[GFS2] Eliminate gl_req_bh

This patch further reduces the memory needs of GFS2 by
eliminating the gl_req_bh variable from struct gfs2_glock.

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

1 files changed, 51 insertions, 56 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 951cb91e7ddb..a8387e0b5068 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -338,7 +338,6 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
         gl->gl_ip = 0;
         gl->gl_ops = glops;
         gl->gl_req_gh = NULL;
-        gl->gl_req_bh = NULL;
         gl->gl_vn = 0;
         gl->gl_stamp = jiffies;
         gl->gl_tchange = jiffies;
@@ -744,6 +743,50 @@ static void state_change(struct gfs2_glock *gl, unsigned int new_state)
 }
 
 /**
+ * drop_bh - Called after a lock module unlock completes
+ * @gl: the glock
+ * @ret: the return status
+ *
+ * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
+ * Doesn't drop the reference on the glock the top half took out
+ *
+ */
+
+static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
+{
+        struct gfs2_sbd *sdp = gl->gl_sbd;
+        const struct gfs2_glock_operations *glops = gl->gl_ops;
+        struct gfs2_holder *gh = gl->gl_req_gh;
+
+        gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
+        gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
+        gfs2_assert_warn(sdp, !ret);
+
+        state_change(gl, LM_ST_UNLOCKED);
+
+        if (glops->go_inval)
+                glops->go_inval(gl, DIO_METADATA);
+
+        if (gh) {
+                spin_lock(&gl->gl_spin);
+                list_del_init(&gh->gh_list);
+                gh->gh_error = 0;
+                spin_unlock(&gl->gl_spin);
+        }
+
+        spin_lock(&gl->gl_spin);
+        gfs2_demote_wake(gl);
+        gl->gl_req_gh = NULL;
+        clear_bit(GLF_LOCK, &gl->gl_flags);
+        spin_unlock(&gl->gl_spin);
+
+        gfs2_glock_put(gl);
+
+        if (gh)
+                gfs2_holder_wake(gh);
+}
+
+/**
  * xmote_bh - Called after the lock module is done acquiring a lock
  * @gl: The glock in question
  * @ret: the int returned from the lock module
@@ -758,6 +801,11 @@ static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
         int prev_state = gl->gl_state;
         int op_done = 1;
 
+        if ((ret & LM_OUT_ST_MASK) == LM_ST_UNLOCKED) {
+                drop_bh(gl, ret);
+                return;
+        }
+
         gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
         gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
         gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));
@@ -783,7 +831,6 @@ static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
                 } else {
                         spin_lock(&gl->gl_spin);
                         if (gl->gl_state != gl->gl_demote_state) {
-                                gl->gl_req_bh = NULL;
                                 spin_unlock(&gl->gl_spin);
                                 gfs2_glock_drop_th(gl);
                                 gfs2_glock_put(gl);
@@ -825,7 +872,6 @@ out:
         if (op_done) {
                 spin_lock(&gl->gl_spin);
                 gl->gl_req_gh = NULL;
-                gl->gl_req_bh = NULL;
                 clear_bit(GLF_LOCK, &gl->gl_flags);
                 spin_unlock(&gl->gl_spin);
         }
@@ -864,7 +910,6 @@ static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
         gfs2_assert_warn(sdp, state != gl->gl_state);
 
         gfs2_glock_hold(gl);
-        gl->gl_req_bh = xmote_bh;
 
         lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags);
 
@@ -878,51 +923,6 @@ static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
 }
 
 /**
- * drop_bh - Called after a lock module unlock completes
- * @gl: the glock
- * @ret: the return status
- *
- * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
- * Doesn't drop the reference on the glock the top half took out
- *
- */
-
-static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
-{
-        struct gfs2_sbd *sdp = gl->gl_sbd;
-        const struct gfs2_glock_operations *glops = gl->gl_ops;
-        struct gfs2_holder *gh = gl->gl_req_gh;
-
-        gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
-        gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
-        gfs2_assert_warn(sdp, !ret);
-
-        state_change(gl, LM_ST_UNLOCKED);
-
-        if (glops->go_inval)
-                glops->go_inval(gl, DIO_METADATA);
-
-        if (gh) {
-                spin_lock(&gl->gl_spin);
-                list_del_init(&gh->gh_list);
-                gh->gh_error = 0;
-                spin_unlock(&gl->gl_spin);
-        }
-
-        spin_lock(&gl->gl_spin);
-        gfs2_demote_wake(gl);
-        gl->gl_req_gh = NULL;
-        gl->gl_req_bh = NULL;
-        clear_bit(GLF_LOCK, &gl->gl_flags);
-        spin_unlock(&gl->gl_spin);
-
-        gfs2_glock_put(gl);
-
-        if (gh)
-                gfs2_holder_wake(gh);
-}
-
-/**
  * gfs2_glock_drop_th - call into the lock module to unlock a lock
  * @gl: the glock
  *
@@ -942,7 +942,6 @@ static void gfs2_glock_drop_th(struct gfs2_glock *gl)
         gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);
 
         gfs2_glock_hold(gl);
-        gl->gl_req_bh = drop_bh;
 
         ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);
 
@@ -971,8 +970,7 @@ static void do_cancels(struct gfs2_holder *gh)
         while (gl->gl_req_gh != gh &&
                !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
                !list_empty(&gh->gh_list)) {
-                if (gl->gl_req_bh && !(gl->gl_req_gh &&
-                                     (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
+                if (!(gl->gl_req_gh && (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
                         spin_unlock(&gl->gl_spin);
                         gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock);
                         msleep(100);
@@ -1042,7 +1040,6 @@ static int glock_wait_internal(struct gfs2_holder *gh)
 
                 spin_lock(&gl->gl_spin);
                 gl->gl_req_gh = NULL;
-                gl->gl_req_bh = NULL;
                 clear_bit(GLF_LOCK, &gl->gl_flags);
                 run_queue(gl);
                 spin_unlock(&gl->gl_spin);
@@ -1535,8 +1532,7 @@ void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
                 gl = gfs2_glock_find(sdp, &async->lc_name);
                 if (gfs2_assert_warn(sdp, gl))
                         return;
-                if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
-                        gl->gl_req_bh(gl, async->lc_ret);
+                xmote_bh(gl, async->lc_ret);
                 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
                         gfs2_glock_put(gl);
                 up_read(&gfs2_umount_flush_sem);
@@ -1898,7 +1894,6 @@ static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl)
                 print_dbg(gi, "  gl_owner = -1\n");
         print_dbg(gi, "  gl_ip = %lu\n", gl->gl_ip);
         print_dbg(gi, "  req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
-        print_dbg(gi, "  req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
         print_dbg(gi, "  lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
         print_dbg(gi, "  object = %s\n", (gl->gl_object) ? "yes" : "no");
         print_dbg(gi, "  reclaim = %s\n",