lightnvm: prevent target type module removal when in use

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>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index ddae430b6eae879333a84885256fcd8b14c0c1b6..60e163be5a89a75c4344b32d527abc09d6b47627 100644 (file)
--- 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 1b0f61233c216ac7f262ff58aee2d4a0bdc76ad6..6df65d14a2c52c42a70690ad72da776e65885a8f 100644 (file)
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -1044,6 +1044,7 @@ 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 7dfa56ebbc6d0f1bd4e215c93d5e642b3231334b..7b80ac911d26ea2417766b3df607a2e6f92129f0 100644 (file)
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -460,6 +460,7 @@ 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);