| 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
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| 2 | /* |
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| 3 | * Copyright (C) 2003 Sistina Software |
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| 4 | * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved. |
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| 5 | * |
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| 6 | * Device-Mapper low-level I/O. |
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| 7 | * |
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| 8 | * This file is released under the GPL. |
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| 9 | */ |
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| 10 | |
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| 11 | #ifndef _LINUX_DM_IO_H |
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| 12 | #define _LINUX_DM_IO_H |
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| 13 | |
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| 14 | #ifdef __KERNEL__ |
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| 15 | |
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| 16 | #include <linux/types.h> |
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| 17 | #include <linux/blk_types.h> |
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| 18 | |
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| 19 | struct dm_io_region { |
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| 20 | struct block_device *bdev; |
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| 21 | sector_t sector; |
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| 22 | sector_t count; /* If this is zero the region is ignored. */ |
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| 23 | }; |
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| 24 | |
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| 25 | struct page_list { |
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| 26 | struct page_list *next; |
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| 27 | struct page *page; |
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| 28 | }; |
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| 29 | |
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| 30 | typedef void (*io_notify_fn)(unsigned int long error, void *context); |
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| 31 | |
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| 32 | enum dm_io_mem_type { |
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| 33 | DM_IO_PAGE_LIST,/* Page list */ |
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| 34 | DM_IO_BIO, /* Bio vector */ |
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| 35 | DM_IO_VMA, /* Virtual memory area */ |
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| 36 | DM_IO_KMEM, /* Kernel memory */ |
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| 37 | }; |
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| 38 | |
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| 39 | struct dm_io_memory { |
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| 40 | enum dm_io_mem_type type; |
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| 41 | |
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| 42 | unsigned int offset; |
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| 43 | |
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| 44 | union { |
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| 45 | struct page_list *pl; |
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| 46 | struct bio *bio; |
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| 47 | void *vma; |
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| 48 | void *addr; |
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| 49 | } ptr; |
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| 50 | }; |
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| 51 | |
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| 52 | struct dm_io_notify { |
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| 53 | io_notify_fn fn; /* Callback for asynchronous requests */ |
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| 54 | void *context; /* Passed to callback */ |
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| 55 | }; |
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| 56 | |
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| 57 | /* |
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| 58 | * IO request structure |
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| 59 | */ |
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| 60 | struct dm_io_client; |
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| 61 | struct dm_io_request { |
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| 62 | blk_opf_t bi_opf; /* Request type and flags */ |
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| 63 | struct dm_io_memory mem; /* Memory to use for io */ |
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| 64 | struct dm_io_notify notify; /* Synchronous if notify.fn is NULL */ |
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| 65 | struct dm_io_client *client; /* Client memory handler */ |
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| 66 | }; |
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| 67 | |
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| 68 | /* |
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| 69 | * For async io calls, users can alternatively use the dm_io() function below |
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| 70 | * and dm_io_client_create() to create private mempools for the client. |
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| 71 | * |
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| 72 | * Create/destroy may block. |
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| 73 | */ |
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| 74 | struct dm_io_client *dm_io_client_create(void); |
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| 75 | void dm_io_client_destroy(struct dm_io_client *client); |
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| 76 | |
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| 77 | /* |
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| 78 | * IO interface using private per-client pools. |
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| 79 | * Each bit in the optional 'sync_error_bits' bitset indicates whether an |
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| 80 | * error occurred doing io to the corresponding region. |
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| 81 | */ |
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| 82 | int dm_io(struct dm_io_request *io_req, unsigned int num_regions, |
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| 83 | struct dm_io_region *region, unsigned int long *sync_error_bits, |
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| 84 | unsigned short ioprio); |
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| 85 | |
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| 86 | #endif /* __KERNEL__ */ |
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| 87 | #endif /* _LINUX_DM_IO_H */ |
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| 88 | |
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