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| author | Jacob Keller <jacob.e.keller@intel.com> | 2020-03-26 11:37:15 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-26 19:39:26 -0700 |
| commit | 12102436acf949b5e6eb087846b47488db2aa440 (patch) | |
| tree | a038e027b09f866f16212663bd27c32d07ffcd3c /include/net | |
| parent | 7ef19d3b1d5e2e1dad64d41df708638f20c5917f (diff) | |
devlink: track snapshot id usage count using an xarray
Each snapshot created for a devlink region must have an id. These ids
are supposed to be unique per "event" that caused the snapshot to be
created. Drivers call devlink_region_snapshot_id_get to obtain a new id
to use for a new event trigger. The id values are tracked per devlink,
so that the same id number can be used if a triggering event creates
multiple snapshots on different regions.
There is no mechanism for snapshot ids to ever be reused. Introduce an
xarray to store the count of how many snapshots are using a given id,
replacing the snapshot_id field previously used for picking the next id.
The devlink_region_snapshot_id_get() function will use xa_alloc to
insert an initial value of 1 value at an available slot between 0 and
U32_MAX.
The new __devlink_snapshot_id_increment() and
__devlink_snapshot_id_decrement() functions will be used to track how
many snapshots currently use an id.
Drivers must now call devlink_snapshot_id_put() in order to release
their reference of the snapshot id after adding region snapshots.
By tracking the total number of snapshots using a given id, it is
possible for the decrement() function to erase the id from the xarray
when it is not in use.
With this method, a snapshot id can become reused again once all
snapshots that referred to it have been deleted via
DEVLINK_CMD_REGION_DEL, and the driver has finished adding snapshots.
This work also paves the way to introduce a mechanism for userspace to
request a snapshot.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/devlink.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/net/devlink.h b/include/net/devlink.h index 9a46bc7fed90..fb9154060e6e 100644 --- a/include/net/devlink.h +++ b/include/net/devlink.h @@ -18,6 +18,7 @@ #include <net/net_namespace.h> #include <net/flow_offload.h> #include <uapi/linux/devlink.h> +#include <linux/xarray.h> struct devlink_ops; @@ -29,13 +30,13 @@ struct devlink { struct list_head resource_list; struct list_head param_list; struct list_head region_list; - u32 snapshot_id; struct list_head reporter_list; struct mutex reporters_lock; /* protects reporter_list */ struct devlink_dpipe_headers *dpipe_headers; struct list_head trap_list; struct list_head trap_group_list; const struct devlink_ops *ops; + struct xarray snapshot_ids; struct device *dev; possible_net_t _net; struct mutex lock; @@ -977,6 +978,7 @@ devlink_region_create(struct devlink *devlink, u32 region_max_snapshots, u64 region_size); void devlink_region_destroy(struct devlink_region *region); int devlink_region_snapshot_id_get(struct devlink *devlink, u32 *id); +void devlink_region_snapshot_id_put(struct devlink *devlink, u32 id); int devlink_region_snapshot_create(struct devlink_region *region, u8 *data, u32 snapshot_id); int devlink_info_serial_number_put(struct devlink_info_req *req, |