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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 2007-05-09 02:33:01 -07:00 committed by Linus Torvalds
parent 891ce20701
commit c8b03afe3d
2 changed files with 173 additions and 1 deletions
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122
drivers/md/dm-io.c
View File

@ -103,6 +103,51 @@ void dm_io_put(unsigned int num_pages)
resize_pool(_num_ios - pages_to_ios(num_pages));
}
/*
* Create a client with mempool and bioset.
*/
struct dm_io_client *dm_io_client_create(unsigned num_pages)
{
unsigned ios = pages_to_ios(num_pages);
struct dm_io_client *client;
client = kmalloc(sizeof(*client), GFP_KERNEL);
if (!client)
return ERR_PTR(-ENOMEM);
client->pool = mempool_create_kmalloc_pool(ios, sizeof(struct io));
if (!client->pool)
goto bad;
client->bios = bioset_create(16, 16);
if (!client->bios)
goto bad;
return client;
bad:
if (client->pool)
mempool_destroy(client->pool);
kfree(client);
return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL(dm_io_client_create);
int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client)
{
return mempool_resize(client->pool, pages_to_ios(num_pages),
GFP_KERNEL);
}
EXPORT_SYMBOL(dm_io_client_resize);
void dm_io_client_destroy(struct dm_io_client *client)
{
mempool_destroy(client->pool);
bioset_free(client->bios);
kfree(client);
}
EXPORT_SYMBOL(dm_io_client_destroy);
/*-----------------------------------------------------------------
* We need to keep track of which region a bio is doing io for.
* In order to save a memory allocation we store this the last
@ -236,6 +281,9 @@ static void bvec_dp_init(struct dpages *dp, struct bio_vec *bvec)
dp->context_ptr = bvec;
}
/*
* Functions for getting the pages from a VMA.
*/
static void vm_get_page(struct dpages *dp,
struct page **p, unsigned long *len, unsigned *offset)
{
@ -265,6 +313,31 @@ static void dm_bio_destructor(struct bio *bio)
bio_free(bio, bios(io->client));
}
/*
* Functions for getting the pages from kernel memory.
*/
static void km_get_page(struct dpages *dp, struct page **p, unsigned long *len,
unsigned *offset)
{
*p = virt_to_page(dp->context_ptr);
*offset = dp->context_u;
*len = PAGE_SIZE - dp->context_u;
}
static void km_next_page(struct dpages *dp)
{
dp->context_ptr += PAGE_SIZE - dp->context_u;
dp->context_u = 0;
}
static void km_dp_init(struct dpages *dp, void *data)
{
dp->get_page = km_get_page;
dp->next_page = km_next_page;
dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
dp->context_ptr = data;
}
/*-----------------------------------------------------------------
* IO routines that accept a list of pages.
*---------------------------------------------------------------*/
@ -451,6 +524,55 @@ int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
return async_io(NULL, num_regions, where, rw, &dp, fn, context);
}
static int dp_init(struct dm_io_request *io_req, struct dpages *dp)
{
/* Set up dpages based on memory type */
switch (io_req->mem.type) {
case DM_IO_PAGE_LIST:
list_dp_init(dp, io_req->mem.ptr.pl, io_req->mem.offset);
break;
case DM_IO_BVEC:
bvec_dp_init(dp, io_req->mem.ptr.bvec);
break;
case DM_IO_VMA:
vm_dp_init(dp, io_req->mem.ptr.vma);
break;
case DM_IO_KMEM:
km_dp_init(dp, io_req->mem.ptr.addr);
break;
default:
return -EINVAL;
}
return 0;
}
/*
* New collapsed (a)synchronous interface
*/
int dm_io(struct dm_io_request *io_req, unsigned num_regions,
struct io_region *where, unsigned long *sync_error_bits)
{
int r;
struct dpages dp;
r = dp_init(io_req, &dp);
if (r)
return r;
if (!io_req->notify.fn)
return sync_io(io_req->client, num_regions, where,
io_req->bi_rw, &dp, sync_error_bits);
return async_io(io_req->client, num_regions, where, io_req->bi_rw,
&dp, io_req->notify.fn, io_req->notify.context);
}
EXPORT_SYMBOL(dm_io);
EXPORT_SYMBOL(dm_io_get);
EXPORT_SYMBOL(dm_io_put);
EXPORT_SYMBOL(dm_io_sync);

52
drivers/md/dm-io.h
View File

@ -20,13 +20,47 @@ struct page_list {
struct page *page;
};
/*
* 'error' is a bitset, with each bit indicating whether an error
* occurred doing io to the corresponding region.
*/
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 */
};
/*
* Before anyone uses the IO interface they should call
@ -38,6 +72,16 @@ typedef void (*io_notify_fn)(unsigned long error, void *context);
int dm_io_get(unsigned int num_pages);
void dm_io_put(unsigned int num_pages);
/*
* 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);
/*
* Synchronous IO.
*
@ -71,4 +115,10 @@ int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw,
int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
void *data, io_notify_fn fn, void *context);
/*
* IO interface using private per-client pools.
*/
int dm_io(struct dm_io_request *io_req, unsigned num_regions,
struct io_region *region, unsigned long *sync_error_bits);
#endif