/* * bufferio(9) ops */ /* * Mark I/O complete on a buffer. * * If a callback has been requested, e.g. the pageout * daemon, do so. Otherwise, awaken waiting processes. * * [ Leffler, et al., says on p.247: * "This routine wakes up the blocked process, frees the buffer * for an asynchronous write, or, for a request by the pagedaemon * process, invokes a procedure specified in the buffer structure" ] * * In real life, the pagedaemon (or other system processes) wants * to do async stuff to, and doesn't want the buffer brelse()'d. * (for swap pager, that puts swap buffers on the free lists (!!!), * for the vn device, that puts allocated buffers on the free lists!) */