[Cluster-devel] [PATCH 1/7] dlm: Change rwlock which is only used in write mode to a spinlock

[David Teigland]

From: Steven Whitehouse <swhit...@redhat.com>

The ls_dirtbl[].lock was an rwlock, but since it was only used in write
mode a spinlock will suffice.

Signed-off-by: Steven Whitehouse <swhit...@redhat.com>
Signed-off-by: David Teigland <teigl...@redhat.com>
---
 fs/dlm/dir.c          |   18 +++++++++---------
 fs/dlm/dlm_internal.h |    2 +-
 fs/dlm/lockspace.c    |    2 +-
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/fs/dlm/dir.c b/fs/dlm/dir.c
index 92969f8..858fba1 100644
--- a/fs/dlm/dir.c
+++ b/fs/dlm/dir.c
@@ -156,7 +156,7 @@ void dlm_dir_remove_entry(struct dlm_ls *ls, int nodeid, 
char *name, int namelen
 
        bucket = dir_hash(ls, name, namelen);
 
-       write_lock(&ls->ls_dirtbl[bucket].lock);
+       spin_lock(&ls->ls_dirtbl[bucket].lock);
 
        de = search_bucket(ls, name, namelen, bucket);
 
@@ -173,7 +173,7 @@ void dlm_dir_remove_entry(struct dlm_ls *ls, int nodeid, 
char *name, int namelen
        list_del(&de->list);
        kfree(de);
  out:
-       write_unlock(&ls->ls_dirtbl[bucket].lock);
+       spin_unlock(&ls->ls_dirtbl[bucket].lock);
 }
 
 void dlm_dir_clear(struct dlm_ls *ls)
@@ -185,14 +185,14 @@ void dlm_dir_clear(struct dlm_ls *ls)
        DLM_ASSERT(list_empty(&ls->ls_recover_list), );
 
        for (i = 0; i < ls->ls_dirtbl_size; i++) {
-               write_lock(&ls->ls_dirtbl[i].lock);
+               spin_lock(&ls->ls_dirtbl[i].lock);
                head = &ls->ls_dirtbl[i].list;
                while (!list_empty(head)) {
                        de = list_entry(head->next, struct dlm_direntry, list);
                        list_del(&de->list);
                        put_free_de(ls, de);
                }
-               write_unlock(&ls->ls_dirtbl[i].lock);
+               spin_unlock(&ls->ls_dirtbl[i].lock);
        }
 }
 
@@ -307,17 +307,17 @@ static int get_entry(struct dlm_ls *ls, int nodeid, char 
*name,
 
        bucket = dir_hash(ls, name, namelen);
 
-       write_lock(&ls->ls_dirtbl[bucket].lock);
+       spin_lock(&ls->ls_dirtbl[bucket].lock);
        de = search_bucket(ls, name, namelen, bucket);
        if (de) {
                *r_nodeid = de->master_nodeid;
-               write_unlock(&ls->ls_dirtbl[bucket].lock);
+               spin_unlock(&ls->ls_dirtbl[bucket].lock);
                if (*r_nodeid == nodeid)
                        return -EEXIST;
                return 0;
        }
 
-       write_unlock(&ls->ls_dirtbl[bucket].lock);
+       spin_unlock(&ls->ls_dirtbl[bucket].lock);
 
        if (namelen > DLM_RESNAME_MAXLEN)
                return -EINVAL;
@@ -330,7 +330,7 @@ static int get_entry(struct dlm_ls *ls, int nodeid, char 
*name,
        de->length = namelen;
        memcpy(de->name, name, namelen);
 
-       write_lock(&ls->ls_dirtbl[bucket].lock);
+       spin_lock(&ls->ls_dirtbl[bucket].lock);
        tmp = search_bucket(ls, name, namelen, bucket);
        if (tmp) {
                kfree(de);
@@ -339,7 +339,7 @@ static int get_entry(struct dlm_ls *ls, int nodeid, char 
*name,
                list_add_tail(&de->list, &ls->ls_dirtbl[bucket].list);
        }
        *r_nodeid = de->master_nodeid;
-       write_unlock(&ls->ls_dirtbl[bucket].lock);
+       spin_unlock(&ls->ls_dirtbl[bucket].lock);
        return 0;
 }
 
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 076e86f..d01ca0a 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -99,7 +99,7 @@ struct dlm_direntry {
 
 struct dlm_dirtable {
        struct list_head        list;
-       rwlock_t                lock;
+       spinlock_t              lock;
 };
 
 struct dlm_rsbtable {
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index aa32e5f..cd8e2df 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -487,7 +487,7 @@ static int new_lockspace(char *name, int namelen, void 
**lockspace,
                goto out_lkbfree;
        for (i = 0; i < size; i++) {
                INIT_LIST_HEAD(&ls->ls_dirtbl[i].list);
-               rwlock_init(&ls->ls_dirtbl[i].lock);
+               spin_lock_init(&ls->ls_dirtbl[i].lock);
        }
 
        INIT_LIST_HEAD(&ls->ls_waiters);
-- 
1.5.5.6