Read/Write Spinlocks...

From: Vijay Kumar Zanvar (vijoeyz_at_hotpop.com)
Date: 08/31/03 

Date: Sun, 31 Aug 2003 22:47:33 +0530

Hello,

The question pertains to read/write spinlock. Each
r/w spinlock is a rwlock+AF8-t structure as follows:

typedef struct +AHs-
    volatile unsigned int lock+ADs-

+ACM-ifdef SPINLOCK+AF8-DEBG
    unsigned magic+ADs-
+ACM-endif

+AH0- rwlock+AF8-t+ADs-

24-bit counter denoting the number of kernel control paths
currently reading the protected data structure, is stored in the
24 LS bits of the lock member. Why the 2's complement of the
total control path is stored and not just the number?

Thanks.
-----------------------------------------------
Vijay Kumar R Zanvar

Sherlock Homles said, +ACI-We approached the case, you remember Watson,
with a blank mind. It is always an advantage.+ACI-