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[PATCH] block: implement elv_insert and use it (fix ordcolor flipping bug)

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q->ordcolor must only be flipped on initial queueing of a hardbarrier
request.

Constructing ordered sequence and requeueing used to pass through
__elv_add_request() which flips q->ordcolor when it sees a barrier
request.

This patch separates out elv_insert() from __elv_add_request() and uses
elv_insert() when constructing ordered sequence and requeueing.
elv_insert() inserts the given request at the specified position and
does nothing else.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Tejun Heo 2006-02-08 01:01:31 -08:00 committed by Linus Torvalds
parent e5ea0a9fca
commit 30e9656cc3
3 changed files with 41 additions and 34 deletions
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70
block/elevator.c
View file

@ -293,7 +293,7 @@ void elv_requeue_request(request_queue_t *q, struct request *rq)
rq->flags &= ~REQ_STARTED; rq->flags &= ~REQ_STARTED;
__elv_add_request(q, rq, ELEVATOR_INSERT_REQUEUE, 0); elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE);
} }
static void elv_drain_elevator(request_queue_t *q) static void elv_drain_elevator(request_queue_t *q)
@ -310,41 +310,11 @@ static void elv_drain_elevator(request_queue_t *q)
} }
} }
void __elv_add_request(request_queue_t *q, struct request *rq, int where, void elv_insert(request_queue_t *q, struct request *rq, int where)
int plug)
{ {
struct list_head *pos; struct list_head *pos;
unsigned ordseq; unsigned ordseq;
if (q->ordcolor)
rq->flags |= REQ_ORDERED_COLOR;
if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
/*
* toggle ordered color
*/
if (blk_barrier_rq(rq))
q->ordcolor ^= 1;
/*
* barriers implicitly indicate back insertion
*/
if (where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
/*
* this request is scheduling boundary, update end_sector
*/
if (blk_fs_request(rq)) {
q->end_sector = rq_end_sector(rq);
q->boundary_rq = rq;
}
} else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
if (plug)
blk_plug_device(q);
rq->q = q; rq->q = q;
switch (where) { switch (where) {
@ -425,6 +395,42 @@ void __elv_add_request(request_queue_t *q, struct request *rq, int where,
} }
} }
void __elv_add_request(request_queue_t *q, struct request *rq, int where,
int plug)
{
if (q->ordcolor)
rq->flags |= REQ_ORDERED_COLOR;
if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
/*
* toggle ordered color
*/
if (blk_barrier_rq(rq))
q->ordcolor ^= 1;
/*
* barriers implicitly indicate back insertion
*/
if (where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
/*
* this request is scheduling boundary, update
* end_sector
*/
if (blk_fs_request(rq)) {
q->end_sector = rq_end_sector(rq);
q->boundary_rq = rq;
}
} else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
if (plug)
blk_plug_device(q);
elv_insert(q, rq, where);
}
void elv_add_request(request_queue_t *q, struct request *rq, int where, void elv_add_request(request_queue_t *q, struct request *rq, int where,
int plug) int plug)
{ {

4
block/ll_rw_blk.c
View file

@ -454,7 +454,7 @@ static void queue_flush(request_queue_t *q, unsigned which)
rq->end_io = end_io; rq->end_io = end_io;
q->prepare_flush_fn(q, rq); q->prepare_flush_fn(q, rq);
__elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
} }
static inline struct request *start_ordered(request_queue_t *q, static inline struct request *start_ordered(request_queue_t *q,
@ -490,7 +490,7 @@ static inline struct request *start_ordered(request_queue_t *q,
else else
q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH; q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH;
__elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
if (q->ordered & QUEUE_ORDERED_PREFLUSH) { if (q->ordered & QUEUE_ORDERED_PREFLUSH) {
queue_flush(q, QUEUE_ORDERED_PREFLUSH); queue_flush(q, QUEUE_ORDERED_PREFLUSH);

1
include/linux/elevator.h
View file

@ -82,6 +82,7 @@ struct elevator_queue
extern void elv_dispatch_sort(request_queue_t *, struct request *); extern void elv_dispatch_sort(request_queue_t *, struct request *);
extern void elv_add_request(request_queue_t *, struct request *, int, int); extern void elv_add_request(request_queue_t *, struct request *, int, int);
extern void __elv_add_request(request_queue_t *, struct request *, int, int); extern void __elv_add_request(request_queue_t *, struct request *, int, int);
extern void elv_insert(request_queue_t *, struct request *, int);
extern int elv_merge(request_queue_t *, struct request **, struct bio *); extern int elv_merge(request_queue_t *, struct request **, struct bio *);
extern void elv_merge_requests(request_queue_t *, struct request *, extern void elv_merge_requests(request_queue_t *, struct request *,
struct request *); struct request *);