btrfs: Fix suspicious RCU usage warning in btrfs_debug_in_rcu

Commit 672d599041c8 ("btrfs: Use wrapper macro for rcu string to remove
duplicate code") replaces some open coded RCU string handling with macro.

It turns out that btrfs_debug_in_rcu() is used for the first time and
the macro lacks lock/unlock of RCU string for non-debug case (i.e. when
the message is not printed), leading to suspicious RCU usage warning
when CONFIG_PROVE_RCU is on.

Fix this by adding a wrapper to call lock/unlock for the non-debug case
too.

Fixes: 672d599041c8 ("btrfs: Use wrapper macro for rcu string to remove duplicate code")
Reported-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a67cc190a84b4e39cbadfcbcef324d72952b57e0..0b856da2fd3b35006b52dc77ddab4dfaadc3f22e 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3390,9 +3390,9 @@ do {                                                                      \
 #define btrfs_debug(fs_info, fmt, args...) \
        btrfs_no_printk(fs_info, KERN_DEBUG fmt, ##args)
 #define btrfs_debug_in_rcu(fs_info, fmt, args...) \
-       btrfs_no_printk(fs_info, KERN_DEBUG fmt, ##args)
+       btrfs_no_printk_in_rcu(fs_info, KERN_DEBUG fmt, ##args)
 #define btrfs_debug_rl_in_rcu(fs_info, fmt, args...) \
-       btrfs_no_printk(fs_info, KERN_DEBUG fmt, ##args)
+       btrfs_no_printk_in_rcu(fs_info, KERN_DEBUG fmt, ##args)
 #define btrfs_debug_rl(fs_info, fmt, args...) \
        btrfs_no_printk(fs_info, KERN_DEBUG fmt, ##args)
 #endif
@@ -3404,6 +3404,13 @@ do {                                                     \
        rcu_read_unlock();                              \
 } while (0)
 
+#define btrfs_no_printk_in_rcu(fs_info, fmt, args...)  \
+do {                                                   \
+       rcu_read_lock();                                \
+       btrfs_no_printk(fs_info, fmt, ##args);          \
+       rcu_read_unlock();                              \
+} while (0)
+
 #define btrfs_printk_ratelimited(fs_info, fmt, args...)                \
 do {                                                           \
        static DEFINE_RATELIMIT_STATE(_rs,                      \