lockd: Mostly remove BKL from the server

This patch removes all but one call to lock_kernel() from the server.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

3 files changed, 21 insertions, 14 deletions

diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
index 031c6569a134..a336e832475d 100644
--- a/fs/lockd/svc4proc.c
+++ b/fs/lockd/svc4proc.c
@@ -230,9 +230,7 @@ static void nlm4svc_callback_exit(struct rpc_task *task, void *data)
 
 static void nlm4svc_callback_release(void *data)
 {
-        lock_kernel();
         nlm_release_call(data);
-        unlock_kernel();
 }
 
 static const struct rpc_call_ops nlm4svc_callback_ops = {
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 84055d31bfc5..6f1ef000975a 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -52,12 +52,13 @@ static const struct rpc_call_ops nlmsvc_grant_ops;
  * The list of blocked locks to retry
  */
 static LIST_HEAD(nlm_blocked);
+static DEFINE_SPINLOCK(nlm_blocked_lock);
 
 /*
  * Insert a blocked lock into the global list
  */
 static void
-nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
+nlmsvc_insert_block_locked(struct nlm_block *block, unsigned long when)
 {
         struct nlm_block *b;
         struct list_head *pos;
@@ -87,6 +88,13 @@ nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
         block->b_when = when;
 }
 
+static void nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
+{
+        spin_lock(&nlm_blocked_lock);
+        nlmsvc_insert_block_locked(block, when);
+        spin_unlock(&nlm_blocked_lock);
+}
+
 /*
  * Remove a block from the global list
  */
@@ -94,7 +102,9 @@ static inline void
 nlmsvc_remove_block(struct nlm_block *block)
 {
         if (!list_empty(&block->b_list)) {
+                spin_lock(&nlm_blocked_lock);
                 list_del_init(&block->b_list);
+                spin_unlock(&nlm_blocked_lock);
                 nlmsvc_release_block(block);
         }
 }
@@ -651,7 +661,7 @@ static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf,
         struct nlm_block *block;
         int rc = -ENOENT;
 
-        lock_kernel();
+        spin_lock(&nlm_blocked_lock);
         list_for_each_entry(block, &nlm_blocked, b_list) {
                 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
                         dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
@@ -665,13 +675,13 @@ static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf,
                         } else if (result == 0)
                                 block->b_granted = 1;
 
-                        nlmsvc_insert_block(block, 0);
+                        nlmsvc_insert_block_locked(block, 0);
                         svc_wake_up(block->b_daemon);
                         rc = 0;
                         break;
                 }
         }
-        unlock_kernel();
+        spin_unlock(&nlm_blocked_lock);
         if (rc == -ENOENT)
                 printk(KERN_WARNING "lockd: grant for unknown block\n");
         return rc;
@@ -803,7 +813,7 @@ static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
 
         dprintk("lockd: GRANT_MSG RPC callback\n");
 
-        lock_kernel();
+        spin_lock(&nlm_blocked_lock);
         /* if the block is not on a list at this point then it has
          * been invalidated. Don't try to requeue it.
          *
@@ -825,19 +835,20 @@ static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
                 /* Call was successful, now wait for client callback */
                 timeout = 60 * HZ;
         }
-        nlmsvc_insert_block(block, timeout);
+        nlmsvc_insert_block_locked(block, timeout);
         svc_wake_up(block->b_daemon);
 out:
-        unlock_kernel();
+        spin_unlock(&nlm_blocked_lock);
 }
 
+/*
+ * FIXME: nlmsvc_release_block() grabs a mutex.  This is not allowed for an
+ * .rpc_release rpc_call_op
+ */
 static void nlmsvc_grant_release(void *data)
 {
         struct nlm_rqst         *call = data;
-
-        lock_kernel();
         nlmsvc_release_block(call->a_block);
-        unlock_kernel();
 }
 
 static const struct rpc_call_ops nlmsvc_grant_ops = {
diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index 0f2ab741ae7c..c3069f38d602 100644
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -260,9 +260,7 @@ static void nlmsvc_callback_exit(struct rpc_task *task, void *data)
 
 static void nlmsvc_callback_release(void *data)
 {
-        lock_kernel();
         nlm_release_call(data);
-        unlock_kernel();
 }
 
 static const struct rpc_call_ops nlmsvc_callback_ops = {