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dm io: prepare for new interface

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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: 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 02:33:00 -07:00 committed by Linus Torvalds
parent c897feb3dc
commit 891ce20701
1 changed files with 44 additions and 17 deletions
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59
drivers/md/dm-io.c
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@ -1,5 +1,6 @@
/* /*
* Copyright (C) 2003 Sistina Software * Copyright (C) 2003 Sistina Software
* Copyright (C) 2006 Red Hat GmbH
* *
* This file is released under the GPL. * This file is released under the GPL.
*/ */
@ -14,11 +15,17 @@
static struct bio_set *_bios; static struct bio_set *_bios;
struct dm_io_client {
mempool_t *pool;
struct bio_set *bios;
};
/* FIXME: can we shrink this ? */ /* FIXME: can we shrink this ? */
struct io { struct io {
unsigned long error; unsigned long error;
atomic_t count; atomic_t count;
struct task_struct *sleeper; struct task_struct *sleeper;
struct dm_io_client *client;
io_notify_fn callback; io_notify_fn callback;
void *context; void *context;
}; };
@ -26,12 +33,24 @@ struct io {
/* /*
* io contexts are only dynamically allocated for asynchronous * io contexts are only dynamically allocated for asynchronous
* io. Since async io is likely to be the majority of io we'll * 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: * have the same number of io contexts as bios! (FIXME: must reduce this).
* must reduce this).
*/ */
static unsigned _num_ios; static unsigned _num_ios;
static mempool_t *_io_pool; 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) static unsigned int pages_to_ios(unsigned int pages)
{ {
return 4 * pages; /* too many ? */ 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; io_notify_fn fn = io->callback;
void *context = io->context; void *context = io->context;
mempool_free(io, _io_pool); mempool_free(io, io_pool(io->client));
fn(r, context); 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) 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(). * to hide it from bio_add_page().
*/ */
num_bvecs = (remaining / (PAGE_SIZE >> SECTOR_SHIFT)) + 2; 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_sector = where->sector + (where->count - remaining);
bio->bi_bdev = where->bdev; bio->bi_bdev = where->bdev;
bio->bi_end_io = endio; bio->bi_end_io = endio;
@ -319,8 +340,9 @@ static void dispatch_io(int rw, unsigned int num_regions,
dec_count(io, 0, 0); dec_count(io, 0, 0);
} }
static int sync_io(unsigned int num_regions, struct io_region *where, static int sync_io(struct dm_io_client *client, unsigned int num_regions,
int rw, struct dpages *dp, unsigned long *error_bits) struct io_region *where, int rw, struct dpages *dp,
unsigned long *error_bits)
{ {
struct io io; struct io io;
@ -332,6 +354,7 @@ static int sync_io(unsigned int num_regions, struct io_region *where,
io.error = 0; io.error = 0;
atomic_set(&io.count, 1); /* see dispatch_io() */ atomic_set(&io.count, 1); /* see dispatch_io() */
io.sleeper = current; io.sleeper = current;
io.client = client;
dispatch_io(rw, num_regions, where, dp, &io, 1); 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)) if (atomic_read(&io.count))
return -EINTR; return -EINTR;
if (error_bits)
*error_bits = io.error; *error_bits = io.error;
return io.error ? -EIO : 0; return io.error ? -EIO : 0;
} }
static int async_io(unsigned int num_regions, struct io_region *where, int rw, static int async_io(struct dm_io_client *client, unsigned int num_regions,
struct dpages *dp, io_notify_fn fn, void *context) struct io_region *where, int rw, struct dpages *dp,
io_notify_fn fn, void *context)
{ {
struct io *io; struct io *io;
@ -363,10 +389,11 @@ static int async_io(unsigned int num_regions, struct io_region *where, int rw,
return -EIO; return -EIO;
} }
io = mempool_alloc(_io_pool, GFP_NOIO); io = mempool_alloc(io_pool(client), GFP_NOIO);
io->error = 0; io->error = 0;
atomic_set(&io->count, 1); /* see dispatch_io() */ atomic_set(&io->count, 1); /* see dispatch_io() */
io->sleeper = NULL; io->sleeper = NULL;
io->client = client;
io->callback = fn; io->callback = fn;
io->context = context; io->context = context;
@ -380,7 +407,7 @@ int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw,
{ {
struct dpages dp; struct dpages dp;
list_dp_init(&dp, pl, offset); 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, 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; struct dpages dp;
bvec_dp_init(&dp, bvec); 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, 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; struct dpages dp;
vm_dp_init(&dp, data); 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, 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; struct dpages dp;
list_dp_init(&dp, pl, offset); 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, 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; struct dpages dp;
bvec_dp_init(&dp, bvec); 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, 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; struct dpages dp;
vm_dp_init(&dp, data); 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); EXPORT_SYMBOL(dm_io_get);