Hello Ajay, Kalle, On 8/29/23 10:31, Kalle Valo wrote: > Kalle Valo <kvalo@xxxxxxxxxx> writes: > >> kernel test robot <lkp@xxxxxxxxx> writes: [...] >>> sparse warnings: (new ones prefixed by >>) >>>>> drivers/net/wireless/microchip/wilc1000/cfg80211.c:361:42: sparse: sparse: incorrect type in assignment (different base types) @@ expected unsigned int key_mgmt_suite @@ got restricted __be32 [usertype] @@ >>> drivers/net/wireless/microchip/wilc1000/cfg80211.c:361:42: sparse: expected unsigned int key_mgmt_suite >>> drivers/net/wireless/microchip/wilc1000/cfg80211.c:361:42: sparse: got restricted __be32 [usertype] >> >> Yeah, this is an old issue but we really should try to fix this, >> especially so as I would like to make wireless code sparse warning free >> in the near future. IIRC there were some problems with nl80211 interface >> as well so this might not be simple fix still. > > For reference here's the old discussion: > > https://patchwork.kernel.org/project/linux-wireless/patch/20220720160302.231516-1-ajay.kathat@xxxxxxxxxxxxx/ > > Any volunteers to help fix this? I would prefers fixes for issues like > this compared to questionable random cleanups we always get. I'm bumping this old thread because it looks like the sparse warning is still present in WILC driver, and I would gladly help getting rid of it, but since there's already been a fair amount of discussions around it, I am not sure what is expected/what should be done. Here is my understanding so far: - Ajay has proposed a patch ([1]) which indeed fixes the warning but involves many casts - Johannes and Jouni then gave details about the original issue leading to those casts ([2]): wpa_supplicant somehow forces the AKM suites values to be be32 at some point, while it should be treated in host endianness - as pointed by Ajay, the corresponding fix has been made since then by Jouni in wpa_supplicant ([3]). The fix make sure to handle key_mgmt_suite in host endianness AND to keep compatibility with current drivers having the be32 fix. - - It could have allowed to simply get rid of the all casts on AKM suites in wilc driver ([4]), but then new kernel/drivers would break with existing userspace, so it is not an option Now, I see multiple options to fix the sparse warning: - apply the same fix as for wpa_supplicant ([3]) in wilc driver (so basically, become compatible with both endianness) - apply the same fix as for wpa_supplicant ([3]), not in wilc but in nl80211 (may need to update not only wilc but any driver having trailing be32 cast on AKM suites) - take the initial quick but not-so-nice double cast fix and call it a day What's your opinion on this ? [1] https://lore.kernel.org/linux-wireless/20220720160302.231516-1-ajay.kathat@xxxxxxxxxxxxx/ [2] https://lore.kernel.org/linux-wireless/e677e3cd1b5c34146017a65f28fabdb673a91d23.camel@xxxxxxxxxxxxxxxx/ [3] https://w1.fi/cgit/hostap/commit/?id=8392ea9e75eacf30cb09671e463d9a37c3eadd6a [4] https://lore.kernel.org/linux-wireless/20230830042300.87184-1-ajay.kathat@xxxxxxxxxxxxx/ -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
