In places (ie. blk_remove_plug), we need to access the queue. Previously we
would go through arq->request->q, but Hugh oopsed because I added a case
which needed the queue, but we had no arq.
It puts a pointer queue that "owns" the as_data in as_data.
drivers/block/as-iosched.c | 41 +++++++++++++++++++----------------------
1 files changed, 19 insertions(+), 22 deletions(-)
diff -puN drivers/block/as-iosched.c~as-fix-hughs-problem drivers/block/as-iosched.c
--- 25/drivers/block/as-iosched.c~as-fix-hughs-problem 2003-02-24 23:33:06.000000000 -0800
+++ 25-akpm/drivers/block/as-iosched.c 2003-02-24 23:33:10.000000000 -0800
@@ -100,13 +100,15 @@ struct as_data {
* run time data
*/
+ struct request_queue *q; /* the "owner" queue */
+
/*
* requests (as_rq s) are present on both sort_list and fifo_list
*/
struct rb_root sort_list[2];
struct list_head fifo_list[2];
- struct as_rq *next_arq[2];/* next in sort order */
+ struct as_rq *next_arq[2]; /* next in sort order */
sector_t last_sector[2]; /* last READ and WRITE sectors */
struct list_head *dispatch; /* driver dispatch queue */
struct list_head *hash; /* request hash */
@@ -291,8 +293,7 @@ __as_add_arq_rb(struct as_data *ad, stru
* direct IO, then move the alias to the dispatch list and then add the
* request.
*/
-static void
-as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
+static void as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
{
struct as_rq *alias;
struct request *rq = arq->request;
@@ -307,8 +308,7 @@ as_add_arq_rb(struct as_data *ad, struct
}
static struct as_rq *
-as_choose_req(struct as_data *ad,
- struct as_rq *arq1, struct as_rq *arq2);
+as_choose_req(struct as_data *ad, struct as_rq *arq1, struct as_rq *arq2);
static inline void
as_del_arq_rb(struct as_data *ad, struct as_rq *arq)
@@ -363,8 +363,7 @@ as_find_arq_rb(struct as_data *ad, secto
/*
* add arq to rbtree and fifo
*/
-static void
-as_add_request(struct as_data *ad, struct as_rq *arq)
+static void as_add_request(struct as_data *ad, struct as_rq *arq)
{
const int data_dir = rq_data_dir(arq->request);
@@ -519,12 +518,9 @@ as_merged_requests(request_queue_t *q, s
/*
* move request from sort list to dispatch queue.
*/
-static void
-as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
+static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
{
- request_queue_t *q = arq->request->q;
-
- as_remove_request(q, arq->request);
+ as_remove_request(ad->q, arq->request);
list_add_tail(&arq->request->queuelist, ad->dispatch);
}
@@ -532,14 +528,14 @@ as_move_to_dispatch(struct as_data *ad,
/*
* move an entry to dispatch queue
*/
-static void
-as_move_request(struct as_data *ad, struct as_rq *arq)
+static void as_move_request(struct as_data *ad, struct as_rq *arq)
{
const int data_dir = rq_data_dir(arq->request);
BUG_ON(!ON_RB(&arq->rb_node));
- ad->last_sector[data_dir] = arq->request->sector + arq->request->nr_sectors;
+ ad->last_sector[data_dir] = arq->request->sector
+ + arq->request->nr_sectors;
if (data_dir == READ)
/* In case we have to anticipate after this */
@@ -825,8 +821,7 @@ static void as_update_arq(struct as_data
if (ad->antic_status == ANTIC_WAIT) {
del_timer(&ad->antic_timer);
- if (arq)
- blk_remove_plug(arq->request->q);
+ blk_remove_plug(ad->q);
schedule_work(&ad->antic_work);
}
ad->antic_status = ANTIC_FINISHED;
@@ -852,7 +847,7 @@ static int can_start_anticipation(struct
*/
del_timer(&ad->antic_timer);
ad->antic_status = ANTIC_FINISHED;
- blk_remove_plug(arq->request->q);
+ blk_remove_plug(ad->q);
schedule_work(&ad->antic_work);
return 0;
}
@@ -879,9 +874,9 @@ static int can_start_anticipation(struct
* read/write expire, batch expire, etc, and moves it to the dispatch
* queue. Returns 1 if a request was found, 0 otherwise.
*/
-static int as_dispatch_request(struct request_queue *q)
+static int as_dispatch_request(struct as_data *ad)
{
- struct as_data *ad = q->elevator.elevator_data;
+ struct request_queue *q = ad->q;
struct as_rq *arq;
const int reads = !list_empty(&ad->fifo_list[READ]);
const int writes = !list_empty(&ad->fifo_list[WRITE]);
@@ -1019,7 +1014,7 @@ static struct request *as_next_request(r
/*
* if there are still requests on the dispatch queue, grab the first
*/
- if (!list_empty(ad->dispatch) || as_dispatch_request(q))
+ if (!list_empty(ad->dispatch) || as_dispatch_request(ad))
rq = list_entry_rq(ad->dispatch->next);
return rq;
}
@@ -1092,7 +1087,7 @@ static int as_queue_notready(request_que
if (ad->antic_status == ANTIC_WAIT)
return 1;
- if (!as_dispatch_request(q))
+ if (!as_dispatch_request(ad))
return 1;
return 0;
@@ -1170,6 +1165,8 @@ static int as_init(request_queue_t *q, e
return -ENOMEM;
memset(ad, 0, sizeof(*ad));
+ ad->q = q; /* Identify what queue the data belongs to */
+
ad->hash = kmalloc(sizeof(struct list_head)*AS_HASH_ENTRIES,GFP_KERNEL);
if (!ad->hash) {
kfree(ad);
_