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From: Yunsheng Lin <linyunsheng@huawei.com>
To: <gregkh@linuxfoundation.org>, <rafael@kernel.org>
Cc: <linux-kernel@vger.kernel.org>, <peterz@infradead.org>,
	<mingo@kernel.org>, <mhocko@kernel.org>, <linuxarm@huawei.com>
Subject: [PATCH] driver core: ensure a device has valid node id in device_add()
Date: Mon, 9 Sep 2019 14:04:23 +0800	[thread overview]
Message-ID: <1568009063-77714-1-git-send-email-linyunsheng@huawei.com> (raw)

Currently a device does not belong to any of the numa nodes
(dev->numa_node is NUMA_NO_NODE) when the node id is neither
specified by fw nor by virtual device layer and the device has
no parent device.

According to discussion in [1]:
Even if a device's numa node is not specified, the device really
does belong to a node.

This patch sets the device node to node 0 in device_add() if the
device's node id is not specified and it either has no parent
device, or the parent device also does not have a valid node id.

[1] https://lkml.org/lkml/2019/9/2/466

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
Changelog RFC -> v1:
1. Drop log error message and use a "if" instead of "? :".
2. Drop the RFC tag.
---
 drivers/base/core.c  | 10 +++++++---
 include/linux/numa.h |  2 ++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 1669d41..f79ad20 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2107,9 +2107,13 @@ int device_add(struct device *dev)
 	if (kobj)
 		dev->kobj.parent = kobj;
 
-	/* use parent numa_node */
-	if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
-		set_dev_node(dev, dev_to_node(parent));
+	/* use parent numa_node or default node 0 */
+	if (!numa_node_valid(dev_to_node(dev))) {
+		if (parent && numa_node_valid(dev_to_node(parent)))
+			set_dev_node(dev, dev_to_node(parent));
+		else
+			set_dev_node(dev, 0);
+	}
 
 	/* first, register with generic layer. */
 	/* we require the name to be set before, and pass NULL */
diff --git a/include/linux/numa.h b/include/linux/numa.h
index 110b0e5..eccc757 100644
--- a/include/linux/numa.h
+++ b/include/linux/numa.h
@@ -13,4 +13,6 @@
 
 #define	NUMA_NO_NODE	(-1)
 
+#define numa_node_valid(node)	((unsigned int)(node) < nr_node_ids)
+
 #endif /* _LINUX_NUMA_H */
-- 
2.8.1


             reply	other threads:[~2019-09-09  6:06 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-09  6:04 Yunsheng Lin [this message]
2019-09-09  9:53 ` [PATCH] driver core: ensure a device has valid node id in device_add() Greg KH
2019-09-10  6:43   ` Yunsheng Lin
2019-09-10  7:13     ` Michal Hocko
2019-09-10  9:31     ` Greg KH
2019-09-10 10:58       ` Yunsheng Lin
2019-09-10 11:04         ` Michal Hocko
2019-09-10 11:12           ` Greg KH
2019-09-10 12:47             ` Yunsheng Lin
2019-09-10 12:53               ` Michal Hocko
2019-09-11  5:33                 ` Michal Hocko
2019-09-11  6:15                   ` Yunsheng Lin
2019-09-11  6:49                     ` Michal Hocko
2019-09-11  7:22                       ` Yunsheng Lin
2019-09-11  7:34                         ` Michal Hocko
2019-09-11 11:03                           ` Yunsheng Lin
2019-09-11 11:41                             ` Yunsheng Lin
2019-09-11 12:02                               ` Michal Hocko
2019-09-23 15:09                       ` Peter Zijlstra
2019-09-09 18:50 ` Michal Hocko
2019-09-10  7:08   ` Yunsheng Lin
2019-09-10  7:24     ` Michal Hocko
2019-09-10 10:40       ` Yunsheng Lin
2019-09-10 11:01         ` Michal Hocko

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