IB/umad: Return EIO in case of when device disassociated

stable inclusion
from stable-5.10.20
commit 1598e9e00a99accc73badd619fe03cde72961463
bugzilla: 50608

--------------------------------

[ Upstream commit 4fc54618 ]

MAD message received by the user has EINVAL error in all flows
including when the device is disassociated. That makes it impossible
for the applications to treat such flow differently.

Change it to return EIO, so the applications will be able to perform
disassociation recovery.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Link: https://lore.kernel.org/r/20210125121339.837518-2-leon@kernel.orgSigned-off-by: NShay Drory <shayd@nvidia.com>
Signed-off-by: NLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/infiniband/core/user_mad.c

@@ -379,6 +379,11 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf,
 
 	mutex_lock(&file->mutex);
 
+	if (file->agents_dead) {
+		mutex_unlock(&file->mutex);
+		return -EIO;
+	}
+
 	while (list_empty(&file->recv_list)) {
 		mutex_unlock(&file->mutex);
 
@@ -524,7 +529,7 @@ static ssize_t ib_umad_write(struct file *filp, const char __user *buf,
 
 	agent = __get_agent(file, packet->mad.hdr.id);
 	if (!agent) {
-		ret = -EINVAL;
+		ret = -EIO;
 		goto err_up;
 	}