[PATCH] afs: Use kfree_rcu() instead of casting kfree() to rcu_callback_t

From: Jann Horn
Date: Fri Mar 06 2020 - 11:17:32 EST


afs_put_addrlist() casts kfree() to rcu_callback_t. Apart from being wrong
in theory, this might also blow up when people start enforcing function
types via compiler instrumentation, and it means the rcu_head has to be
first in struct afs_addr_list.

Use kfree_rcu() instead, it's simpler and more correct.

Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
---
compile-tested only

fs/afs/addr_list.c | 2 +-
fs/afs/internal.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/afs/addr_list.c b/fs/afs/addr_list.c
index df415c05939e..de1ae0bead3b 100644
--- a/fs/afs/addr_list.c
+++ b/fs/afs/addr_list.c
@@ -19,7 +19,7 @@
void afs_put_addrlist(struct afs_addr_list *alist)
{
if (alist && refcount_dec_and_test(&alist->usage))
- call_rcu(&alist->rcu, (rcu_callback_t)kfree);
+ kfree_rcu(alist, rcu);
}

/*
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 1d81fc4c3058..35f951ac296f 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -81,7 +81,7 @@ enum afs_call_state {
* List of server addresses.
*/
struct afs_addr_list {
- struct rcu_head rcu; /* Must be first */
+ struct rcu_head rcu;
refcount_t usage;
u32 version; /* Version */
unsigned char max_addrs;

base-commit: aeb542a1b5c507ea117d21c3e3e012ba16f065ac
--
2.25.0.265.gbab2e86ba0-goog