ebpf: migrate bpf_prog's flags to bitfield

As we need to add further flags to the bpf_prog structure, lets migrate
both bools to a bitfield representation. The size of the base structure
(excluding insns) remains unchanged at 40 bytes.

Add also tags for the kmemchecker, so that it doesn't throw false
positives. Even in case gcc would generate suboptimal code, it's not
being accessed in performance critical paths.

Signed-off-by: Daniel Borkmann <[e-mail]>
Acked-by: Alexei Starovoitov <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

arch/arm/net/bpf_jit_32.c

···
 
 	set_memory_ro((unsigned long)header, header->pages);
 	fp->bpf_func = (void *)ctx.target;
-	fp->jited = true;
+	fp->jited = 1;
 out:
 	kfree(ctx.offsets);
 	return;

arch/arm64/net/bpf_jit_comp.c

···
 
 	set_memory_ro((unsigned long)header, header->pages);
 	prog->bpf_func = (void *)ctx.image;
-	prog->jited = true;
+	prog->jited = 1;
 out:
 	kfree(ctx.offset);
 }

arch/mips/net/bpf_jit.c

···
 		bpf_jit_dump(fp->len, alloc_size, 2, ctx.target);
 
 	fp->bpf_func = (void *)ctx.target;
-	fp->jited = true;
+	fp->jited = 1;
 
 out:
 	kfree(ctx.offsets);

arch/powerpc/net/bpf_jit_comp.c

···
 		((u64 *)image)[1] = local_paca->kernel_toc;
 #endif
 		fp->bpf_func = (void *)image;
-		fp->jited = true;
+		fp->jited = 1;
 	}
 out:
 	kfree(addrs);

arch/s390/net/bpf_jit_comp.c

···
 	if (jit.prg_buf) {
 		set_memory_ro((unsigned long)header, header->pages);
 		fp->bpf_func = (void *) jit.prg_buf;
-		fp->jited = true;
+		fp->jited = 1;
 	}
 free_addrs:
 	kfree(jit.addrs);

arch/sparc/net/bpf_jit_comp.c

···
 	if (image) {
 		bpf_flush_icache(image, image + proglen);
 		fp->bpf_func = (void *)image;
-		fp->jited = true;
+		fp->jited = 1;
 	}
 out:
 	kfree(addrs);

arch/x86/net/bpf_jit_comp.c

···
 		bpf_flush_icache(header, image + proglen);
 		set_memory_ro((unsigned long)header, header->pages);
 		prog->bpf_func = (void *)image;
-		prog->jited = true;
+		prog->jited = 1;
 	}
 out:
 	kfree(addrs);

include/linux/filter.h

···
 
 struct bpf_prog {
 	u16			pages;		/* Number of allocated pages */
-	bool			jited;		/* Is our filter JIT'ed? */
-	bool			gpl_compatible;	/* Is our filter GPL compatible? */
+	kmemcheck_bitfield_begin(meta);
+	u16			jited:1,	/* Is our filter JIT'ed? */
+				gpl_compatible:1; /* Is filter GPL compatible? */
+	kmemcheck_bitfield_end(meta);
 	u32			len;		/* Number of filter blocks */
 	enum bpf_prog_type	type;		/* Type of BPF program */
 	struct bpf_prog_aux	*aux;		/* Auxiliary fields */

kernel/bpf/core.c

···
 	if (fp == NULL)
 		return NULL;
 
+	kmemcheck_annotate_bitfield(fp, meta);
+
 	aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
 	if (aux == NULL) {
 		vfree(fp);
···
 
 	fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
 	if (fp != NULL) {
+		kmemcheck_annotate_bitfield(fp, meta);
+
 		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
 		fp->pages = size / PAGE_SIZE;
 

kernel/bpf/syscall.c

···
 		goto free_prog;
 
 	prog->orig_prog = NULL;
-	prog->jited = false;
+	prog->jited = 0;
 
 	atomic_set(&prog->aux->refcnt, 1);
-	prog->gpl_compatible = is_gpl;
+	prog->gpl_compatible = is_gpl ? 1 : 0;
 
 	/* find program type: socket_filter vs tracing_filter */
 	err = find_prog_type(type, prog);

net/core/filter.c

···
 	int err;
 
 	fp->bpf_func = NULL;
-	fp->jited = false;
+	fp->jited = 0;
 
 	err = bpf_check_classic(fp->insns, fp->len);
 	if (err) {