From 63a7138671c50a6f2c27bbd1a308dc75967062a3 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 8 Feb 2008 12:41:03 +0100 Subject: [PATCH] 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 --- block/blk-core.c | 23 +++++++++++++++++------ include/linux/blkdev.h | 4 +++- 2 files changed, 20 insertions(+), 7 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 4afb39c8233..fba4ca7c608 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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->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->q = q; - rq->special = NULL; + rq->cmd_len = 0; + memset(rq->cmd, 0, sizeof(rq->cmd)); rq->data_len = 0; + rq->sense_len = 0; rq->data = NULL; - rq->nr_phys_segments = 0; rq->sense = NULL; rq->end_io = NULL; rq->end_io_data = NULL; - rq->completion_data = NULL; rq->next_rq = NULL; } diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 90392a9d7a9..e1888cc5b8a 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -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; -- 2.41.1