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block: shrink rq_map_data a bit 

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.

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2022-08-05 16:39:04 -06:00
parent d322f355e9
commit f5d632d15e
2 changed files with 5 additions and 5 deletions
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2
block/blk-map.c
View File

@ -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) {

8
include/linux/blk-mq.h
View File

@ -963,11 +963,11 @@ 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 *,