \
+ if ( _name ) \
+ xc__hypercall_buffer_free_pages(_xch, HYPERCALL_BUFFER(_name), \
+ _nr); \
+ } while (0)
/*
* Array of hypercall buffers.
--
1.9.1
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