Re: [PATCH V3 2/3] ARM: net: bpf_jit: make code generation lessdependent on struct sk_filter.

From: Andrew Morton
Date: Fri Apr 26 2013 - 15:26:10 EST


On Fri, 26 Apr 2013 16:04:44 +0200 Arnd Bergmann <arnd@xxxxxxxx> wrote:

> On Wednesday 24 April 2013 19:27:08 Nicolas Schichan wrote:
> > @@ -858,7 +858,7 @@ b_epilogue:
> > }
> >
> >
> > -void bpf_jit_compile(struct sk_filter *fp)
> > +static void __bpf_jit_compile(struct jit_ctx *out_ctx)
> > {
> > struct jit_ctx ctx;
> > unsigned tmp_idx;
> > @@ -867,11 +867,10 @@ void bpf_jit_compile(struct sk_filter *fp)
> > if (!bpf_jit_enable)
> > return;
> >
> > - memset(&ctx, 0, sizeof(ctx));
> > - ctx.skf = fp;
> > + ctx = *out_ctx;
> > ctx.ret0_fp_idx = -1;
> >
> > - ctx.offsets = kzalloc(4 * (ctx.skf->len + 1), GFP_KERNEL);
> > + ctx.offsets = kzalloc(4 * (ctx.prog_len + 1), GFP_KERNEL);
> > if (ctx.offsets == NULL)
> > return;
> >
> > @@ -921,13 +920,26 @@ void bpf_jit_compile(struct sk_filter *fp)
> > print_hex_dump(KERN_INFO, "BPF JIT code: ",
> > DUMP_PREFIX_ADDRESS, 16, 4, ctx.target,
> > alloc_size, false);
> > -
> > - fp->bpf_func = (void *)ctx.target;
> > out:
> > kfree(ctx.offsets);
> > +
> > + *out_ctx = ctx;
> > return;
>
> This part of the patch, in combination with 79617801e "filter: bpf_jit_comp:
> refactor and unify BPF JIT image dump output" is now causing build errors
> in linux-next:
>
> arch/arm/net/bpf_jit_32.c: In function '__bpf_jit_compile':
> arch/arm/net/bpf_jit_32.c:930:16: error: 'fp' undeclared (first use in this function)
> bpf_jit_dump(fp->len, alloc_size, 2, ctx.target);

Thanks, I did this. There may be a smarter way...

--- a/arch/arm/net/bpf_jit_32.c~arm-net-bpf_jit-make-code-generation-less-dependent-on-struct-sk_filter-fix
+++ a/arch/arm/net/bpf_jit_32.c
@@ -858,7 +858,7 @@ b_epilogue:
}


-static void __bpf_jit_compile(struct jit_ctx *out_ctx)
+static void __bpf_jit_compile(struct sk_filter *fp, struct jit_ctx *out_ctx)
{
struct jit_ctx ctx;
unsigned tmp_idx;
@@ -934,7 +934,7 @@ void bpf_jit_compile(struct sk_filter *f
ctx.prog_len = fp->len;
ctx.prog_insns = fp->insns;

- __bpf_jit_compile(&ctx);
+ __bpf_jit_compile(fp, &ctx);
if (ctx.target)
fp->bpf_func = (void *)ctx.target;
}
_

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