[GFS2] Use atomic_t rather than kref in glock.c

Use atomic_t as the ref count in glocks rather than a kref.
This is another step towards using RCU for the glock hash.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

2 files changed, 13 insertions, 23 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index cf54b0b001fd..2316490723c0 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -15,7 +15,6 @@
 #include <linux/delay.h>
 #include <linux/sort.h>
 #include <linux/jhash.h>
-#include <linux/kref.h>
 #include <linux/kallsyms.h>
 #include <linux/gfs2_ondisk.h>
 #include <linux/list.h>
@@ -179,23 +178,7 @@ static void glock_free(struct gfs2_glock *gl)
 
 void gfs2_glock_hold(struct gfs2_glock *gl)
 {
-        kref_get(&gl->gl_ref);
-}
-
-/* All work is done after the return from kref_put() so we
-   can release the write_lock before the free. */
-
-static void kill_glock(struct kref *kref)
-{
-        struct gfs2_glock *gl = container_of(kref, struct gfs2_glock, gl_ref);
-        struct gfs2_sbd *sdp = gl->gl_sbd;
-
-        gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
-        gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
-        gfs2_assert(sdp, list_empty(&gl->gl_holders));
-        gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
-        gfs2_assert(sdp, list_empty(&gl->gl_waiters2));
-        gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
+        atomic_inc(&gl->gl_ref);
 }
 
 /**
@@ -207,12 +190,19 @@ static void kill_glock(struct kref *kref)
 int gfs2_glock_put(struct gfs2_glock *gl)
 {
         int rv = 0;
+        struct gfs2_sbd *sdp = gl->gl_sbd;
 
         write_lock(gl_lock_addr(gl->gl_hash));
-        if (kref_put(&gl->gl_ref, kill_glock)) {
+        if (atomic_dec_and_test(&gl->gl_ref)) {
                 hlist_del(&gl->gl_list);
                 write_unlock(gl_lock_addr(gl->gl_hash));
                 BUG_ON(spin_is_locked(&gl->gl_spin));
+                gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
+                gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
+                gfs2_assert(sdp, list_empty(&gl->gl_holders));
+                gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
+                gfs2_assert(sdp, list_empty(&gl->gl_waiters2));
+                gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
                 glock_free(gl);
                 rv = 1;
                 goto out;
@@ -267,7 +257,7 @@ static struct gfs2_glock *search_bucket(unsigned int hash,
                 if (gl->gl_sbd != sdp)
                         continue;
 
-                kref_get(&gl->gl_ref);
+                atomic_inc(&gl->gl_ref);
 
                 return gl;
         }
@@ -333,7 +323,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 
         gl->gl_flags = 0;
         gl->gl_name = name;
-        kref_init(&gl->gl_ref);
+        atomic_set(&gl->gl_ref, 1);
         gl->gl_state = LM_ST_UNLOCKED;
         gl->gl_hash = hash;
         gl->gl_owner = NULL;
@@ -2124,7 +2114,7 @@ static int dump_glock(struct gfs2_glock *gl)
                         printk(" %u", x);
         }
         printk(" \n");
-        printk(KERN_INFO "  gl_ref = %d\n", atomic_read(&gl->gl_ref.refcount));
+        printk(KERN_INFO "  gl_ref = %d\n", atomic_read(&gl->gl_ref));
         printk(KERN_INFO "  gl_state = %u\n", gl->gl_state);
         printk(KERN_INFO "  gl_owner = %s\n", gl->gl_owner->comm);
         print_symbol(KERN_INFO "  gl_ip = %s\n", gl->gl_ip);
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index c68d39271ede..89df68b32fc6 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -164,7 +164,7 @@ struct gfs2_glock {
         struct hlist_node gl_list;
         unsigned long gl_flags;         /* GLF_... */
         struct lm_lockname gl_name;
-        struct kref gl_ref;
+        atomic_t gl_ref;
 
         spinlock_t gl_spin;