On Fri, Jul 18, 2025 at 09:43:46AM +0900, Byungchul Park wrote: > On Fri, Jul 18, 2025 at 01:42:38AM +0800, kernel test robot wrote: > > Hi Byungchul, > > > > kernel test robot noticed the following build warnings: > > > > [auto build test WARNING on c65d34296b2252897e37835d6007bbd01b255742] > > > > url: https://github.com/intel-lab-lkp/linux/commits/Byungchul-Park/netmem-introduce-struct-netmem_desc-mirroring-struct-page/20250717-150253 > > base: c65d34296b2252897e37835d6007bbd01b255742 > > patch link: https://lore.kernel.org/r/20250717070052.6358-13-byungchul%40sk.com > > patch subject: [Intel-wired-lan] [PATCH net-next v11 12/12] libeth: xdp: access ->pp through netmem_desc instead of page > > config: arm-randconfig-r072-20250717 (https://download.01.org/0day-ci/archive/20250718/202507180111.jygqJHzk-lkp@xxxxxxxxx/config) > > compiler: arm-linux-gnueabi-gcc (GCC) 8.5.0 > > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250718/202507180111.jygqJHzk-lkp@xxxxxxxxx/reproduce) > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > > the same patch/commit), kindly add following tags > > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > > | Closes: https://lore.kernel.org/oe-kbuild-all/202507180111.jygqJHzk-lkp@xxxxxxxxx/ > > > > All warnings (new ones prefixed by >>): > > > > In file included from include/linux/container_of.h:5, > > from include/linux/list.h:5, > > from include/linux/timer.h:5, > > from include/linux/netdevice.h:24, > > from include/trace/events/xdp.h:8, > > from include/linux/bpf_trace.h:5, > > from include/net/libeth/xdp.h:7, > > from drivers/net/ethernet/intel/libeth/tx.c:6: > > include/net/libeth/xdp.h: In function 'libeth_xdp_prepare_buff': > > >> include/net/libeth/xdp.h:1295:23: warning: passing argument 1 of 'page_pool_page_is_pp' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers] > > pp_page_to_nmdesc(page)->pp->p.offset, len, true); > > ^~~~ > > include/linux/build_bug.h:30:63: note: in definition of macro 'BUILD_BUG_ON_INVALID' > > #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e)))) > > ^ > > include/net/netmem.h:301:2: note: in expansion of macro 'DEBUG_NET_WARN_ON_ONCE' > > DEBUG_NET_WARN_ON_ONCE(!page_pool_page_is_pp(p)); \ > > ^~~~~~~~~~~~~~~~~~~~~~ > > include/net/libeth/xdp.h:1295:5: note: in expansion of macro 'pp_page_to_nmdesc' > > pp_page_to_nmdesc(page)->pp->p.offset, len, true); > > ^~~~~~~~~~~~~~~~~ > > In file included from arch/arm/include/asm/cacheflush.h:10, > > from include/linux/cacheflush.h:5, > > from include/linux/highmem.h:8, > > from include/linux/bvec.h:10, > > from include/linux/skbuff.h:17, > > from include/net/net_namespace.h:43, > > from include/linux/netdevice.h:38, > > from include/trace/events/xdp.h:8, > > from include/linux/bpf_trace.h:5, > > from include/net/libeth/xdp.h:7, > > from drivers/net/ethernet/intel/libeth/tx.c:6: > > include/linux/mm.h:4176:54: note: expected 'struct page *' but argument is of type 'const struct page *' > > static inline bool page_pool_page_is_pp(struct page *page) > > ~~~~~~~~~~~~~^~~~ > > Oh. page_pool_page_is_pp() in the mainline code already has this issue > that the helper cannot take const struct page * as argument. > > How should we resolve the issue? Changing page_pool_page_is_pp() to > macro and using _Generic again looks too much. Or should we? Any idea? option 1. Remove 'const' on declaration of struct page in libeth_xdp_prepare_buff() but maybe bad. option 2. Use __pp_page_to_nmdesc() instead of pp_page_to_nmdesc() in libeth_xdp_prepare_buff() to skip checking if it's a pp page. option 3. Change page_pool_page_is_pp() to macro and use _Generic to cover const casting. More? Byungchul > Byungchul > > > vim +1295 include/net/libeth/xdp.h > > > > 1263 > > 1264 bool libeth_xdp_buff_add_frag(struct libeth_xdp_buff *xdp, > > 1265 const struct libeth_fqe *fqe, > > 1266 u32 len); > > 1267 > > 1268 /** > > 1269 * libeth_xdp_prepare_buff - fill &libeth_xdp_buff with head FQE data > > 1270 * @xdp: XDP buffer to attach the head to > > 1271 * @fqe: FQE containing the head buffer > > 1272 * @len: buffer len passed from HW > > 1273 * > > 1274 * Internal, use libeth_xdp_process_buff() instead. Initializes XDP buffer > > 1275 * head with the Rx buffer data: data pointer, length, headroom, and > > 1276 * truesize/tailroom. Zeroes the flags. > > 1277 * Uses faster single u64 write instead of per-field access. > > 1278 */ > > 1279 static inline void libeth_xdp_prepare_buff(struct libeth_xdp_buff *xdp, > > 1280 const struct libeth_fqe *fqe, > > 1281 u32 len) > > 1282 { > > 1283 const struct page *page = __netmem_to_page(fqe->netmem); > > 1284 > > 1285 #ifdef __LIBETH_WORD_ACCESS > > 1286 static_assert(offsetofend(typeof(xdp->base), flags) - > > 1287 offsetof(typeof(xdp->base), frame_sz) == > > 1288 sizeof(u64)); > > 1289 > > 1290 *(u64 *)&xdp->base.frame_sz = fqe->truesize; > > 1291 #else > > 1292 xdp_init_buff(&xdp->base, fqe->truesize, xdp->base.rxq); > > 1293 #endif > > 1294 xdp_prepare_buff(&xdp->base, page_address(page) + fqe->offset, > > > 1295 pp_page_to_nmdesc(page)->pp->p.offset, len, true); > > 1296 } > > 1297 > > > > -- > > 0-DAY CI Kernel Test Service > > https://github.com/intel/lkp-tests/wiki
