NAME    [Toc]    [Back]

       BUF_LOCK - General: Locks the specified I/O buffer

SYNOPSIS    [Toc]    [Back]

       void BUF_LOCK(
               struct buf *bp );

ARGUMENTS    [Toc]    [Back]

       Specifies a pointer to a buf structure.

DESCRIPTION    [Toc]    [Back]

       The  BUF_LOCK routine locks the specified I/O buffer.  The
       routine masks all disk and tape controller interrupts  (by
       calling  the splbio routine). It sets the mutual exclusion
       buffer lock member, b_lock, of the specified buf structure
       pointer.

       The  BUF_LOCK  routine then sets the b_flags member of the
       specified buf structure pointer to B_BUSY to indicate that
       this  buffer  is  being used. Finally, BUF_LOCK resets the
       CPU priority level (by calling the splx routine).

NOTES    [Toc]    [Back]

       You should design in your kernel modules to hold  the  I/O
       buffer  lock  for as short a period of time as possible to
       allow maximum concurrency. You should also release the I/O
       buffer  lock  by  calling  the  BUF_UNLOCK  routine before
       returning from the module's entry point.

RETURN VALUES    [Toc]    [Back]

       None

SEE ALSO    [Toc]    [Back]

       Routines: BUF_UNLOCK(9r)



                                                     BUF_LOCK(9r)