drbd: increase module count on /proc/drbd access
If someone holds /proc/drbd open, previously rmmod would
"succeed" in starting the unload, but then block on remove_proc_entry,
leading to a situation where the lsmod does not show drbd anymore,
but /proc/drbd being still there (but no longer accessible).
I'd rather have rmmod fail up front in this case.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index 49d817c..efba62c 100644
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -34,6 +34,7 @@
#include "drbd_int.h"
static int drbd_proc_open(struct inode *inode, struct file *file);
+static int drbd_proc_release(struct inode *inode, struct file *file);
struct proc_dir_entry *drbd_proc;
@@ -42,7 +43,7 @@
.open = drbd_proc_open,
.read = seq_read,
.llseek = seq_lseek,
- .release = single_release,
+ .release = drbd_proc_release,
};
void seq_printf_with_thousands_grouping(struct seq_file *seq, long v)
@@ -304,7 +305,15 @@
static int drbd_proc_open(struct inode *inode, struct file *file)
{
- return single_open(file, drbd_seq_show, PDE(inode)->data);
+ if (try_module_get(THIS_MODULE))
+ return single_open(file, drbd_seq_show, PDE(inode)->data);
+ return -ENODEV;
+}
+
+static int drbd_proc_release(struct inode *inode, struct file *file)
+{
+ module_put(THIS_MODULE);
+ return single_release(inode, file);
}
/* PROC FS stuff end */