apparmor: use per file locks for transactional queries

As made mention of in commit 1dea3b41e84c5 ("apparmor: speed up
transactional queries"), a single lock is currently used to synchronize
transactional queries. We can, use the lock allocated for each file by
VFS instead.

Signed-off-by: Hamza Mahfooz <someguy@effective-light.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>

diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index a515d1f..0920f51 100644 (file)
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -811,8 +811,6 @@ struct multi_transaction {
 };
 
 #define MULTI_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct multi_transaction))
-/* TODO: replace with per file lock */
-static DEFINE_SPINLOCK(multi_transaction_lock);
 
 static void multi_transaction_kref(struct kref *kref)
 {
@@ -846,10 +844,10 @@ static void multi_transaction_set(struct file *file,
        AA_BUG(n > MULTI_TRANSACTION_LIMIT);
 
        new->size = n;
-       spin_lock(&multi_transaction_lock);
+       spin_lock(&file->f_lock);
        old = (struct multi_transaction *) file->private_data;
        file->private_data = new;
-       spin_unlock(&multi_transaction_lock);
+       spin_unlock(&file->f_lock);
        put_multi_transaction(old);
 }
 
@@ -878,9 +876,10 @@ static ssize_t multi_transaction_read(struct file *file, char __user *buf,
        struct multi_transaction *t;
        ssize_t ret;
 
-       spin_lock(&multi_transaction_lock);
+       spin_lock(&file->f_lock);
        t = get_multi_transaction(file->private_data);
-       spin_unlock(&multi_transaction_lock);
+       spin_unlock(&file->f_lock);
+
        if (!t)
                return 0;