dm io: new interface
Add a new API to dm-io.c that uses a private mempool and bio_set for each client. The new functions to use are dm_io_client_create(), dm_io_client_destroy(), dm_io_client_resize() and dm_io(). Signed-off-by: Heinz Mauelshagen <hjm@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: Milan Broz <mbroz@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Heinz Mauelshagen
Linus Torvalds
Родитель
891ce20701
Коммит
c8b03afe3d
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@ -103,6 +103,51 @@ void dm_io_put(unsigned int num_pages)
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resize_pool(_num_ios - pages_to_ios(num_pages));
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}
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/*
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* Create a client with mempool and bioset.
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*/
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struct dm_io_client *dm_io_client_create(unsigned num_pages)
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{
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unsigned ios = pages_to_ios(num_pages);
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struct dm_io_client *client;
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client = kmalloc(sizeof(*client), GFP_KERNEL);
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if (!client)
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return ERR_PTR(-ENOMEM);
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client->pool = mempool_create_kmalloc_pool(ios, sizeof(struct io));
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if (!client->pool)
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goto bad;
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client->bios = bioset_create(16, 16);
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if (!client->bios)
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goto bad;
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return client;
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bad:
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if (client->pool)
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mempool_destroy(client->pool);
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kfree(client);
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return ERR_PTR(-ENOMEM);
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}
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EXPORT_SYMBOL(dm_io_client_create);
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int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client)
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{
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return mempool_resize(client->pool, pages_to_ios(num_pages),
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GFP_KERNEL);
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}
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EXPORT_SYMBOL(dm_io_client_resize);
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void dm_io_client_destroy(struct dm_io_client *client)
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{
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mempool_destroy(client->pool);
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bioset_free(client->bios);
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kfree(client);
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}
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EXPORT_SYMBOL(dm_io_client_destroy);
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/*-----------------------------------------------------------------
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* We need to keep track of which region a bio is doing io for.
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* In order to save a memory allocation we store this the last
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@ -236,6 +281,9 @@ static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec)
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dp->context_ptr = bvec;
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}
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/*
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* Functions for getting the pages from a VMA.
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*/
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static void vm_get_page(struct dpages *dp,
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struct page **p, unsigned long *len, unsigned *offset)
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{
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@ -265,6 +313,31 @@ static void dm_bio_destructor(struct bio *bio)
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bio_free(bio, bios(io->client));
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}
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/*
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* Functions for getting the pages from kernel memory.
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*/
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static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
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unsigned *offset)
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{
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*p = virt_to_page(dp->context_ptr);
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*offset = dp->context_u;
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*len = PAGE_SIZE - dp->context_u;
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}
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static void km_next_page(struct dpages *dp)
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{
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dp->context_ptr += PAGE_SIZE - dp->context_u;
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dp->context_u = 0;
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}
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static void km_dp_init(struct dpages *dp, void *data)
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{
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dp->get_page = km_get_page;
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dp->next_page = km_next_page;
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dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
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dp->context_ptr = data;
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}
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/*-----------------------------------------------------------------
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* IO routines that accept a list of pages.
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*---------------------------------------------------------------*/
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@ -451,6 +524,55 @@ int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
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return async_io(NULL, num_regions, where, rw, &dp, fn, context);
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}
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static int dp_init(struct dm_io_request *io_req, struct dpages *dp)
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{
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/* Set up dpages based on memory type */
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switch (io_req->mem.type) {
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case DM_IO_PAGE_LIST:
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list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
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break;
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case DM_IO_BVEC:
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bvec_dp_init(dp, io_req->mem.ptr.bvec);
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break;
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case DM_IO_VMA:
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vm_dp_init(dp, io_req->mem.ptr.vma);
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break;
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case DM_IO_KMEM:
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km_dp_init(dp, io_req->mem.ptr.addr);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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/*
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* New collapsed (a)synchronous interface
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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 *where, unsigned long *sync_error_bits)
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{
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int r;
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struct dpages dp;
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r = dp_init(io_req, &dp);
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if (r)
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return r;
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if (!io_req->notify.fn)
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return sync_io(io_req->client, num_regions, where,
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io_req->bi_rw, &dp, sync_error_bits);
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return async_io(io_req->client, num_regions, where, io_req->bi_rw,
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&dp, io_req->notify.fn, io_req->notify.context);
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}
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EXPORT_SYMBOL(dm_io);
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EXPORT_SYMBOL(dm_io_get);
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EXPORT_SYMBOL(dm_io_put);
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EXPORT_SYMBOL(dm_io_sync);
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@ -20,13 +20,47 @@ struct page_list {
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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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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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/*
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* Before anyone uses the IO interface they should call
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@ -38,6 +72,16 @@ typedef void (*io_notify_fn)(unsigned long error, void *context);
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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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/*
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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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/*
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* Synchronous IO.
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*
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@ -71,4 +115,10 @@ int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw,
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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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/*
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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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#endif
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