2005-04-17 06:20:36 +08:00
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/*
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* Copyright (C) 2003 Sistina Software
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*
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* This file is released under the GPL.
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*/
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#ifndef _DM_IO_H
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#define _DM_IO_H
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#include "dm.h"
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struct io_region {
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struct block_device *bdev;
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sector_t sector;
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sector_t count;
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};
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struct page_list {
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struct page_list *next;
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struct page *page;
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};
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/*
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* 'error' is a bitset, with each bit indicating whether an error
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* occurred doing io to the corresponding region.
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*/
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typedef void (*io_notify_fn)(unsigned long error, void *context);
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2007-05-09 17:33:01 +08:00
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enum dm_io_mem_type {
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DM_IO_PAGE_LIST,/* Page list */
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DM_IO_BVEC, /* Bio vector */
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DM_IO_VMA, /* Virtual memory area */
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DM_IO_KMEM, /* Kernel memory */
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};
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struct dm_io_memory {
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enum dm_io_mem_type type;
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union {
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struct page_list *pl;
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struct bio_vec *bvec;
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void *vma;
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void *addr;
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} ptr;
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unsigned offset;
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};
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struct dm_io_notify {
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io_notify_fn fn; /* Callback for asynchronous requests */
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void *context; /* Passed to callback */
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};
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/*
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* IO request structure
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*/
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struct dm_io_client;
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struct dm_io_request {
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int bi_rw; /* READ|WRITE - not READA */
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struct dm_io_memory mem; /* Memory to use for io */
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struct dm_io_notify notify; /* Synchronous if notify.fn is NULL */
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struct dm_io_client *client; /* Client memory handler */
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};
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2005-04-17 06:20:36 +08:00
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/*
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* Before anyone uses the IO interface they should call
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* dm_io_get(), specifying roughly how many pages they are
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* expecting to perform io on concurrently.
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*
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* This function may block.
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*/
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int dm_io_get(unsigned int num_pages);
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void dm_io_put(unsigned int num_pages);
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2007-05-09 17:33:01 +08:00
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/*
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* For async io calls, users can alternatively use the dm_io() function below
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* and dm_io_client_create() to create private mempools for the client.
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*
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* Create/destroy may block.
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*/
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struct dm_io_client *dm_io_client_create(unsigned num_pages);
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int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client);
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void dm_io_client_destroy(struct dm_io_client *client);
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2005-04-17 06:20:36 +08:00
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/*
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* Synchronous IO.
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*
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* Please ensure that the rw flag in the next two functions is
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* either READ or WRITE, ie. we don't take READA. Any
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* regions with a zero count field will be ignored.
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*/
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int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw,
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struct page_list *pl, unsigned int offset,
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unsigned long *error_bits);
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int dm_io_sync_bvec(unsigned int num_regions, struct io_region *where, int rw,
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struct bio_vec *bvec, unsigned long *error_bits);
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int dm_io_sync_vm(unsigned int num_regions, struct io_region *where, int rw,
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void *data, unsigned long *error_bits);
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/*
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* Aynchronous IO.
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*
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* The 'where' array may be safely allocated on the stack since
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* the function takes a copy.
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*/
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int dm_io_async(unsigned int num_regions, struct io_region *where, int rw,
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struct page_list *pl, unsigned int offset,
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io_notify_fn fn, void *context);
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int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw,
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struct bio_vec *bvec, io_notify_fn fn, void *context);
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int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
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void *data, io_notify_fn fn, void *context);
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2007-05-09 17:33:01 +08:00
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/*
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* IO interface using private per-client pools.
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*/
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int dm_io(struct dm_io_request *io_req, unsigned num_regions,
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struct io_region *region, unsigned long *sync_error_bits);
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2005-04-17 06:20:36 +08:00
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#endif
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