ext4: use built-in RCU list checking in mballoc

list_for_each_entry_rcu() has built-in RCU and lock checking.

Pass cond argument to list_for_each_entry_rcu() to silence
false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled
by default.

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Link: https://lore.kernel.org/r/20200213152558.7070-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 51a78eb..1027e01 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4302,7 +4302,8 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb,
 
        spin_lock(&lg->lg_prealloc_lock);
        list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
-                                               pa_inode_list) {
+                               pa_inode_list,
+                               lockdep_is_held(&lg->lg_prealloc_lock)) {
                spin_lock(&pa->pa_lock);
                if (atomic_read(&pa->pa_count)) {
                        /*
@@ -4386,7 +4387,8 @@ static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
        /* Add the prealloc space to lg */
        spin_lock(&lg->lg_prealloc_lock);
        list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
-                                               pa_inode_list) {
+                               pa_inode_list,
+                               lockdep_is_held(&lg->lg_prealloc_lock)) {
                spin_lock(&tmp_pa->pa_lock);
                if (tmp_pa->pa_deleted) {
                        spin_unlock(&tmp_pa->pa_lock);