[PATCH] separate bdi congestion functions from queue congestion functions

Separate out the concept of "queue congestion" from "backing-dev congestion".
Congestion is a backing-dev concept, not a queue concept.

The blk_* congestion functions are retained, as wrappers around the core
backing-dev congestion functions.

This proper layering is needed so that NFS can cleanly use the congestion
functions, and so that CONFIG_BLOCK=n actually links.

Cc: "Thomas Maier" <balagi@justmail.de>
Cc: "Jens Axboe" <jens.axboe@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: David Howells <dhowells@redhat.com>
Cc: Peter Osterlund <petero2@telia.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 0 insertions, 71 deletions

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 132a858ce2c..136066583c6 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -56,11 +56,6 @@ static kmem_cache_t *requestq_cachep;
  */
 static kmem_cache_t *iocontext_cachep;
 
-static wait_queue_head_t congestion_wqh[2] = {
-                __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
-                __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
-        };
-
 /*
  * Controlling structure to kblockd
  */
@@ -112,37 +107,6 @@ static void blk_queue_congestion_threshold(struct request_queue *q)
         q->nr_congestion_off = nr;
 }
 
-/*
- * A queue has just exitted congestion.  Note this in the global counter of
- * congested queues, and wake up anyone who was waiting for requests to be
- * put back.
- */
-void blk_clear_queue_congested(request_queue_t *q, int rw)
-{
-        enum bdi_state bit;
-        wait_queue_head_t *wqh = &congestion_wqh[rw];
-
-        bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
-        clear_bit(bit, &q->backing_dev_info.state);
-        smp_mb__after_clear_bit();
-        if (waitqueue_active(wqh))
-                wake_up(wqh);
-}
-EXPORT_SYMBOL(blk_clear_queue_congested);
-
-/*
- * A queue has just entered congestion.  Flag that in the queue's VM-visible
- * state flags and increment the global gounter of congested queues.
- */
-void blk_set_queue_congested(request_queue_t *q, int rw)
-{
-        enum bdi_state bit;
-
-        bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
-        set_bit(bit, &q->backing_dev_info.state);
-}
-EXPORT_SYMBOL(blk_set_queue_congested);
-
 /**
  * blk_get_backing_dev_info - get the address of a queue's backing_dev_info
  * @bdev:       device
@@ -2755,41 +2719,6 @@ void blk_end_sync_rq(struct request *rq, int error)
 }
 EXPORT_SYMBOL(blk_end_sync_rq);
 
-/**
- * blk_congestion_wait - wait for a queue to become uncongested
- * @rw: READ or WRITE
- * @timeout: timeout in jiffies
- *
- * Waits for up to @timeout jiffies for a queue (any queue) to exit congestion.
- * If no queues are congested then just wait for the next request to be
- * returned.
- */
-long blk_congestion_wait(int rw, long timeout)
-{
-        long ret;
-        DEFINE_WAIT(wait);
-        wait_queue_head_t *wqh = &congestion_wqh[rw];
-
-        prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
-        ret = io_schedule_timeout(timeout);
-        finish_wait(wqh, &wait);
-        return ret;
-}
-
-EXPORT_SYMBOL(blk_congestion_wait);
-
-/**
- * blk_congestion_end - wake up sleepers on a congestion queue
- * @rw: READ or WRITE
- */
-void blk_congestion_end(int rw)
-{
-        wait_queue_head_t *wqh = &congestion_wqh[rw];
-
-        if (waitqueue_active(wqh))
-                wake_up(wqh);
-}
-
 /*
  * Has to be called with the request spinlock acquired
  */