HID: fix a potential bug in pointer casting
Li Zefan [Wed, 14 Nov 2007 10:31:05 +0000 (11:31 +0100)]
Don't directly cast list_head * to foo *, this works only when list
is the first member of struct foo, and we should not make the assumption
how members are ordered in the structure.

i.e. struct *f = (struct *f)pos will work if:
struct foo {
struct list_head list;
int i;
};

but will fail if:
struct foo {
int i;
struct list_head list;
}

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/usbhid/hid-tmff.c

index 69882a7..144578b 100644 (file)
@@ -137,7 +137,8 @@ static int hid_tmff_play(struct input_dev *dev, void *data, struct ff_effect *ef
 int hid_tmff_init(struct hid_device *hid)
 {
        struct tmff_device *tmff;
-       struct list_head *pos;
+       struct hid_report *report;
+       struct list_head *report_list;
        struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
        struct input_dev *input_dev = hidinput->input;
        const signed short *ff_bits = ff_joystick;
@@ -149,8 +150,8 @@ int hid_tmff_init(struct hid_device *hid)
                return -ENOMEM;
 
        /* Find the report to use */
-       list_for_each(pos, &hid->report_enum[HID_OUTPUT_REPORT].report_list) {
-               struct hid_report *report = (struct hid_report *)pos;
+       report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
+       list_for_each_entry(report, report_list, list) {
                int fieldnum;
 
                for (fieldnum = 0; fieldnum < report->maxfield; ++fieldnum) {