diff options
Diffstat (limited to 'drivers/block/loop/loop_file_fmt.c')
| -rw-r--r-- | drivers/block/loop/loop_file_fmt.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/block/loop/loop_file_fmt.c b/drivers/block/loop/loop_file_fmt.c new file mode 100644 index 000000000000..f29c15ed044b --- /dev/null +++ b/drivers/block/loop/loop_file_fmt.c @@ -0,0 +1,244 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * loop_file_fmt.c + * + * File format subsystem for the loop device module. + * + * Copyright (C) 2019 Manuel Bentele + */ + +#include <linux/kernel.h> +#include <linux/module.h> + +#include "loop_file_fmt.h" + +/* storage for all registered file format drivers */ +static struct loop_file_fmt_driver *loop_file_fmt_drivers[MAX_LO_FILE_FMT] = { + NULL +}; + +int loop_file_fmt_register_driver(struct loop_file_fmt_driver *drv) +{ + int ret = 0; + + if (drv == NULL) + return -EFAULT; + + if (drv->file_fmt_type > MAX_LO_FILE_FMT) + return -EINVAL; + + if (loop_file_fmt_drivers[drv->file_fmt_type] == NULL) { + loop_file_fmt_drivers[drv->file_fmt_type] = drv; + printk(KERN_INFO "loop: successfully registered file format " + "driver %s\n", drv->name); + } else { + printk(KERN_WARNING "loop: driver for file format already " + "registered\n"); + ret = -EBUSY; + } + + return ret; +} +EXPORT_SYMBOL(loop_file_fmt_register_driver); + +void loop_file_fmt_unregister_driver(struct loop_file_fmt_driver *drv) +{ + if (drv == NULL) + return; + + if (drv->file_fmt_type > MAX_LO_FILE_FMT) + return; + + loop_file_fmt_drivers[drv->file_fmt_type] = NULL; + printk(KERN_INFO "loop: successfully unregistered file format driver " + "%s\n", drv->name); +} +EXPORT_SYMBOL(loop_file_fmt_unregister_driver); + +struct loop_file_fmt *loop_file_fmt_alloc(void) +{ + return kzalloc(sizeof(struct loop_file_fmt), GFP_KERNEL); +} + +void loop_file_fmt_free(struct loop_file_fmt *lo_fmt) +{ + kfree(lo_fmt); +} + +int loop_file_fmt_set_lo(struct loop_file_fmt *lo_fmt, struct loop_device *lo) +{ + if (lo_fmt == NULL) + return -EINVAL; + + lo_fmt->lo = lo; + + return 0; +} +EXPORT_SYMBOL(loop_file_fmt_set_lo); + +struct loop_device *loop_file_fmt_get_lo(struct loop_file_fmt *lo_fmt) +{ + return lo_fmt->lo; +} +EXPORT_SYMBOL(loop_file_fmt_get_lo); + +int loop_file_fmt_init(struct loop_file_fmt *lo_fmt) +{ + struct loop_file_fmt_ops* ops; + struct module *drv; + + if (lo_fmt->file_fmt_type > MAX_LO_FILE_FMT) + return -EINVAL; + + /* check if new file format driver is registered */ + if (loop_file_fmt_drivers[lo_fmt->file_fmt_type] == NULL) { + printk(KERN_ERR "loop_file_fmt: file format driver is not " + "available\n"); + return -ENODEV; + } + + printk(KERN_INFO "loop_file_fmt: use file format driver %s\n", + loop_file_fmt_drivers[lo_fmt->file_fmt_type]->name); + + drv = loop_file_fmt_drivers[lo_fmt->file_fmt_type]->owner; + if (!try_module_get(drv)) { + printk(KERN_ERR "loop_file_fmt: file format driver %s can not " + "be accessed\n", + loop_file_fmt_drivers[lo_fmt->file_fmt_type]->name); + return -ENODEV; + } + + ops = loop_file_fmt_drivers[lo_fmt->file_fmt_type]->ops; + if (likely(ops->init)) + return ops->init(lo_fmt); + else + return -ENOSYS; +} + +void loop_file_fmt_exit(struct loop_file_fmt *lo_fmt) +{ + struct loop_file_fmt_ops* ops; + struct module *drv; + + ops = loop_file_fmt_drivers[lo_fmt->file_fmt_type]->ops; + if (likely(ops->exit)) + ops->exit(lo_fmt); + + drv = loop_file_fmt_drivers[lo_fmt->file_fmt_type]->owner; + module_put(drv); +} + +int loop_file_fmt_read(struct loop_file_fmt *lo_fmt, + struct request *rq) +{ + struct loop_file_fmt_ops* ops = + loop_file_fmt_drivers[lo_fmt->file_fmt_type]->ops; + + if (likely(ops->read)) + return ops->read(lo_fmt, rq); + else + return -ENOSYS; +} + +int loop_file_fmt_read_aio(struct loop_file_fmt *lo_fmt, + struct request *rq) +{ + struct loop_file_fmt_ops* ops = + loop_file_fmt_drivers[lo_fmt->file_fmt_type]->ops; + + if (likely(ops->read_aio)) + return ops->read_aio(lo_fmt, rq); + else + return -ENOSYS; +} + +int loop_file_fmt_write(struct loop_file_fmt *lo_fmt, + struct request *rq) +{ + struct loop_file_fmt_ops* ops = + loop_file_fmt_drivers[lo_fmt->file_fmt_type]->ops; + + if (likely(ops->write)) + return ops->write(lo_fmt, rq); + else + return -ENOSYS; +} + +int loop_file_fmt_write_aio(struct loop_file_fmt *lo_fmt, + struct request *rq) +{ + struct loop_file_fmt_ops* ops = + loop_file_fmt_drivers[lo_fmt->file_fmt_type]->ops; + + if (likely(ops->write_aio)) + return ops->write_aio(lo_fmt, rq); + else + return -ENOSYS; +} + +int loop_file_fmt_discard(struct loop_file_fmt *lo_fmt, + struct request *rq) +{ + struct loop_file_fmt_ops* ops = + loop_file_fmt_drivers[lo_fmt->file_fmt_type]->ops; + + if (likely(ops->discard)) + return ops->discard(lo_fmt, rq); + else + return -ENOSYS; +} + +int loop_file_fmt_flush(struct loop_file_fmt *lo_fmt, + struct request *rq) +{ + struct loop_file_fmt_ops* ops = + loop_file_fmt_drivers[lo_fmt->file_fmt_type]->ops; + + if (likely(ops->flush)) + return ops->flush(lo_fmt, rq); + else + return -ENOSYS; +} + +int loop_file_fmt_change(struct loop_file_fmt *lo_fmt, + __u32 file_fmt_type_new) +{ + if (file_fmt_type_new > MAX_LO_FILE_FMT) + return -EINVAL; + + /* + * Unload the old file format driver and after that, + * load the new driver + */ + loop_file_fmt_exit(lo_fmt); + lo_fmt->file_fmt_type = file_fmt_type_new; + printk(KERN_ERR "loop: change file format driver"); + return loop_file_fmt_init(lo_fmt); +} + +ssize_t loop_file_fmt_print_type(__u32 file_fmt_type, char *file_fmt_name) +{ + ssize_t len = 0; + + switch(file_fmt_type) { + case LO_FILE_FMT_RAW: + len = sprintf(file_fmt_name, "%s", "RAW"); + break; + case LO_FILE_FMT_QCOW: + len = sprintf(file_fmt_name, "%s", "QCOW"); + break; + case LO_FILE_FMT_VDI: + len = sprintf(file_fmt_name, "%s", "VDI"); + break; + case LO_FILE_FMT_VMDK: + len = sprintf(file_fmt_name, "%s", "VMDK"); + break; + default: + len = sprintf(file_fmt_name, "%s", "ERROR: Unsupported loop " + "file format!"); + break; + } + + return len; +} +EXPORT_SYMBOL(loop_file_fmt_print_type); |