locks: add a new struct file_locking_context pointer to struct inode

[mirror_ubuntu-jammy-kernel.git] / fs / locks.c

diff --git a/fs/locks.c b/fs/locks.c
index ae1e7cf721d6abb8a156d7f650a99e68d4cb68ff..526d5fca67c8f46be67b181b2b6ff8c6d36a3dbc 100644 (file)
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -202,8 +202,49 @@ static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
  */
 static DEFINE_SPINLOCK(blocked_lock_lock);
 
+static struct kmem_cache *flctx_cache __read_mostly;
 static struct kmem_cache *filelock_cache __read_mostly;
 
+static struct file_lock_context *
+locks_get_lock_context(struct inode *inode)
+{
+       struct file_lock_context *new;
+
+       if (likely(inode->i_flctx))
+               goto out;
+
+       new = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
+       if (!new)
+               goto out;
+
+       INIT_LIST_HEAD(&new->flc_flock);
+
+       /*
+        * Assign the pointer if it's not already assigned. If it is, then
+        * free the context we just allocated.
+        */
+       spin_lock(&inode->i_lock);
+       if (likely(!inode->i_flctx)) {
+               inode->i_flctx = new;
+               new = NULL;
+       }
+       spin_unlock(&inode->i_lock);
+
+       if (new)
+               kmem_cache_free(flctx_cache, new);
+out:
+       return inode->i_flctx;
+}
+
+void
+locks_free_lock_context(struct file_lock_context *ctx)
+{
+       if (ctx) {
+               WARN_ON_ONCE(!list_empty(&ctx->flc_flock));
+               kmem_cache_free(flctx_cache, ctx);
+       }
+}
+
 static void locks_init_lock_heads(struct file_lock *fl)
 {
        INIT_HLIST_NODE(&fl->fl_link);
@@ -2636,6 +2677,9 @@ static int __init filelock_init(void)
 {
        int i;
 
+       flctx_cache = kmem_cache_create("file_lock_ctx",
+                       sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
+
        filelock_cache = kmem_cache_create("file_lock_cache",
                        sizeof(struct file_lock), 0, SLAB_PANIC, NULL);