Patch "padata: add pd get/put refcnt helper" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    padata: add pd get/put refcnt helper

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     padata-add-pd-get-put-refcnt-helper.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit d1444a04911d5920736008f3cade522d0602585c
Author: Chen Ridong <chenridong@xxxxxxxxxx>
Date:   Fri Jan 10 06:16:37 2025 +0000

    padata: add pd get/put refcnt helper
    
    [ Upstream commit ae154202cc6a189b035359f3c4e143d5c24d5352 ]
    
    Add helpers for pd to get/put refcnt to make code consice.
    
    Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
    Acked-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
    Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
    Stable-dep-of: dd7d37ccf6b1 ("padata: avoid UAF for reorder_work")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/kernel/padata.c b/kernel/padata.c
index e4e0121ef3da2..02bb06a2c797d 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -60,6 +60,22 @@ struct padata_mt_job_state {
 static void padata_free_pd(struct parallel_data *pd);
 static void __init padata_mt_helper(struct work_struct *work);
 
+static inline void padata_get_pd(struct parallel_data *pd)
+{
+	refcount_inc(&pd->refcnt);
+}
+
+static inline void padata_put_pd_cnt(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_cnt(pd, 1);
+}
+
 static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
 {
 	int cpu, target_cpu;
@@ -211,7 +227,7 @@ 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;
 
@@ -385,8 +401,7 @@ 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_cnt(pd, cnt);
 }
 
 /**
@@ -683,8 +698,7 @@ 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;
 
@@ -1132,8 +1146,7 @@ void padata_free_shell(struct padata_shell *ps)
 	mutex_lock(&ps->pinst->lock);
 	list_del(&ps->list);
 	pd = rcu_dereference_protected(ps->pd, 1);
-	if (refcount_dec_and_test(&pd->refcnt))
-		padata_free_pd(pd);
+	padata_put_pd(pd);
 	mutex_unlock(&ps->pinst->lock);
 
 	kfree(ps);