cdrom: protect cdrom_device_info list by mutex

This patch protects the list of cdrom_device_info by cdrom_mutex
when the file in /proc/sys/dev/cdrom/ is written.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index fbcf4b3f8d0e699539dadf6acaa93e5c89c09efb..326ef1b4a4ea4af15da7754b782297bfeca85d59 100644 (file)
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -3427,6 +3427,7 @@ static void cdrom_update_settings(void)
 {
        struct cdrom_device_info *cdi;
 
+       mutex_lock(&cdrom_mutex);
        for (cdi = topCdromPtr; cdi != NULL; cdi = cdi->next) {
                if (autoclose && CDROM_CAN(CDC_CLOSE_TRAY))
                        cdi->options |= CDO_AUTO_CLOSE;
@@ -3445,6 +3446,7 @@ static void cdrom_update_settings(void)
                else
                        cdi->options &= ~CDO_CHECK_TYPE;
        }
+       mutex_unlock(&cdrom_mutex);
 }
 
 static int cdrom_sysctl_handler(ctl_table *ctl, int write, struct file * filp,