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SubjectRe: [PATCH] lightnvm: prevent target type module removal when in use
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On 09/08/2017 02:35 PM, Rakesh Pandit wrote:
> If target type module e.g. pblk here is unloaded (rmmod) while module
> is in use (after creating target) system crashes. We fix this by
> using module API refcnt.
>
> Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
> ---
> drivers/lightnvm/core.c | 4 ++++
> drivers/lightnvm/pblk-init.c | 1 +
> include/linux/lightnvm.h | 1 +
> 3 files changed, 6 insertions(+)
>
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index bbea2c8..c39f87d 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -22,6 +22,7 @@
> #include <linux/types.h>
> #include <linux/sem.h>
> #include <linux/bitmap.h>
> +#include <linux/module.h>
> #include <linux/moduleparam.h>
> #include <linux/miscdevice.h>
> #include <linux/lightnvm.h>
> @@ -316,6 +317,8 @@ static int nvm_create_tgt(struct nvm_dev *dev, struct nvm_ioctl_create *create)
> list_add_tail(&t->list, &dev->targets);
> mutex_unlock(&dev->mlock);
>
> + __module_get(tt->owner);
> +
> return 0;
> err_sysfs:
> if (tt->exit)
> @@ -351,6 +354,7 @@ static void __nvm_remove_target(struct nvm_target *t)
>
> nvm_remove_tgt_dev(t->dev, 1);
> put_disk(tdisk);
> + module_put(t->type->owner);
>
> list_del(&t->list);
> kfree(t);
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index 5fe926b..77d6120 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -1059,6 +1059,7 @@ static struct nvm_tgt_type tt_pblk = {
>
> .sysfs_init = pblk_sysfs_init,
> .sysfs_exit = pblk_sysfs_exit,
> + .owner = THIS_MODULE,
> };
>
> static int __init pblk_module_init(void)
> diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
> index 81b71c6d..78a22e0 100644
> --- a/include/linux/lightnvm.h
> +++ b/include/linux/lightnvm.h
> @@ -461,6 +461,7 @@ struct nvm_tgt_type {
>
> /* For internal use */
> struct list_head list;
> + struct module *owner;
> };
>
> extern struct nvm_tgt_type *nvm_find_target_type(const char *, int);
>

Thanks Rakesh. I've picked it up for 4.15.

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