Am 14.07.20 um 10:25 schrieb Dan Carpenter:
On Tue, Jul 14, 2020 at 03:39:13AM +0200, Roland Scheidegger wrote:
Am 26.06.20 um 12:39 schrieb Dan Carpenter:
These if statements are supposed to be true if we ended the list_for_each_entry() loops without hitting a break statement but they don't work.
In the first loop, we increment "i" after the "if (i == unit)" condition so we don't necessarily know that "i" is not equal to unit at the end of the loop.
So, if I understand this right, this would only really be a problem if there's no list entries at all, right? That is i == unit == 0. Not sure if that can actually happen, but in any case the fix looks correct.
An empty list and there is another potential issue where unit is exactly off by one.
list_for_each_entry(con, &dev_priv->dev->mode_config.connector_list, head) { if (i == unit) break; ++i; <-- this is the last iteration and it's off by one so now i == unit but we didn't exit via the break statement. }
if (i != unit) { ^^^^^^^^^ Since we didn't exit by the break statement we want this to be true but it's false instead.
DRM_ERROR("Could not find initial display unit.\n");I don't know how *likely* this is, but static checkers complain. Technically correct is the best kind of correct! ;)
Ahh indeed seems obvious now. But kinda difficult to spot :-).
Thanks again,
Roland
regards, dan carpenter