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block: remove deadline __deadline manipulation helpers 

No users left since the removal of the legacy request interface, we can
remove all the magic bit stealing now and make it a normal field.

But use WRITE_ONCE/READ_ONCE on the new deadline field, given that we
don't seem to have any mechanism to guarantee a new value actually
gets seen by other threads.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2018-11-14 17:02:05 +01:00 committed by Jens Axboe
parent 8f4236d900
commit 079076b341
4 changed files with 8 additions and 43 deletions
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4
block/blk-mq.c
View File

@ -325,7 +325,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
rq->special = NULL;
/* tag was already set */
rq->extra_len = 0;
rq->__deadline = 0;
WRITE_ONCE(rq->deadline, 0);
rq->timeout = 0;
@ -839,7 +839,7 @@ static bool blk_mq_req_expired(struct request *rq, unsigned long *next)
if (rq->rq_flags & RQF_TIMED_OUT)
return false;
deadline = blk_rq_deadline(rq);
deadline = READ_ONCE(rq->deadline);
if (time_after_eq(jiffies, deadline))
return true;

8
block/blk-timeout.c
View File

@ -84,7 +84,7 @@ void blk_abort_request(struct request *req)
* immediately and that scan sees the new timeout value.
* No need for fancy synchronizations.
*/
blk_rq_set_deadline(req, jiffies);
WRITE_ONCE(req->deadline, jiffies);
kblockd_schedule_work(&req->q->timeout_work);
}
EXPORT_SYMBOL_GPL(blk_abort_request);
@ -121,14 +121,16 @@ void blk_add_timer(struct request *req)
req->timeout = q->rq_timeout;
req->rq_flags &= ~RQF_TIMED_OUT;
blk_rq_set_deadline(req, jiffies + req->timeout);
expiry = jiffies + req->timeout;
WRITE_ONCE(req->deadline, expiry);
/*
* If the timer isn't already pending or this timeout is earlier
* than an existing one, modify the timer. Round up to next nearest
* second.
*/
expiry = blk_rq_timeout(round_jiffies_up(blk_rq_deadline(req)));
expiry = blk_rq_timeout(round_jiffies_up(expiry));
if (!timer_pending(&q->timeout) ||
time_before(expiry, q->timeout.expires)) {

35
block/blk.h
View File

@ -238,26 +238,6 @@ void blk_account_io_start(struct request *req, bool new_io);
void blk_account_io_completion(struct request *req, unsigned int bytes);
void blk_account_io_done(struct request *req, u64 now);
/*
* EH timer and IO completion will both attempt to 'grab' the request, make
* sure that only one of them succeeds. Steal the bottom bit of the
* __deadline field for this.
*/
static inline int blk_mark_rq_complete(struct request *rq)
{
return test_and_set_bit(0, &rq->__deadline);
}
static inline void blk_clear_rq_complete(struct request *rq)
{
clear_bit(0, &rq->__deadline);
}
static inline bool blk_rq_is_complete(struct request *rq)
{
return test_bit(0, &rq->__deadline);
}
/*
* Internal elevator interface
*/
@ -322,21 +302,6 @@ static inline void req_set_nomerge(struct request_queue *q, struct request *req)
q->last_merge = NULL;
}
/*
* Steal a bit from this field for legacy IO path atomic IO marking. Note that
* setting the deadline clears the bottom bit, potentially clearing the
* completed bit. The user has to be OK with this (current ones are fine).
*/
static inline void blk_rq_set_deadline(struct request *rq, unsigned long time)
{
rq->__deadline = time & ~0x1UL;
}
static inline unsigned long blk_rq_deadline(struct request *rq)
{
return rq->__deadline & ~0x1UL;
}
/*
* Internal io_context interface
*/

4
include/linux/blkdev.h
View File

@ -224,9 +224,7 @@ struct request {
refcount_t ref;
unsigned int timeout;
/* access through blk_rq_set_deadline, blk_rq_deadline */
unsigned long __deadline;
unsigned long deadline;
union {
struct __call_single_data csd;