forked from Minki/linux
40326d8a33
Currently loop disables merge. While it makes sense for buffer IO mode, directio mode can benefit from request merge. Without merge, loop could send small size IO to underlayer disk and harm performance. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
95 lines
2.3 KiB
C
95 lines
2.3 KiB
C
/*
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* loop.h
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*
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* Written by Theodore Ts'o, 3/29/93.
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*
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* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
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* permitted under the GNU General Public License.
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*/
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#ifndef _LINUX_LOOP_H
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#define _LINUX_LOOP_H
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/blk-mq.h>
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#include <linux/spinlock.h>
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#include <linux/mutex.h>
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#include <linux/kthread.h>
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#include <uapi/linux/loop.h>
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/* Possible states of device */
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enum {
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Lo_unbound,
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Lo_bound,
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Lo_rundown,
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};
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struct loop_func_table;
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struct loop_device {
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int lo_number;
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atomic_t lo_refcnt;
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loff_t lo_offset;
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loff_t lo_sizelimit;
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int lo_flags;
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int (*transfer)(struct loop_device *, int cmd,
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struct page *raw_page, unsigned raw_off,
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struct page *loop_page, unsigned loop_off,
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int size, sector_t real_block);
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char lo_file_name[LO_NAME_SIZE];
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char lo_crypt_name[LO_NAME_SIZE];
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char lo_encrypt_key[LO_KEY_SIZE];
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int lo_encrypt_key_size;
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struct loop_func_table *lo_encryption;
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__u32 lo_init[2];
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kuid_t lo_key_owner; /* Who set the key */
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int (*ioctl)(struct loop_device *, int cmd,
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unsigned long arg);
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struct file * lo_backing_file;
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struct block_device *lo_device;
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void *key_data;
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gfp_t old_gfp_mask;
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spinlock_t lo_lock;
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int lo_state;
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struct mutex lo_ctl_mutex;
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struct kthread_worker worker;
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struct task_struct *worker_task;
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bool use_dio;
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struct request_queue *lo_queue;
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struct blk_mq_tag_set tag_set;
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struct gendisk *lo_disk;
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};
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struct loop_cmd {
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struct kthread_work work;
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struct request *rq;
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struct list_head list;
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bool use_aio; /* use AIO interface to handle I/O */
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long ret;
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struct kiocb iocb;
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struct bio_vec *bvec;
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};
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/* Support for loadable transfer modules */
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struct loop_func_table {
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int number; /* filter type */
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int (*transfer)(struct loop_device *lo, int cmd,
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struct page *raw_page, unsigned raw_off,
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struct page *loop_page, unsigned loop_off,
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int size, sector_t real_block);
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int (*init)(struct loop_device *, const struct loop_info64 *);
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/* release is called from loop_unregister_transfer or clr_fd */
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int (*release)(struct loop_device *);
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int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
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struct module *owner;
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};
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int loop_register_transfer(struct loop_func_table *funcs);
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int loop_unregister_transfer(int number);
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#endif
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