On 3/27/19 1:39 PM, Igor Konopko wrote:
This patch adds a counter, which is responsible for tracking inflight
target creations.
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.
With this patch we are able to track such a scenarios and wait with
completing nvm_unregister() and freeing memory until target creation
will be completed.
Signed-off-by: Igor Konopko <igor.j.konopko@xxxxxxxxx>
---
drivers/lightnvm/core.c | 19 ++++++++++++++++++-
include/linux/lightnvm.h | 2 ++
2 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index e2abe88..62ed662 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -1083,6 +1083,7 @@ static int nvm_core_init(struct nvm_dev *dev)
INIT_LIST_HEAD(&dev->targets);
mutex_init(&dev->mlock);
spin_lock_init(&dev->lock);
+ dev->create_inflight = 0;
ret = nvm_register_map(dev);
if (ret)
@@ -1180,6 +1181,11 @@ void nvm_unregister(struct nvm_dev *dev)
struct nvm_target *t, *tmp;
mutex_lock(&dev->mlock);
+ while (dev->create_inflight > 0) {
+ mutex_unlock(&dev->mlock);
+ io_schedule();
+ mutex_lock(&dev->mlock);
+ }
list_for_each_entry_safe(t, tmp, &dev->targets, list) {
if (t->dev->parent != dev)
continue;
@@ -1198,6 +1204,7 @@ 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 +1215,17 @@ static int __nvm_configure_create(struct nvm_ioctl_create *create)
return -EINVAL;
}
- return nvm_create_tgt(dev, create);
+ mutex_lock(&dev->mlock);
+ dev->create_inflight++;
+ mutex_unlock(&dev->mlock);
+
+ ret = nvm_create_tgt(dev, create);
+
+ mutex_lock(&dev->mlock);
+ dev->create_inflight--;
+ mutex_unlock(&dev->mlock);
+
+ 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..e462d1d 100644
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -428,6 +428,8 @@ struct nvm_dev {
char name[DISK_NAME_LEN];
void *private_data;
+ int create_inflight;
+
void *rmap;
struct mutex mlock;
Hi Igor,
I think this may be better implemented with kref. Such that target
creator can take a reference upon target initialize and release it again
afterwards. Then the one turning of the lights can get to run the final
cleanup routine.
-Matias
