/* * Copyright (C) 2003 Sistina Software * Copyright (C) 2004 - 2008 Red Hat, Inc. All rights reserved. * * Device-Mapper low-level I/O. * * This file is released under the GPL. */ #ifndef _LINUX_DM_IO_H #define _LINUX_DM_IO_H #ifdef __KERNEL__ #include <linux/types.h> struct dm_io_region { struct block_device *bdev; sector_t sector; sector_t count; /* If this is zero the region is ignored. */ }; struct page_list { struct page_list *next; struct page *page; }; typedef void (*io_notify_fn)(unsigned long error, void *context); enum dm_io_mem_type { DM_IO_PAGE_LIST,/* Page list */ DM_IO_BVEC, /* Bio vector */ DM_IO_VMA, /* Virtual memory area */ DM_IO_KMEM, /* Kernel memory */ }; struct dm_io_memory { enum dm_io_mem_type type; union { struct page_list *pl; struct bio_vec *bvec; void *vma; void *addr; } ptr; unsigned offset; }; struct dm_io_notify { io_notify_fn fn; /* Callback for asynchronous requests */ void *context; /* Passed to callback */ }; /* * IO request structure */ struct dm_io_client; struct dm_io_request { int bi_rw; /* READ|WRITE - not READA */ struct dm_io_memory mem; /* Memory to use for io */ struct dm_io_notify notify; /* Synchronous if notify.fn is NULL */ struct dm_io_client *client; /* Client memory handler */ }; /* * For async io calls, users can alternatively use the dm_io() function below * and dm_io_client_create() to create private mempools for the client. * * Create/destroy may block. */ struct dm_io_client *dm_io_client_create(unsigned num_pages); int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client); void dm_io_client_destroy(struct dm_io_client *client); /* * IO interface using private per-client pools. * Each bit in the optional 'sync_error_bits' bitset indicates whether an * error occurred doing io to the corresponding region. */ int dm_io(struct dm_io_request *io_req, unsigned num_regions, struct dm_io_region *region, unsigned long *sync_error_bits); #endif /* __KERNEL__ */ #endif /* _LINUX_DM_IO_H */