releases/4.9.136/ib-rxe-put-the-pool-on-allocation-failure.patch

From 027918605e719867a162666a40c529d85d7e7c78 Mon Sep 17 00:00:00 2001
From: Doug Ledford <dledford@redhat.com>
Date: Mon, 9 Oct 2017 09:11:32 -0400
Subject: IB/rxe: put the pool on allocation failure

[ Upstream commit 6b9f8970cd30929cb6b372fa44fa66da9e59c650 ]

If the allocation of elem fails, it is not sufficient to simply check
for NULL and return.  We need to also put our reference on the pool or
else we will leave the pool with a permanent ref count and we will never
be able to free it.

Fixes: 4831ca9e4a8e ("IB/rxe: check for allocation failure on elem")
Suggested-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/infiniband/sw/rxe/rxe_pool.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c
index 1c4e5b2e6835..527ca662da69 100644
--- a/drivers/infiniband/sw/rxe/rxe_pool.c
+++ b/drivers/infiniband/sw/rxe/rxe_pool.c
@@ -402,23 +402,25 @@ void *rxe_alloc(struct rxe_pool *pool)
 
 	kref_get(&pool->rxe->ref_cnt);
 
-	if (atomic_inc_return(&pool->num_elem) > pool->max_elem) {
-		atomic_dec(&pool->num_elem);
-		rxe_dev_put(pool->rxe);
-		rxe_pool_put(pool);
-		return NULL;
-	}
+	if (atomic_inc_return(&pool->num_elem) > pool->max_elem)
+		goto out_put_pool;
 
 	elem = kmem_cache_zalloc(pool_cache(pool),
 				 (pool->flags & RXE_POOL_ATOMIC) ?
 				 GFP_ATOMIC : GFP_KERNEL);
 	if (!elem)
-		return NULL;
+		goto out_put_pool;
 
 	elem->pool = pool;
 	kref_init(&elem->ref_cnt);
 
 	return elem;
+
+out_put_pool:
+	atomic_dec(&pool->num_elem);
+	rxe_dev_put(pool->rxe);
+	rxe_pool_put(pool);
+	return NULL;
 }
 
 void rxe_elem_release(struct kref *kref)
-- 
2.17.1