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>

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 18bfd5d..7b545c3 100644 (file)
--- 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) {