Re: [PATCH] fs/ext4/mballoc.c: Convert to list_for_each_entry_rcu()

Aneesh Kumar K.V
2008-02-19T09:50:18Z

On Tue, Feb 19, 2008 at 01:31:18AM +0100, Roel Kluin wrote:
> Please verify, this patch was not yet tested
> ---
> Convert list_for_each_rcu() to list_for_each_entry_rcu()
>
> Signed-off-by: Roel Kluin <12o3l@tiscali.nl>

NACK. This patch doesn't build. You have extra cur in the conversion.
Right changes attached.

ext4: Convert list_for_each_rcu() to list_for_each_entry_rcu()

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

The list_for_each_entry_rcu() primitive should be used instead of
list_for_each_rcu(), as the former is easier to use and provides
better type safety.

http://groups.google.com/group/linux.kernel/browse_thread/thread/45749c83451cebeb/0633a65759ce7713?lnk=raot

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---

fs/ext4/mballoc.c | 18 +++++-------------
1 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 52d3af2..89772b9 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3135,10 +3135,10 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
{
int bsbits, max;
ext4_lblk_t end;
- struct list_head *cur;
loff_t size, orig_size, start_off;
ext4_lblk_t start, orig_start;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
+ struct ext4_prealloc_space *pa;

/* do normalize only data requests, metadata requests
do not need preallocation */
@@ -3224,12 +3224,9 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,

/* check we don't cross already preallocated blocks */
rcu_read_lock();
- list_for_each_rcu(cur, &ei->i_prealloc_list) {
- struct ext4_prealloc_space *pa;
+ list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
unsigned long pa_end;

- pa = list_entry(cur, struct ext4_prealloc_space, pa_inode_list);
-
if (pa->pa_deleted)
continue;
spin_lock(&pa->pa_lock);
@@ -3271,10 +3268,8 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,

/* XXX: extra loop to check we really don't overlap preallocations */
rcu_read_lock();
- list_for_each_rcu(cur, &ei->i_prealloc_list) {
- struct ext4_prealloc_space *pa;
+ list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
unsigned long pa_end;
- pa = list_entry(cur, struct ext4_prealloc_space, pa_inode_list);
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0) {
pa_end = pa->pa_lstart + pa->pa_len;
@@ -3401,7 +3396,6 @@ static noinline int ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_locality_group *lg;
struct ext4_prealloc_space *pa;
- struct list_head *cur;

/* only data can be preallocated */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
@@ -3409,8 +3403,7 @@ static noinline int ext4_mb_use_preallocated(struct ext4_allocation_context *ac)

/* first, try per-file preallocation */
rcu_read_lock();
- list_for_each_rcu(cur, &ei->i_prealloc_list) {
- pa = list_entry(cur, struct ext4_prealloc_space, pa_inode_list);
+ list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {

/* all fields in this condition don't change,
* so we can skip locking for them */
@@ -3442,8 +3435,7 @@ static noinline int ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
return 0;

rcu_read_lock();
- list_for_each_rcu(cur, &lg->lg_prealloc_list) {
- pa = list_entry(cur, struct ext4_prealloc_space, pa_inode_list);
+ list_for_each_entry_rcu(pa, &lg->lg_prealloc_list, pa_inode_list) {
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0 && pa->pa_free >= ac->ac_o_ex.fe_len) {
atomic_inc(&pa->pa_count);