From e8937681797c9af491c8a1e362a9db4f4aa1f471 Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Thu, 26 Mar 2020 11:37:08 -0700 Subject: devlink: prepare to support region operations Modify the devlink region code in preparation for adding new operations on regions. Create a devlink_region_ops structure, and move the name pointer from within the devlink_region structure into the ops structure (similar to the devlink_health_reporter_ops). This prepares the regions to enable support of additional operations in the future such as requesting snapshots, or accessing the region directly without a snapshot. In order to re-use the constant strings in the mlx4 driver their declaration must be changed to 'const char * const' to ensure the compiler realizes that both the data and the pointer cannot change. Signed-off-by: Jacob Keller Reviewed-by: Jakub Kicinski Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/devlink.h | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/net/devlink.h b/include/net/devlink.h index 37230e23b5b0..85db5dd5184d 100644 --- a/include/net/devlink.h +++ b/include/net/devlink.h @@ -498,6 +498,14 @@ struct devlink_info_req; typedef void devlink_snapshot_data_dest_t(const void *data); +/** + * struct devlink_region_ops - Region operations + * @name: region name + */ +struct devlink_region_ops { + const char *name; +}; + struct devlink_fmsg; struct devlink_health_reporter; @@ -963,10 +971,10 @@ void devlink_port_param_value_changed(struct devlink_port *devlink_port, u32 param_id); void devlink_param_value_str_fill(union devlink_param_value *dst_val, const char *src); -struct devlink_region *devlink_region_create(struct devlink *devlink, - const char *region_name, - u32 region_max_snapshots, - u64 region_size); +struct devlink_region * +devlink_region_create(struct devlink *devlink, + const struct devlink_region_ops *ops, + u32 region_max_snapshots, u64 region_size); void devlink_region_destroy(struct devlink_region *region); u32 devlink_region_snapshot_id_get(struct devlink *devlink); int devlink_region_snapshot_create(struct devlink_region *region, -- cgit v1.2.3 From a0a09f6bb2c1501e24246edf2a7d42558d263b2b Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Thu, 26 Mar 2020 11:37:09 -0700 Subject: devlink: convert snapshot destructor callback to region op It does not makes sense that two snapshots for a given region would use different destructors. Simplify snapshot creation by adding a .destructor op for regions. This operation will replace the data_destructor for the snapshot creation, and makes snapshot creation easier. Noticed-by: Jakub Kicinski Signed-off-by: Jacob Keller Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/devlink.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/net/devlink.h b/include/net/devlink.h index 85db5dd5184d..8869ad75b965 100644 --- a/include/net/devlink.h +++ b/include/net/devlink.h @@ -496,14 +496,14 @@ enum devlink_param_generic_id { struct devlink_region; struct devlink_info_req; -typedef void devlink_snapshot_data_dest_t(const void *data); - /** * struct devlink_region_ops - Region operations * @name: region name + * @destructor: callback used to free snapshot memory when deleting */ struct devlink_region_ops { const char *name; + void (*destructor)(const void *data); }; struct devlink_fmsg; @@ -978,8 +978,7 @@ devlink_region_create(struct devlink *devlink, void devlink_region_destroy(struct devlink_region *region); u32 devlink_region_snapshot_id_get(struct devlink *devlink); int devlink_region_snapshot_create(struct devlink_region *region, - u8 *data, u32 snapshot_id, - devlink_snapshot_data_dest_t *data_destructor); + u8 *data, u32 snapshot_id); int devlink_info_serial_number_put(struct devlink_info_req *req, const char *sn); int devlink_info_driver_name_put(struct devlink_info_req *req, -- cgit v1.2.3 From 7ef19d3b1d5e2e1dad64d41df708638f20c5917f Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Thu, 26 Mar 2020 11:37:14 -0700 Subject: devlink: report error once U32_MAX snapshot ids have been used The devlink_snapshot_id_get() function returns a snapshot id. The snapshot id is a u32, so there is no way to indicate an error code. A future change is going to possibly add additional cases where this function could fail. Refactor the function to return the snapshot id in an argument, so that it can return zero or an error value. This ensures that snapshot ids cannot be confused with error values, and aids in the future refactor of snapshot id allocation management. Because there is no current way to release previously used snapshot ids, add a simple check ensuring that an error is reported in case the snapshot_id would over flow. Signed-off-by: Jacob Keller Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/devlink.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/net/devlink.h b/include/net/devlink.h index 8869ad75b965..9a46bc7fed90 100644 --- a/include/net/devlink.h +++ b/include/net/devlink.h @@ -976,7 +976,7 @@ devlink_region_create(struct devlink *devlink, const struct devlink_region_ops *ops, u32 region_max_snapshots, u64 region_size); void devlink_region_destroy(struct devlink_region *region); -u32 devlink_region_snapshot_id_get(struct devlink *devlink); +int devlink_region_snapshot_id_get(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, -- cgit v1.2.3 From 12102436acf949b5e6eb087846b47488db2aa440 Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Thu, 26 Mar 2020 11:37:15 -0700 Subject: 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 Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/devlink.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include') 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 #include #include +#include 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, -- cgit v1.2.3 From b9a17abfde842bb09f894ba96a5cd9f5944f6bfa Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Thu, 26 Mar 2020 11:37:16 -0700 Subject: devlink: implement DEVLINK_CMD_REGION_NEW Implement support for the DEVLINK_CMD_REGION_NEW command for creating snapshots. This new command parallels the existing DEVLINK_CMD_REGION_DEL. In order for DEVLINK_CMD_REGION_NEW to work for a region, the new ".snapshot" operation must be implemented in the region's ops structure. The desired snapshot id must be provided. This helps avoid confusion on the purpose of DEVLINK_CMD_REGION_NEW, and keeps the API simpler. The requested id will be inserted into the xarray tracking the number of snapshots using each id. If this id is already used by another snapshot on any region, an error will be returned. Signed-off-by: Jacob Keller Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller --- include/net/devlink.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include') diff --git a/include/net/devlink.h b/include/net/devlink.h index fb9154060e6e..a1a02cd5890b 100644 --- a/include/net/devlink.h +++ b/include/net/devlink.h @@ -501,10 +501,16 @@ struct devlink_info_req; * struct devlink_region_ops - Region operations * @name: region name * @destructor: callback used to free snapshot memory when deleting + * @snapshot: callback to request an immediate snapshot. On success, + * the data variable must be updated to point to the snapshot data. + * The function will be called while the devlink instance lock is + * held. */ struct devlink_region_ops { const char *name; void (*destructor)(const void *data); + int (*snapshot)(struct devlink *devlink, struct netlink_ext_ack *extack, + u8 **data); }; struct devlink_fmsg; -- cgit v1.2.3