[PATCH v2] part: return -ENOSYS when get_info not valid.

[schspa]

In some case, get_info() interface can be NULL, add this check to stop
from crash.

Signed-off-by: schspa <sch...@gmail.com>
---
 disk/part.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/disk/part.c b/disk/part.c
index a6a8f7052b..f9b9b89861 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -668,6 +668,13 @@ int part_get_info_by_name_type(struct blk_desc *dev_desc, 
const char *name,
        part_drv = part_driver_lookup_type(dev_desc);
        if (!part_drv)
                return -1;
+
+       if (!part_drv->get_info) {
+               log_debug("## Driver %s does not have the get_info() method\n",
+                      part_drv->name);
+               return -ENOSYS;
+       }
+
        for (i = 1; i < part_drv->max_entries; i++) {
                ret = part_drv->get_info(dev_desc, i, info);
                if (ret != 0) {
-- 
2.33.1