[PATCH 1/3] block: shrink rq_map_data a bit
From: Jens Axboe <axboe@kernel.dk>
Date: 2022-08-06 15:20:12
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
We don't need full ints for several of these members. Change the page_order and nr_entries to unsigned shorts, and the true/false from_user and null_mapped to booleans. This shrinks the struct from 32 to 24 bytes on 64-bit archs. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- block/blk-map.c | 2 +- include/linux/blk-mq.h | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/block/blk-map.c b/block/blk-map.c
index df8b066cd548..4043c5809cd4 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c@@ -158,7 +158,7 @@ static int bio_copy_user_iov(struct request *rq, struct rq_map_data *map_data, bio_init(bio, NULL, bio->bi_inline_vecs, nr_pages, req_op(rq)); if (map_data) { - nr_pages = 1 << map_data->page_order; + nr_pages = 1U << map_data->page_order; i = map_data->offset / PAGE_SIZE; } while (len) {
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index effee1dc715a..1f21590439d4 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h@@ -964,11 +964,11 @@ blk_status_t blk_insert_cloned_request(struct request *rq); struct rq_map_data { struct page **pages; - int page_order; - int nr_entries; unsigned long offset; - int null_mapped; - int from_user; + unsigned short page_order; + unsigned short nr_entries; + bool null_mapped; + bool from_user; }; int blk_rq_map_user(struct request_queue *, struct request *,
--
2.35.1