INTRO (9) NetBSD Kernel Developer's Manual INTRO (9) NAME ...

BUFQ (9) NetBSD Kernel Developer’s Manual BUFQ (9)NAMEbufq, bufq_state, bufq_alloc, bufq_drain, bufq_free, bufq_getstrategyname,bufq_move, BUFQ_PUT, BUFQ_GET, BUFQ_PEEK, BUFQ_CANCEL —device buffer queuesSYNOPSIS#include intbufq_alloc(struct bufq_state ∗∗bufq , const char ∗strategy , int flags);voidbufq_drain(struct bufq_state ∗bufq);voidbufq_free(struct bufq_state ∗bufq);const char ∗bufq_getstrategyname(struct bufq_state ∗bufq);voidbufq_move(struct bufq_state ∗dst , struct bufq_state ∗src);voidBUFQ_PUT(struct bufq_state ∗bufq , struct buf ∗bp);struct buf ∗BUFQ_GET(struct bufq_state ∗bufq);struct buf ∗BUFQ_PEEK(struct bufq_state ∗bufq);struct buf ∗BUFQ_CANCEL(struct bufq_state ∗bufq , struct buf ∗bp);DESCRIPTIONThe bufq subsystem is a set of operations for the management of device buffer queues.The primary data type for using the operations is the bufq_state structure, which is opaque for users.FUNCTIONSbufq_alloc(bufq , strategy , flags)Allocate and initialize a bufq_state descriptor.The argument strategy specifies a buffer queue strategy to be used for this buffer queue. Thefollowing special values can be used:BUFQ_STRAT_ANYLet bufq_alloc() select a strategy.BUFQ_DISK_DEFAULT_STRAT Let bufq_alloc() select a strategy, assuming it willbe used for a normal disk device.Valid bits for the flags are:BUFQ_SORT_RAWBLOCK sort by b_rawblknoBUFQ_SORT_CYLINDER sort by b_cylinder and then by b_rawblknoBUFQ_EXACTFail if a strategy specified by strategy is not available. Inthat case, bufq_alloc returns ENOENT. Ifthis flag is notspecified, bufq_alloc() will silently use one of availablestrategies.NetBSD 3.0 December 26, 2005 1