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-rw-r--r--lib/rhashtable.c8
-rw-r--r--lib/sbitmap.c11
2 files changed, 17 insertions, 2 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 0a105d4af166..97f59abc3e92 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -416,8 +416,12 @@ static void rht_deferred_worker(struct work_struct *work)
else if (tbl->nest)
err = rhashtable_rehash_alloc(ht, tbl, tbl->size);
- if (!err)
- err = rhashtable_rehash_table(ht);
+ if (!err || err == -EEXIST) {
+ int nerr;
+
+ nerr = rhashtable_rehash_table(ht);
+ err = err ?: nerr;
+ }
mutex_unlock(&ht->mutex);
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 5b382c1244ed..155fe38756ec 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -591,6 +591,17 @@ EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up);
void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
unsigned int cpu)
{
+ /*
+ * Once the clear bit is set, the bit may be allocated out.
+ *
+ * Orders READ/WRITE on the asssociated instance(such as request
+ * of blk_mq) by this bit for avoiding race with re-allocation,
+ * and its pair is the memory barrier implied in __sbitmap_get_word.
+ *
+ * One invariant is that the clear bit has to be zero when the bit
+ * is in use.
+ */
+ smp_mb__before_atomic();
sbitmap_deferred_clear_bit(&sbq->sb, nr);
/*