[PATCH 1/5] padata: introduce internal padata_get/put_pd() helpers

[Nicolai Stange]

The next commit in this series will add yet another code site decrementing
a struct parallel_data's refcount and invoking dealloction as appropriate.

With that, it's due to provide proper helper functions for managing
parallel_datas' refcounts and to convert the existing open-coded
refcount manipulation sites.

Implement padata_put_pd() as well as a padata_put_pd_many() for batched
releases as needed in padata_serial_worker(). For symmetry reasons, also
provide a padata_put_get(), even though its implementation is fairly
trivial.

Convert the exisiting open-coded parallel_data ->refcnt manipulation code
sites to these new helpers.

Signed-off-by: Nicolai Stange <nstange@xxxxxxx>
---
 kernel/padata.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index e5819bb8bd1d..3bd1e23f089b 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -45,6 +45,10 @@ struct padata_mt_job_state {
 };
 
 static void padata_free_pd(struct parallel_data *pd);
+static inline void padata_get_pd(struct parallel_data *pd);
+static void padata_put_pd_many(struct parallel_data *pd, int cnt);
+static inline void padata_put_pd(struct parallel_data *pd);
+
 static void __init padata_mt_helper(struct work_struct *work);
 
 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
@@ -198,7 +202,7 @@ int padata_do_parallel(struct padata_shell *ps,
 	if ((pinst->flags & PADATA_RESET))
 		goto out;
 
-	refcount_inc(&pd->refcnt);
+	padata_get_pd(pd);
 	padata->pd = pd;
 	padata->cb_cpu = *cb_cpu;
 
@@ -370,8 +374,7 @@ static void padata_serial_worker(struct work_struct *serial_work)
 	}
 	local_bh_enable();
 
-	if (refcount_sub_and_test(cnt, &pd->refcnt))
-		padata_free_pd(pd);
+	padata_put_pd_many(pd, cnt);
 }
 
 /**
@@ -608,6 +611,22 @@ static void padata_free_pd(struct parallel_data *pd)
 	kfree(pd);
 }
 
+static inline void padata_get_pd(struct parallel_data *pd)
+{
+	refcount_inc(&pd->refcnt);
+}
+
+static void padata_put_pd_many(struct parallel_data *pd, int cnt)
+{
+	if (refcount_sub_and_test(cnt, &pd->refcnt))
+		padata_free_pd(pd);
+}
+
+static inline void padata_put_pd(struct parallel_data *pd)
+{
+	padata_put_pd_many(pd, 1);
+}
+
 static void __padata_start(struct padata_instance *pinst)
 {
 	pinst->flags |= PADATA_INIT;
@@ -654,8 +673,7 @@ static int padata_replace(struct padata_instance *pinst)
 	synchronize_rcu();
 
 	list_for_each_entry_continue_reverse(ps, &pinst->pslist, list)
-		if (refcount_dec_and_test(&ps->opd->refcnt))
-			padata_free_pd(ps->opd);
+		padata_put_pd(ps->opd);
 
 	pinst->flags &= ~PADATA_RESET;
 
-- 
2.37.3