afs: Make vnode->cb_interest RCU safe
Use RCU-based freeing for afs_cb_interest struct objects and use RCU on
vnode->cb_interest. Use that change to allow afs_check_validity() to use
read_seqbegin_or_lock() instead of read_seqlock_excl().
This also requires the caller of afs_check_validity() to hold the RCU read
lock across the call.
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/fs/afs/super.c b/fs/afs/super.c
index a81c235..f76473a 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -677,7 +677,7 @@ static struct inode *afs_alloc_inode(struct super_block *sb)
vnode->volume = NULL;
vnode->lock_key = NULL;
vnode->permit_cache = NULL;
- vnode->cb_interest = NULL;
+ RCU_INIT_POINTER(vnode->cb_interest, NULL);
#ifdef CONFIG_AFS_FSCACHE
vnode->cache = NULL;
#endif
@@ -707,7 +707,7 @@ static void afs_destroy_inode(struct inode *inode)
_debug("DESTROY INODE %p", inode);
- ASSERTCMP(vnode->cb_interest, ==, NULL);
+ ASSERTCMP(rcu_access_pointer(vnode->cb_interest), ==, NULL);
atomic_dec(&afs_count_active_inodes);
}
