From 043b3e22768d5d909cb1474fc21ae2fbaf026c0c Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 1 May 2020 09:40:41 -0700 Subject: [PATCH] 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 v4: - inline the notification code 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 Reviewed-by: Jacob Keller Signed-off-by: David S. Miller --- .../networking/devlink/devlink-region.rst | 7 ++- net/core/devlink.c | 57 +++++++++++++++++----- .../selftests/drivers/net/netdevsim/devlink.sh | 13 +++++ 3 files changed, 62 insertions(+), 15 deletions(-) diff --git a/Documentation/networking/devlink/devlink-region.rst b/Documentation/networking/devlink/devlink-region.rst index 04e04d1..daf3542 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 2b7c60c..43a9d5b 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -4086,6 +4086,8 @@ static int devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) { struct devlink *devlink = info->user_ptr[0]; + struct devlink_snapshot *snapshot; + struct nlattr *snapshot_id_attr; struct devlink_region *region; const char *region_name; u32 snapshot_id; @@ -4097,11 +4099,6 @@ 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 +4116,25 @@ 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 +4144,27 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) if (err) goto err_snapshot_create; + if (!snapshot_id_attr) { + struct sk_buff *msg; + + 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_snapshot_create: @@ -4145,6 +4172,10 @@ err_snapshot_create: err_snapshot_capture: __devlink_snapshot_id_decrement(devlink, snapshot_id); return err; + +err_notify: + devlink_region_snapshot_del(region, snapshot); + return err; } static int devlink_nl_cmd_region_read_chunk_fill(struct sk_buff *msg, diff --git a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh index 9f97414..ad539ec 100755 --- a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh +++ b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh @@ -151,6 +151,19 @@ 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" } -- 2.7.4