Hi Zeng.
Looking through the arch specific implementations of __arch_parity().
Some architectures uses #defines, other uses inline static functions.
Any particular reason that you select one approach over the other
in the different cases?
ia64:
+#define __arch_parity32(x) ((unsigned int) __arch_parity64((x) & 0xfffffffful))
+#define __arch_parity16(x) ((unsigned int) __arch_parity64((x) & 0xfffful))
+#define __arch_parity8(x) ((unsigned int) __arch_parity64((x) & 0xfful))
+#define __arch_parity4(x) ((unsigned int) __arch_parity64((x) & 0xful))
tile:
+static inline unsigned int __arch_parity32(unsigned int w)
+{
+ return __builtin_popcount(w) & 1;
+}
+
+static inline unsigned int __arch_parity16(unsigned int w)
+{
+ return __arch_parity32(w & 0xffff);
+}
+
+static inline unsigned int __arch_parity8(unsigned int w)
+{
+ return __arch_parity32(w & 0xff);
+}
+
+static inline unsigned int __arch_parity4(unsigned int w)
+{
+ return __arch_parity32(w & 0xf);
+}
Just two examples.
Adding the parity helpers seems like veny nice simplifications.
A few comments to some of those I looked at.
(I am not subscribed to lkml, so you get it as comments here)
[PATCH 21/31] mtd: use parity16 in ssfdc.c
The original code semes to check that the parity equals the
value of first bit in the address.
This seems lost after the conversion.
[PATCH 20/31] scsi: use parity32 in isci/phy.c
+ if (parity32(phy_cap.all))
phy_cap.parity = 1;
Could be written like this - simpler IMO:
phy_cap.parity = parity32(phy_cap.all);
Sam
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