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| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-12-10 23:52:13 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-12-10 23:52:13 +0000 |
| commit | 9ca170a3c0cbb0d5251cef6f5a3300fa436ba8ec (patch) | |
| tree | 78c023bd85bcbf01b5e81ae9586093aabe201312 /drivers/md | |
| parent | c26655ca3ca7550740a63820ee981e5c7c797523 (diff) | |
| download | op-kernel-dev-9ca170a3c0cbb0d5251cef6f5a3300fa436ba8ec.zip op-kernel-dev-9ca170a3c0cbb0d5251cef6f5a3300fa436ba8ec.tar.gz | |
dm kcopyd: accept zero size jobs
dm-kcopyd: accept zero-size jobs
This patch changes dm-kcopyd so that it accepts zero-size jobs and completes
them immediatelly via its completion thread.
It is needed for multisnapshots snapshot resizing. When we are writing to
a chunk beyond origin end, no copying is done. To simplify the code, we submit
an empty request to kcopyd and let kcopyd complete it. If we didn't submit
a request to kcopyd and called the completion routine immediatelly, it would
violate the principle that completion is called only from one thread and
it would need additional locking.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-kcopyd.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c index 3e3fc06..addf834 100644 --- a/drivers/md/dm-kcopyd.c +++ b/drivers/md/dm-kcopyd.c @@ -450,7 +450,10 @@ 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); + if (unlikely(!job->source.count)) + push(&kc->complete_jobs, job); + else + push(&kc->pages_jobs, job); wake(kc); } |
