Re: [PATCH net-next 3/3] net/mlx5: Apply devlink default eswitch mode during init

From: Mark Bloch

Date: Thu May 21 2026 - 09:53:12 EST

On 21/05/2026 10:24, Tariq Toukan wrote:
> From: Mark Bloch <mbloch@xxxxxxxxxx>
>
> Apply devlink default eswitch mode for mlx5 devices after successful
> device initialization while holding the devlink instance lock.
>
> At this point the devlink instance is registered and the mlx5 devlink
> operations are available, so the default eswitch mode can be applied to
> the matching PCI devlink handle.
>
> Signed-off-by: Mark Bloch <mbloch@xxxxxxxxxx>
> Reviewed-by: Shay Drori <shayd@xxxxxxxxxx>
> Reviewed-by: Moshe Shemesh <moshe@xxxxxxxxxx>
> Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/main.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> index 0c6e4efe38c8..4528097f3d84 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
> @@ -1391,6 +1391,21 @@ static void mlx5_unload(struct mlx5_core_dev *dev)
> mlx5_free_bfreg(dev, &dev->priv.bfreg);
> }
>
> +static void mlx5_devl_apply_default_esw_mode(struct mlx5_core_dev *dev)
> +{
> + struct devlink *devlink = priv_to_devlink(dev);
> + int err;
> +
> + if (!MLX5_ESWITCH_MANAGER(dev))
> + return;
> +
> + devl_assert_locked(devlink);
> + err = devl_apply_default_esw_mode(devlink);
> + if (err)
> + mlx5_core_warn(dev, "Couldn't apply default eswitch mode, err %d\n",
> + err);
> +}
> +
> int mlx5_init_one_devl_locked(struct mlx5_core_dev *dev)
> {
> bool light_probe = mlx5_dev_is_lightweight(dev);
> @@ -1437,6 +1452,7 @@ int mlx5_init_one_devl_locked(struct mlx5_core_dev *dev)
> mlx5_core_err(dev, "mlx5_hwmon_dev_register failed with error code %d\n", err);
>
> mutex_unlock(&dev->intf_state_mutex);
> + mlx5_devl_apply_default_esw_mode(dev);
> return 0;
>
> err_register:
> @@ -1538,6 +1554,7 @@ int mlx5_load_one_devl_locked(struct mlx5_core_dev *dev, bool recovery)
> goto err_attach;
>
> mutex_unlock(&dev->intf_state_mutex);
> + mlx5_devl_apply_default_esw_mode(dev);
> return 0;
>
> err_attach:

NIPA flagged this patch with a build_allmodconfig_warn failure:
https://netdev-ctrl.bots.linux.dev/logs/build/1098506/14585935/build_allmodconfig_warn/

I do not see how this mlx5 patch is related to the reported issue,
but I looked into it anyway.

After the kernel has been built once, the issue can be reproduced by rerunning sparse
only on version.o, which filters out the unrelated noise. I had an older sparse installed,
so I used a local copy:

rm -f arch/x86/boot/version.o
make V=1 C=1 CHECK=/labhome/mbloch/bin/sparse arch/x86/boot/version.o

This gives the same error reported by NIPA:

...
...
make -f ./scripts/Makefile.vmlinux
make -f ./scripts/Makefile.build obj=arch/x86/boot arch/x86/boot/bzImage
make -f ./scripts/Makefile.build obj=arch/x86/boot/compressed arch/x86/boot/compressed/vmlinux
# CC arch/x86/boot/version.o
gcc -Wp,-MMD,arch/x86/boot/.version.o.d -nostdinc -I./arch/x86/include -I./arch/x86/include/generated -I./include -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -std=gnu11 -fms-extensions -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS -Wall -Wstrict-prototypes -march=i386 -mregparm=3 -fno-strict-aliasing -fomit-frame-pointer -fno-pic -mno-mmx -mno-sse -fcf-protection=none -ffreestanding -fno-stack-protector -Wno-address-of-packed-member -mpreferred-stack-boundary=2 -D_SETUP -fno-asynchronous-unwind-tables -Wimplicit-fallthrough=5 -DKBUILD_MODFILE='"arch/x86/boot/version"' -DKBUILD_BASENAME='"version"' -DKBUILD_MODNAME='"version"' -D__KBUILD_MODNAME=version -c -o arch/x86/boot/version.o arch/x86/boot/version.c
# CHECK arch/x86/boot/version.c
/labhome/mbloch/bin/sparse -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise -Wno-return-void -Wno-unknown-attribute -D__x86_64__ --arch=x86 -mlittle-endian -m64 -Wp,-MMD,arch/x86/boot/.version.o.d -nostdinc -I./arch/x86/include -I./arch/x86/include/generated -I./include -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -std=gnu11 -fms-extensions -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS -Wall -Wstrict-prototypes -march=i386 -mregparm=3 -fno-strict-aliasing -fomit-frame-pointer -fno-pic -mno-mmx -mno-sse -fcf-protection=none -ffreestanding -fno-stack-protector -Wno-address-of-packed-member -mpreferred-stack-boundary=2 -D_SETUP -fno-asynchronous-unwind-tables -Wimplicit-fallthrough=5 -DKBUILD_MODFILE='"arch/x86/boot/version"' -DKBUILD_BASENAME='"version"' -DKBUILD_MODNAME='"version"' -D__KBUILD_MODNAME=version arch/x86/boot/version.c
arch/x86/boot/version.c: note: in included file (through arch/x86/include/uapi/asm/bitsperlong.h, include/uapi/asm-generic/int-ll64.h, include/asm-generic/int-ll64.h, include/uapi/asm-generic/types.h, ...):
./include/asm-generic/bitsperlong.h:23:2: error: Inconsistent word size. Check asm/bitsperlong.h
./include/asm-generic/bitsperlong.h:27:33: error: static assertion failed: "Inconsistent word size. Check asm/bitsperlong.h"
# cmd_gen_symversions_c arch/x86/boot/version.o
if nm arch/x86/boot/version.o 2>/dev/null | grep -q ' __export_symbol_'; then gcc -E -D__GENKSYMS__ -Wp,-MMD,arch/x86/boot/.version.o.d -nostdinc -I./arch/x86/include -I./arch/x86/include/generated -I./include -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -std=gnu11 -fms-extensions -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS -Wall -Wstrict-prototypes -march=i386 -mregparm=3 -fno-strict-aliasing -fomit-frame-pointer -fno-pic -mno-mmx -mno-sse -fcf-protection=none -ffreestanding -fno-stack-protector -Wno-address-of-packed-member -mpreferred-stack-boundary=2 -D_SETUP -fno-asynchronous-unwind-tables -Wimplicit-fallthrough=5 -DKBUILD_MODFILE='"arch/x86/boot/version"' -DKBUILD_BASENAME='"version"' -DKBUILD_MODNAME='"version"' -D__KBUILD_MODNAME=version arch/x86/boot/version.c | ./scripts/genksyms/genksyms >> arch/x86/boot/.version.o.cmd; fi
# LD arch/x86/boot/setup.elf
ld -m elf_x86_64 -z noexecstack -m elf_i386 -z noexecstack -T arch/x86/boot/setup.ld arch/x86/boot/a20.o arch/x86/boot/bioscall.o arch/x86/boot/cmdline.o arch/x86/boot/copy.o arch/x86/boot/cpu.o arch/x86/boot/cpuflags.o arch/x86/boot/cpucheck.o arch/x86/boot/early_serial_console.o arch/x86/boot/edd.o arch/x86/boot/header.o arch/x86/boot/main.o arch/x86/boot/memory.o arch/x86/boot/pm.o arch/x86/boot/pmjump.o arch/x86/boot/printf.o arch/x86/boot/regs.o arch/x86/boot/string.o arch/x86/boot/tty.o arch/x86/boot/video.o arch/x86/boot/video-mode.o arch/x86/boot/version.o arch/x86/boot/video-vga.o arch/x86/boot/video-vesa.o arch/x86/boot/video-bios.o -o arch/x86/boot/setup.elf
# OBJCOPY arch/x86/boot/setup.bin
objcopy -O binary arch/x86/boot/setup.elf arch/x86/boot/setup.bin
# BUILD arch/x86/boot/bzImage
(dd if=arch/x86/boot/setup.bin bs=4k conv=sync status=none; cat arch/x86/boot/vmlinux.bin) >arch/x86/boot/bzImage
mkdir -p ./arch/x86_64/boot
ln -fsn ../../x86/boot/bzImage ./arch/x86_64/boot/bzImage

To me this looks like sparse is getting a conflicting set of flags.
The command line contains both "-D__x86_64__ -m64" and "-m16 -march=i386 -D_SETUP".

I confirmed that the following patch "fixes" the issue, but I do not know whether
this is the right fix. This area is outside my comfort zone, so it would be
helpful if someone more familiar with the x86 build/sparse flow could take a
look:

diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 3f9fb3698d66..80923864f6f9 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -71,6 +71,10 @@ $(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE

SETUP_OBJS = $(addprefix $(obj)/,$(setup-y))

+realmode-checkflags-$(CONFIG_X86_64) := -m32 -U__x86_64__ -D__i386__
+REALMODE_CHECKFLAGS := $(filter-out -m64 -D__x86_64__,$(CHECKFLAGS)) $(realmode-checkflags-y)
+$(SETUP_OBJS): CHECKFLAGS := $(REALMODE_CHECKFLAGS)
+
sed-zoffset := -e 's/^$[0-9a-fA-F]*$ [a-zA-Z] $startup_32\|efi.._stub_entry\|efi\(32$\?_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|_e\?data\|_e\?sbat\|z_.*\)$$/\#define ZO_\2 0x\1/p'

quiet_cmd_zoffset = ZOFFSET $@
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index a0fb39abc5c8..341b0ff20c3d 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -29,6 +29,10 @@ targets += $(realmode-y)

REALMODE_OBJS = $(addprefix $(obj)/,$(realmode-y))

+realmode-checkflags-$(CONFIG_X86_64) := -m32 -U__x86_64__ -D__i386__
+REALMODE_CHECKFLAGS := $(filter-out -m64 -D__x86_64__,$(CHECKFLAGS)) $(realmode-checkflags-y)
+$(REALMODE_OBJS): CHECKFLAGS := $(REALMODE_CHECKFLAGS)
+
sed-pasyms := -n -r -e 's/^([0-9a-fA-F]+) [ABCDGRSTVW] (.+)$$/pa_\2 = \2;/p'

quiet_cmd_pasyms = PASYMS $@