[dm-devel] [RFC PATCH 05/13] dm headers: rename kcopyd.c to dm-kcopyd.c to be consistent with other Device-Mapper file names
Heinz Mauelshagen
hjm at redhat.com
Wed Mar 5 18:55:56 UTC 2008
Signed-off-by: Heinz Mauelshagen <hjm at redhat.com>
---
drivers/md/dm-kcopyd.c | 708 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/md/kcopyd.c | 708 ------------------------------------------------
2 files changed, 708 insertions(+), 708 deletions(-)
create mode 100644 drivers/md/dm-kcopyd.c
delete mode 100644 drivers/md/kcopyd.c
diff --git linux-2.6.25-rc4.orig/drivers/md/dm-kcopyd.c linux-2.6.25-rc4/drivers/md/dm-kcopyd.c
new file mode 100644
index 0000000..f3831f3
--- /dev/null
+++ linux-2.6.25-rc4/drivers/md/dm-kcopyd.c
@@ -0,0 +1,708 @@
+/*
+ * 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 <asm/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"
+
+static struct workqueue_struct *_kcopyd_wq;
+static struct work_struct _kcopyd_work;
+
+static void wake(void)
+{
+ queue_work(_kcopyd_wq, &_kcopyd_work);
+}
+
+/*-----------------------------------------------------------------
+ * Each kcopyd client has its own little pool of preallocated
+ * pages for kcopyd io.
+ *---------------------------------------------------------------*/
+struct kcopyd_client {
+ struct list_head list;
+
+ 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;
+};
+
+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 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 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 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 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 kcopyd_client *kc;
+ struct list_head list;
+ unsigned long flags;
+
+ /*
+ * Error state of the job.
+ */
+ int read_err;
+ unsigned int write_err;
+
+ /*
+ * Either READ or WRITE
+ */
+ int rw;
+ struct io_region source;
+
+ /*
+ * The destinations for the transfer.
+ */
+ unsigned int num_dests;
+ struct io_region dests[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.
+ */
+ 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;
+static mempool_t *_job_pool;
+
+/*
+ * 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.
+ */
+static DEFINE_SPINLOCK(_job_lock);
+
+static LIST_HEAD(_complete_jobs);
+static LIST_HEAD(_io_jobs);
+static LIST_HEAD(_pages_jobs);
+
+static int jobs_init(void)
+{
+ _job_cache = KMEM_CACHE(kcopyd_job, 0);
+ if (!_job_cache)
+ return -ENOMEM;
+
+ _job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache);
+ if (!_job_pool) {
+ kmem_cache_destroy(_job_cache);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void jobs_exit(void)
+{
+ BUG_ON(!list_empty(&_complete_jobs));
+ BUG_ON(!list_empty(&_io_jobs));
+ BUG_ON(!list_empty(&_pages_jobs));
+
+ mempool_destroy(_job_pool);
+ kmem_cache_destroy(_job_cache);
+ _job_pool = NULL;
+ _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 kcopyd_job *job = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&_job_lock, flags);
+
+ if (!list_empty(jobs)) {
+ job = list_entry(jobs->next, struct kcopyd_job, list);
+ list_del(&job->list);
+ }
+ spin_unlock_irqrestore(&_job_lock, flags);
+
+ return job;
+}
+
+static void push(struct list_head *jobs, struct kcopyd_job *job)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&_job_lock, flags);
+ list_add_tail(&job->list, jobs);
+ spin_unlock_irqrestore(&_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 int write_err = job->write_err;
+ kcopyd_notify_fn fn = job->fn;
+ struct kcopyd_client *kc = job->kc;
+
+ kcopyd_put_pages(kc, job->pages);
+ mempool_free(job, _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;
+
+ if (error) {
+ if (job->rw == WRITE)
+ job->write_err |= error;
+ else
+ job->read_err = 1;
+
+ if (!test_bit(KCOPYD_IGNORE_ERROR, &job->flags)) {
+ push(&_complete_jobs, job);
+ wake();
+ return;
+ }
+ }
+
+ if (job->rw == WRITE)
+ push(&_complete_jobs, job);
+
+ else {
+ job->rw = WRITE;
+ push(&_io_jobs, job);
+ }
+
+ wake();
+}
+
+/*
+ * 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(&_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, int (*fn) (struct kcopyd_job *))
+{
+ struct kcopyd_job *job;
+ int r, count = 0;
+
+ while ((job = pop(jobs))) {
+
+ r = fn(job);
+
+ if (r < 0) {
+ /* error this rogue job */
+ if (job->rw == WRITE)
+ job->write_err = (unsigned int) -1;
+ else
+ job->read_err = 1;
+ push(&_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 *ignored)
+{
+ /*
+ * 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(&_complete_jobs, run_complete_job);
+ process_jobs(&_pages_jobs, run_pages_job);
+ process_jobs(&_io_jobs, 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)
+{
+ atomic_inc(&job->kc->nr_jobs);
+ push(&_pages_jobs, job);
+ wake();
+}
+
+#define SUB_JOB_SIZE 128
+static void segment_complete(int read_err,
+ unsigned int 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(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_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_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 kcopyd_copy(struct kcopyd_client *kc, struct io_region *from,
+ unsigned int num_dests, struct io_region *dests,
+ unsigned int flags, kcopyd_notify_fn fn, void *context)
+{
+ struct kcopyd_job *job;
+
+ /*
+ * Allocate a new job.
+ */
+ job = mempool_alloc(_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;
+}
+
+/*
+ * 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 */
+
+/*-----------------------------------------------------------------
+ * Unit setup
+ *---------------------------------------------------------------*/
+static DEFINE_MUTEX(_client_lock);
+static LIST_HEAD(_clients);
+
+static void client_add(struct kcopyd_client *kc)
+{
+ mutex_lock(&_client_lock);
+ list_add(&kc->list, &_clients);
+ mutex_unlock(&_client_lock);
+}
+
+static void client_del(struct kcopyd_client *kc)
+{
+ mutex_lock(&_client_lock);
+ list_del(&kc->list);
+ mutex_unlock(&_client_lock);
+}
+
+static DEFINE_MUTEX(kcopyd_init_lock);
+static int kcopyd_clients = 0;
+
+static int kcopyd_init(void)
+{
+ int r;
+
+ mutex_lock(&kcopyd_init_lock);
+
+ if (kcopyd_clients) {
+ /* Already initialized. */
+ kcopyd_clients++;
+ mutex_unlock(&kcopyd_init_lock);
+ return 0;
+ }
+
+ r = jobs_init();
+ if (r) {
+ mutex_unlock(&kcopyd_init_lock);
+ return r;
+ }
+
+ _kcopyd_wq = create_singlethread_workqueue("kcopyd");
+ if (!_kcopyd_wq) {
+ jobs_exit();
+ mutex_unlock(&kcopyd_init_lock);
+ return -ENOMEM;
+ }
+
+ kcopyd_clients++;
+ INIT_WORK(&_kcopyd_work, do_work);
+ mutex_unlock(&kcopyd_init_lock);
+ return 0;
+}
+
+static void kcopyd_exit(void)
+{
+ mutex_lock(&kcopyd_init_lock);
+ kcopyd_clients--;
+ if (!kcopyd_clients) {
+ jobs_exit();
+ destroy_workqueue(_kcopyd_wq);
+ _kcopyd_wq = NULL;
+ }
+ mutex_unlock(&kcopyd_init_lock);
+}
+
+int kcopyd_client_create(unsigned int nr_pages, struct kcopyd_client **result)
+{
+ int r = 0;
+ struct kcopyd_client *kc;
+
+ r = kcopyd_init();
+ if (r)
+ return r;
+
+ kc = kmalloc(sizeof(*kc), GFP_KERNEL);
+ if (!kc) {
+ kcopyd_exit();
+ return -ENOMEM;
+ }
+
+ spin_lock_init(&kc->lock);
+ kc->pages = NULL;
+ kc->nr_pages = kc->nr_free_pages = 0;
+ r = client_alloc_pages(kc, nr_pages);
+ if (r) {
+ kfree(kc);
+ kcopyd_exit();
+ return r;
+ }
+
+ kc->io_client = dm_io_client_create(nr_pages);
+ if (IS_ERR(kc->io_client)) {
+ r = PTR_ERR(kc->io_client);
+ client_free_pages(kc);
+ kfree(kc);
+ kcopyd_exit();
+ return r;
+ }
+
+ init_waitqueue_head(&kc->destroyq);
+ atomic_set(&kc->nr_jobs, 0);
+
+ client_add(kc);
+ *result = kc;
+ return 0;
+}
+
+void kcopyd_client_destroy(struct kcopyd_client *kc)
+{
+ /* Wait for completion of all jobs submitted by this client. */
+ wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs));
+
+ dm_io_client_destroy(kc->io_client);
+ client_free_pages(kc);
+ client_del(kc);
+ kfree(kc);
+ kcopyd_exit();
+}
+
+EXPORT_SYMBOL(kcopyd_client_create);
+EXPORT_SYMBOL(kcopyd_client_destroy);
+EXPORT_SYMBOL(kcopyd_copy);
diff --git linux-2.6.25-rc4.orig/drivers/md/kcopyd.c linux-2.6.25-rc4/drivers/md/kcopyd.c
deleted file mode 100644
index f3831f3..0000000
--- linux-2.6.25-rc4.orig/drivers/md/kcopyd.c
+++ /dev/null
@@ -1,708 +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 <asm/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"
-
-static struct workqueue_struct *_kcopyd_wq;
-static struct work_struct _kcopyd_work;
-
-static void wake(void)
-{
- queue_work(_kcopyd_wq, &_kcopyd_work);
-}
-
-/*-----------------------------------------------------------------
- * Each kcopyd client has its own little pool of preallocated
- * pages for kcopyd io.
- *---------------------------------------------------------------*/
-struct kcopyd_client {
- struct list_head list;
-
- 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;
-};
-
-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 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 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 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 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 kcopyd_client *kc;
- struct list_head list;
- unsigned long flags;
-
- /*
- * Error state of the job.
- */
- int read_err;
- unsigned int write_err;
-
- /*
- * Either READ or WRITE
- */
- int rw;
- struct io_region source;
-
- /*
- * The destinations for the transfer.
- */
- unsigned int num_dests;
- struct io_region dests[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.
- */
- 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;
-static mempool_t *_job_pool;
-
-/*
- * 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.
- */
-static DEFINE_SPINLOCK(_job_lock);
-
-static LIST_HEAD(_complete_jobs);
-static LIST_HEAD(_io_jobs);
-static LIST_HEAD(_pages_jobs);
-
-static int jobs_init(void)
-{
- _job_cache = KMEM_CACHE(kcopyd_job, 0);
- if (!_job_cache)
- return -ENOMEM;
-
- _job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache);
- if (!_job_pool) {
- kmem_cache_destroy(_job_cache);
- return -ENOMEM;
- }
-
- return 0;
-}
-
-static void jobs_exit(void)
-{
- BUG_ON(!list_empty(&_complete_jobs));
- BUG_ON(!list_empty(&_io_jobs));
- BUG_ON(!list_empty(&_pages_jobs));
-
- mempool_destroy(_job_pool);
- kmem_cache_destroy(_job_cache);
- _job_pool = NULL;
- _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 kcopyd_job *job = NULL;
- unsigned long flags;
-
- spin_lock_irqsave(&_job_lock, flags);
-
- if (!list_empty(jobs)) {
- job = list_entry(jobs->next, struct kcopyd_job, list);
- list_del(&job->list);
- }
- spin_unlock_irqrestore(&_job_lock, flags);
-
- return job;
-}
-
-static void push(struct list_head *jobs, struct kcopyd_job *job)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&_job_lock, flags);
- list_add_tail(&job->list, jobs);
- spin_unlock_irqrestore(&_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 int write_err = job->write_err;
- kcopyd_notify_fn fn = job->fn;
- struct kcopyd_client *kc = job->kc;
-
- kcopyd_put_pages(kc, job->pages);
- mempool_free(job, _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;
-
- if (error) {
- if (job->rw == WRITE)
- job->write_err |= error;
- else
- job->read_err = 1;
-
- if (!test_bit(KCOPYD_IGNORE_ERROR, &job->flags)) {
- push(&_complete_jobs, job);
- wake();
- return;
- }
- }
-
- if (job->rw == WRITE)
- push(&_complete_jobs, job);
-
- else {
- job->rw = WRITE;
- push(&_io_jobs, job);
- }
-
- wake();
-}
-
-/*
- * 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(&_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, int (*fn) (struct kcopyd_job *))
-{
- struct kcopyd_job *job;
- int r, count = 0;
-
- while ((job = pop(jobs))) {
-
- r = fn(job);
-
- if (r < 0) {
- /* error this rogue job */
- if (job->rw == WRITE)
- job->write_err = (unsigned int) -1;
- else
- job->read_err = 1;
- push(&_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 *ignored)
-{
- /*
- * 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(&_complete_jobs, run_complete_job);
- process_jobs(&_pages_jobs, run_pages_job);
- process_jobs(&_io_jobs, 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)
-{
- atomic_inc(&job->kc->nr_jobs);
- push(&_pages_jobs, job);
- wake();
-}
-
-#define SUB_JOB_SIZE 128
-static void segment_complete(int read_err,
- unsigned int 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(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_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_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 kcopyd_copy(struct kcopyd_client *kc, struct io_region *from,
- unsigned int num_dests, struct io_region *dests,
- unsigned int flags, kcopyd_notify_fn fn, void *context)
-{
- struct kcopyd_job *job;
-
- /*
- * Allocate a new job.
- */
- job = mempool_alloc(_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;
-}
-
-/*
- * 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 */
-
-/*-----------------------------------------------------------------
- * Unit setup
- *---------------------------------------------------------------*/
-static DEFINE_MUTEX(_client_lock);
-static LIST_HEAD(_clients);
-
-static void client_add(struct kcopyd_client *kc)
-{
- mutex_lock(&_client_lock);
- list_add(&kc->list, &_clients);
- mutex_unlock(&_client_lock);
-}
-
-static void client_del(struct kcopyd_client *kc)
-{
- mutex_lock(&_client_lock);
- list_del(&kc->list);
- mutex_unlock(&_client_lock);
-}
-
-static DEFINE_MUTEX(kcopyd_init_lock);
-static int kcopyd_clients = 0;
-
-static int kcopyd_init(void)
-{
- int r;
-
- mutex_lock(&kcopyd_init_lock);
-
- if (kcopyd_clients) {
- /* Already initialized. */
- kcopyd_clients++;
- mutex_unlock(&kcopyd_init_lock);
- return 0;
- }
-
- r = jobs_init();
- if (r) {
- mutex_unlock(&kcopyd_init_lock);
- return r;
- }
-
- _kcopyd_wq = create_singlethread_workqueue("kcopyd");
- if (!_kcopyd_wq) {
- jobs_exit();
- mutex_unlock(&kcopyd_init_lock);
- return -ENOMEM;
- }
-
- kcopyd_clients++;
- INIT_WORK(&_kcopyd_work, do_work);
- mutex_unlock(&kcopyd_init_lock);
- return 0;
-}
-
-static void kcopyd_exit(void)
-{
- mutex_lock(&kcopyd_init_lock);
- kcopyd_clients--;
- if (!kcopyd_clients) {
- jobs_exit();
- destroy_workqueue(_kcopyd_wq);
- _kcopyd_wq = NULL;
- }
- mutex_unlock(&kcopyd_init_lock);
-}
-
-int kcopyd_client_create(unsigned int nr_pages, struct kcopyd_client **result)
-{
- int r = 0;
- struct kcopyd_client *kc;
-
- r = kcopyd_init();
- if (r)
- return r;
-
- kc = kmalloc(sizeof(*kc), GFP_KERNEL);
- if (!kc) {
- kcopyd_exit();
- return -ENOMEM;
- }
-
- spin_lock_init(&kc->lock);
- kc->pages = NULL;
- kc->nr_pages = kc->nr_free_pages = 0;
- r = client_alloc_pages(kc, nr_pages);
- if (r) {
- kfree(kc);
- kcopyd_exit();
- return r;
- }
-
- kc->io_client = dm_io_client_create(nr_pages);
- if (IS_ERR(kc->io_client)) {
- r = PTR_ERR(kc->io_client);
- client_free_pages(kc);
- kfree(kc);
- kcopyd_exit();
- return r;
- }
-
- init_waitqueue_head(&kc->destroyq);
- atomic_set(&kc->nr_jobs, 0);
-
- client_add(kc);
- *result = kc;
- return 0;
-}
-
-void kcopyd_client_destroy(struct kcopyd_client *kc)
-{
- /* Wait for completion of all jobs submitted by this client. */
- wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs));
-
- dm_io_client_destroy(kc->io_client);
- client_free_pages(kc);
- client_del(kc);
- kfree(kc);
- kcopyd_exit();
-}
-
-EXPORT_SYMBOL(kcopyd_client_create);
-EXPORT_SYMBOL(kcopyd_client_destroy);
-EXPORT_SYMBOL(kcopyd_copy);
--
1.5.4.1
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