Jeff Johnson <quic_jjohnson@xxxxxxxxxxx> writes: > On 2/5/2024 8:17 AM, Kalle Valo wrote: >> Kang Yang <quic_kangyang@xxxxxxxxxxx> writes: >>> + if (WARN_ON(skb->len < ie_offset)) >>> + return -EINVAL; >>> + >>> + ie = (u8 *)cfg80211_find_vendor_ie(oui, oui_type, >>> + skb->data + ie_offset, >>> + skb->len - ie_offset); >> >> So cfg80211_find_vendor_ie() returns: >> >> static inline const u8 * >> cfg80211_find_vendor_ie(unsigned int oui, int oui_type, >> const u8 *ies, unsigned int len) >> >> You are casting away the const here. I see that other drivers do the >> same as the assumption is that the pointer points to the same buffer, >> but I still don't really like casting away const. Thoughts? > > I'm not a fan of typecasting either. > > However, the problem here is that from the perspective of > cfg80211_find_vendor_ie() the buffer is const (not modified in any way > by the function), but from the perspective of every caller the buffer is > part of a message that is in RAM. > > So you have to decide if you want to change the prototype to remove the > const from cfg80211_find_vendor_ie() or if you want to keep the current > semantic to cast away the const. > > This is one of the rare cases where I think the typecast is ok. Makes sense, thanks for the comment. -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
