dm kcopyd: prepare for callback race fix

upstream commit: 73830857bca6f6c9dbd48e906daea50bea42d676

Use a variable in segment_complete() to point to the dm_kcopyd_client
struct and only release job->pages in run_complete_job() if any are
defined.  These changes are needed by the next patch.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index 0a225da21272543c33b4992a9bf1c83b923b8bbf..9d379070918bb05f6dda228e3724b9b19b8610ca 100644 (file)
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -297,7 +297,8 @@ static int run_complete_job(struct kcopyd_job *job)
        dm_kcopyd_notify_fn fn = job->fn;
        struct dm_kcopyd_client *kc = job->kc;
 
-       kcopyd_put_pages(kc, job->pages);
+       if (job->pages)
+               kcopyd_put_pages(kc, job->pages);
        mempool_free(job, kc->job_pool);
        fn(read_err, write_err, context);
 
@@ -461,6 +462,7 @@ static void segment_complete(int read_err, unsigned long write_err,
        sector_t progress = 0;
        sector_t count = 0;
        struct kcopyd_job *job = (struct kcopyd_job *) context;
+       struct dm_kcopyd_client *kc = job->kc;
 
        mutex_lock(&job->lock);
 
@@ -490,7 +492,7 @@ static void segment_complete(int read_err, unsigned long write_err,
 
        if (count) {
                int i;
-               struct kcopyd_job *sub_job = mempool_alloc(job->kc->job_pool,
+               struct kcopyd_job *sub_job = mempool_alloc(kc->job_pool,
                                                           GFP_NOIO);
 
                *sub_job = *job;