[Qemu-devel] [PATCHv4 1/4] util: introduce MIN_NON_ZERO

[Peter Lieven <pl@kamp.de>]

at least in block layer we have the case of limits being defined for a
BlockDriverState. However, in this context often zero (0) has the special
meanining of undefined which means no limit. If two of those limits are
combined and the minimum is needed the minimum function should only return
zero if both parameters are zero.

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 include/qemu/osdep.h |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 1565404..9a238df 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -68,6 +68,10 @@ typedef signed int              int_fast16_t;
 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
 #endif
 
+#ifndef MIN_NON_ZERO
+#define MIN_NON_ZERO(a, b) ((!!(a) && (a) < (b)) ? (a) : (b))
+#endif
+
 #ifndef ROUND_UP
 #define ROUND_UP(n,d) (((n) + (d) - 1) & -(d))
 #endif
-- 
1.7.9.5