From: Heinz Mauelshagen <hjm@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
Cc: Milan Broz <mbroz@xxxxxxxxxx>
---
drivers/md/dm-io.c | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++
drivers/md/dm-io.h | 52 ++++++++++++++++++++++
2 files changed, 173 insertions(+), 1 deletion(-)
Index: linux-2.6.21/drivers/md/dm-io.c
===================================================================
--- linux-2.6.21.orig/drivers/md/dm-io.c 2007-05-08 16:28:10.000000000 +0100
+++ linux-2.6.21/drivers/md/dm-io.c 2007-05-08 16:28:26.000000000 +0100
@@ -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->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_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_regi
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);
Index: linux-2.6.21/drivers/md/dm-io.h
===================================================================
--- linux-2.6.21.orig/drivers/md/dm-io.h 2007-05-08 16:25:41.000000000 +0100
+++ linux-2.6.21/drivers/md/dm-io.h 2007-05-08 16:28:11.000000000 +0100
@@ -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
@@ -39,6 +73,16 @@ 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.
*
* Please ensure that the rw flag in the next two functions is
@@ -71,4 +115,10 @@ int dm_io_async_bvec(unsigned int num_re
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
--
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