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Commit 891ce207 authored by Heinz Mauelshagen's avatar Heinz Mauelshagen Committed by Linus Torvalds
Browse files

dm io: prepare for new interface 



Introduce struct dm_io_client to prepare for per-client mempools and bio_sets.

Temporary functions bios() and io_pool() choose between the per-client
structures and the global ones so the old and new interfaces can co-exist.

Make error_bits optional.

Signed-off-by: default avatarHeinz Mauelshagen <hjm@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Cc: Milan Broz <mbroz@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c897feb3

drivers/md/dm-io.c

+44 −17
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2003 Sistina Software

 * Copyright (C) 2006 Red Hat GmbH

 *

 * This file is released under the GPL.

 */
@@ -14,11 +15,17 @@ 


static struct bio_set *_bios;



struct dm_io_client {

	mempool_t *pool;

	struct bio_set *bios;

};



/* FIXME: can we shrink this ? */

struct io {

	unsigned long error;

	atomic_t count;

	struct task_struct *sleeper;

	struct dm_io_client *client;

	io_notify_fn callback;

	void *context;

};
@@ -26,12 +33,24 @@ struct io { 
/*

 * io contexts are only dynamically allocated for asynchronous

 * io.  Since async io is likely to be the majority of io we'll

 * have the same number of io contexts as buffer heads ! (FIXME:

 * must reduce this).

 * have the same number of io contexts as bios! (FIXME: must reduce this).

 */

static unsigned _num_ios;

static mempool_t *_io_pool;



/*

 * Temporary functions to allow old and new interfaces to co-exist.

 */

static struct bio_set *bios(struct dm_io_client *client)

{

	return client ? client->bios : _bios;

}



static mempool_t *io_pool(struct dm_io_client *client)

{

	return client ? client->pool : _io_pool;

}



static unsigned int pages_to_ios(unsigned int pages)

{

	return 4 * pages;	/* too many ? */
@@ -118,7 +137,7 @@ static void dec_count(struct io *io, unsigned int region, int error) 
			io_notify_fn fn = io->callback;

			void *context = io->context;



			mempool_free(io, _io_pool);

			mempool_free(io, io_pool(io->client));

			fn(r, context);

		}

	}
@@ -241,7 +260,9 @@ static void vm_dp_init(struct dpages *dp, void *data) 


static void dm_bio_destructor(struct bio *bio)

{

	bio_free(bio, _bios);

	struct io *io = bio->bi_private;



	bio_free(bio, bios(io->client));

}



/*-----------------------------------------------------------------
@@ -264,7 +285,7 @@ static void do_region(int rw, unsigned int region, struct io_region *where, 
		 * to hide it from bio_add_page().

		 */

		num_bvecs = (remaining / (PAGE_SIZE >> SECTOR_SHIFT)) + 2;

		bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, _bios);

		bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, bios(io->client));

		bio->bi_sector = where->sector + (where->count - remaining);

		bio->bi_bdev = where->bdev;

		bio->bi_end_io = endio;
@@ -319,8 +340,9 @@ static void dispatch_io(int rw, unsigned int num_regions, 
	dec_count(io, 0, 0);

}



static int sync_io(unsigned int num_regions, struct io_region *where,

	    int rw, struct dpages *dp, unsigned long *error_bits)

static int sync_io(struct dm_io_client *client, unsigned int num_regions,

		   struct io_region *where, int rw, struct dpages *dp,

		   unsigned long *error_bits)

{

	struct io io;
@@ -332,6 +354,7 @@ static int sync_io(unsigned int num_regions, struct io_region *where, 
	io.error = 0;

	atomic_set(&io.count, 1); /* see dispatch_io() */

	io.sleeper = current;

	io.client = client;



	dispatch_io(rw, num_regions, where, dp, &io, 1);
@@ -348,12 +371,15 @@ static int sync_io(unsigned int num_regions, struct io_region *where, 
	if (atomic_read(&io.count))

		return -EINTR;



	if (error_bits)

		*error_bits = io.error;



	return io.error ? -EIO : 0;

}



static int async_io(unsigned int num_regions, struct io_region *where, int rw,

	     struct dpages *dp, io_notify_fn fn, void *context)

static int async_io(struct dm_io_client *client, unsigned int num_regions,

		    struct io_region *where, int rw, struct dpages *dp,

		    io_notify_fn fn, void *context)

{

	struct io *io;
@@ -363,10 +389,11 @@ static int async_io(unsigned int num_regions, struct io_region *where, int rw, 
		return -EIO;

	}



	io = mempool_alloc(_io_pool, GFP_NOIO);

	io = mempool_alloc(io_pool(client), GFP_NOIO);

	io->error = 0;

	atomic_set(&io->count, 1); /* see dispatch_io() */

	io->sleeper = NULL;

	io->client = client;

	io->callback = fn;

	io->context = context;
@@ -380,7 +407,7 @@ int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw, 
{

	struct dpages dp;

	list_dp_init(&dp, pl, offset);

	return sync_io(num_regions, where, rw, &dp, error_bits);

	return sync_io(NULL, num_regions, where, rw, &dp, error_bits);

}



int dm_io_sync_bvec(unsigned int num_regions, struct io_region *where, int rw,
@@ -388,7 +415,7 @@ int dm_io_sync_bvec(unsigned int num_regions, struct io_region *where, int rw, 
{

	struct dpages dp;

	bvec_dp_init(&dp, bvec);

	return sync_io(num_regions, where, rw, &dp, error_bits);

	return sync_io(NULL, num_regions, where, rw, &dp, error_bits);

}



int dm_io_sync_vm(unsigned int num_regions, struct io_region *where, int rw,
@@ -396,7 +423,7 @@ int dm_io_sync_vm(unsigned int num_regions, struct io_region *where, int rw, 
{

	struct dpages dp;

	vm_dp_init(&dp, data);

	return sync_io(num_regions, where, rw, &dp, error_bits);

	return sync_io(NULL, num_regions, where, rw, &dp, error_bits);

}



int dm_io_async(unsigned int num_regions, struct io_region *where, int rw,
@@ -405,7 +432,7 @@ int dm_io_async(unsigned int num_regions, struct io_region *where, int rw, 
{

	struct dpages dp;

	list_dp_init(&dp, pl, offset);

	return async_io(num_regions, where, rw, &dp, fn, context);

	return async_io(NULL, num_regions, where, rw, &dp, fn, context);

}



int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw,
@@ -413,7 +440,7 @@ int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw, 
{

	struct dpages dp;

	bvec_dp_init(&dp, bvec);

	return async_io(num_regions, where, rw, &dp, fn, context);

	return async_io(NULL, num_regions, where, rw, &dp, fn, context);

}



int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw,
@@ -421,7 +448,7 @@ int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw, 
{

	struct dpages dp;

	vm_dp_init(&dp, data);

	return async_io(num_regions, where, rw, &dp, fn, context);

	return async_io(NULL, num_regions, where, rw, &dp, fn, context);

}



EXPORT_SYMBOL(dm_io_get);