> On 20 Mar 2019, at 16.38, Marcin Dziegielewski <marcin.dziegielewski@xxxxxxxxx> wrote:
>
> Currently if we issue reboot to the system pblk will close
> ungracefully and in consequence it will need recovery on load.
>
> This patch propose utilize of reboot notifier feature to trigger
> gracefull pblk shutdown on reboot.
>
> Signed-off-by: Marcin Dziegielewski <marcin.dziegielewski@xxxxxxxxx>
> ---
> drivers/lightnvm/core.c | 64 +++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 51 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 5f82036..5488051 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -27,6 +27,7 @@
> #include <linux/miscdevice.h>
> #include <linux/lightnvm.h>
> #include <linux/sched/sysctl.h>
> +#include <linux/reboot.h>
>
> static LIST_HEAD(nvm_tgt_types);
> static DECLARE_RWSEM(nvm_tgtt_lock);
> @@ -1138,6 +1139,48 @@ struct nvm_dev *nvm_alloc_dev(int node)
> }
> EXPORT_SYMBOL(nvm_alloc_dev);
>
> +static void _nvm_unregister(struct nvm_dev *dev, bool graceful)
> +{
> + struct nvm_target *t, *tmp;
> +
> + mutex_lock(&dev->mlock);
> + list_for_each_entry_safe(t, tmp, &dev->targets, list) {
> + if (t->dev->parent != dev)
> + continue;
> + __nvm_remove_target(t, graceful);
> + }
> + mutex_unlock(&dev->mlock);
> +
> + list_del(&dev->devices);
> +
> + nvm_free(dev);
> +}
> +
> +static int nvm_notify_reboot(struct notifier_block *this,
> + unsigned long code, void *x)
> +{
> + struct nvm_dev *dev, *t;
> +
> + down_write(&nvm_lock);
> + if (list_empty(&nvm_devices)) {
> + up_write(&nvm_lock);
> + return NOTIFY_DONE;
> + }
> +
> + list_for_each_entry_safe(dev, t, &nvm_devices, devices)
> + _nvm_unregister(dev, true);
> +
> + up_write(&nvm_lock);
> +
> + return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block nvm_notifier = {
> + .notifier_call = nvm_notify_reboot,
> + .next = NULL,
> + .priority = INT_MAX, /* before any real devices */
Why this priority?
> +};
> +
> int nvm_register(struct nvm_dev *dev)
> {
> int ret, exp_pool_size;
> @@ -1161,8 +1204,11 @@ int nvm_register(struct nvm_dev *dev)
> return -ENOMEM;
> }
>
> - /* register device with a supported media manager */
> down_write(&nvm_lock);
> + if (list_empty(&nvm_devices))
> + register_reboot_notifier(&nvm_notifier);
> +
> + /* register device with a supported media manager */
> list_add(&dev->devices, &nvm_devices);
> up_write(&nvm_lock);
>
> @@ -1172,21 +1218,13 @@ int nvm_register(struct nvm_dev *dev)
>
> void nvm_unregister(struct nvm_dev *dev)
> {
> - struct nvm_target *t, *tmp;
> + down_write(&nvm_lock);
>
> - mutex_lock(&dev->mlock);
> - list_for_each_entry_safe(t, tmp, &dev->targets, list) {
> - if (t->dev->parent != dev)
> - continue;
> - __nvm_remove_target(t, false);
> - }
> - mutex_unlock(&dev->mlock);
> + _nvm_unregister(dev, false);
You are adding an extra lock dependency here. I cannot see any obvious
problem with it, but you probably want to test this with lock debugging
enabled.
>
> - down_write(&nvm_lock);
> - list_del(&dev->devices);
> + if (list_empty(&nvm_devices))
> + unregister_reboot_notifier(&nvm_notifier);
> up_write(&nvm_lock);
> -
> - nvm_free(dev);
> }
> EXPORT_SYMBOL(nvm_unregister);
>
> --
> 1.8.3.1
Otherwise, I think adding this functionality is beneficial.
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