buf_unlock(9r) [osf1 man page]

BUF_UNLOCK(9r)															    BUF_UNLOCK(9r)

NAME

       BUF_UNLOCK - General: Unlocks the specified I/O buffer

SYNOPSIS

       void BUF_UNLOCK(
	       struct buf *bp );

ARGUMENTS

       Specifies a pointer to a buf structure.

DESCRIPTION

       The  BUF_UNLOCK	routine  unlocks  the specified I/O buffer that was locked in a previous call to BUF_LOCK.  The routine masks all disk and
       tape controller interrupts (by calling the splbio routine). It resets the mutual exclusion buffer lock member, b_lock, of the specified buf
       structure pointer.

       The  BUF_UNLOCK	routine  then  resets  the b_flags member of the specified buf structure pointer to indicate that this buffer is not being
       used. Finally, BUF_UNLOCK resets the CPU priority level (by calling the splx routine).

NOTES

       You must have locked the specified I/O buffer by calling BUF_LOCK prior to calling the BUF_UNLOCK routine.

RETURN VALUES

       None

SEE ALSO

       Routines: BUF_LOCK(9r)

																    BUF_UNLOCK(9r)

spl(9r) 																   spl(9r)

NAME

       spl - General: Sets the processor priority to mask different levels of interrupts

SYNOPSIS

       #include <machine/cpu.h>

       int getspl(
	       void ); int splbio(
	       void ); int splclock(
	       void ); int spldevhigh(
	       void ); int splextreme(
	       void ); int splhigh(
	       void ); int splimp(
	       void ); int splnet(
	       void ); int splnone(
	       void ); int splsched(
	       void ); int splsoftclock(
	       void ); int spltty(
	       void ); int splvm(
	       void ); int splx(
	       int x );

ARGUMENTS

       Specifies a CPU priority level. This level must be a value returned by a previous call to one of the spl routines.

DESCRIPTION

       The  operating  system	supports  the naming of spl routines to indicate the associated device types. Named spl routines make it easier to
       determine which routine you should use to set the priority level for a given device type. The following table summarizes the uses  for  the
       different spl routines: Obtains the spl value.  Masks all disk and tape controller interrupts.  Masks all hardware clock interrupts.  Masks
       all device and software interrupts.  Blocks against all but halt interrupts.  Masks all interrupts except  for  realtime  devices,  machine
       checks, and halt interrupts.  Masks all LAN hardware interrupts.  Masks all network software interrupts.  Unmasks (enables) all interrupts.
       Masks all scheduling interrupts (usually the hardware clock).  Masks all software clock interrupts.  Masks all tty (terminal device) inter-
       rupts.  Masks all virtual memory clock interrupts.  Resets the CPU priority to the level specified by the argument.

NOTES

       The  binding  of  any  spl  routine  with a specific CPU priority level is highly machine dependent. With the exceptions of the splhigh and
       splnone routines, knowledge of the explicit bindings is not required to create new device drivers. You always use splhigh to mask (disable)
       all interrupts and splnone to unmask (enable) all interrupts.

RETURN VALUES

       Upon  successful  completion,  each  spl routine returns an integer value that represents the CPU priority level that existed before it was
       changed by a call to the specified spl routine.

EXAMPLE

       The following code fragment shows the use of spl routines as part of a disk strategy routine:

       int s;
	.
	.
	.  s = splbio(); /* Mask (disable) all disk interrupts */
	.
	.
	.  [Code to deal with data that can be modified by the disk interrupt code]
	.
	.
	.  splx(s); /* Restore CPU priority to what it was */

																	   spl(9r)