[PATCH rdma-rc 3/8] RDMA/restrack: Rewrite PID namespace check to be reliable

[Leon Romanovsky <leon@kernel.org>]

From: Leon Romanovsky <leonro@mellanox.com>

task_active_pid_ns() is wrong API to check PID namespace because it
posses some restrictions and return PID namespace where the process
was allocated. It created mismatches with current namespace, which
can be different.

Rewrite whole rdma_is_visible_in_pid_ns() logic to provide reliable
results without any relation to allocated PID namespace.

Fixes: 8be565e65fa9 ("RDMA/nldev: Factor out the PID namespace check")
Fixes: 6a6c306a09b5 ("RDMA/restrack: Make is_visible_in_pid_ns() as an API")
Reviewed-by: Mark Zhang <markz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
 drivers/infiniband/core/nldev.c    |  3 +--
 drivers/infiniband/core/restrack.c | 15 +++++++--------
 include/rdma/restrack.h            |  3 +--
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index 87d40d1ecdde..020c26976558 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -382,8 +382,7 @@ static int fill_res_info(struct sk_buff *msg, struct ib_device *device)
 	for (i = 0; i < RDMA_RESTRACK_MAX; i++) {
 		if (!names[i])
 			continue;
-		curr = rdma_restrack_count(device, i,
-					   task_active_pid_ns(current));
+		curr = rdma_restrack_count(device, i);
 		ret = fill_res_info_entry(msg, names[i], curr);
 		if (ret)
 			goto err;
diff --git a/drivers/infiniband/core/restrack.c b/drivers/infiniband/core/restrack.c
index bddff426ee0f..a07665f7ef8c 100644
--- a/drivers/infiniband/core/restrack.c
+++ b/drivers/infiniband/core/restrack.c
@@ -107,10 +107,8 @@ void rdma_restrack_clean(struct ib_device *dev)
  * rdma_restrack_count() - the current usage of specific object
  * @dev:  IB device
  * @type: actual type of object to operate
- * @ns:   PID namespace
  */
-int rdma_restrack_count(struct ib_device *dev, enum rdma_restrack_type type,
-			struct pid_namespace *ns)
+int rdma_restrack_count(struct ib_device *dev, enum rdma_restrack_type type)
 {
 	struct rdma_restrack_root *rt = &dev->res[type];
 	struct rdma_restrack_entry *e;
@@ -119,10 +117,9 @@ int rdma_restrack_count(struct ib_device *dev, enum rdma_restrack_type type,
 
 	xa_lock(&rt->xa);
 	xas_for_each(&xas, e, U32_MAX) {
-		if (ns == &init_pid_ns ||
-		    (!rdma_is_kernel_res(e) &&
-		     ns == task_active_pid_ns(e->task)))
-			cnt++;
+		if (!rdma_is_visible_in_pid_ns(e))
+			continue;
+		cnt++;
 	}
 	xa_unlock(&rt->xa);
 	return cnt;
@@ -360,5 +357,7 @@ bool rdma_is_visible_in_pid_ns(struct rdma_restrack_entry *res)
 	 */
 	if (rdma_is_kernel_res(res))
 		return task_active_pid_ns(current) == &init_pid_ns;
-	return task_active_pid_ns(current) == task_active_pid_ns(res->task);
+
+	/* PID 0 means that resource is not found in current namespace */
+	return task_pid_vnr(res->task);
 }
diff --git a/include/rdma/restrack.h b/include/rdma/restrack.h
index b0fc6b26bdf5..83df1ec6664e 100644
--- a/include/rdma/restrack.h
+++ b/include/rdma/restrack.h
@@ -105,8 +105,7 @@ struct rdma_restrack_entry {
 };
 
 int rdma_restrack_count(struct ib_device *dev,
-			enum rdma_restrack_type type,
-			struct pid_namespace *ns);
+			enum rdma_restrack_type type);
 
 void rdma_restrack_kadd(struct rdma_restrack_entry *res);
 void rdma_restrack_uadd(struct rdma_restrack_entry *res);
-- 
2.20.1