LU-6529 ldlm: reclaim granted locks defensively

[fs/lustre-release.git] / libcfs / libcfs / hash.c

diff --git a/libcfs/libcfs/hash.c b/libcfs/libcfs/hash.c
index 504ed55..44bfaf4 100644 (file)
--- a/libcfs/libcfs/hash.c
+++ b/libcfs/libcfs/hash.c
@@ -1586,7 +1586,7 @@ EXPORT_SYMBOL(cfs_hash_size_get);
  */
 static int
 cfs_hash_for_each_relax(struct cfs_hash *hs, cfs_hash_for_each_cb_t func,
-                       void *data)
+                       void *data, int start)
 {
        struct hlist_node       *hnode;
        struct hlist_node       *tmp;
@@ -1594,19 +1594,25 @@ cfs_hash_for_each_relax(struct cfs_hash *hs, cfs_hash_for_each_cb_t func,
        __u32                   version;
        int                     count = 0;
        int                     stop_on_change;
-       int                     rc;
-       int                     i;
+       int                     rc = 0;
+       int                     i, end = -1;
        ENTRY;
 
        stop_on_change = cfs_hash_with_rehash_key(hs) ||
                         !cfs_hash_with_no_itemref(hs) ||
                         hs->hs_ops->hs_put_locked == NULL;
        cfs_hash_lock(hs, 0);
+again:
        LASSERT(!cfs_hash_is_rehashing(hs));
 
        cfs_hash_for_each_bucket(hs, &bd, i) {
                struct hlist_head *hhead;
 
+               if (i < start)
+                       continue;
+               else if (end > 0 && i >= end)
+                       break;
+
                 cfs_hash_bd_lock(hs, &bd, 0);
                 version = cfs_hash_bd_version_get(&bd);
 
@@ -1646,14 +1652,20 @@ cfs_hash_for_each_relax(struct cfs_hash *hs, cfs_hash_for_each_cb_t func,
                if (rc) /* callback wants to break iteration */
                        break;
         }
-        cfs_hash_unlock(hs, 0);
 
-        return count;
+       if (start > 0 && rc != 0) {
+               end = start;
+               start = 0;
+               goto again;
+       }
+
+       cfs_hash_unlock(hs, 0);
+       return count;
 }
 
 int
 cfs_hash_for_each_nolock(struct cfs_hash *hs,
-                         cfs_hash_for_each_cb_t func, void *data)
+                        cfs_hash_for_each_cb_t func, void *data, int start)
 {
         ENTRY;
 
@@ -1667,11 +1679,11 @@ cfs_hash_for_each_nolock(struct cfs_hash *hs,
            hs->hs_ops->hs_put_locked == NULL))
                RETURN(-EOPNOTSUPP);
 
-        cfs_hash_for_each_enter(hs);
-        cfs_hash_for_each_relax(hs, func, data);
-        cfs_hash_for_each_exit(hs);
+       cfs_hash_for_each_enter(hs);
+       cfs_hash_for_each_relax(hs, func, data, start);
+       cfs_hash_for_each_exit(hs);
 
-        RETURN(0);
+       RETURN(0);
 }
 EXPORT_SYMBOL(cfs_hash_for_each_nolock);
 
@@ -1701,13 +1713,13 @@ cfs_hash_for_each_empty(struct cfs_hash *hs,
            hs->hs_ops->hs_put_locked == NULL))
                return -EOPNOTSUPP;
 
-        cfs_hash_for_each_enter(hs);
-        while (cfs_hash_for_each_relax(hs, func, data)) {
-                CDEBUG(D_INFO, "Try to empty hash: %s, loop: %u\n",
-                       hs->hs_name, i++);
-        }
-        cfs_hash_for_each_exit(hs);
-        RETURN(0);
+       cfs_hash_for_each_enter(hs);
+       while (cfs_hash_for_each_relax(hs, func, data, 0)) {
+               CDEBUG(D_INFO, "Try to empty hash: %s, loop: %u\n",
+                      hs->hs_name, i++);
+       }
+       cfs_hash_for_each_exit(hs);
+       RETURN(0);
 }
 EXPORT_SYMBOL(cfs_hash_for_each_empty);