biowait(9F)

NAME

biowait − suspend processes pending completion of block I/O

SYNOPSIS

#include <sys/types.h>
#include <sys/buf.h>
int biowait(struct buf ∗bp);

ARGUMENTS

bp Pointer to the buf structure.

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI).

DESCRIPTION

biowait() suspends process execution during a block I/O transfer by calling sleep(). Block driver routines using the buf structure to allocate buffers can use the biowait() function to suspend a process while waiting for a read or write request to complete.

biowait() is one of three functions used to aid block I/O transfers. The other functions in this group are biodone(9F), which notifies biowait() that the I/O is complete, and brelse(9F), which frees the buffer allocated for the transfer.

Because biowait() calls sleep(), drivers using the biowait() must also include biodone(9F) in their interrupt routines. The biodone(9F) function awakens biowait() when the I/O transfer is complete.

Because biowait() calls sleep(), biowait() cannot be called from an interrupt routine.

RETURN VALUES

None. However, biowait() returns any error that may have occurred during the I/O transfer to the user using geterror(9F).

CONTEXT

biowait() can be called from user context only.

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