[PATCH] 01/05 Implement generic dispatch queue
Implements generic dispatch queue which can replace all
dispatch queues implemented by each iosched. This reduces
code duplication, eases enforcing semantics over dispatch
queue, and simplifies specific ioscheds.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index efdc9b5..2c7b915 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -203,6 +203,7 @@
enum rq_flag_bits {
__REQ_RW, /* not set, read. set, write */
__REQ_FAILFAST, /* no low level driver retries */
+ __REQ_SORTED, /* elevator knows about this request */
__REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
__REQ_HARDBARRIER, /* may not be passed by drive either */
__REQ_CMD, /* is a regular fs rw request */
@@ -235,6 +236,7 @@
#define REQ_RW (1 << __REQ_RW)
#define REQ_FAILFAST (1 << __REQ_FAILFAST)
+#define REQ_SORTED (1 << __REQ_SORTED)
#define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
#define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
#define REQ_CMD (1 << __REQ_CMD)
@@ -333,6 +335,13 @@
end_flush_fn *end_flush_fn;
/*
+ * Dispatch queue sorting
+ */
+ sector_t last_sector;
+ struct request *boundary_rq;
+ unsigned int max_back_kb;
+
+ /*
* Auto-unplugging state
*/
struct timer_list unplug_timer;
@@ -454,6 +463,7 @@
#define blk_pm_request(rq) \
((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
+#define blk_sorted_rq(rq) ((rq)->flags & REQ_SORTED)
#define blk_barrier_rq(rq) ((rq)->flags & REQ_HARDBARRIER)
#define blk_barrier_preflush(rq) ((rq)->flags & REQ_BAR_PREFLUSH)
#define blk_barrier_postflush(rq) ((rq)->flags & REQ_BAR_POSTFLUSH)
@@ -611,12 +621,7 @@
static inline void blkdev_dequeue_request(struct request *req)
{
- BUG_ON(list_empty(&req->queuelist));
-
- list_del_init(&req->queuelist);
-
- if (req->rl)
- elv_remove_request(req->q, req);
+ elv_dequeue_request(req->q, req);
}
/*