[patch 4/4] io controller: Put IO controller to use in device mapper and standard make_request() function

From: vgoyal
Date: Thu Nov 06 2008 - 10:35:16 EST



o Tweak standard make_request() function and also the device mapper make
request functions to enable use of IO controller.

Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>

Index: linux17/drivers/md/dm.c
===================================================================
--- linux17.orig/drivers/md/dm.c 2008-11-05 18:12:42.000000000 -0500
+++ linux17/drivers/md/dm.c 2008-11-06 09:16:32.000000000 -0500
@@ -22,6 +22,7 @@
#include <linux/hdreg.h>
#include <linux/blktrace_api.h>
#include <linux/smp_lock.h>
+#include <linux/biocontrol.h>

#define DM_MSG_PREFIX "core"

@@ -885,6 +886,7 @@ static int dm_request(struct request_que
int r = -EIO;
int rw = bio_data_dir(bio);
struct mapped_device *md = q->queuedata;
+ int ret;

/*
* There is no use in forwarding any barrier request since we can't
@@ -895,6 +897,13 @@ static int dm_request(struct request_que
return 0;
}

+ if (!bio_cgroup_disabled() && blk_queue_bio_group_enabled(q)) {
+ ret = bio_group_controller(q, bio);
+ if (ret)
+ /* Either bio got buffered for bio_endio() done */
+ return 0;
+ }
+
down_read(&md->io_lock);

disk_stat_inc(dm_disk(md), ios[rw]);
@@ -1081,6 +1090,10 @@ static struct mapped_device *alloc_dev(i
md->queue->unplug_fn = dm_unplug_all;
blk_queue_merge_bvec(md->queue, dm_merge_bvec);

+ /* Initialize queue spin lock */
+ md->queue->queue_lock = &md->queue->__queue_lock;
+ spin_lock_init(md->queue->queue_lock);
+
md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache);
if (!md->io_pool)
goto bad_io_pool;
Index: linux17/block/blk-core.c
===================================================================
--- linux17.orig/block/blk-core.c 2008-11-06 09:14:20.000000000 -0500
+++ linux17/block/blk-core.c 2008-11-06 09:16:32.000000000 -0500
@@ -1117,10 +1117,18 @@ static int __make_request(struct request
int el_ret, nr_sectors, barrier, err;
const unsigned short prio = bio_prio(bio);
const int sync = bio_sync(bio);
- int rw_flags;
+ int rw_flags, ret;

nr_sectors = bio_sectors(bio);

+ if (!bio_cgroup_disabled() && blk_queue_bio_group_enabled(q)) {
+ ret = bio_group_controller(q, bio);
+ if (ret) {
+ /* Either bio got buffered for bio_endio() done */
+ return 0;
+ }
+ }
+
/*
* low level driver can indicate that it wants pages above a
* certain limit bounced to low memory (ie for highmem, or even

--

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