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>

5 files changed, 7 insertions, 12 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index b8858fb0caf..8bdebb6781e 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -357,7 +357,6 @@ static int blkcg_reset_stats(struct cgroup *cgroup, struct cftype *cftype,
 {
 	struct blkcg *blkcg = cgroup_to_blkcg(cgroup);
 	struct blkcg_gq *blkg;
-	struct hlist_node *n;
 	int i;
 
 	mutex_lock(&blkcg_pol_mutex);
@@ -368,7 +367,7 @@ static int blkcg_reset_stats(struct cgroup *cgroup, struct cftype *cftype,
 	 * stat updates.  This is a debug feature which shouldn't exist
 	 * anyway.  If you get hit by a race, retry.
 	 */
-	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
+	hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
 		for (i = 0; i < BLKCG_MAX_POLS; i++) {
 			struct blkcg_policy *pol = blkcg_policy[i];
 
@@ -415,11 +414,10 @@ void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
 		       bool show_total)
 {
 	struct blkcg_gq *blkg;
-	struct hlist_node *n;
 	u64 total = 0;
 
 	spin_lock_irq(&blkcg->lock);
-	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
+	hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node)
 		if (blkcg_policy_enabled(blkg->q, pol))
 			total += prfill(sf, blkg->pd[pol->plid], data);
 	spin_unlock_irq(&blkcg->lock);
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index fab4cdd3f7b..9c4bb8266bc 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -164,7 +164,6 @@ EXPORT_SYMBOL(put_io_context);
  */
 void put_io_context_active(struct io_context *ioc)
 {
-	struct hlist_node *n;
 	unsigned long flags;
 	struct io_cq *icq;
 
@@ -180,7 +179,7 @@ void put_io_context_active(struct io_context *ioc)
 	 */
 retry:
 	spin_lock_irqsave_nested(&ioc->lock, flags, 1);
-	hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node) {
+	hlist_for_each_entry(icq, &ioc->icq_list, ioc_node) {
 		if (icq->flags & ICQ_EXITED)
 			continue;
 		if (spin_trylock(icq->q->queue_lock)) {
diff --git a/block/bsg.c b/block/bsg.c
index 3ca92ebf6bb..420a5a9f1b2 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -800,11 +800,10 @@ static struct bsg_device *bsg_add_device(struct inode *inode,
 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q)
 {
 	struct bsg_device *bd;
-	struct hlist_node *entry;
 
 	mutex_lock(&bsg_mutex);
 
-	hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) {
+	hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) {
 		if (bd->queue == q) {
 			atomic_inc(&bd->ref_count);
 			goto found;
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index e62e9205b80..ec52807cdd0 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1435,7 +1435,6 @@ static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
 {
 	struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
 	struct blkcg_gq *blkg;
-	struct hlist_node *n;
 
 	if (val < CFQ_WEIGHT_MIN || val > CFQ_WEIGHT_MAX)
 		return -EINVAL;
@@ -1443,7 +1442,7 @@ static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
 	spin_lock_irq(&blkcg->lock);
 	blkcg->cfq_weight = (unsigned int)val;
 
-	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
+	hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
 		struct cfq_group *cfqg = blkg_to_cfqg(blkg);
 
 		if (cfqg && !cfqg->dev_weight)
diff --git a/block/elevator.c b/block/elevator.c
index 603b2c17874..d0acb31cc08 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -288,10 +288,10 @@ static struct request *elv_rqhash_find(struct request_queue *q, sector_t offset)
 {
 	struct elevator_queue *e = q->elevator;
 	struct hlist_head *hash_list = &e->hash[ELV_HASH_FN(offset)];
-	struct hlist_node *entry, *next;
+	struct hlist_node *next;
 	struct request *rq;
 
-	hlist_for_each_entry_safe(rq, entry, next, hash_list, hash) {
+	hlist_for_each_entry_safe(rq, next, hash_list, hash) {
 		BUG_ON(!ELV_ON_HASH(rq));
 
 		if (unlikely(!rq_mergeable(rq))) {