Merge tag 'v4.1-rc6' into drm-next

Linux 4.1-rc6

backmerge 4.1-rc6 as some of the later pull reqs are based on newer bases
and I'd prefer to do the fixup myself.

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index dbcbcc59aa92..843ceca9a21e 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -17,6 +17,7 @@
 #ifndef _LINUX_RHASHTABLE_H
 #define _LINUX_RHASHTABLE_H
 
+#include <linux/atomic.h>
 #include <linux/compiler.h>
 #include <linux/errno.h>
 #include <linux/jhash.h>
@@ -100,6 +101,7 @@ struct rhashtable;
  * @key_len: Length of key
  * @key_offset: Offset of key in struct to be hashed
  * @head_offset: Offset of rhash_head in struct to be hashed
+ * @insecure_max_entries: Maximum number of entries (may be exceeded)
  * @max_size: Maximum size while expanding
  * @min_size: Minimum size while shrinking
  * @nulls_base: Base value to generate nulls marker
@@ -115,6 +117,7 @@ struct rhashtable_params {
 	size_t			key_len;
 	size_t			key_offset;
 	size_t			head_offset;
+	unsigned int		insecure_max_entries;
 	unsigned int		max_size;
 	unsigned int		min_size;
 	u32			nulls_base;
@@ -286,6 +289,18 @@ static inline bool rht_grow_above_100(const struct rhashtable *ht,
 		(!ht->p.max_size || tbl->size < ht->p.max_size);
 }
 
+/**
+ * rht_grow_above_max - returns true if table is above maximum
+ * @ht:		hash table
+ * @tbl:	current table
+ */
+static inline bool rht_grow_above_max(const struct rhashtable *ht,
+				      const struct bucket_table *tbl)
+{
+	return ht->p.insecure_max_entries &&
+	       atomic_read(&ht->nelems) >= ht->p.insecure_max_entries;
+}
+
 /* The bucket lock is selected based on the hash and protects mutations
  * on a group of hash buckets.
  *
@@ -589,6 +604,10 @@ restart:
 		goto out;
 	}
 
+	err = -E2BIG;
+	if (unlikely(rht_grow_above_max(ht, tbl)))
+		goto out;
+
 	if (unlikely(rht_grow_above_100(ht, tbl))) {
 slow_path:
 		spin_unlock_bh(lock);