Re: [patch net-next v2 1/2] netdevsim: implement support for devlink region and snapshots

[Jakub Kicinski]

On Tue, 13 Aug 2019 16:48:42 +0200, Jiri Pirko wrote:
> From: Jiri Pirko <j...@mellanox.com>
> 
> Implement dummy region of size 32K and allow user to create snapshots
> or random data using debugfs file trigger.
> 
> Signed-off-by: Jiri Pirko <j...@mellanox.com>

Hmm.. did you send the right version?

> diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
> index 127aef85dc99..8485dd805f7c 100644
> --- a/drivers/net/netdevsim/dev.c
> +++ b/drivers/net/netdevsim/dev.c
> @@ -27,6 +27,41 @@
>  
>  static struct dentry *nsim_dev_ddir;
>  
> +#define NSIM_DEV_DUMMY_REGION_SIZE (1024 * 32)
> +
> +static ssize_t nsim_dev_take_snapshot_write(struct file *file,
> +                                         const char __user *data,
> +                                         size_t count, loff_t *ppos)
> +{
> +     struct nsim_dev *nsim_dev = file->private_data;
> +     void *dummy_data;
> +     u32 id;
> +     int err;
> +
> +     dummy_data = kmalloc(NSIM_DEV_DUMMY_REGION_SIZE, GFP_KERNEL);
> +     if (!dummy_data) {
> +             pr_err("Failed to allocate memory for region snapshot\n");

not needed, without __GFP_NOWARN there will be a huge OOM splat, anyway.

> +             goto out;

                return -ENOMEM;

> +     }
> +
> +     get_random_bytes(dummy_data, NSIM_DEV_DUMMY_REGION_SIZE);
> +
> +     id = devlink_region_shapshot_id_get(priv_to_devlink(nsim_dev));
> +     err = devlink_region_snapshot_create(nsim_dev->dummy_region,
> +                                          dummy_data, id, kfree);
> +     if (err)
> +             pr_err("Failed to create region snapshot\n");

                return err;
        }

> +
> +out:
> +     return count;
> +}
> +
> +static const struct file_operations nsim_dev_take_snapshot_fops = {
> +     .open = simple_open,
> +     .write = nsim_dev_take_snapshot_write,
> +     .llseek = generic_file_llseek,
> +};
> +
>  static int nsim_dev_debugfs_init(struct nsim_dev *nsim_dev)
>  {
>       char dev_ddir_name[16];
> @@ -44,6 +79,8 @@ static int nsim_dev_debugfs_init(struct nsim_dev *nsim_dev)
>                          &nsim_dev->max_macs);
>       debugfs_create_bool("test1", 0600, nsim_dev->ddir,
>                           &nsim_dev->test1);
> +     debugfs_create_file("take_snapshot", 0200, nsim_dev->ddir, nsim_dev,
> +                         &nsim_dev_take_snapshot_fops);
>       return 0;
>  }
>  
> @@ -248,6 +285,26 @@ static void 
> nsim_devlink_param_load_driverinit_values(struct devlink *devlink)
>               nsim_dev->test1 = saved_value.vbool;
>  }
>  
> +#define NSIM_DEV_DUMMY_REGION_SNAPSHOT_MAX 16
> +
> +static int nsim_dev_dummy_region_init(struct nsim_dev *nsim_dev,
> +                                   struct devlink *devlink)
> +{
> +     nsim_dev->dummy_region =
> +             devlink_region_create(devlink, "dummy",
> +                                   NSIM_DEV_DUMMY_REGION_SNAPSHOT_MAX,
> +                                   NSIM_DEV_DUMMY_REGION_SIZE);
> +     if (IS_ERR(nsim_dev->dummy_region))
> +             return PTR_ERR(nsim_dev->dummy_region);
> +
> +     return 0;

        return PTR_ERR_OR_ZERO(nsim_dev->dummy_region);

> +}