[PATCH for-next v2 3/4] RDMA/nldev: ib_pd can be pointed by multiple ib_ucontext

[Shamir Rabinovitch <shamir.rabinovitch@xxxxxxxxxx>]

In shared object model ib_pd can belong to 1 or more ib_ucontext.
Fix the nldev code so it could report multiple context ids.

Signed-off-by: Shamir Rabinovitch <shamir.rabinovitch@xxxxxxxxxx>
---
 drivers/infiniband/core/nldev.c | 93 +++++++++++++++++++++++++++++++--
 1 file changed, 88 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index cbd712f5f8b2..f4cc92b897ff 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -41,6 +41,9 @@
 #include "core_priv.h"
 #include "cma_priv.h"
 #include "restrack.h"
+#include "uverbs.h"
+
+static bool is_visible_in_pid_ns(struct rdma_restrack_entry *res);
 
 static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_DEV_INDEX]     = { .type = NLA_U32 },
@@ -584,11 +587,80 @@ static int fill_res_mr_entry(struct sk_buff *msg, bool has_cap_net_admin,
 err:	return -EMSGSIZE;
 }
 
+struct context_id {
+	struct list_head list;
+	u32 id;
+};
+
+static void pd_context(struct ib_pd *pd, struct list_head *list)
+{
+	struct ib_device *device = pd->device;
+	struct rdma_restrack_entry *res;
+	struct rdma_restrack_root *rt;
+	struct ib_uverbs_file *ufile;
+	struct ib_ucontext *ucontext;
+	struct ib_uobject *uobj;
+	unsigned long flags;
+	unsigned long id;
+	bool found;
+
+	rt = &device->res[RDMA_RESTRACK_CTX];
+
+	xa_lock(&rt->xa);
+
+	xa_for_each(&rt->xa, id, res) {
+		if (!is_visible_in_pid_ns(res))
+			continue;
+
+		if (!rdma_restrack_get(res))
+			continue;
+
+		xa_unlock(&rt->xa);
+
+		ucontext = container_of(res, struct ib_ucontext, res);
+		ufile = ucontext->ufile;
+		found = false;
+
+		/* See locking requirements in struct ib_uverbs_file */
+		down_read(&ufile->hw_destroy_rwsem);
+		spin_lock_irqsave(&ufile->uobjects_lock, flags);
+
+		list_for_each_entry(uobj, &ufile->uobjects, list) {
+			if (uobj->object == pd) {
+				found = true;
+				goto found;
+			}
+		}
+
+found:		spin_unlock_irqrestore(&ufile->uobjects_lock, flags);
+		up_read(&ufile->hw_destroy_rwsem);
+
+		if (found) {
+			struct context_id *ctx_id =
+				kmalloc(sizeof(*ctx_id), GFP_KERNEL);
+
+			if (WARN_ON_ONCE(!ctx_id))
+				goto next;
+
+			ctx_id->id = ucontext->res.id;
+			list_add(&ctx_id->list, list);
+		}
+
+next:		rdma_restrack_put(res);
+		xa_lock(&rt->xa);
+	}
+
+	xa_unlock(&rt->xa);
+}
+
 static int fill_res_pd_entry(struct sk_buff *msg, bool has_cap_net_admin,
 			     struct rdma_restrack_entry *res, uint32_t port)
 {
 	struct ib_pd *pd = container_of(res, struct ib_pd, res);
 	struct ib_device *dev = pd->device;
+	struct context_id *ctx_id;
+	struct context_id *tmp;
+	LIST_HEAD(pd_context_ids);
 
 	if (has_cap_net_admin) {
 		if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_LOCAL_DMA_LKEY,
@@ -606,10 +678,14 @@ static int fill_res_pd_entry(struct sk_buff *msg, bool has_cap_net_admin,
 	if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_PDN, res->id))
 		goto err;
 
-	if (!rdma_is_kernel_res(res) &&
-	    nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_CTXN,
-			pd->uobject->context->res.id))
-		goto err;
+	if (!rdma_is_kernel_res(res)) {
+		pd_context(pd, &pd_context_ids);
+		list_for_each_entry(ctx_id, &pd_context_ids, list) {
+			if (nla_put_u32(msg, RDMA_NLDEV_ATTR_RES_CTXN,
+				ctx_id->id))
+				goto err;
+		}
+	}
 
 	if (fill_res_name_pid(msg, res))
 		goto err;
@@ -617,9 +693,16 @@ static int fill_res_pd_entry(struct sk_buff *msg, bool has_cap_net_admin,
 	if (fill_res_entry(dev, msg, res))
 		goto err;
 
+	list_for_each_entry_safe(ctx_id, tmp, &pd_context_ids, list)
+		kfree(ctx_id);
+
 	return 0;
 
-err:	return -EMSGSIZE;
+err:
+	list_for_each_entry_safe(ctx_id, tmp, &pd_context_ids, list)
+		kfree(ctx_id);
+
+	return -EMSGSIZE;
 }
 
 static int nldev_get_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
-- 
2.20.1