dm io: new interface (c8b03afe) · Commits · 戴 / test

drivers/md/dm-io.c

+122 −0

Original line number	Diff line number	Diff line
		@@ -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);

drivers/md/dm-io.h

+51 −1

Original line number	Diff line number	Diff line
		@@ -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

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