block: fixup rq_init() a bit

Rearrange fields in cache order and initialize some fields that
we didn't previously init. Remove init of ->completion_data, it's
part of a union with ->hash. Luckily clearing the rb node is the same
as setting it to null!

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2008-02-08 12:41:03 +01:00
parent a4ffc0a0b2
commit 63a7138671
2 changed files with 24 additions and 11 deletions

View File

@ -102,27 +102,38 @@ struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
}
EXPORT_SYMBOL(blk_get_backing_dev_info);
/*
* We can't just memset() the structure, since the allocation path
* already stored some information in the request.
*/
void rq_init(struct request_queue *q, struct request *rq)
{
INIT_LIST_HEAD(&rq->queuelist);
INIT_LIST_HEAD(&rq->donelist);
rq->errors = 0;
rq->q = q;
rq->sector = rq->hard_sector = (sector_t) -1;
rq->nr_sectors = rq->hard_nr_sectors = 0;
rq->current_nr_sectors = rq->hard_cur_sectors = 0;
rq->bio = rq->biotail = NULL;
INIT_HLIST_NODE(&rq->hash);
RB_CLEAR_NODE(&rq->rb_node);
rq->ioprio = 0;
rq->buffer = NULL;
rq->ref_count = 1;
rq->q = q;
rq->special = NULL;
rq->data_len = 0;
rq->data = NULL;
rq->rq_disk = NULL;
rq->nr_phys_segments = 0;
rq->nr_hw_segments = 0;
rq->ioprio = 0;
rq->special = NULL;
rq->buffer = NULL;
rq->tag = -1;
rq->errors = 0;
rq->ref_count = 1;
rq->cmd_len = 0;
memset(rq->cmd, 0, sizeof(rq->cmd));
rq->data_len = 0;
rq->sense_len = 0;
rq->data = NULL;
rq->sense = NULL;
rq->end_io = NULL;
rq->end_io_data = NULL;
rq->completion_data = NULL;
rq->next_rq = NULL;
}

View File

@ -137,7 +137,9 @@ enum rq_flag_bits {
#define BLK_MAX_CDB 16
/*
* try to put the fields that are referenced together in the same cacheline
* try to put the fields that are referenced together in the same cacheline.
* if you modify this structure, be sure to check block/blk-core.c:rq_init()
* as well!
*/
struct request {
struct list_head queuelist;