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