From 8449debb60f91a5761cd70f391f96f000d19a9ae Mon Sep 17 00:00:00 2001 From: Joursoir Date: Fri, 13 Jan 2023 19:45:00 +0400 Subject: redirect requests to target device Task: 1 --- sbdd.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 51 insertions(+), 5 deletions(-) diff --git a/sbdd.c b/sbdd.c index fb62971..7d4a64e 100644 --- a/sbdd.c +++ b/sbdd.c @@ -36,8 +36,28 @@ struct sbdd { static struct sbdd __sbdd; static int __sbdd_major = 0; +static struct bio_set __sbdd_bio_set; static char *__sbdd_disk = "/dev/disk/by-id/ata-QEMU_HARDDISK_QM00001"; +struct sbdd_io_bio { + struct bio *original_bio; +}; + +static void io_end_bio(struct bio *bio) +{ + struct sbdd_io_bio *io_bio = bio->bi_private; + + pr_debug("I/O operation is completed\n"); + + io_bio->original_bio->bi_status = bio->bi_status; + bio_endio(io_bio->original_bio); + bio_put(bio); + kfree(io_bio); + + if (atomic_dec_and_test(&__sbdd.refs_cnt)) + wake_up(&__sbdd.exitwait); +} + /*static sector_t sbdd_xfer(struct bio_vec* bvec, sector_t pos, int dir) { void *buff = page_address(bvec->bv_page) + bvec->bv_offset; @@ -67,7 +87,29 @@ static char *__sbdd_disk = "/dev/disk/by-id/ata-QEMU_HARDDISK_QM0000 static void sbdd_xfer_bio(struct bio *bio) { - /* TODO: send request to another device */ + struct bio *bio_clone; + struct sbdd_io_bio *io_bio; + + io_bio = kmalloc(sizeof(*io_bio), GFP_KERNEL); + if (!io_bio) { + pr_err("unable to allocate space for struct io_bio\n"); + return; + } + io_bio->original_bio = bio; + + bio_clone = bio_clone_fast(bio, GFP_NOIO, &__sbdd_bio_set); + if (!bio_clone) { + pr_err("unable to clone bio\n"); + kfree(io_bio); + return; + } + + bio_set_dev(bio_clone, __sbdd.bdev); + bio_clone->bi_private = io_bio; + bio_clone->bi_end_io = io_end_bio; + + pr_debug("submitting bio...\n"); + submit_bio(bio_clone); } static blk_qc_t sbdd_make_request(struct request_queue *q, struct bio *bio) @@ -81,10 +123,6 @@ static blk_qc_t sbdd_make_request(struct request_queue *q, struct bio *bio) atomic_inc(&__sbdd.refs_cnt); sbdd_xfer_bio(bio); - bio_endio(bio); - - if (atomic_dec_and_test(&__sbdd.refs_cnt)) - wake_up(&__sbdd.exitwait); return BLK_STS_OK; } @@ -103,6 +141,12 @@ static int sbdd_create(void) unsigned short lblock_size; unsigned int max_sectors; + ret = bioset_init(&__sbdd_bio_set, BIO_POOL_SIZE, 0, 0); + if (ret) { + pr_err("create BIO set failed: %d\n", ret); + return ret; + } + /* This call is somewhat redundant, but used anyways by tradition. The number is to be displayed in /proc/devices (0 for auto). @@ -203,6 +247,8 @@ static void sbdd_delete(void) unregister_blkdev(__sbdd_major, SBDD_NAME); __sbdd_major = 0; } + + bioset_exit(&__sbdd_bio_set); } /* -- cgit v1.2.3-18-g5258