Reference Guide

ZCOM Tables and Data Structures
ZCOM Kernel Data
Chapter 3134
ZC_SLOCK - Super IFT spinlock
This lock protects against deadlock situations while multiple IFTs need
to be access simultaneously. A piece of code must obtain this lock first if
it is going to lock multiple IFTs.
Each of the above fields is a data structure (zlock_t) with the data fields
shown in Table 3-52.
LOCKP - Pointer to kernel spinlock structure
This is a pointer to the spinlock structure allocated dynamically from the
kernel. It is used for the locking mechanism in the kernel.
REFCOUNT - Lock reference count
This is to support locks that could be acquired recursively in the ZCOM
subsystem. Every time when the ZCOM lock is acquired, this count is
incremented. When the ZCOM lock is released, this count is
decremented. Only when this count reaches zero, the kernel lock (via the
LOCKP pointer) is released.
Table 3-52 Super IFT spinlock (ZC_SLOCK) Data Structure
Field Name Field Description Field Type
Size
(Bytes)
LOCKP Pointer to kernel spinlock structure pointer 8
REFCOUNT Lock reference count int 4
SPARE1 Reserved, not used int 4