X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;ds=sidebyside;f=drivers%2Fmd%2Fdm-io.c;h=10f457ca6af2568ab9073f8a7ab7477a0f946a94;hb=e070bf9ef85e293d9dc586fbfabc008795564c0e;hp=da663d2ff552b4b3a4d44bec0c4ec84e4e904365;hpb=0eaae62abaa1ad1f231932b6cdd9fb1b91df6651;p=safe%2Fjmp%2Flinux-2.6 diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c index da663d2..10f457c 100644 --- a/drivers/md/dm-io.c +++ b/drivers/md/dm-io.c @@ -1,103 +1,127 @@ /* * Copyright (C) 2003 Sistina Software + * Copyright (C) 2006 Red Hat GmbH * * This file is released under the GPL. */ -#include "dm-io.h" +#include "dm.h" + +#include #include #include #include #include #include +#include + +#define DM_MSG_PREFIX "io" -static struct bio_set *_bios; +#define DM_IO_MAX_REGIONS BITS_PER_LONG -/* FIXME: can we shrink this ? */ +struct dm_io_client { + mempool_t *pool; + struct bio_set *bios; +}; + +/* + * Aligning 'struct io' reduces the number of bits required to store + * its address. Refer to store_io_and_region_in_bio() below. + */ struct io { - unsigned long error; + unsigned long error_bits; + unsigned long eopnotsupp_bits; atomic_t count; struct task_struct *sleeper; + struct dm_io_client *client; io_notify_fn callback; void *context; -}; +} __attribute__((aligned(DM_IO_MAX_REGIONS))); + +static struct kmem_cache *_dm_io_cache; /* * 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; static unsigned int pages_to_ios(unsigned int pages) { return 4 * pages; /* too many ? */ } -static int resize_pool(unsigned int new_ios) +/* + * Create a client with mempool and bioset. + */ +struct dm_io_client *dm_io_client_create(unsigned num_pages) { - int r = 0; - - if (_io_pool) { - if (new_ios == 0) { - /* free off the pool */ - mempool_destroy(_io_pool); - _io_pool = NULL; - bioset_free(_bios); - - } else { - /* resize the pool */ - r = mempool_resize(_io_pool, new_ios, GFP_KERNEL); - } + unsigned ios = pages_to_ios(num_pages); + struct dm_io_client *client; - } else { - /* create new pool */ - _io_pool = mempool_create_kmalloc_pool(new_ios, - sizeof(struct io)); - if (!_io_pool) - return -ENOMEM; - - _bios = bioset_create(16, 16, 4); - if (!_bios) { - mempool_destroy(_io_pool); - _io_pool = NULL; - return -ENOMEM; - } - } + client = kmalloc(sizeof(*client), GFP_KERNEL); + if (!client) + return ERR_PTR(-ENOMEM); + + client->pool = mempool_create_slab_pool(ios, _dm_io_cache); + if (!client->pool) + goto bad; + + client->bios = bioset_create(16, 0); + if (!client->bios) + goto bad; - if (!r) - _num_ios = new_ios; + return client; - return r; + bad: + if (client->pool) + mempool_destroy(client->pool); + kfree(client); + return ERR_PTR(-ENOMEM); } +EXPORT_SYMBOL(dm_io_client_create); -int dm_io_get(unsigned int num_pages) +int dm_io_client_resize(unsigned num_pages, struct dm_io_client *client) { - return resize_pool(_num_ios + pages_to_ios(num_pages)); + return mempool_resize(client->pool, pages_to_ios(num_pages), + GFP_KERNEL); } +EXPORT_SYMBOL(dm_io_client_resize); -void dm_io_put(unsigned int num_pages) +void dm_io_client_destroy(struct dm_io_client *client) { - resize_pool(_num_ios - pages_to_ios(num_pages)); + 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 - * bvec which we know is unused (blech). - * XXX This is ugly and can OOPS with some configs... find another way. + * To avoid a memory allocation to store just 5 or 6 bits, we + * ensure the 'struct io' pointer is aligned so enough low bits are + * always zero and then combine it with the region number directly in + * bi_private. *---------------------------------------------------------------*/ -static inline void bio_set_region(struct bio *bio, unsigned region) +static void store_io_and_region_in_bio(struct bio *bio, struct io *io, + unsigned region) { - bio->bi_io_vec[bio->bi_max_vecs - 1].bv_len = region; + if (unlikely(!IS_ALIGNED((unsigned long)io, DM_IO_MAX_REGIONS))) { + DMCRIT("Unaligned struct io pointer %p", io); + BUG(); + } + + bio->bi_private = (void *)((unsigned long)io | region); } -static inline unsigned bio_get_region(struct bio *bio) +static void retrieve_io_and_region_from_bio(struct bio *bio, struct io **io, + unsigned *region) { - return bio->bi_io_vec[bio->bi_max_vecs - 1].bv_len; + unsigned long val = (unsigned long)bio->bi_private; + + *io = (void *)(val & -(unsigned long)DM_IO_MAX_REGIONS); + *region = val & (DM_IO_MAX_REGIONS - 1); } /*----------------------------------------------------------------- @@ -106,39 +130,43 @@ static inline unsigned bio_get_region(struct bio *bio) *---------------------------------------------------------------*/ static void dec_count(struct io *io, unsigned int region, int error) { - if (error) - set_bit(region, &io->error); + if (error) { + set_bit(region, &io->error_bits); + if (error == -EOPNOTSUPP) + set_bit(region, &io->eopnotsupp_bits); + } if (atomic_dec_and_test(&io->count)) { if (io->sleeper) wake_up_process(io->sleeper); else { - int r = io->error; + unsigned long r = io->error_bits; io_notify_fn fn = io->callback; void *context = io->context; - mempool_free(io, _io_pool); + mempool_free(io, io->client->pool); fn(r, context); } } } -static int endio(struct bio *bio, unsigned int done, int error) +static void endio(struct bio *bio, int error) { - struct io *io = (struct io *) bio->bi_private; - - /* keep going until we've finished */ - if (bio->bi_size) - return 1; + struct io *io; + unsigned region; if (error && bio_data_dir(bio) == READ) zero_fill_bio(bio); - dec_count(io, bio_get_region(bio), error); + /* + * The bio destructor in bio_put() may use the io object. + */ + retrieve_io_and_region_from_bio(bio, &io, ®ion); + bio_put(bio); - return 0; + dec_count(io, region, error); } /*----------------------------------------------------------------- @@ -208,6 +236,9 @@ 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) { @@ -232,13 +263,43 @@ static void vm_dp_init(struct dpages *dp, void *data) static void dm_bio_destructor(struct bio *bio) { - bio_free(bio, _bios); + unsigned region; + struct io *io; + + retrieve_io_and_region_from_bio(bio, &io, ®ion); + + bio_free(bio, io->client->bios); +} + +/* + * 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. *---------------------------------------------------------------*/ -static void do_region(int rw, unsigned int region, struct io_region *where, +static void do_region(int rw, unsigned region, struct dm_io_region *where, struct dpages *dp, struct io *io) { struct bio *bio; @@ -248,19 +309,23 @@ static void do_region(int rw, unsigned int region, struct io_region *where, unsigned num_bvecs; sector_t remaining = where->count; - while (remaining) { + /* + * where->count may be zero if rw holds a write barrier and we + * need to send a zero-sized barrier. + */ + do { /* - * Allocate a suitably sized bio, we add an extra - * bvec for bio_get/set_region(). + * Allocate a suitably sized-bio. */ - num_bvecs = (remaining / (PAGE_SIZE >> 9)) + 2; - bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, _bios); + num_bvecs = dm_sector_div_up(remaining, + (PAGE_SIZE >> SECTOR_SHIFT)); + num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev), num_bvecs); + bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios); bio->bi_sector = where->sector + (where->count - remaining); bio->bi_bdev = where->bdev; bio->bi_end_io = endio; - bio->bi_private = io; bio->bi_destructor = dm_bio_destructor; - bio_set_region(bio, region); + store_io_and_region_in_bio(bio, io, region); /* * Try and add as many pages as possible. @@ -278,18 +343,20 @@ static void do_region(int rw, unsigned int region, struct io_region *where, atomic_inc(&io->count); submit_bio(rw, bio); - } + } while (remaining); } static void dispatch_io(int rw, unsigned int num_regions, - struct io_region *where, struct dpages *dp, + struct dm_io_region *where, struct dpages *dp, struct io *io, int sync) { int i; struct dpages old_pages = *dp; + BUG_ON(num_regions > DM_IO_MAX_REGIONS); + if (sync) - rw |= (1 << BIO_RW_SYNC); + rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG); /* * For multiple regions we need to be careful to rewind @@ -297,65 +364,83 @@ static void dispatch_io(int rw, unsigned int num_regions, */ for (i = 0; i < num_regions; i++) { *dp = old_pages; - if (where[i].count) + if (where[i].count || (rw & (1 << BIO_RW_BARRIER))) do_region(rw, i, where + i, dp, io); } /* - * Drop the extra refence that we were holding to avoid + * Drop the extra reference that we were holding to avoid * the io being completed too early. */ 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 dm_io_region *where, int rw, struct dpages *dp, + unsigned long *error_bits) { - struct io io; + /* + * gcc <= 4.3 can't do the alignment for stack variables, so we must + * align it on our own. + * volatile prevents the optimizer from removing or reusing + * "io_" field from the stack frame (allowed in ANSI C). + */ + volatile char io_[sizeof(struct io) + __alignof__(struct io) - 1]; + struct io *io = (struct io *)PTR_ALIGN(&io_, __alignof__(struct io)); - if (num_regions > 1 && rw != WRITE) { + if (num_regions > 1 && (rw & RW_MASK) != WRITE) { WARN_ON(1); return -EIO; } - io.error = 0; - atomic_set(&io.count, 1); /* see dispatch_io() */ - io.sleeper = current; +retry: + io->error_bits = 0; + io->eopnotsupp_bits = 0; + atomic_set(&io->count, 1); /* see dispatch_io() */ + io->sleeper = current; + io->client = client; - dispatch_io(rw, num_regions, where, dp, &io, 1); + dispatch_io(rw, num_regions, where, dp, io, 1); while (1) { set_current_state(TASK_UNINTERRUPTIBLE); - if (!atomic_read(&io.count) || signal_pending(current)) + if (!atomic_read(&io->count)) break; io_schedule(); } set_current_state(TASK_RUNNING); - if (atomic_read(&io.count)) - return -EINTR; + if (io->eopnotsupp_bits && (rw & (1 << BIO_RW_BARRIER))) { + rw &= ~(1 << BIO_RW_BARRIER); + goto retry; + } + + if (error_bits) + *error_bits = io->error_bits; - *error_bits = io.error; - return io.error ? -EIO : 0; + return io->error_bits ? -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 dm_io_region *where, int rw, struct dpages *dp, + io_notify_fn fn, void *context) { struct io *io; - if (num_regions > 1 && rw != WRITE) { + if (num_regions > 1 && (rw & RW_MASK) != WRITE) { WARN_ON(1); fn(1, context); return -EIO; } - io = mempool_alloc(_io_pool, GFP_NOIO); - io->error = 0; + io = mempool_alloc(client->pool, GFP_NOIO); + io->error_bits = 0; + io->eopnotsupp_bits = 0; atomic_set(&io->count, 1); /* see dispatch_io() */ io->sleeper = NULL; + io->client = client; io->callback = fn; io->context = context; @@ -363,61 +448,71 @@ static int async_io(unsigned int num_regions, struct io_region *where, int rw, return 0; } -int dm_io_sync(unsigned int num_regions, struct io_region *where, int rw, - struct page_list *pl, unsigned int offset, - unsigned long *error_bits) +static int dp_init(struct dm_io_request *io_req, struct dpages *dp) { - struct dpages dp; - list_dp_init(&dp, pl, offset); - return sync_io(num_regions, where, rw, &dp, error_bits); -} + /* 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; + } -int dm_io_sync_bvec(unsigned int num_regions, struct io_region *where, int rw, - struct bio_vec *bvec, unsigned long *error_bits) -{ - struct dpages dp; - bvec_dp_init(&dp, bvec); - return sync_io(num_regions, where, rw, &dp, error_bits); + return 0; } -int dm_io_sync_vm(unsigned int num_regions, struct io_region *where, int rw, - void *data, unsigned long *error_bits) +/* + * New collapsed (a)synchronous interface. + * + * If the IO is asynchronous (i.e. it has notify.fn), you must either unplug + * the queue with blk_unplug() some time later or set the BIO_RW_SYNC bit in + * io_req->bi_rw. If you fail to do one of these, the IO will be submitted to + * the disk after q->unplug_delay, which defaults to 3ms in blk-settings.c. + */ +int dm_io(struct dm_io_request *io_req, unsigned num_regions, + struct dm_io_region *where, unsigned long *sync_error_bits) { + int r; struct dpages dp; - vm_dp_init(&dp, data); - return sync_io(num_regions, where, rw, &dp, error_bits); -} -int dm_io_async(unsigned int num_regions, struct io_region *where, int rw, - struct page_list *pl, unsigned int offset, - io_notify_fn fn, void *context) -{ - struct dpages dp; - list_dp_init(&dp, pl, offset); - return async_io(num_regions, where, rw, &dp, fn, context); + 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); -int dm_io_async_bvec(unsigned int num_regions, struct io_region *where, int rw, - struct bio_vec *bvec, io_notify_fn fn, void *context) +int __init dm_io_init(void) { - struct dpages dp; - bvec_dp_init(&dp, bvec); - return async_io(num_regions, where, rw, &dp, fn, context); + _dm_io_cache = KMEM_CACHE(io, 0); + if (!_dm_io_cache) + return -ENOMEM; + + return 0; } -int dm_io_async_vm(unsigned int num_regions, struct io_region *where, int rw, - void *data, io_notify_fn fn, void *context) +void dm_io_exit(void) { - struct dpages dp; - vm_dp_init(&dp, data); - return async_io(num_regions, where, rw, &dp, fn, context); + kmem_cache_destroy(_dm_io_cache); + _dm_io_cache = NULL; } - -EXPORT_SYMBOL(dm_io_get); -EXPORT_SYMBOL(dm_io_put); -EXPORT_SYMBOL(dm_io_sync); -EXPORT_SYMBOL(dm_io_async); -EXPORT_SYMBOL(dm_io_sync_bvec); -EXPORT_SYMBOL(dm_io_async_bvec); -EXPORT_SYMBOL(dm_io_sync_vm); -EXPORT_SYMBOL(dm_io_async_vm);