> On 16 Apr 2019, at 12.16, Igor Konopko <[email protected]> wrote: > > When creation process is still in progress, target is not yet on > targets list. This causes a chance for removing whole lightnvm > subsystem by calling nvm_unregister() in the meantime and finally by > causing kernel panic inside target init function. > > This patch changes the behaviour by adding kref variable which tracks > all the users of nvm_dev structure. When nvm_dev is allocated, kref > value is set to 1. Then before every target creation the value is > increased and decreased after target removal. The extra reference > is decreased when nvm subsystem is unregistered. > > Signed-off-by: Igor Konopko <[email protected]> > --- > drivers/lightnvm/core.c | 41 +++++++++++++++++++++++++++++++---------- > include/linux/lightnvm.h | 1 + > 2 files changed, 32 insertions(+), 10 deletions(-) > > diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c > index e2abe88..0e9f7996 100644 > --- a/drivers/lightnvm/core.c > +++ b/drivers/lightnvm/core.c > @@ -45,6 +45,8 @@ struct nvm_dev_map { > int num_ch; > }; > > +static void nvm_free(struct kref *ref); > + > static struct nvm_target *nvm_find_target(struct nvm_dev *dev, const char > *name) > { > struct nvm_target *tgt; > @@ -501,6 +503,7 @@ static int nvm_remove_tgt(struct nvm_dev *dev, struct > nvm_ioctl_remove *remove) > } > __nvm_remove_target(t, true); > mutex_unlock(&dev->mlock); > + kref_put(&dev->ref, nvm_free); > > return 0; > } > @@ -1094,15 +1097,16 @@ static int nvm_core_init(struct nvm_dev *dev) > return ret; > } > > -static void nvm_free(struct nvm_dev *dev) > +static void nvm_free(struct kref *ref) > { > - if (!dev) > - return; > + struct nvm_dev *dev = container_of(ref, struct nvm_dev, ref); > > if (dev->dma_pool) > dev->ops->destroy_dma_pool(dev->dma_pool); > > - nvm_unregister_map(dev); > + if (dev->rmap) > + nvm_unregister_map(dev); > + > kfree(dev->lun_map); > kfree(dev); > } > @@ -1139,7 +1143,13 @@ static int nvm_init(struct nvm_dev *dev) > > struct nvm_dev *nvm_alloc_dev(int node) > { > - return kzalloc_node(sizeof(struct nvm_dev), GFP_KERNEL, node); > + struct nvm_dev *dev; > + > + dev = kzalloc_node(sizeof(struct nvm_dev), GFP_KERNEL, node); > + if (dev) > + kref_init(&dev->ref); > + > + return dev; > } > EXPORT_SYMBOL(nvm_alloc_dev); > > @@ -1147,12 +1157,16 @@ int nvm_register(struct nvm_dev *dev) > { > int ret, exp_pool_size; > > - if (!dev->q || !dev->ops) > + if (!dev->q || !dev->ops) { > + kref_put(&dev->ref, nvm_free); > return -EINVAL; > + } > > ret = nvm_init(dev); > - if (ret) > + if (ret) { > + kref_put(&dev->ref, nvm_free); > return ret; > + } > > exp_pool_size = max_t(int, PAGE_SIZE, > (NVM_MAX_VLBA * (sizeof(u64) + dev->geo.sos))); > @@ -1162,7 +1176,7 @@ int nvm_register(struct nvm_dev *dev) > exp_pool_size); > if (!dev->dma_pool) { > pr_err("nvm: could not create dma pool\n"); > - nvm_free(dev); > + kref_put(&dev->ref, nvm_free); > return -ENOMEM; > } > > @@ -1184,6 +1198,7 @@ void nvm_unregister(struct nvm_dev *dev) > if (t->dev->parent != dev) > continue; > __nvm_remove_target(t, false); > + kref_put(&dev->ref, nvm_free); > } > mutex_unlock(&dev->mlock); > > @@ -1191,13 +1206,14 @@ void nvm_unregister(struct nvm_dev *dev) > list_del(&dev->devices); > up_write(&nvm_lock); > > - nvm_free(dev); > + kref_put(&dev->ref, nvm_free); > } > EXPORT_SYMBOL(nvm_unregister); > > static int __nvm_configure_create(struct nvm_ioctl_create *create) > { > struct nvm_dev *dev; > + int ret; > > down_write(&nvm_lock); > dev = nvm_find_nvm_dev(create->dev); > @@ -1208,7 +1224,12 @@ static int __nvm_configure_create(struct > nvm_ioctl_create *create) > return -EINVAL; > } > > - return nvm_create_tgt(dev, create); > + kref_get(&dev->ref); > + ret = nvm_create_tgt(dev, create); > + if (ret) > + kref_put(&dev->ref, nvm_free); > + > + return ret; > } > > static long nvm_ioctl_info(struct file *file, void __user *arg) > diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h > index d3b0270..4d0d565 100644 > --- a/include/linux/lightnvm.h > +++ b/include/linux/lightnvm.h > @@ -428,6 +428,7 @@ struct nvm_dev { > char name[DISK_NAME_LEN]; > void *private_data; > > + struct kref ref; > void *rmap; > > struct mutex mlock; > -- > 2.9.5
Much better with the kref() Reviewed-by: Javier González <[email protected]>
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