[Devel] [PATCH 03/12] Replace obj_no_grab and obj_no_drop ckpt ops with NULL

[Matt Helsley]

Distributing the ckpt_obj_ops would require sharing these functions when
we can get by with simple NULL pointers in the grab/drop operations.

Signed-off-by: Matt Helsley <matthltc at us.ibm.com>
---
 checkpoint/objhash.c |   36 ++++++++++++++++--------------------
 1 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
index 832520d..999d731 100644
--- a/checkpoint/objhash.c
+++ b/checkpoint/objhash.c
@@ -47,16 +47,6 @@ struct ckpt_obj_hash {
 
 /* helper grab/drop/users functions */
 
-static void obj_no_drop(void *ptr, int lastref)
-{
-	return;
-}
-
-static int obj_no_grab(void *ptr)
-{
-	return 0;
-}
-
 static int obj_inode_grab(void *ptr)
 {
 	return igrab((struct inode *) ptr) ? 0 : -EBADF;
@@ -346,8 +336,8 @@ static void *restore_lsm_string_wrap(struct ckpt_ctx *ctx)
 static const struct ckpt_obj_ops ckpt_obj_ignored_ops = {
 	.obj_name = "IGNORED",
 	.obj_type = CKPT_OBJ_IGNORE,
-	.ref_drop = obj_no_drop,
-	.ref_grab = obj_no_grab,
+	.ref_drop = NULL,
+	.ref_grab = NULL,
 };
 
 /* inode object */
@@ -412,8 +402,8 @@ static const struct ckpt_obj_ops ckpt_obj_sighand_ops = {
 static const struct ckpt_obj_ops ckpt_obj_signal_ops = {
 	.obj_name = "SIGNAL",
 	.obj_type = CKPT_OBJ_SIGNAL,
-	.ref_drop = obj_no_drop,
-	.ref_grab = obj_no_grab,
+	.ref_drop = NULL,
+	.ref_grab = NULL,
 };
 /* ns object */
 static const struct ckpt_obj_ops ckpt_obj_nsproxy_ops = {
@@ -519,8 +509,8 @@ static const struct ckpt_obj_ops ckpt_obj_tty_ops = {
 static const struct ckpt_obj_ops ckpt_obj_security_ptr_ops = {
 	.obj_name = "SECURITY PTR",
 	.obj_type = CKPT_OBJ_SECURITY_PTR,
-	.ref_drop = obj_no_drop,
-	.ref_grab = obj_no_grab,
+	.ref_drop = NULL,
+	.ref_grab = NULL,
 };
 /*
  * LSM security strings - at restart
@@ -578,7 +568,8 @@ static void obj_hash_clear(struct ckpt_obj_hash *obj_hash)
 
 	for (i = 0; i < CKPT_OBJ_HASH_TOTAL; i++) {
 		hlist_for_each_entry_safe(obj, n, t, &h[i], hash) {
-			obj->ops->ref_drop(obj->ptr, 1);
+			if (obj->ops->ref_drop)
+				obj->ops->ref_drop(obj->ptr, 1);
 			kfree(obj);
 		}
 	}
@@ -692,7 +683,10 @@ static struct ckpt_obj *obj_new(struct ckpt_ctx *ctx, void *ptr,
 		i = hash_long((unsigned long) objref, CKPT_OBJ_HASH_NBITS);
 	}
 
-	ret = ops->ref_grab(obj->ptr);
+	if (ops->ref_grab)
+		ret = ops->ref_grab(obj->ptr);
+	else
+		ret = 0;
 	if (ret < 0) {
 		kfree(obj);
 		obj = ERR_PTR(ret);
@@ -1081,9 +1075,11 @@ int restore_obj(struct ckpt_ctx *ctx, struct ckpt_hdr_objref *h)
 	 * On success, this clears the extra reference taken by obj_new(),
 	 * and on failure, this cleans up the object itself.
 	 */
-	ops->ref_drop(ptr, 0);
+	if (ops->ref_drop)
+		ops->ref_drop(ptr, 0);
 	if (IS_ERR(obj)) {
-		ops->ref_drop(ptr, 1);
+		if (ops->ref_drop)
+			ops->ref_drop(ptr, 1);
 		return PTR_ERR(obj);
 	}
 	return obj->objref;
-- 
1.6.3.3

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