Commit e14575b3 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: convert REQ_ATOM_COMPLETE to stealing rq->__deadline bit 



We only have one atomic flag left. Instead of using an entire
unsigned long for that, steal the bottom bit of the deadline
field that we already reserved.

Remove ->atomic_flags, since it's now unused.

Reviewed-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0a72e7f4

block/blk-core.c

+1 −1
Original line number Diff line number Diff line
@@ -2853,7 +2853,7 @@ void blk_start_request(struct request *req) 
		wbt_issue(req->q->rq_wb, &req->issue_stat);

	}



	BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags));

	BUG_ON(blk_rq_is_complete(req));

	blk_add_timer(req);

}

EXPORT_SYMBOL(blk_start_request);

block/blk-mq-debugfs.c

+1 −8
Original line number Diff line number Diff line
@@ -294,12 +294,6 @@ static const char *const rqf_name[] = { 
};

#undef RQF_NAME



#define RQAF_NAME(name) [REQ_ATOM_##name] = #name

static const char *const rqaf_name[] = {

	RQAF_NAME(COMPLETE),

};

#undef RQAF_NAME



int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)

{

	const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
@@ -316,8 +310,7 @@ int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq) 
	seq_puts(m, ", .rq_flags=");

	blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,

		       ARRAY_SIZE(rqf_name));

	seq_puts(m, ", .atomic_flags=");

	blk_flags_show(m, rq->atomic_flags, rqaf_name, ARRAY_SIZE(rqaf_name));

	seq_printf(m, ", complete=%d", blk_rq_is_complete(rq));

	seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,

		   rq->internal_tag);

	if (mq_ops->show_rq)

block/blk-mq.c

+1 −1
Original line number Diff line number Diff line
@@ -294,7 +294,6 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, 
		rq->rq_flags |= RQF_PREEMPT;

	if (blk_queue_io_stat(data->q))

		rq->rq_flags |= RQF_IO_STAT;

	/* do not touch atomic flags, it needs atomic ops against the timer */

	rq->cpu = -1;

	INIT_HLIST_NODE(&rq->hash);

	RB_CLEAR_NODE(&rq->rb_node);
@@ -313,6 +312,7 @@ 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;



	INIT_LIST_HEAD(&rq->timeout_list);

	rq->timeout = 0;

block/blk.h

+9 −10
Original line number Diff line number Diff line
@@ -119,25 +119,24 @@ 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);



/*

 * Internal atomic flags for request handling

 */

enum rq_atomic_flags {

	REQ_ATOM_COMPLETE = 0,

};



/*

 * EH timer and IO completion will both attempt to 'grab' the request, make

 * sure that only one of them succeeds

 * 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(REQ_ATOM_COMPLETE, &rq->atomic_flags);

	return test_and_set_bit(0, &rq->__deadline);

}



static inline void blk_clear_rq_complete(struct request *rq)

{

	clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);

	clear_bit(0, &rq->__deadline);

}



static inline bool blk_rq_is_complete(struct request *rq)

{

	return test_bit(0, &rq->__deadline);

}



/*

include/linux/blkdev.h

+0 −2
Original line number Diff line number Diff line
@@ -156,8 +156,6 @@ struct request { 


	int internal_tag;



	unsigned long atomic_flags;



	/* the following two fields are internal, NEVER access directly */

	unsigned int __data_len;	/* total data len */

	int tag;