diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2011-10-31 20:18:58 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2011-10-31 20:18:58 +0000 |
| commit | 7f06965390e4a10fb6906c886324bfd0a96961be (patch) | |
| tree | 5a6fd96cd56fb9d80bf1a40110ebfcdb5a8a7aa3 | |
| parent | fbdc86f3bd597e108fa03d998132d04fcfe1d669 (diff) | |
dm kcopyd: add dm_kcopyd_zero to zero an area
This patch introduces dm_kcopyd_zero() to make it easy to use
kcopyd to write zeros into the requested areas instead
instead of copying. It is implemented by passing a NULL
copying source to dm_kcopyd_copy().
The forthcoming thin provisioning target uses this.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
| -rw-r--r-- | drivers/md/dm-kcopyd.c | 31 | ||||
| -rw-r--r-- | include/linux/dm-kcopyd.h | 4 |
2 files changed, 30 insertions, 5 deletions
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c index 32ac70861d66..bed444c93d8d 100644 --- a/drivers/md/dm-kcopyd.c +++ b/drivers/md/dm-kcopyd.c @@ -66,6 +66,8 @@ struct dm_kcopyd_client { struct list_head pages_jobs; }; +static struct page_list zero_page_list; + static void wake(struct dm_kcopyd_client *kc) { queue_work(kc->kcopyd_wq, &kc->kcopyd_work); @@ -254,6 +256,9 @@ int __init dm_kcopyd_init(void) if (!_job_cache) return -ENOMEM; + zero_page_list.next = &zero_page_list; + zero_page_list.page = ZERO_PAGE(0); + return 0; } @@ -322,7 +327,7 @@ static int run_complete_job(struct kcopyd_job *job) dm_kcopyd_notify_fn fn = job->fn; struct dm_kcopyd_client *kc = job->kc; - if (job->pages) + if (job->pages && job->pages != &zero_page_list) kcopyd_put_pages(kc, job->pages); /* * If this is the master job, the sub jobs have already @@ -484,6 +489,8 @@ static void dispatch_job(struct kcopyd_job *job) atomic_inc(&kc->nr_jobs); if (unlikely(!job->source.count)) push(&kc->complete_jobs, job); + else if (job->pages == &zero_page_list) + push(&kc->io_jobs, job); else push(&kc->pages_jobs, job); wake(kc); @@ -592,14 +599,20 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, 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->pages = NULL; + if (from) { + job->source = *from; + job->pages = NULL; + job->rw = READ; + } else { + memset(&job->source, 0, sizeof job->source); + job->source.count = job->dests[0].count; + job->pages = &zero_page_list; + job->rw = WRITE; + } job->fn = fn; job->context = context; @@ -617,6 +630,14 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from, } EXPORT_SYMBOL(dm_kcopyd_copy); +int dm_kcopyd_zero(struct dm_kcopyd_client *kc, + unsigned num_dests, struct dm_io_region *dests, + unsigned flags, dm_kcopyd_notify_fn fn, void *context) +{ + return dm_kcopyd_copy(kc, NULL, num_dests, dests, flags, fn, context); +} +EXPORT_SYMBOL(dm_kcopyd_zero); + void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, dm_kcopyd_notify_fn fn, void *context) { diff --git a/include/linux/dm-kcopyd.h b/include/linux/dm-kcopyd.h index 5e54458e920f..47d9d376e4e7 100644 --- a/include/linux/dm-kcopyd.h +++ b/include/linux/dm-kcopyd.h @@ -57,5 +57,9 @@ void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc, dm_kcopyd_notify_fn fn, void *context); void dm_kcopyd_do_callback(void *job, int read_err, unsigned long write_err); +int dm_kcopyd_zero(struct dm_kcopyd_client *kc, + unsigned num_dests, struct dm_io_region *dests, + unsigned flags, dm_kcopyd_notify_fn fn, void *context); + #endif /* __KERNEL__ */ #endif /* _LINUX_DM_KCOPYD_H */ |