jbd2: Remove GFP_ATOMIC kmalloc from inside spinlock critical region

Fix jbd2_dev_to_name(), a function used when pretty-printting jbd2 and
ext4 tracepoints.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 6 insertions, 5 deletions

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 18bfd5dab642..7b545c3b3942 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2410,6 +2410,7 @@ const char *jbd2_dev_to_name(dev_t device)
         int     i = hash_32(device, CACHE_SIZE_BITS);
         char    *ret;
         struct block_device *bd;
+        static struct devname_cache *new_dev;
 
         rcu_read_lock();
         if (devcache[i] && devcache[i]->device == device) {
@@ -2419,20 +2420,20 @@ const char *jbd2_dev_to_name(dev_t device)
         }
         rcu_read_unlock();
 
+        new_dev = kmalloc(sizeof(struct devname_cache), GFP_KERNEL);
+        if (!new_dev)
+                return "NODEV-ALLOCFAILURE"; /* Something non-NULL */
         spin_lock(&devname_cache_lock);
         if (devcache[i]) {
                 if (devcache[i]->device == device) {
+                        kfree(new_dev);
                         ret = devcache[i]->devname;
                         spin_unlock(&devname_cache_lock);
                         return ret;
                 }
                 call_rcu(&devcache[i]->rcu, free_devcache);
         }
-        devcache[i] = kmalloc(sizeof(struct devname_cache), GFP_KERNEL);
-        if (!devcache[i]) {
-                spin_unlock(&devname_cache_lock);
-                return "NODEV-ALLOCFAILURE"; /* Something non-NULL */
-        }
+        devcache[i] = new_dev;
         devcache[i]->device = device;
         bd = bdget(device);
         if (bd) {