hlist: drop the node parameter from iterators

I'm not sure why, but the hlist for each entry iterators were conceived

        list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

        hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

 - Fix up the actual hlist iterators in linux/list.h
 - Fix up the declaration of other iterators based on the hlist ones.
 - A very small amount of places were using the 'node' parameter, this
 was modified to use 'obj->member' instead.
 - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
 properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
    <+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
    ...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 22 insertions, 27 deletions

diff --git a/include/linux/list.h b/include/linux/list.h
index cc6d2aa6b415..d991cc147c98 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -666,54 +666,49 @@ static inline void hlist_move_list(struct hlist_head *old,
         for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
              pos = n)
 
+#define hlist_entry_safe(ptr, type, member) \
+        (ptr) ? hlist_entry(ptr, type, member) : NULL
+
 /**
  * hlist_for_each_entry - iterate over list of given type
- * @tpos:       the type * to use as a loop cursor.
- * @pos:        the &struct hlist_node to use as a loop cursor.
+ * @pos:        the type * to use as a loop cursor.
  * @head:       the head for your list.
  * @member:     the name of the hlist_node within the struct.
  */
-#define hlist_for_each_entry(tpos, pos, head, member)                    \
-        for (pos = (head)->first;                                        \
-             pos &&                                                      \
-                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
-             pos = pos->next)
+#define hlist_for_each_entry(pos, head, member)                         \
+        for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
+             pos;                                                       \
+             pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
 
 /**
  * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
- * @tpos:       the type * to use as a loop cursor.
- * @pos:        the &struct hlist_node to use as a loop cursor.
+ * @pos:        the type * to use as a loop cursor.
  * @member:     the name of the hlist_node within the struct.
  */
-#define hlist_for_each_entry_continue(tpos, pos, member)                 \
-        for (pos = (pos)->next;                                          \
-             pos &&                                                      \
-                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
-             pos = pos->next)
+#define hlist_for_each_entry_continue(pos, member)                      \
+        for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\
+             pos;                                                       \
+             pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
 
 /**
  * hlist_for_each_entry_from - iterate over a hlist continuing from current point
- * @tpos:       the type * to use as a loop cursor.
- * @pos:        the &struct hlist_node to use as a loop cursor.
+ * @pos:        the type * to use as a loop cursor.
  * @member:     the name of the hlist_node within the struct.
  */
-#define hlist_for_each_entry_from(tpos, pos, member)                     \
-        for (; pos &&                                                    \
-                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
-             pos = pos->next)
+#define hlist_for_each_entry_from(pos, member)                          \
+        for (; pos;                                                     \
+             pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
 
 /**
  * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
- * @tpos:       the type * to use as a loop cursor.
- * @pos:        the &struct hlist_node to use as a loop cursor.
+ * @pos:        the type * to use as a loop cursor.
  * @n:          another &struct hlist_node to use as temporary storage
  * @head:       the head for your list.
  * @member:     the name of the hlist_node within the struct.
  */
-#define hlist_for_each_entry_safe(tpos, pos, n, head, member)            \
-        for (pos = (head)->first;                                        \
-             pos && ({ n = pos->next; 1; }) &&                           \
-                ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
-             pos = n)
+#define hlist_for_each_entry_safe(pos, n, head, member)                 \
+        for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
+             pos && ({ n = pos->member.next; 1; });                     \
+             pos = hlist_entry_safe(n, typeof(*pos), member))
 
 #endif