From 904a1abd878380f9e56fe1c251e4c07c913249ce Mon Sep 17 00:00:00 2001 From: Joursoir Date: Thu, 12 Jan 2023 17:59:59 +0400 Subject: open and copy the characterictics of a target device Task: 1 --- sbdd.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/sbdd.c b/sbdd.c index 09d1925..8d8474f 100644 --- a/sbdd.c +++ b/sbdd.c @@ -21,6 +21,8 @@ #include #define SBDD_NAME "sbdd" +#define SBDD_BDEV_MODE (FMODE_READ | FMODE_WRITE) +#define TARGET_DEV "/dev/disk/by-id/ata-QEMU_HARDDISK_QM00001" struct sbdd { wait_queue_head_t exitwait; @@ -30,6 +32,7 @@ struct sbdd { sector_t capacity; struct gendisk *gd; struct request_queue *q; + struct block_device *bdev; }; static struct sbdd __sbdd; @@ -97,6 +100,8 @@ static struct block_device_operations const __sbdd_bdev_ops = { static int sbdd_create(void) { int ret = 0; + unsigned short lblock_size; + unsigned int max_sectors; /* This call is somewhat redundant, but used anyways by tradition. @@ -126,6 +131,20 @@ static int sbdd_create(void) pr_info("allocating disk\n"); __sbdd.gd = alloc_disk(1); + /* Get a handle on the device */ + pr_info("opening %s\n", TARGET_DEV); + __sbdd.bdev = blkdev_get_by_path(TARGET_DEV, SBDD_BDEV_MODE, THIS_MODULE); + if (!__sbdd.bdev || IS_ERR(__sbdd.bdev)) { + pr_err("blkdev_get_by_path(\"%s\") failed with %ld\n", + TARGET_DEV, PTR_ERR(__sbdd.bdev)); + return -ENOENT; + } + + /* Configure queue */ + lblock_size = bdev_logical_block_size(__sbdd.bdev); + blk_queue_logical_block_size(__sbdd.q, lblock_size); + pr_info("\tlogical block size: %u\n", lblock_size); + /* Configure gendisk */ __sbdd.gd->queue = __sbdd.q; __sbdd.gd->major = __sbdd_major; @@ -133,7 +152,13 @@ static int sbdd_create(void) __sbdd.gd->fops = &__sbdd_bdev_ops; /* Represents name in /proc/partitions and /sys/block */ scnprintf(__sbdd.gd->disk_name, DISK_NAME_LEN, SBDD_NAME); + __sbdd.capacity = get_capacity(__sbdd.bdev->bd_disk); set_capacity(__sbdd.gd, __sbdd.capacity); + pr_info("\tdevice capacity: %llu\n", __sbdd.capacity); + + max_sectors = queue_max_hw_sectors(bdev_get_queue(__sbdd.bdev)); + blk_queue_max_hw_sectors(__sbdd.q, max_sectors); + pr_info("\tmax sectors: %u\n", max_sectors); /* Allocating gd does not make it available, add_disk() required. @@ -158,6 +183,11 @@ static void sbdd_delete(void) del_gendisk(__sbdd.gd); } + if (__sbdd.bdev) { + pr_info("release a handle on the %s\n", TARGET_DEV); + blkdev_put(__sbdd.bdev, SBDD_BDEV_MODE); + } + if (__sbdd.q) { pr_info("cleaning up queue\n"); blk_cleanup_queue(__sbdd.q); -- cgit v1.2.3-18-g5258