diff options
Diffstat (limited to 'drivers/md/kcopyd.c')
| -rw-r--r-- | drivers/md/kcopyd.c | 654 |
1 files changed, 0 insertions, 654 deletions
diff --git a/drivers/md/kcopyd.c b/drivers/md/kcopyd.c deleted file mode 100644 index 17345844b03e..000000000000 --- a/drivers/md/kcopyd.c +++ /dev/null @@ -1,654 +0,0 @@ -/* - * Copyright (C) 2002 Sistina Software (UK) Limited. - * Copyright (C) 2006 Red Hat GmbH - * - * This file is released under the GPL. - * - * Kcopyd provides a simple interface for copying an area of one - * block-device to one or more other block-devices, with an asynchronous - * completion notification. - */ - -#include <linux/types.h> -#include <asm/atomic.h> -#include <linux/blkdev.h> -#include <linux/fs.h> -#include <linux/init.h> -#include <linux/list.h> -#include <linux/mempool.h> -#include <linux/module.h> -#include <linux/pagemap.h> -#include <linux/slab.h> -#include <linux/vmalloc.h> -#include <linux/workqueue.h> -#include <linux/mutex.h> - -#include "kcopyd.h" -#include "dm.h" - -/*----------------------------------------------------------------- - * Each kcopyd client has its own little pool of preallocated - * pages for kcopyd io. - *---------------------------------------------------------------*/ -struct dm_kcopyd_client { - spinlock_t lock; - struct page_list *pages; - unsigned int nr_pages; - unsigned int nr_free_pages; - - struct dm_io_client *io_client; - - wait_queue_head_t destroyq; - atomic_t nr_jobs; - - mempool_t *job_pool; - - struct workqueue_struct *kcopyd_wq; - struct work_struct kcopyd_work; - -/* - * We maintain three lists of jobs: - * - * i) jobs waiting for pages - * ii) jobs that have pages, and are waiting for the io to be issued. - * iii) jobs that have completed. - * - * All three of these are protected by job_lock. - */ - spinlock_t job_lock; - struct list_head complete_jobs; - struct list_head io_jobs; - struct list_head pages_jobs; -}; - -static void wake(struct dm_kcopyd_client *kc) -{ - queue_work(kc->kcopyd_wq, &kc->kcopyd_work); -} - -static struct page_list *alloc_pl(void) -{ - struct page_list *pl; - - pl = kmalloc(sizeof(*pl), GFP_KERNEL); - if (!pl) - return NULL; - - pl->page = alloc_page(GFP_KERNEL); - if (!pl->page) { - kfree(pl); - return NULL; - } - - return pl; -} - -static void free_pl(struct page_list *pl) -{ - __free_page(pl->page); - kfree(pl); -} - -static int kcopyd_get_pages(struct dm_kcopyd_client *kc, - unsigned int nr, struct page_list **pages) -{ - struct page_list *pl; - - spin_lock(&kc->lock); - if (kc->nr_free_pages < nr) { - spin_unlock(&kc->lock); - return -ENOMEM; - } - - kc->nr_free_pages -= nr; - for (*pages = pl = kc->pages; --nr; pl = pl->next) - ; - - kc->pages = pl->next; - pl->next = NULL; - - spin_unlock(&kc->lock); - - return 0; -} - -static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl) -{ - struct page_list *cursor; - - spin_lock(&kc->lock); - for (cursor = pl; cursor->next; cursor = cursor->next) - kc->nr_free_pages++; - - kc->nr_free_pages++; - cursor->next = kc->pages; - kc->pages = pl; - spin_unlock(&kc->lock); -} - -/* - * These three functions resize the page pool. - */ -static void drop_pages(struct page_list *pl) -{ - struct page_list *next; - - while (pl) { - next = pl->next; - free_pl(pl); - pl = next; - } -} - -static int client_alloc_pages(struct dm_kcopyd_client *kc, unsigned int nr) -{ - unsigned int i; - struct page_list *pl = NULL, *next; - - for (i = 0; i < nr; i++) { - next = alloc_pl(); - if (!next) { - if (pl) - drop_pages(pl); - return -ENOMEM; - } - next->next = pl; - pl = next; - } - - kcopyd_put_pages(kc, pl); - kc->nr_pages += nr; - return 0; -} - -static void client_free_pages(struct dm_kcopyd_client *kc) -{ - BUG_ON(kc->nr_free_pages != kc->nr_pages); - drop_pages(kc->pages); - kc->pages = NULL; - kc->nr_free_pages = kc->nr_pages = 0; -} - -/*----------------------------------------------------------------- - * kcopyd_jobs need to be allocated by the *clients* of kcopyd, - * for this reason we use a mempool to prevent the client from - * ever having to do io (which could cause a deadlock). - *---------------------------------------------------------------*/ -struct kcopyd_job { - struct dm_kcopyd_client *kc; - struct list_head list; - unsigned long flags; - - /* - * Error state of the job. - */ - int read_err; - unsigned long write_err; - - /* - * Either READ or WRITE - */ - int rw; - struct dm_io_region source; - - /* - * The destinations for the transfer. - */ - unsigned int num_dests; - struct dm_io_region dests[DM_KCOPYD_MAX_REGIONS]; - - sector_t offset; - unsigned int nr_pages; - struct page_list *pages; - - /* - * Set this to ensure you are notified when the job has - * completed. 'context' is for callback to use. - */ - dm_kcopyd_notify_fn fn; - void *context; - - /* - * These fields are only used if the job has been split - * into more manageable parts. - */ - struct mutex lock; - atomic_t sub_jobs; - sector_t progress; -}; - -/* FIXME: this should scale with the number of pages */ -#define MIN_JOBS 512 - -static struct kmem_cache *_job_cache; - -int __init dm_kcopyd_init(void) -{ - _job_cache = KMEM_CACHE(kcopyd_job, 0); - if (!_job_cache) - return -ENOMEM; - - return 0; -} - -void dm_kcopyd_exit(void) -{ - kmem_cache_destroy(_job_cache); - _job_cache = NULL; -} - -/* - * Functions to push and pop a job onto the head of a given job - * list. - */ -static struct kcopyd_job *pop(struct list_head *jobs, - struct dm_kcopyd_client *kc) -{ - struct kcopyd_job *job = NULL; - unsigned long flags; - - spin_lock_irqsave(&kc->job_lock, flags); - - if (!list_empty(jobs)) { - job = list_entry(jobs->next, struct kcopyd_job, list); - list_del(&job->list); - } - spin_unlock_irqrestore(&kc->job_lock, flags); - - return job; -} - -static void push(struct list_head *jobs, struct kcopyd_job *job) -{ - unsigned long flags; - struct dm_kcopyd_client *kc = job->kc; - - spin_lock_irqsave(&kc->job_lock, flags); - list_add_tail(&job->list, jobs); - spin_unlock_irqrestore(&kc->job_lock, flags); -} - -/* - * These three functions process 1 item from the corresponding - * job list. - * - * They return: - * < 0: error - * 0: success - * > 0: can't process yet. - */ -static int run_complete_job(struct kcopyd_job *job) -{ - void *context = job->context; - int read_err = job->read_err; - unsigned long write_err = job->write_err; - dm_kcopyd_notify_fn fn = job->fn; - struct dm_kcopyd_client *kc = job->kc; - - kcopyd_put_pages(kc, job->pages); - mempool_free(job, kc->job_pool); - fn(read_err, write_err, context); - - if (atomic_dec_and_test(&kc->nr_jobs)) - wake_up(&kc->destroyq); - - return 0; -} - -static void complete_io(unsigned long error, void *context) -{ - struct kcopyd_job *job = (struct kcopyd_job *) context; - struct dm_kcopyd_client *kc = job->kc; - - if (error) { - if (job->rw == WRITE) - job->write_err |= error; - else - job->read_err = 1; - - if (!test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { - push(&kc->complete_jobs, job); - wake(kc); - return; - } - } - - if (job->rw == WRITE) - push(&kc->complete_jobs, job); - - else { - job->rw = WRITE; - push(&kc->io_jobs, job); - } - - wake(kc); -} - -/* - * Request io on as many buffer heads as we can currently get for - * a particular job. - */ -static int run_io_job(struct kcopyd_job *job) -{ - int r; - struct dm_io_request io_req = { - .bi_rw = job->rw, - .mem.type = DM_IO_PAGE_LIST, - .mem.ptr.pl = job->pages, - .mem.offset = job->offset, - .notify.fn = complete_io, - .notify.context = job, - .client = job->kc->io_client, - }; - - if (job->rw == READ) - r = dm_io(&io_req, 1, &job->source, NULL); - else - r = dm_io(&io_req, job->num_dests, job->dests, NULL); - - return r; -} - -static int run_pages_job(struct kcopyd_job *job) -{ - int r; - - job->nr_pages = dm_div_up(job->dests[0].count + job->offset, - PAGE_SIZE >> 9); - r = kcopyd_get_pages(job->kc, job->nr_pages, &job->pages); - if (!r) { - /* this job is ready for io */ - push(&job->kc->io_jobs, job); - return 0; - } - - if (r == -ENOMEM) - /* can't complete now */ - return 1; - - return r; -} - -/* - * Run through a list for as long as possible. Returns the count - * of successful jobs. - */ -static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc, - int (*fn) (struct kcopyd_job *)) -{ - struct kcopyd_job *job; - int r, count = 0; - - while ((job = pop(jobs, kc))) { - - r = fn(job); - - if (r < 0) { - /* error this rogue job */ - if (job->rw == WRITE) - job->write_err = (unsigned long) -1L; - else - job->read_err = 1; - push(&kc->complete_jobs, job); - break; - } - - if (r > 0) { - /* - * We couldn't service this job ATM, so - * push this job back onto the list. - */ - push(jobs, job); - break; - } - - count++; - } - - return count; -} - -/* - * kcopyd does this every time it's woken up. - */ -static void do_work(struct work_struct *work) -{ - struct dm_kcopyd_client *kc = container_of(work, - struct dm_kcopyd_client, kcopyd_work); - - /* - * The order that these are called is *very* important. - * complete jobs can free some pages for pages jobs. - * Pages jobs when successful will jump onto the io jobs - * list. io jobs call wake when they complete and it all - * starts again. - */ - process_jobs(&kc->complete_jobs, kc, run_complete_job); - process_jobs(&kc->pages_jobs, kc, run_pages_job); - process_jobs(&kc->io_jobs, kc, run_io_job); -} - -/* - * If we are copying a small region we just dispatch a single job - * to do the copy, otherwise the io has to be split up into many - * jobs. - */ -static void dispatch_job(struct kcopyd_job *job) -{ - struct dm_kcopyd_client *kc = job->kc; - atomic_inc(&kc->nr_jobs); - push(&kc->pages_jobs, job); - wake(kc); -} - -#define SUB_JOB_SIZE 128 -static void segment_complete(int read_err, unsigned long write_err, - void *context) -{ - /* FIXME: tidy this function */ - sector_t progress = 0; - sector_t count = 0; - struct kcopyd_job *job = (struct kcopyd_job *) context; - - mutex_lock(&job->lock); - - /* update the error */ - if (read_err) - job->read_err = 1; - - if (write_err) - job->write_err |= write_err; - - /* - * Only dispatch more work if there hasn't been an error. - */ - if ((!job->read_err && !job->write_err) || - test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) { - /* get the next chunk of work */ - progress = job->progress; - count = job->source.count - progress; - if (count) { - if (count > SUB_JOB_SIZE) - count = SUB_JOB_SIZE; - - job->progress += count; - } - } - mutex_unlock(&job->lock); - - if (count) { - int i; - struct kcopyd_job *sub_job = mempool_alloc(job->kc->job_pool, - GFP_NOIO); - - *sub_job = *job; - sub_job->source.sector += progress; - sub_job->source.count = count; - - for (i = 0; i < job->num_dests; i++) { - sub_job->dests[i].sector += progress; - sub_job->dests[i].count = count; - } - - sub_job->fn = segment_complete; - sub_job->context = job; - dispatch_job(sub_job); - - } else if (atomic_dec_and_test(&job->sub_jobs)) { - - /* - * To avoid a race we must keep the job around - * until after the notify function has completed. - * Otherwise the client may try and stop the job - * after we've completed. - */ - job->fn(read_err, write_err, job->context); - mempool_free(job, job->kc->job_pool); - } -} - -/* - * Create some little jobs that will do the move between - * them. - */ -#define SPLIT_COUNT 8 -static void split_job(struct kcopyd_job *job) -{ - int i; - - atomic_set(&job->sub_jobs, SPLIT_COUNT); - for (i = 0; i < SPLIT_COUNT; i++) - segment_complete(0, 0u, job); -} - -int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, - unsigned int num_dests, struct dm_io_region *dests, - unsigned int flags, dm_kcopyd_notify_fn fn, void *context) -{ - struct kcopyd_job *job; - - /* - * Allocate a new job. - */ - job = mempool_alloc(kc->job_pool, GFP_NOIO); - - /* - * set up for the read. - */ - job->kc = kc; - job->flags = flags; - job->read_err = 0; - job->write_err = 0; - job->rw = READ; - - job->source = *from; - - job->num_dests = num_dests; - memcpy(&job->dests, dests, sizeof(*dests) * num_dests); - - job->offset = 0; - job->nr_pages = 0; - job->pages = NULL; - - job->fn = fn; - job->context = context; - - if (job->source.count < SUB_JOB_SIZE) - dispatch_job(job); - - else { - mutex_init(&job->lock); - job->progress = 0; - split_job(job); - } - - return 0; -} -EXPORT_SYMBOL(dm_kcopyd_copy); - -/* - * Cancels a kcopyd job, eg. someone might be deactivating a - * mirror. - */ -#if 0 -int kcopyd_cancel(struct kcopyd_job *job, int block) -{ - /* FIXME: finish */ - return -1; -} -#endif /* 0 */ - -/*----------------------------------------------------------------- - * Client setup - *---------------------------------------------------------------*/ -int dm_kcopyd_client_create(unsigned int nr_pages, - struct dm_kcopyd_client **result) -{ - int r = -ENOMEM; - struct dm_kcopyd_client *kc; - - kc = kmalloc(sizeof(*kc), GFP_KERNEL); - if (!kc) - return -ENOMEM; - - spin_lock_init(&kc->lock); - spin_lock_init(&kc->job_lock); - INIT_LIST_HEAD(&kc->complete_jobs); - INIT_LIST_HEAD(&kc->io_jobs); - INIT_LIST_HEAD(&kc->pages_jobs); - - kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache); - if (!kc->job_pool) - goto bad_slab; - - INIT_WORK(&kc->kcopyd_work, do_work); - kc->kcopyd_wq = create_singlethread_workqueue("kcopyd"); - if (!kc->kcopyd_wq) - goto bad_workqueue; - - kc->pages = NULL; - kc->nr_pages = kc->nr_free_pages = 0; - r = client_alloc_pages(kc, nr_pages); - if (r) - goto bad_client_pages; - - kc->io_client = dm_io_client_create(nr_pages); - if (IS_ERR(kc->io_client)) { - r = PTR_ERR(kc->io_client); - goto bad_io_client; - } - - init_waitqueue_head(&kc->destroyq); - atomic_set(&kc->nr_jobs, 0); - - *result = kc; - return 0; - -bad_io_client: - client_free_pages(kc); -bad_client_pages: - destroy_workqueue(kc->kcopyd_wq); -bad_workqueue: - mempool_destroy(kc->job_pool); -bad_slab: - kfree(kc); - - return r; -} -EXPORT_SYMBOL(dm_kcopyd_client_create); - -void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc) -{ - /* Wait for completion of all jobs submitted by this client. */ - wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs)); - - BUG_ON(!list_empty(&kc->complete_jobs)); - BUG_ON(!list_empty(&kc->io_jobs)); - BUG_ON(!list_empty(&kc->pages_jobs)); - destroy_workqueue(kc->kcopyd_wq); - dm_io_client_destroy(kc->io_client); - client_free_pages(kc); - mempool_destroy(kc->job_pool); - kfree(kc); -} -EXPORT_SYMBOL(dm_kcopyd_client_destroy); |