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Message-Id: <20200430175759.1301789-3-kuba@kernel.org>
Date: Thu, 30 Apr 2020 10:57:57 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net, jiri@...nulli.us
Cc: netdev@...r.kernel.org, kernel-team@...com,
jacob.e.keller@...el.com, Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH net-next v3 2/3] devlink: let kernel allocate region snapshot id
Currently users have to choose a free snapshot id before
calling DEVLINK_CMD_REGION_NEW. This is potentially racy
and inconvenient.
Make the DEVLINK_ATTR_REGION_SNAPSHOT_ID optional and try
to allocate id automatically. Send a message back to the
caller with the snapshot info.
Example use:
$ devlink region new netdevsim/netdevsim1/dummy
netdevsim/netdevsim1/dummy: snapshot 1
$ id=$(devlink -j region new netdevsim/netdevsim1/dummy | \
jq '.[][][][]')
$ devlink region dump netdevsim/netdevsim1/dummy snapshot $id
[...]
$ devlink region del netdevsim/netdevsim1/dummy snapshot $id
v3:
- send the notification only once snapshot creation completed.
v2:
- don't wrap the line containing extack;
- add a few sentences to the docs.
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
.../networking/devlink/devlink-region.rst | 7 +-
net/core/devlink.c | 69 +++++++++++++++----
.../drivers/net/netdevsim/devlink.sh | 13 ++++
3 files changed, 74 insertions(+), 15 deletions(-)
diff --git a/Documentation/networking/devlink/devlink-region.rst b/Documentation/networking/devlink/devlink-region.rst
index 04e04d1ff627..daf35427fce1 100644
--- a/Documentation/networking/devlink/devlink-region.rst
+++ b/Documentation/networking/devlink/devlink-region.rst
@@ -23,7 +23,9 @@ states, but see also :doc:`devlink-health`
Regions may optionally support capturing a snapshot on demand via the
``DEVLINK_CMD_REGION_NEW`` netlink message. A driver wishing to allow
requested snapshots must implement the ``.snapshot`` callback for the region
-in its ``devlink_region_ops`` structure.
+in its ``devlink_region_ops`` structure. If snapshot id is not set in
+the ``DEVLINK_CMD_REGION_NEW`` request kernel will allocate one and send
+the snapshot information to user space.
example usage
-------------
@@ -45,7 +47,8 @@ example usage
$ devlink region del pci/0000:00:05.0/cr-space snapshot 1
# Request an immediate snapshot, if supported by the region
- $ devlink region new pci/0000:00:05.0/cr-space snapshot 5
+ $ devlink region new pci/0000:00:05.0/cr-space
+ pci/0000:00:05.0/cr-space: snapshot 5
# Dump a snapshot:
$ devlink region dump pci/0000:00:05.0/fw-health snapshot 1
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 92afb85bad89..4df947fb90d9 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -4082,10 +4082,41 @@ static int devlink_nl_cmd_region_del(struct sk_buff *skb,
return 0;
}
+static int
+devlink_nl_snapshot_id_notify(struct devlink *devlink, struct genl_info *info,
+ struct devlink_region *region, u32 snapshot_id)
+{
+ struct devlink_snapshot *snapshot;
+ struct sk_buff *msg;
+ int err;
+
+ snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);
+ if (WARN_ON(!snapshot))
+ return -EINVAL;
+
+ msg = devlink_nl_region_notify_build(region, snapshot,
+ DEVLINK_CMD_REGION_NEW,
+ info->snd_portid, info->snd_seq);
+ err = PTR_ERR_OR_ZERO(msg);
+ if (err)
+ goto err_notify;
+
+ err = genlmsg_reply(msg, info);
+ if (err)
+ goto err_notify;
+
+ return 0;
+
+err_notify:
+ devlink_region_snapshot_del(region, snapshot);
+ return err;
+}
+
static int
devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info)
{
struct devlink *devlink = info->user_ptr[0];
+ struct nlattr *snapshot_id_attr;
struct devlink_region *region;
const char *region_name;
u32 snapshot_id;
@@ -4097,11 +4128,6 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info)
return -EINVAL;
}
- if (!info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]) {
- NL_SET_ERR_MSG_MOD(info->extack, "No snapshot id provided");
- return -EINVAL;
- }
-
region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]);
region = devlink_region_get_by_name(devlink, region_name);
if (!region) {
@@ -4119,16 +4145,25 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info)
return -ENOSPC;
}
- snapshot_id = nla_get_u32(info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]);
+ snapshot_id_attr = info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID];
+ if (snapshot_id_attr) {
+ snapshot_id = nla_get_u32(snapshot_id_attr);
- if (devlink_region_snapshot_get_by_id(region, snapshot_id)) {
- NL_SET_ERR_MSG_MOD(info->extack, "The requested snapshot id is already in use");
- return -EEXIST;
- }
+ if (devlink_region_snapshot_get_by_id(region, snapshot_id)) {
+ NL_SET_ERR_MSG_MOD(info->extack, "The requested snapshot id is already in use");
+ return -EEXIST;
+ }
- err = __devlink_snapshot_id_insert(devlink, snapshot_id);
- if (err)
- return err;
+ err = __devlink_snapshot_id_insert(devlink, snapshot_id);
+ if (err)
+ return err;
+ } else {
+ err = __devlink_region_snapshot_id_get(devlink, &snapshot_id);
+ if (err) {
+ NL_SET_ERR_MSG_MOD(info->extack, "Failed to allocate a new snapshot id");
+ return err;
+ }
+ }
err = region->ops->snapshot(devlink, info->extack, &data);
if (err)
@@ -4138,6 +4173,14 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info)
if (err)
goto err_snapshot_create;
+ if (!snapshot_id_attr) {
+ /* destroys the snapshot on failure */
+ err = devlink_nl_snapshot_id_notify(devlink, info,
+ region, snapshot_id);
+ if (err)
+ return err;
+ }
+
return 0;
err_snapshot_create:
diff --git a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
index 1d15afd62941..de4b32fc4223 100755
--- a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
+++ b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
@@ -166,6 +166,19 @@ regions_test()
check_region_snapshot_count dummy post-second-delete 2
+ sid=$(devlink -j region new $DL_HANDLE/dummy | jq '.[][][][]')
+ check_err $? "Failed to create a new snapshot with id allocated by the kernel"
+
+ check_region_snapshot_count dummy post-first-request 3
+
+ devlink region dump $DL_HANDLE/dummy snapshot $sid >> /dev/null
+ check_err $? "Failed to dump a snapshot with id allocated by the kernel"
+
+ devlink region del $DL_HANDLE/dummy snapshot $sid
+ check_err $? "Failed to delete snapshot with id allocated by the kernel"
+
+ check_region_snapshot_count dummy post-first-request 2
+
log_test "regions test"
}
--
2.25.4
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