[PATCH] RDMA/core: Add error handling in rdma_user_mmap_disassociate.

[Danila Chernetsov <listdansp@mail.ru>]

rdma_user_mmap_disassociate can be called before
ib_set_client_data(device, &uverbs_client, uverbs_dev); and cause an error
 when calling ib_get_client_data.
Also, consider checking the result of ib_get_client_data to handle errors
 in other functions.

Fixes: 51976c6cd786 ("RDMA/core: Provide rdma_user_mmap_disassociate() to disassociate mmap pages")
Signed-off-by: Danila Chernetsov <listdansp@mail.ru>
---
 drivers/infiniband/core/uverbs_main.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 973fe2c7ef53..a8a2d87f4d3e 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -901,10 +901,12 @@ void uverbs_user_mmap_disassociate(struct ib_uverbs_file *ufile)
  * This function should be called by drivers that need to disable mmaps for the
  * device, for instance because it is going to be reset.
  */
-void rdma_user_mmap_disassociate(struct ib_device *device)
+int rdma_user_mmap_disassociate(struct ib_device *device)
 {
 	struct ib_uverbs_device *uverbs_dev =
 		ib_get_client_data(device, &uverbs_client);
+	if (!uverbs_dev)
+		return -ENODEV;
 	struct ib_uverbs_file *ufile;
 
 	mutex_lock(&uverbs_dev->lists_mutex);
@@ -913,6 +915,7 @@ void rdma_user_mmap_disassociate(struct ib_device *device)
 			uverbs_user_mmap_disassociate(ufile);
 	}
 	mutex_unlock(&uverbs_dev->lists_mutex);
+	return 0;
 }
 EXPORT_SYMBOL(rdma_user_mmap_disassociate);
 
-- 
2.25.1