[RFC patch 08/19] bpf: Replace cant_sleep() with cant_migrate()

From: Thomas Gleixner
Date: Fri Feb 14 2020 - 11:45:52 EST


As already discussed in the previous change which introduced
BPF_RUN_PROG_PIN_ON_CPU() BPF only requires to disable migration to
guarantee per CPUness.

If RT substitutes the preempt disable based migration protection then the
cant_sleep() check will obviously trigger as preemption is not disabled.

Replace it by cant_migrate() which maps to cant_sleep() on a non RT kernel
and will verify that migration is disabled on a full RT kernel.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
include/linux/filter.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -561,7 +561,7 @@ DECLARE_STATIC_KEY_FALSE(bpf_stats_enabl

#define __BPF_PROG_RUN(prog, ctx, dfunc) ({ \
u32 ret; \
- cant_sleep(); \
+ cant_migrate(); \
if (static_branch_unlikely(&bpf_stats_enabled_key)) { \
struct bpf_prog_stats *stats; \
u64 start = sched_clock(); \