Thread (38 messages) 38 messages, 5 authors, 2021-06-14

Re: [PATCH rdma-next v1 02/15] RDMA/core: Replace the ib_port_data hw_stats pointers with a ib_port pointer

From: Greg KH <gregkh@linuxfoundation.org>
Date: 2021-06-07 10:23:28
Also in: lkml

On Mon, Jun 07, 2021 at 11:17:27AM +0300, Leon Romanovsky wrote:
quoted hunk ↗ jump to hunk
From: Jason Gunthorpe <jgg@nvidia.com>

It is much saner to store a pointer to the kobject structure that contains
the cannonical stats pointer than to copy the stats pointers into a public
structure.

Future patches will require the sysfs pointer for other purposes.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
 drivers/infiniband/core/core_priv.h |  1 +
 drivers/infiniband/core/nldev.c     |  8 ++------
 drivers/infiniband/core/sysfs.c     | 14 +++++++++++---
 include/rdma/ib_verbs.h             |  3 ++-
 4 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/infiniband/core/core_priv.h b/drivers/infiniband/core/core_priv.h
index 29809dd30041..ec5c2c3db423 100644
--- a/drivers/infiniband/core/core_priv.h
+++ b/drivers/infiniband/core/core_priv.h
@@ -378,6 +378,7 @@ struct net_device *rdma_read_gid_attr_ndev_rcu(const struct ib_gid_attr *attr);
 
 void ib_free_port_attrs(struct ib_core_device *coredev);
 int ib_setup_port_attrs(struct ib_core_device *coredev);
+struct rdma_hw_stats *ib_get_hw_stats_port(struct ib_device *ibdev, u32 port_num);
 
 int rdma_compatdev_set(u8 enable);
 
diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index 01316926cef6..e9b4b2cccaa0 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -2066,7 +2066,8 @@ static int stat_get_doit_default_counter(struct sk_buff *skb,
 	}
 
 	port = nla_get_u32(tb[RDMA_NLDEV_ATTR_PORT_INDEX]);
-	if (!rdma_is_port_valid(device, port)) {
+	stats = ib_get_hw_stats_port(device, port);
+	if (!stats) {
 		ret = -EINVAL;
 		goto err;
 	}
@@ -2088,11 +2089,6 @@ static int stat_get_doit_default_counter(struct sk_buff *skb,
 		goto err_msg;
 	}
 
-	stats = device->port_data ? device->port_data[port].hw_stats : NULL;
-	if (stats == NULL) {
-		ret = -EINVAL;
-		goto err_msg;
-	}
 	mutex_lock(&stats->lock);
 
 	num_cnts = device->ops.get_hw_stats(device, stats, port, 0);
diff --git a/drivers/infiniband/core/sysfs.c b/drivers/infiniband/core/sysfs.c
index d11ceff2b4e4..b153dee1e0fa 100644
--- a/drivers/infiniband/core/sysfs.c
+++ b/drivers/infiniband/core/sysfs.c
@@ -1031,8 +1031,6 @@ static void setup_hw_stats(struct ib_device *device, struct ib_port *port,
 			goto err;
 		port->hw_stats_ag = hsag;
 		port->hw_stats = stats;
-		if (device->port_data)
-			device->port_data[port_num].hw_stats = stats;
 	} else {
 		struct kobject *kobj = &device->dev.kobj;
 		ret = sysfs_create_group(kobj, hsag);
@@ -1053,6 +1051,14 @@ static void setup_hw_stats(struct ib_device *device, struct ib_port *port,
 	kfree(stats);
 }
 
+struct rdma_hw_stats *ib_get_hw_stats_port(struct ib_device *ibdev,
+					   u32 port_num)
+{
+	if (!ibdev->port_data || !rdma_is_port_valid(ibdev, port_num))
+		return NULL;
+	return ibdev->port_data[port_num].sysfs->hw_stats;
+}
+
 static int add_port(struct ib_core_device *coredev, int port_num)
 {
 	struct ib_device *device = rdma_device_to_ibdev(&coredev->dev);
@@ -1171,6 +1177,8 @@ static int add_port(struct ib_core_device *coredev, int port_num)
 		setup_hw_stats(device, p, port_num);
 
 	list_add_tail(&p->kobj.entry, &coredev->port_list);
+	if (device->port_data && is_full_dev)
+		device->port_data[port_num].sysfs = p;
You are saving off a pointer to a reference counted structure without
incrementing the reference count on it?  That's brave, and really wrong.
Properly increment/decrement it when using and when done with it.

thnaks,

greg k-h
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