On Thu, Oct 1, 2026 at 10:19 AM David Marchand <[email protected]> wrote:
> On Wed, 30 Sept 2026 at 17:37, Maxime Coquelin > <[email protected]> wrote: > > On Wed, Sep 30, 2026 at 5:26 PM Stephen Hemminger < > [email protected]> wrote: > >> > >> On Wed, 30 Sep 2026 11:57:59 +0200 > >> Maxime Coquelin <[email protected]> wrote: > >> > >> > This patch adds a compatibility define for __counted_by attribute, > >> > which is not present in older compilers but required for recent UAPI > >> > headers like vfio.h. > >> > > >> > Signed-off-by: Maxime Coquelin <[email protected]> > >> > --- > >> > config/rte_config.h | 9 +++++++++ > >> > 1 file changed, 9 insertions(+) > >> > > >> > diff --git a/config/rte_config.h b/config/rte_config.h > >> > index 0447cdf2ad..307e7dac62 100644 > >> > --- a/config/rte_config.h > >> > +++ b/config/rte_config.h > >> > @@ -25,6 +25,15 @@ > >> > #define RTE_TOOLCHAIN_MSVC 1 > >> > #endif > >> > > >> > +/* > >> > + * Compatibility define for Linux kernel UAPI headers that may use > __counted_by > >> > + * attribute for bounds checking. This attribute is not understood > by userspace > >> > + * compilers, so define it as empty if not already provided. > >> > + */ > >> > +#ifndef __counted_by > >> > +#define __counted_by(m) > >> > +#endif > >> > + > >> > /* legacy defines */ > >> > #ifdef RTE_EXEC_ENV_LINUX > >> > #define RTE_EXEC_ENV_LINUXAPP 1 > >> > >> NAK this is best done by keeping up to date stddef over in virtio > headers. > > > > This is for VFIO, not Virtio but that does not change the issue. > > > > Problem is importing stddef in UAPI as currently done, does not work, > > because the system version is included first so the imported one is > discarded. > > > > An alternative solution I tested would be to include the imported > headers first, > > but it means imported headers get silently intermixed, which worked in > my test > > but could lead to hard to debug issues. > > I don't like the alternative, for the reason you listed, plus the fact > that this intermixing is invisible. > At the moment, using an imported uapi header is opt-in, and I prefer > it like this. > > > > While not ideal, the solution proposed in this patch is harmless, we are > talking > > about an attribute defined as empty. > > Your solution of wrapping __counted_by is simple. > > On the other hand, fixing the existing import script would require > relying on an external tool (unifef), which could be acceptable. > Your solution is certainly more future-proof. If others agree, can you send a series that supersedes mine so that we can get it merged early? Eugenio will need to rebase his series on top of it. Thanks, Maxime > I tried some: > > diff --git a/devtools/linux-uapi.sh b/devtools/linux-uapi.sh > index dbf3163bc8..189164928c 100755 > --- a/devtools/linux-uapi.sh > +++ b/devtools/linux-uapi.sh > @@ -13,6 +13,9 @@ file="" > check_headers=false > quiet=false > > +# Require unifdef > +unifdef -h 2>&1 >/dev/null || { echo "This script requires unifdef."; > exit 1; } > + > print_usage() > { > echo "Usage: $(basename $0) [-h] [-i FILE] [-u VERSION] [-c] [-q]" > @@ -85,6 +88,9 @@ fixup_includes() > sed -i 's|#\(define\)[[:space:]]*_UAPI|#\1 |' $path > sed -i 's|#\(endif[[:space:]]*/[*]\)[[:space:]]*_UAPI|#\1 |' $path > > + unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ -o ${path}.tmp > $path || [ $? -lt 2 ] > + mv -f ${path}.tmp $path > + > # Prepend include path with "uapi/" if the header is imported > for include in $(sed -ne 's/^#include <\(.*\)>$/\1/p' $path); do > if [ -f "$base_path$include" ]; then > diff --git a/doc/guides/contributing/linux_uapi.rst > b/doc/guides/contributing/linux_uapi.rst > index b8febfc420..a3490bfbb6 100644 > --- a/doc/guides/contributing/linux_uapi.rst > +++ b/doc/guides/contributing/linux_uapi.rst > @@ -27,6 +27,8 @@ Importing or updating an uAPI header file > To ensure that imported uAPI headers are unmodified > and sourced from an official Linux kernel release, > a helper script is provided and must be used. > +This script requires the ``unifdef`` tool. > + > Below is an example to import ``linux/vduse.h`` file from Linux ``v6.10``: > > .. code-block:: console > > > Then imported linux/types.h, linux/posix_types.h and linux/stddef.h. > > And net/nbl needs some fixing... as it includes uapi/linux/vfio.h too > late... > Only occurence in the whole DPDK tree: > $ git grep -l '# *include.*uapi' :^devtools/linux-uapi.sh > :^doc/guides/contributing/linux_uapi.rst | while read file; do [ $(git > grep -B100 '# *include.*uapi' $file | grep '# *include' | wc -l) = 1 ] > || echo $file; done > drivers/net/nbl/nbl_common/nbl_userdev.c > > > -- > David Marchand > >
