SCO OpenServer

brelse(D3oddi)

brelse -- release a block buffer

Synopsis

#include <sys/buf.h>

void brelse(struct buf bp);

Description

The brelse function is called by a block device driver to release a block buffer to the free pool of buffers. The contents of the buffer are lost and the driver is not allowed to make any further reference to it. This routine is called by iodone(D3oddi) at the completion of a block I/O request if the bit B_ASYNC is set in bp->b_flags.

The bp argument is a pointer to the buffer header relating to the buffer to be released.

When the routine is first called, the buffer header is checked to see if an error has occured on the request (bp->b_flags has B_ERROR set). If so, these additional actions occur:

The B_STALE and B_AGE flags are set in bp->b_flags.
The B_ERROR and B_DELWRI flags are removed from bp->b_flags.
The bp->b_error field is set to zero.
All processes associated with bp that are sleeping waiting for the header of this buffer or a free buffer are awakened. On completion of brelse, b_proc is set to zero to release the process's ownership of the buffer.

Arguments

Return values

brelse does not return a value.

Usage

Context and synchronization

context

Hardware applicability

Version applicability

oddi: 1, 2, 2mp, 3, 3mp, 4, 4mp, 5, 5mp, 6, 6mp block drivers.

Differences between versions

References

iodone(D3oddi)

``ODDI driver interface version for SCO OpenServer 5'' in HDK Technical Reference