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From:   Xiaomeng Tong <xiam0nd.tong@gmail.com>
To:     torvalds@linux-foundation.org
Cc:     arnd@arndb.de, jakobkoschel@gmail.com,
        linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org,
        keescook@chromium.org, jannh@google.com,
        linux-kbuild@vger.kernel.org, linux-mm@kvack.org,
        netdev@vger.kernel.org, Xiaomeng Tong <xiam0nd.tong@gmail.com>
Subject: [PATCH 2/6] list: add new MACROs to make iterator invisiable outside the loop
Date:   Tue,  1 Mar 2022 15:58:35 +0800
Message-Id: <20220301075839.4156-3-xiam0nd.tong@gmail.com>
In-Reply-To: <20220301075839.4156-1-xiam0nd.tong@gmail.com>
References: <20220301075839.4156-1-xiam0nd.tong@gmail.com>
Precedence: bulk

For each list_for_each_entry* macros(10 variants), implements a respective
new *_inside one. Such as the new macro list_for_each_entry_inside for
list_for_each_entry. The idea is to be as compatible with the original
interface as possible and to minimize code changes.

Here are 2 examples:

list_for_each_entry_inside:
 - declare the iterator-variable pos inside the loop. Thus, the origin
   declare of the inputed *pos* outside the loop should be removed. In
   other words, the inputed *pos* now is just a string name.
 - add a new "type" argument as the type of the container struct this is
   embedded in, and should be inputed when calling the macro.

list_for_each_entry_safe_continue_inside:
 - declare the iterator-variable pos and n inside the loop. Thus, the
   origin declares of the inputed *pos* and *n* outside the loop should
   be removed. In other words, the inputed *pos* and *n* now are just
   string name.
 - add a new "start" argument as the given iterator to start with and
   can be used to get the container struct *type*. This should be inputed
   when calling the macro.

Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
---
 include/linux/list.h | 156 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 156 insertions(+)

diff --git a/include/linux/list.h b/include/linux/list.h
index dd6c2041d..1595ce865 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -639,6 +639,19 @@ static inline void list_splice_tail_init(struct list_head *list,
 	     !list_entry_is_head(pos, head, member);			\
 	     pos = list_next_entry(pos, member))
 
+/**
+ * list_for_each_entry_inside
+ *  - iterate over list of given type and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @type:	the type of the container struct this is embedded in.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry_inside(pos, type, head, member)		\
+	for (type * pos = list_first_entry(head, type, member);		\
+	     !list_entry_is_head(pos, head, member);			\
+	     pos = list_next_entry(pos, member))
+
 /**
  * list_for_each_entry_reverse - iterate backwards over list of given type.
  * @pos:	the type * to use as a loop cursor.
@@ -650,6 +663,19 @@ static inline void list_splice_tail_init(struct list_head *list,
 	     !list_entry_is_head(pos, head, member); 			\
 	     pos = list_prev_entry(pos, member))
 
+/**
+ * list_for_each_entry_reverse_inside
+ * - iterate backwards over list of given type and keep iterator inside the loop.
+ * @pos:	the type * to use as a loop cursor.
+ * @type:	the type of the container struct this is embedded in.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry_reverse_inside(pos, type, head, member)	\
+	for (type * pos = list_last_entry(head, type, member);		\
+	     !list_entry_is_head(pos, head, member);			\
+	     pos = list_prev_entry(pos, member))
+
 /**
  * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
  * @pos:	the type * to use as a start point
@@ -675,6 +701,22 @@ static inline void list_splice_tail_init(struct list_head *list,
 	     !list_entry_is_head(pos, head, member);			\
 	     pos = list_next_entry(pos, member))
 
+/**
+ * list_for_each_entry_continue_inside
+ *  - continue iteration over list of given type and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @start:	the given iterator to start with.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Continue to iterate over list of given type, continuing after
+ * the current position.
+ */
+#define list_for_each_entry_continue_inside(pos, start, head, member)	\
+	for (typeof(*start) *pos = list_next_entry(start, member);	\
+	     !list_entry_is_head(pos, head, member);			\
+	     pos = list_next_entry(pos, member))
+
 /**
  * list_for_each_entry_continue_reverse - iterate backwards from the given point
  * @pos:	the type * to use as a loop cursor.
@@ -689,6 +731,22 @@ static inline void list_splice_tail_init(struct list_head *list,
 	     !list_entry_is_head(pos, head, member);			\
 	     pos = list_prev_entry(pos, member))
 
+/**
+ * list_for_each_entry_continue_reverse_inside
+ *  - iterate backwards from the given point and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @start:	the given iterator to start with.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Start to iterate over list of given type backwards, continuing after
+ * the current position.
+ */
+#define list_for_each_entry_continue_reverse_inside(pos, start, head, member)	\
+	for (typeof(*start) *pos = list_prev_entry(start, member);		\
+	     !list_entry_is_head(pos, head, member);				\
+	     pos = list_prev_entry(pos, member))
+
 /**
  * list_for_each_entry_from - iterate over list of given type from the current point
  * @pos:	the type * to use as a loop cursor.
@@ -701,6 +759,20 @@ static inline void list_splice_tail_init(struct list_head *list,
 	for (; !list_entry_is_head(pos, head, member);			\
 	     pos = list_next_entry(pos, member))
 
+/**
+ * list_for_each_entry_from_inside
+ *  - iterate over list of given type from the current point and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @start:	the given iterator to start with.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Iterate over list of given type, continuing from current position.
+ */
+#define list_for_each_entry_from_inside(pos, start, head, member)			\
+	for (typeof(*start) *pos = start; !list_entry_is_head(pos, head, member);	\
+	     pos = list_next_entry(pos, member))
+
 /**
  * list_for_each_entry_from_reverse - iterate backwards over list of given type
  *                                    from the current point
@@ -714,6 +786,21 @@ static inline void list_splice_tail_init(struct list_head *list,
 	for (; !list_entry_is_head(pos, head, member);			\
 	     pos = list_prev_entry(pos, member))
 
+/**
+ * list_for_each_entry_from_reverse_inside
+ *  - iterate backwards over list of given type from the current point
+ *    and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @start:	the given iterator to start with.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Iterate backwards over list of given type, continuing from current position.
+ */
+#define list_for_each_entry_from_reverse_inside(pos, start, head, member)		\
+	for (typeof(*start) *pos = start; !list_entry_is_head(pos, head, member);	\
+	     pos = list_prev_entry(pos, member))
+
 /**
  * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
  * @pos:	the type * to use as a loop cursor.
@@ -727,6 +814,22 @@ static inline void list_splice_tail_init(struct list_head *list,
 	     !list_entry_is_head(pos, head, member); 			\
 	     pos = n, n = list_next_entry(n, member))
 
+/**
+ * list_for_each_entry_safe_inside
+ *  - iterate over list of given type safe against removal of list entry
+ *    and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @n:		another type * to use as temporary storage
+ * @type:	the type of the container struct this is embedded in.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry_safe_inside(pos, n, type, head, member)	\
+	for (type * pos = list_first_entry(head, type, member),		\
+		*n = list_next_entry(pos, member);			\
+	     !list_entry_is_head(pos, head, member);			\
+	     pos = n, n = list_next_entry(n, member))
+
 /**
  * list_for_each_entry_safe_continue - continue list iteration safe against removal
  * @pos:	the type * to use as a loop cursor.
@@ -743,6 +846,24 @@ static inline void list_splice_tail_init(struct list_head *list,
 	     !list_entry_is_head(pos, head, member);				\
 	     pos = n, n = list_next_entry(n, member))
 
+/**
+ * list_for_each_entry_safe_continue_inside
+ *  - continue list iteration safe against removal and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @n:		another type * to use as temporary storage
+ * @start:	the given iterator to start with.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Iterate over list of given type, continuing after current point,
+ * safe against removal of list entry.
+ */
+#define list_for_each_entry_safe_continue_inside(pos, n, start, head, member)	\
+	for (typeof(*start) *pos = list_next_entry(start, member),		\
+		*n = list_next_entry(pos, member);				\
+	     !list_entry_is_head(pos, head, member);				\
+	     pos = n, n = list_next_entry(n, member))
+
 /**
  * list_for_each_entry_safe_from - iterate over list from current point safe against removal
  * @pos:	the type * to use as a loop cursor.
@@ -758,6 +879,23 @@ static inline void list_splice_tail_init(struct list_head *list,
 	     !list_entry_is_head(pos, head, member);				\
 	     pos = n, n = list_next_entry(n, member))
 
+/**
+ * list_for_each_entry_safe_from_inside
+ *  - iterate over list from current point safe against removal and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @n:		another type * to use as temporary storage
+ * @start:	the given iterator to start with.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Iterate over list of given type from current point, safe against
+ * removal of list entry.
+ */
+#define list_for_each_entry_safe_from_inside(pos, n, start, head, member)	\
+	for (typeof(*start) *pos = start, *n = list_next_entry(pos, member);	\
+	     !list_entry_is_head(pos, head, member);				\
+	     pos = n, n = list_next_entry(n, member))
+
 /**
  * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
  * @pos:	the type * to use as a loop cursor.
@@ -774,6 +912,24 @@ static inline void list_splice_tail_init(struct list_head *list,
 	     !list_entry_is_head(pos, head, member); 			\
 	     pos = n, n = list_prev_entry(n, member))
 
+/**
+ * list_for_each_entry_safe_reverse_insde
+ *  - iterate backwards over list safe against removal and keep iterator inside the loop
+ * @pos:	the type * to use as a loop cursor.
+ * @n:		another type * to use as temporary storage
+ * @type:	the type of the struct this is enmbeded in.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Iterate backwards over list of given type, safe against removal
+ * of list entry.
+ */
+#define list_for_each_entry_safe_reverse_inside(pos, n, type, head, member)	\
+	for (type * pos = list_last_entry(head, type, member),			\
+		*n = list_prev_entry(pos, member);				\
+	     !list_entry_is_head(pos, head, member);				\
+	     pos = n, n = list_prev_entry(n, member))
+
 /**
  * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
  * @pos:	the loop cursor used in the list_for_each_entry_safe loop
-- 
2.17.1