[PATCH] lightnvm: missing nvm_lock acquire

Wenwei Tao
2015-11-24T15:26:03Z

To avoid race conditions, traverse dev, media manager,
and targeet lists and also register, unregister entries
to/from them, should be always under the nvm_lock control.

Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com>
---
drivers/lightnvm/core.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index f659e60..39aec3a 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -333,19 +333,19 @@ EXPORT_SYMBOL(nvm_register);

void nvm_unregister(char *disk_name)
{
+ down_write(&nvm_lock);
struct nvm_dev *dev = nvm_find_nvm_dev(disk_name);

if (!dev) {
pr_err("nvm: could not find device %s to unregister\n",
disk_name);
+ up_write(&nvm_lock);
return;
}

- nvm_exit(dev);
-
- down_write(&nvm_lock);
list_del(&dev->devices);
up_write(&nvm_lock);
+ nvm_exit(dev);
}
EXPORT_SYMBOL(nvm_unregister);

@@ -365,12 +365,15 @@ static int nvm_create_target(struct nvm_dev *dev,
void *targetdata;
int ret = 0;

+ down_write(&nvm_lock);
if (!dev->mt) {
/* register with device with a supported NVM manager */
list_for_each_entry(mt, &nvm_mgrs, list) {
ret = mt->register_mgr(dev);
- if (ret < 0)
+ if (ret < 0) {
+ up_write(&nvm_lock);
return ret; /* initialization failed */
+ }
if (ret > 0) {
dev->mt = mt;
break; /* successfully initialized */
@@ -379,6 +382,7 @@ static int nvm_create_target(struct nvm_dev *dev,

if (!ret) {
pr_info("nvm: no compatible nvm manager found.\n");
+ up_write(&nvm_lock);
return -ENODEV;
}
}
@@ -386,10 +390,10 @@ static int nvm_create_target(struct nvm_dev *dev,
tt = nvm_find_target_type(create->tgttype);
if (!tt) {
pr_err("nvm: target type %s not found\n", create->tgttype);
+ up_write(&nvm_lock);
return -EINVAL;
}

- down_write(&nvm_lock);
list_for_each_entry(t, &dev->online_targets, list) {
if (!strcmp(create->tgtname, t->disk->disk_name)) {
pr_err("nvm: target name already exists.\n");
@@ -472,8 +476,9 @@ static int __nvm_configure_create(struct nvm_ioctl_create *create)
{
struct nvm_dev *dev;
struct nvm_ioctl_create_simple *s;
-
+ down_write(&nvm_lock);
dev = nvm_find_nvm_dev(create->dev);
+ up_write(&nvm_lock);
if (!dev) {
pr_err("nvm: device not found\n");
return -EINVAL;
@@ -532,7 +537,9 @@ static int nvm_configure_show(const char *val)
return -EINVAL;
}

+ down_write(&nvm_lock);
dev = nvm_find_nvm_dev(devname);
+ up_write(&nvm_lock);
if (!dev) {
pr_err("nvm: device not found\n");
return -EINVAL;
--
1.9.1