Commit a1d91404 authored by NeilBrown's avatar NeilBrown Committed by Jens Axboe
Browse files

pktcdvd: use bio_clone_fast() instead of bio_clone() 



pktcdvd doesn't change the bi_io_vec of the clone bio,
so it is more efficient to use bio_clone_fast(), and not clone
the bi_io_vec.
This requires providing a bio_set, and it is safest to
provide a dedicated bio_set rather than sharing
fs_bio_set, which filesytems use.
This new bio_set, pkt_bio_set, can also be use for the bio_split()
call as the two allocations (bio_clone_fast, and bio_split) are
independent, neither can block a bio allocated by the other.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8cb0defb

drivers/block/pktcdvd.c

+10 −2
Original line number Diff line number Diff line
@@ -98,6 +98,7 @@ static int write_congestion_on = PKT_WRITE_CONGESTION_ON; 
static int write_congestion_off = PKT_WRITE_CONGESTION_OFF;

static struct mutex ctl_mutex;	/* Serialize open/close/setup/teardown */

static mempool_t *psd_pool;

static struct bio_set *pkt_bio_set;



static struct class	*class_pktcdvd = NULL;    /* /sys/class/pktcdvd */

static struct dentry	*pkt_debugfs_root = NULL; /* /sys/kernel/debug/pktcdvd */
@@ -2310,7 +2311,7 @@ static void pkt_end_io_read_cloned(struct bio *bio) 


static void pkt_make_request_read(struct pktcdvd_device *pd, struct bio *bio)

{

	struct bio *cloned_bio = bio_clone(bio, GFP_NOIO);

	struct bio *cloned_bio = bio_clone_fast(bio, GFP_NOIO, pkt_bio_set);

	struct packet_stacked_data *psd = mempool_alloc(psd_pool, GFP_NOIO);



	psd->pd = pd;
@@ -2455,7 +2456,7 @@ static blk_qc_t pkt_make_request(struct request_queue *q, struct bio *bio) 


			split = bio_split(bio, last_zone -

					  bio->bi_iter.bi_sector,

					  GFP_NOIO, fs_bio_set);

					  GFP_NOIO, pkt_bio_set);

			bio_chain(split, bio);

		} else {

			split = bio;
@@ -2924,6 +2925,11 @@ static int __init pkt_init(void) 
					sizeof(struct packet_stacked_data));

	if (!psd_pool)

		return -ENOMEM;

	pkt_bio_set = bioset_create(BIO_POOL_SIZE, 0, 0);

	if (!pkt_bio_set) {

		mempool_destroy(psd_pool);

		return -ENOMEM;

	}



	ret = register_blkdev(pktdev_major, DRIVER_NAME);

	if (ret < 0) {
@@ -2956,6 +2962,7 @@ out: 
	unregister_blkdev(pktdev_major, DRIVER_NAME);

out2:

	mempool_destroy(psd_pool);

	bioset_free(pkt_bio_set);

	return ret;

}
@@ -2969,6 +2976,7 @@ static void __exit pkt_exit(void) 


	unregister_blkdev(pktdev_major, DRIVER_NAME);

	mempool_destroy(psd_pool);

	bioset_free(pkt_bio_set);

}



MODULE_DESCRIPTION("Packet writing layer for CD/DVD drives");

CRA Git | Maintained and supported by SUSTech CRA and CCSE