1 files changed, 137 insertions, 185 deletions

diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
index d60a8d8f109d..26fef9945cc9 100644
--- a/fs/dlm/ast.c
+++ b/fs/dlm/ast.c
@@ -12,55 +12,67 @@
 #include <trace/events/dlm.h>
 
 #include "dlm_internal.h"
+#include "memory.h"
 #include "lock.h"
 #include "user.h"
 #include "ast.h"
 
-static uint64_t dlm_cb_seq;
-static DEFINE_SPINLOCK(dlm_cb_seq_spin);
+void dlm_release_callback(struct kref *ref)
+{
+	struct dlm_callback *cb = container_of(ref, struct dlm_callback, ref);
+
+	dlm_free_cb(cb);
+}
+
+void dlm_callback_set_last_ptr(struct dlm_callback **from,
+			       struct dlm_callback *to)
+{
+	if (*from)
+		kref_put(&(*from)->ref, dlm_release_callback);
+
+	if (to)
+		kref_get(&to->ref);
+
+	*from = to;
+}
 
-static void dlm_dump_lkb_callbacks(struct dlm_lkb *lkb)
+void dlm_purge_lkb_callbacks(struct dlm_lkb *lkb)
 {
-	int i;
-
-	log_print("last_bast %x %llu flags %x mode %d sb %d %x",
-		  lkb->lkb_id,
-		  (unsigned long long)lkb->lkb_last_bast.seq,
-		  lkb->lkb_last_bast.flags,
-		  lkb->lkb_last_bast.mode,
-		  lkb->lkb_last_bast.sb_status,
-		  lkb->lkb_last_bast.sb_flags);
-
-	log_print("last_cast %x %llu flags %x mode %d sb %d %x",
-		  lkb->lkb_id,
-		  (unsigned long long)lkb->lkb_last_cast.seq,
-		  lkb->lkb_last_cast.flags,
-		  lkb->lkb_last_cast.mode,
-		  lkb->lkb_last_cast.sb_status,
-		  lkb->lkb_last_cast.sb_flags);
-
-	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
-		log_print("cb %x %llu flags %x mode %d sb %d %x",
-			  lkb->lkb_id,
-			  (unsigned long long)lkb->lkb_callbacks[i].seq,
-			  lkb->lkb_callbacks[i].flags,
-			  lkb->lkb_callbacks[i].mode,
-			  lkb->lkb_callbacks[i].sb_status,
-			  lkb->lkb_callbacks[i].sb_flags);
+	struct dlm_callback *cb, *safe;
+
+	list_for_each_entry_safe(cb, safe, &lkb->lkb_callbacks, list) {
+		list_del(&cb->list);
+		kref_put(&cb->ref, dlm_release_callback);
 	}
+
+	lkb->lkb_flags &= ~DLM_IFL_CB_PENDING;
+
+	/* invalidate */
+	dlm_callback_set_last_ptr(&lkb->lkb_last_cast, NULL);
+	dlm_callback_set_last_ptr(&lkb->lkb_last_cb, NULL);
+	lkb->lkb_last_bast_mode = -1;
 }
 
-int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
-			 int status, uint32_t sbflags, uint64_t seq)
+int dlm_enqueue_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
+			     int status, uint32_t sbflags)
 {
 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
-	uint64_t prev_seq;
+	int rv = DLM_ENQUEUE_CALLBACK_SUCCESS;
+	struct dlm_callback *cb;
 	int prev_mode;
-	int i, rv;
 
-	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
-		if (lkb->lkb_callbacks[i].seq)
-			continue;
+	if (flags & DLM_CB_BAST) {
+		/* if cb is a bast, it should be skipped if the blocking mode is
+		 * compatible with the last granted mode
+		 */
+		if (lkb->lkb_last_cast) {
+			if (dlm_modes_compat(mode, lkb->lkb_last_cast->mode)) {
+				log_debug(ls, "skip %x bast mode %d for cast mode %d",
+					  lkb->lkb_id, mode,
+					  lkb->lkb_last_cast->mode);
+				goto out;
+			}
+		}
 
 		/*
 		 * Suppress some redundant basts here, do more on removal.
@@ -68,148 +80,95 @@ int dlm_add_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
 		 * is a bast for the same mode or a more restrictive mode.
 		 * (the addional > PR check is needed for PR/CW inversion)
 		 */
-
-		if ((i > 0) && (flags & DLM_CB_BAST) &&
-		    (lkb->lkb_callbacks[i-1].flags & DLM_CB_BAST)) {
-
-			prev_seq = lkb->lkb_callbacks[i-1].seq;
-			prev_mode = lkb->lkb_callbacks[i-1].mode;
+		if (lkb->lkb_last_cb && lkb->lkb_last_cb->flags & DLM_CB_BAST) {
+			prev_mode = lkb->lkb_last_cb->mode;
 
 			if ((prev_mode == mode) ||
 			    (prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
-
-				log_debug(ls, "skip %x add bast %llu mode %d "
-					  "for bast %llu mode %d",
-					  lkb->lkb_id,
-					  (unsigned long long)seq,
-					  mode,
-					  (unsigned long long)prev_seq,
-					  prev_mode);
-				rv = 0;
+				log_debug(ls, "skip %x add bast mode %d for bast mode %d",
+					  lkb->lkb_id, mode, prev_mode);
 				goto out;
 			}
 		}
-
-		lkb->lkb_callbacks[i].seq = seq;
-		lkb->lkb_callbacks[i].flags = flags;
-		lkb->lkb_callbacks[i].mode = mode;
-		lkb->lkb_callbacks[i].sb_status = status;
-		lkb->lkb_callbacks[i].sb_flags = (sbflags & 0x000000FF);
-		rv = 0;
-		break;
 	}
 
-	if (i == DLM_CALLBACKS_SIZE) {
-		log_error(ls, "no callbacks %x %llu flags %x mode %d sb %d %x",
-			  lkb->lkb_id, (unsigned long long)seq,
-			  flags, mode, status, sbflags);
-		dlm_dump_lkb_callbacks(lkb);
-		rv = -1;
+	cb = dlm_allocate_cb();
+	if (!cb) {
+		rv = DLM_ENQUEUE_CALLBACK_FAILURE;
 		goto out;
 	}
- out:
-	return rv;
-}
-
-int dlm_rem_lkb_callback(struct dlm_ls *ls, struct dlm_lkb *lkb,
-			 struct dlm_callback *cb, int *resid)
-{
-	int i, rv;
-
-	*resid = 0;
-
-	if (!lkb->lkb_callbacks[0].seq) {
-		rv = -ENOENT;
-		goto out;
-	}
-
-	/* oldest undelivered cb is callbacks[0] */
-
-	memcpy(cb, &lkb->lkb_callbacks[0], sizeof(struct dlm_callback));
-	memset(&lkb->lkb_callbacks[0], 0, sizeof(struct dlm_callback));
 
-	/* shift others down */
-
-	for (i = 1; i < DLM_CALLBACKS_SIZE; i++) {
-		if (!lkb->lkb_callbacks[i].seq)
-			break;
-		memcpy(&lkb->lkb_callbacks[i-1], &lkb->lkb_callbacks[i],
-		       sizeof(struct dlm_callback));
-		memset(&lkb->lkb_callbacks[i], 0, sizeof(struct dlm_callback));
-		(*resid)++;
+	cb->flags = flags;
+	cb->mode = mode;
+	cb->sb_status = status;
+	cb->sb_flags = (sbflags & 0x000000FF);
+	kref_init(&cb->ref);
+	if (!(lkb->lkb_flags & DLM_IFL_CB_PENDING)) {
+		lkb->lkb_flags |= DLM_IFL_CB_PENDING;
+		rv = DLM_ENQUEUE_CALLBACK_NEED_SCHED;
 	}
+	list_add_tail(&cb->list, &lkb->lkb_callbacks);
 
-	/* if cb is a bast, it should be skipped if the blocking mode is
-	   compatible with the last granted mode */
-
-	if ((cb->flags & DLM_CB_BAST) && lkb->lkb_last_cast.seq) {
-		if (dlm_modes_compat(cb->mode, lkb->lkb_last_cast.mode)) {
-			cb->flags |= DLM_CB_SKIP;
-
-			log_debug(ls, "skip %x bast %llu mode %d "
-				  "for cast %llu mode %d",
-				  lkb->lkb_id,
-				  (unsigned long long)cb->seq,
-				  cb->mode,
-				  (unsigned long long)lkb->lkb_last_cast.seq,
-				  lkb->lkb_last_cast.mode);
-			rv = 0;
-			goto out;
-		}
-	}
+	if (flags & DLM_CB_CAST)
+		dlm_callback_set_last_ptr(&lkb->lkb_last_cast, cb);
 
-	if (cb->flags & DLM_CB_CAST) {
-		memcpy(&lkb->lkb_last_cast, cb, sizeof(struct dlm_callback));
-		lkb->lkb_last_cast_time = ktime_get();
-	}
+	dlm_callback_set_last_ptr(&lkb->lkb_last_cb, cb);
 
-	if (cb->flags & DLM_CB_BAST) {
-		memcpy(&lkb->lkb_last_bast, cb, sizeof(struct dlm_callback));
-		lkb->lkb_last_bast_time = ktime_get();
-	}
-	rv = 0;
  out:
 	return rv;
 }
 
+int dlm_dequeue_lkb_callback(struct dlm_lkb *lkb, struct dlm_callback **cb)
+{
+	/* oldest undelivered cb is callbacks first entry */
+	*cb = list_first_entry_or_null(&lkb->lkb_callbacks,
+				       struct dlm_callback, list);
+	if (!*cb)
+		return DLM_DEQUEUE_CALLBACK_EMPTY;
+
+	/* remove it from callbacks so shift others down */
+	list_del(&(*cb)->list);
+	if (list_empty(&lkb->lkb_callbacks))
+		return DLM_DEQUEUE_CALLBACK_LAST;
+
+	return DLM_DEQUEUE_CALLBACK_SUCCESS;
+}
+
 void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
 		uint32_t sbflags)
 {
 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
-	uint64_t new_seq, prev_seq;
 	int rv;
 
-	spin_lock(&dlm_cb_seq_spin);
-	new_seq = ++dlm_cb_seq;
-	if (!dlm_cb_seq)
-		new_seq = ++dlm_cb_seq;
-	spin_unlock(&dlm_cb_seq_spin);
-
 	if (lkb->lkb_flags & DLM_IFL_USER) {
-		dlm_user_add_ast(lkb, flags, mode, status, sbflags, new_seq);
+		dlm_user_add_ast(lkb, flags, mode, status, sbflags);
 		return;
 	}
 
-	mutex_lock(&lkb->lkb_cb_mutex);
-	prev_seq = lkb->lkb_callbacks[0].seq;
-
-	rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, new_seq);
-	if (rv < 0)
-		goto out;
-
-	if (!prev_seq) {
+	spin_lock(&lkb->lkb_cb_lock);
+	rv = dlm_enqueue_lkb_callback(lkb, flags, mode, status, sbflags);
+	switch (rv) {
+	case DLM_ENQUEUE_CALLBACK_NEED_SCHED:
 		kref_get(&lkb->lkb_ref);
 
-		mutex_lock(&ls->ls_cb_mutex);
+		spin_lock(&ls->ls_cb_lock);
 		if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
 			list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
 		} else {
 			queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
 		}
-		mutex_unlock(&ls->ls_cb_mutex);
+		spin_unlock(&ls->ls_cb_lock);
+		break;
+	case DLM_ENQUEUE_CALLBACK_FAILURE:
+		WARN_ON_ONCE(1);
+		break;
+	case DLM_ENQUEUE_CALLBACK_SUCCESS:
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		break;
 	}
- out:
-	mutex_unlock(&lkb->lkb_cb_mutex);
+	spin_unlock(&lkb->lkb_cb_lock);
 }
 
 void dlm_callback_work(struct work_struct *work)
@@ -218,53 +177,46 @@ void dlm_callback_work(struct work_struct *work)
 	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
 	void (*castfn) (void *astparam);
 	void (*bastfn) (void *astparam, int mode);
-	struct dlm_callback callbacks[DLM_CALLBACKS_SIZE];
-	int i, rv, resid;
-
-	memset(&callbacks, 0, sizeof(callbacks));
+	struct dlm_callback *cb;
+	int rv;
 
-	mutex_lock(&lkb->lkb_cb_mutex);
-	if (!lkb->lkb_callbacks[0].seq) {
-		/* no callback work exists, shouldn't happen */
-		log_error(ls, "dlm_callback_work %x no work", lkb->lkb_id);
-		dlm_print_lkb(lkb);
-		dlm_dump_lkb_callbacks(lkb);
-	}
+	spin_lock(&lkb->lkb_cb_lock);
+	rv = dlm_dequeue_lkb_callback(lkb, &cb);
+	spin_unlock(&lkb->lkb_cb_lock);
 
-	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
-		rv = dlm_rem_lkb_callback(ls, lkb, &callbacks[i], &resid);
-		if (rv < 0)
-			break;
-	}
+	if (WARN_ON_ONCE(rv == DLM_DEQUEUE_CALLBACK_EMPTY))
+		goto out;
 
-	if (resid) {
-		/* cbs remain, loop should have removed all, shouldn't happen */
-		log_error(ls, "dlm_callback_work %x resid %d", lkb->lkb_id,
-			  resid);
-		dlm_print_lkb(lkb);
-		dlm_dump_lkb_callbacks(lkb);
-	}
-	mutex_unlock(&lkb->lkb_cb_mutex);
+	for (;;) {
+		castfn = lkb->lkb_astfn;
+		bastfn = lkb->lkb_bastfn;
+
+		if (cb->flags & DLM_CB_BAST) {
+			trace_dlm_bast(ls, lkb, cb->mode);
+			lkb->lkb_last_bast_time = ktime_get();
+			lkb->lkb_last_bast_mode = cb->mode;
+			bastfn(lkb->lkb_astparam, cb->mode);
+		} else if (cb->flags & DLM_CB_CAST) {
+			lkb->lkb_lksb->sb_status = cb->sb_status;
+			lkb->lkb_lksb->sb_flags = cb->sb_flags;
+			trace_dlm_ast(ls, lkb);
+			lkb->lkb_last_cast_time = ktime_get();
+			castfn(lkb->lkb_astparam);
+		}
 
-	castfn = lkb->lkb_astfn;
-	bastfn = lkb->lkb_bastfn;
+		kref_put(&cb->ref, dlm_release_callback);
 
-	for (i = 0; i < DLM_CALLBACKS_SIZE; i++) {
-		if (!callbacks[i].seq)
+		spin_lock(&lkb->lkb_cb_lock);
+		rv = dlm_dequeue_lkb_callback(lkb, &cb);
+		if (rv == DLM_DEQUEUE_CALLBACK_EMPTY) {
+			lkb->lkb_flags &= ~DLM_IFL_CB_PENDING;
+			spin_unlock(&lkb->lkb_cb_lock);
 			break;
-		if (callbacks[i].flags & DLM_CB_SKIP) {
-			continue;
-		} else if (callbacks[i].flags & DLM_CB_BAST) {
-			trace_dlm_bast(ls, lkb, callbacks[i].mode);
-			bastfn(lkb->lkb_astparam, callbacks[i].mode);
-		} else if (callbacks[i].flags & DLM_CB_CAST) {
-			lkb->lkb_lksb->sb_status = callbacks[i].sb_status;
-			lkb->lkb_lksb->sb_flags = callbacks[i].sb_flags;
-			trace_dlm_ast(ls, lkb);
-			castfn(lkb->lkb_astparam);
 		}
+		spin_unlock(&lkb->lkb_cb_lock);
 	}
 
+out:
 	/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
 	dlm_put_lkb(lkb);
 }
@@ -289,9 +241,9 @@ void dlm_callback_stop(struct dlm_ls *ls)
 void dlm_callback_suspend(struct dlm_ls *ls)
 {
 	if (ls->ls_callback_wq) {
-		mutex_lock(&ls->ls_cb_mutex);
+		spin_lock(&ls->ls_cb_lock);
 		set_bit(LSFL_CB_DELAY, &ls->ls_flags);
-		mutex_unlock(&ls->ls_cb_mutex);
+		spin_unlock(&ls->ls_cb_lock);
 
 		flush_workqueue(ls->ls_callback_wq);
 	}
@@ -308,10 +260,8 @@ void dlm_callback_resume(struct dlm_ls *ls)
 	if (!ls->ls_callback_wq)
 		return;
 
-	clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
-
 more:
-	mutex_lock(&ls->ls_cb_mutex);
+	spin_lock(&ls->ls_cb_lock);
 	list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
 		list_del_init(&lkb->lkb_cb_list);
 		queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
@@ -320,7 +270,9 @@ more:
 			break;
 	}
 	empty = list_empty(&ls->ls_cb_delay);
-	mutex_unlock(&ls->ls_cb_mutex);
+	if (empty)
+		clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
+	spin_unlock(&ls->ls_cb_lock);
 
 	sum += count;
 	if (!empty) {