[PATCH net-next] net: filter: constify detection of pkt_type_offset

[PATCH net-next] net: filter: constify detection of pkt_type_offset

[Hannes Frederic Sowa]

Currently we have 2 pkt_type_offset functions doing the same thing and
spread across the architecture files. Remove those and replace them
with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
zero sized sk_buff member right in front of the bitfield with offsetof.
This new offset marker does not change size of struct sk_buff.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
---
 arch/mips/net/bpf_jit.c      | 27 +--------------------------
 arch/s390/net/bpf_jit_comp.c | 35 +----------------------------------
 include/linux/skbuff.h       | 10 ++++++++++
 net/core/filter.c            | 26 +-------------------------
 4 files changed, 13 insertions(+), 85 deletions(-)

diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 0e97ccd..7edc083 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -765,27 +765,6 @@ static u64 jit_get_skb_w(struct sk_buff *skb, unsigned offset)
 	return (u64)err << 32 | ntohl(ret);
 }
 
-#ifdef __BIG_ENDIAN_BITFIELD
-#define PKT_TYPE_MAX	(7 << 5)
-#else
-#define PKT_TYPE_MAX	7
-#endif
-static int pkt_type_offset(void)
-{
-	struct sk_buff skb_probe = {
-		.pkt_type = ~0,
-	};
-	u8 *ct = (u8 *)&skb_probe;
-	unsigned int off;
-
-	for (off = 0; off < sizeof(struct sk_buff); off++) {
-		if (ct[off] == PKT_TYPE_MAX)
-			return off;
-	}
-	pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n");
-	return -1;
-}
-
 static int build_body(struct jit_ctx *ctx)
 {
 	void *load_func[] = {jit_get_skb_b, jit_get_skb_h, jit_get_skb_w};
@@ -1332,11 +1311,7 @@ jmp_cmp:
 		case BPF_ANC | SKF_AD_PKTTYPE:
 			ctx->flags |= SEEN_SKB;
 
-			off = pkt_type_offset();
-
-			if (off < 0)
-				return -1;
-			emit_load_byte(r_tmp, r_skb, off, ctx);
+			emit_load_byte(r_tmp, r_skb, PKT_TYPE_OFFSET(), ctx);
 			/* Keep only the last 3 bits */
 			emit_andi(r_A, r_tmp, PKT_TYPE_MAX, ctx);
 #ifdef __BIG_ENDIAN_BITFIELD
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 555f5c7..c52ac77 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -227,37 +227,6 @@ static void bpf_jit_epilogue(struct bpf_jit *jit)
 	EMIT2(0x07fe);
 }
 
-/* Helper to find the offset of pkt_type in sk_buff
- * Make sure its still a 3bit field starting at the MSBs within a byte.
- */
-#define PKT_TYPE_MAX 0xe0
-static int pkt_type_offset;
-
-static int __init bpf_pkt_type_offset_init(void)
-{
-	struct sk_buff skb_probe = {
-		.pkt_type = ~0,
-	};
-	char *ct = (char *)&skb_probe;
-	int off;
-
-	pkt_type_offset = -1;
-	for (off = 0; off < sizeof(struct sk_buff); off++) {
-		if (!ct[off])
-			continue;
-		if (ct[off] == PKT_TYPE_MAX)
-			pkt_type_offset = off;
-		else {
-			/* Found non matching bit pattern, fix needed. */
-			WARN_ON_ONCE(1);
-			pkt_type_offset = -1;
-			return -1;
-		}
-	}
-	return 0;
-}
-device_initcall(bpf_pkt_type_offset_init);
-
 /*
  * make sure we dont leak kernel information to user
  */
@@ -757,12 +726,10 @@ call_fn:	/* lg %r1,<d(function)>(%r13) */
 		}
 		break;
 	case BPF_ANC | SKF_AD_PKTTYPE:
-		if (pkt_type_offset < 0)
-			goto out;
 		/* lhi %r5,0 */
 		EMIT4(0xa7580000);
 		/* ic %r5,<d(pkt_type_offset)>(%r2) */
-		EMIT4_DISP(0x43502000, pkt_type_offset);
+		EMIT4_DISP(0x43502000, PKT_TYPE_OFFSET());
 		/* srl %r5,5 */
 		EMIT4_DISP(0x88500000, 5);
 		break;
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 07c9fdd..756e3d0 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -548,6 +548,16 @@ struct sk_buff {
 				ip_summed:2,
 				nohdr:1,
 				nfctinfo:3;
+
+/* if you move pkt_type around you also must adapt those constants */
+#ifdef __BIG_ENDIAN_BITFIELD
+#define PKT_TYPE_MAX	(7 << 5)
+#else
+#define PKT_TYPE_MAX	7
+#endif
+#define PKT_TYPE_OFFSET()	offsetof(struct sk_buff, __pkt_type_offset)
+
+	__u8			__pkt_type_offset[0];
 	__u8			pkt_type:3,
 				fclone:2,
 				ipvs_property:1,
diff --git a/net/core/filter.c b/net/core/filter.c
index dfc716f..6cdc303 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -87,30 +87,6 @@ int sk_filter(struct sock *sk, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(sk_filter);
 
-/* Helper to find the offset of pkt_type in sk_buff structure. We want
- * to make sure its still a 3bit field starting at a byte boundary;
- * taken from arch/x86/net/bpf_jit_comp.c.
- */
-#ifdef __BIG_ENDIAN_BITFIELD
-#define PKT_TYPE_MAX	(7 << 5)
-#else
-#define PKT_TYPE_MAX	7
-#endif
-static unsigned int pkt_type_offset(void)
-{
-	struct sk_buff skb_probe = { .pkt_type = ~0, };
-	u8 *ct = (u8 *) &skb_probe;
-	unsigned int off;
-
-	for (off = 0; off < sizeof(struct sk_buff); off++) {
-		if (ct[off] == PKT_TYPE_MAX)
-			return off;
-	}
-
-	pr_err_once("Please fix %s, as pkt_type couldn't be found!\n", __func__);
-	return -1;
-}
-
 static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
 {
 	return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
@@ -191,7 +167,7 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
 
 	case SKF_AD_OFF + SKF_AD_PKTTYPE:
 		*insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
-				    pkt_type_offset());
+				    PKT_TYPE_OFFSET());
 		if (insn->off < 0)
 			return false;
 		insn++;
-- 
1.9.3

Re: [PATCH net-next] net: filter: constify detection of pkt_type_offset

[Daniel Borkmann]

On 09/12/2014 12:22 PM, Hannes Frederic Sowa wrote:
> Currently we have 2 pkt_type_offset functions doing the same thing and
> spread across the architecture files. Remove those and replace them
> with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
> zero sized sk_buff member right in front of the bitfield with offsetof.
> This new offset marker does not change size of struct sk_buff.
>
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: Markos Chandras <markos.chandras@imgtec.com>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>

Thanks for doing this, Hannes!
...
>   static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
>   {
>   	return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
> @@ -191,7 +167,7 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
>
>   	case SKF_AD_OFF + SKF_AD_PKTTYPE:
>   		*insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
> -				    pkt_type_offset());
> +				    PKT_TYPE_OFFSET());
>   		if (insn->off < 0)
>   			return false;
>   		insn++;

I think this can now be rewritten as ...

	case SKF_AD_OFF + SKF_AD_PKTTYPE:
		*insn++ = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
				      PKT_TYPE_OFFSET());
		*insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX);

... since we are guaranteed to have always >0 insn->off and despite the
__s16 type in off we might be able to safely assume that sk_buff will
never get extended so far w/o fist fights first, where this could wrap
around. ;) Alternatively, perhaps a BUILD_BUG_ON() for really being
paranoid?

Re: [PATCH net-next] net: filter: constify detection of pkt_type_offset

[Hannes Frederic Sowa]

On Fr, 2014-09-12 at 12:55 +0200, Daniel Borkmann wrote:
> On 09/12/2014 12:22 PM, Hannes Frederic Sowa wrote:
> > Currently we have 2 pkt_type_offset functions doing the same thing and
> > spread across the architecture files. Remove those and replace them
> > with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
> > zero sized sk_buff member right in front of the bitfield with offsetof.
> > This new offset marker does not change size of struct sk_buff.
> >
> > Cc: Eric Dumazet <eric.dumazet@gmail.com>
> > Cc: Markos Chandras <markos.chandras@imgtec.com>
> > Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> > Cc: Daniel Borkmann <dborkman@redhat.com>
> > Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
> > Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
> > Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> 
> Thanks for doing this, Hannes!
> ...
> >   static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
> >   {
> >   	return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
> > @@ -191,7 +167,7 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
> >
> >   	case SKF_AD_OFF + SKF_AD_PKTTYPE:
> >   		*insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
> > -				    pkt_type_offset());
> > +				    PKT_TYPE_OFFSET());
> >   		if (insn->off < 0)
> >   			return false;
> >   		insn++;
> 
> I think this can now be rewritten as ...
> 
> 	case SKF_AD_OFF + SKF_AD_PKTTYPE:
> 		*insn++ = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
> 				      PKT_TYPE_OFFSET());
> 		*insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX);
> 
> ... since we are guaranteed to have always >0 insn->off and despite the
> __s16 type in off we might be able to safely assume that sk_buff will
> never get extended so far w/o fist fights first, where this could wrap
> around. ;) Alternatively, perhaps a BUILD_BUG_ON() for really being
> paranoid?

Ok, but in a follow-up patch?

Thanks,
Hannes

Re: [PATCH net-next] net: filter: constify detection of pkt_type_offset

[Daniel Borkmann]

On 09/12/2014 01:18 PM, Hannes Frederic Sowa wrote:
> On Fr, 2014-09-12 at 12:55 +0200, Daniel Borkmann wrote:
>> On 09/12/2014 12:22 PM, Hannes Frederic Sowa wrote:
>>> Currently we have 2 pkt_type_offset functions doing the same thing and
>>> spread across the architecture files. Remove those and replace them
>>> with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
>>> zero sized sk_buff member right in front of the bitfield with offsetof.
>>> This new offset marker does not change size of struct sk_buff.
>>>
>>> Cc: Eric Dumazet <eric.dumazet@gmail.com>
>>> Cc: Markos Chandras <markos.chandras@imgtec.com>
>>> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
>>> Cc: Daniel Borkmann <dborkman@redhat.com>
>>> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
>>> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
>>> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
>>
>> Thanks for doing this, Hannes!
>> ...
>>>    static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
>>>    {
>>>    	return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
>>> @@ -191,7 +167,7 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
>>>
>>>    	case SKF_AD_OFF + SKF_AD_PKTTYPE:
>>>    		*insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
>>> -				    pkt_type_offset());
>>> +				    PKT_TYPE_OFFSET());
>>>    		if (insn->off < 0)
>>>    			return false;
>>>    		insn++;
>>
>> I think this can now be rewritten as ...
>>
>> 	case SKF_AD_OFF + SKF_AD_PKTTYPE:
>> 		*insn++ = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
>> 				      PKT_TYPE_OFFSET());
>> 		*insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX);
>>
>> ... since we are guaranteed to have always >0 insn->off and despite the
>> __s16 type in off we might be able to safely assume that sk_buff will
>> never get extended so far w/o fist fights first, where this could wrap
>> around. ;) Alternatively, perhaps a BUILD_BUG_ON() for really being
>> paranoid?
>
> Ok, but in a follow-up patch?

I'm fine if you want to propose that in a follow-up, sure.

[PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Hannes Frederic Sowa]

Currently we have 2 pkt_type_offset functions doing the same thing and
spread across the architecture files. Remove those and replace them
with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
zero sized sk_buff member right in front of the bitfield with offsetof.
This new offset marker does not change size of struct sk_buff.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
---

v2) Incorporated Daniel's feedback. I first misinterpreted the feedback
    as something not related to pkt_type_offset.

 arch/mips/net/bpf_jit.c      | 27 +--------------------------
 arch/s390/net/bpf_jit_comp.c | 35 +----------------------------------
 include/linux/skbuff.h       | 10 ++++++++++
 net/core/filter.c            | 31 ++-----------------------------
 4 files changed, 14 insertions(+), 89 deletions(-)

diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 0e97ccd..7edc083 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -765,27 +765,6 @@ static u64 jit_get_skb_w(struct sk_buff *skb, unsigned offset)
 	return (u64)err << 32 | ntohl(ret);
 }
 
-#ifdef __BIG_ENDIAN_BITFIELD
-#define PKT_TYPE_MAX	(7 << 5)
-#else
-#define PKT_TYPE_MAX	7
-#endif
-static int pkt_type_offset(void)
-{
-	struct sk_buff skb_probe = {
-		.pkt_type = ~0,
-	};
-	u8 *ct = (u8 *)&skb_probe;
-	unsigned int off;
-
-	for (off = 0; off < sizeof(struct sk_buff); off++) {
-		if (ct[off] == PKT_TYPE_MAX)
-			return off;
-	}
-	pr_err_once("Please fix pkt_type_offset(), as pkt_type couldn't be found\n");
-	return -1;
-}
-
 static int build_body(struct jit_ctx *ctx)
 {
 	void *load_func[] = {jit_get_skb_b, jit_get_skb_h, jit_get_skb_w};
@@ -1332,11 +1311,7 @@ jmp_cmp:
 		case BPF_ANC | SKF_AD_PKTTYPE:
 			ctx->flags |= SEEN_SKB;
 
-			off = pkt_type_offset();
-
-			if (off < 0)
-				return -1;
-			emit_load_byte(r_tmp, r_skb, off, ctx);
+			emit_load_byte(r_tmp, r_skb, PKT_TYPE_OFFSET(), ctx);
 			/* Keep only the last 3 bits */
 			emit_andi(r_A, r_tmp, PKT_TYPE_MAX, ctx);
 #ifdef __BIG_ENDIAN_BITFIELD
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 555f5c7..c52ac77 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -227,37 +227,6 @@ static void bpf_jit_epilogue(struct bpf_jit *jit)
 	EMIT2(0x07fe);
 }
 
-/* Helper to find the offset of pkt_type in sk_buff
- * Make sure its still a 3bit field starting at the MSBs within a byte.
- */
-#define PKT_TYPE_MAX 0xe0
-static int pkt_type_offset;
-
-static int __init bpf_pkt_type_offset_init(void)
-{
-	struct sk_buff skb_probe = {
-		.pkt_type = ~0,
-	};
-	char *ct = (char *)&skb_probe;
-	int off;
-
-	pkt_type_offset = -1;
-	for (off = 0; off < sizeof(struct sk_buff); off++) {
-		if (!ct[off])
-			continue;
-		if (ct[off] == PKT_TYPE_MAX)
-			pkt_type_offset = off;
-		else {
-			/* Found non matching bit pattern, fix needed. */
-			WARN_ON_ONCE(1);
-			pkt_type_offset = -1;
-			return -1;
-		}
-	}
-	return 0;
-}
-device_initcall(bpf_pkt_type_offset_init);
-
 /*
  * make sure we dont leak kernel information to user
  */
@@ -757,12 +726,10 @@ call_fn:	/* lg %r1,<d(function)>(%r13) */
 		}
 		break;
 	case BPF_ANC | SKF_AD_PKTTYPE:
-		if (pkt_type_offset < 0)
-			goto out;
 		/* lhi %r5,0 */
 		EMIT4(0xa7580000);
 		/* ic %r5,<d(pkt_type_offset)>(%r2) */
-		EMIT4_DISP(0x43502000, pkt_type_offset);
+		EMIT4_DISP(0x43502000, PKT_TYPE_OFFSET());
 		/* srl %r5,5 */
 		EMIT4_DISP(0x88500000, 5);
 		break;
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 07c9fdd..756e3d0 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -548,6 +548,16 @@ struct sk_buff {
 				ip_summed:2,
 				nohdr:1,
 				nfctinfo:3;
+
+/* if you move pkt_type around you also must adapt those constants */
+#ifdef __BIG_ENDIAN_BITFIELD
+#define PKT_TYPE_MAX	(7 << 5)
+#else
+#define PKT_TYPE_MAX	7
+#endif
+#define PKT_TYPE_OFFSET()	offsetof(struct sk_buff, __pkt_type_offset)
+
+	__u8			__pkt_type_offset[0];
 	__u8			pkt_type:3,
 				fclone:2,
 				ipvs_property:1,
diff --git a/net/core/filter.c b/net/core/filter.c
index dfc716f..601f28d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -87,30 +87,6 @@ int sk_filter(struct sock *sk, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(sk_filter);
 
-/* Helper to find the offset of pkt_type in sk_buff structure. We want
- * to make sure its still a 3bit field starting at a byte boundary;
- * taken from arch/x86/net/bpf_jit_comp.c.
- */
-#ifdef __BIG_ENDIAN_BITFIELD
-#define PKT_TYPE_MAX	(7 << 5)
-#else
-#define PKT_TYPE_MAX	7
-#endif
-static unsigned int pkt_type_offset(void)
-{
-	struct sk_buff skb_probe = { .pkt_type = ~0, };
-	u8 *ct = (u8 *) &skb_probe;
-	unsigned int off;
-
-	for (off = 0; off < sizeof(struct sk_buff); off++) {
-		if (ct[off] == PKT_TYPE_MAX)
-			return off;
-	}
-
-	pr_err_once("Please fix %s, as pkt_type couldn't be found!\n", __func__);
-	return -1;
-}
-
 static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
 {
 	return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
@@ -190,11 +166,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
 		break;
 
 	case SKF_AD_OFF + SKF_AD_PKTTYPE:
-		*insn = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
-				    pkt_type_offset());
-		if (insn->off < 0)
-			return false;
-		insn++;
+		*insn++ = BPF_LDX_MEM(BPF_B, BPF_REG_A, BPF_REG_CTX,
+				      PKT_TYPE_OFFSET());
 		*insn = BPF_ALU32_IMM(BPF_AND, BPF_REG_A, PKT_TYPE_MAX);
 #ifdef __BIG_ENDIAN_BITFIELD
 		insn++;
-- 
1.9.3

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Alexei Starovoitov]

On Fri, Sep 12, 2014 at 02:04:43PM +0200, Hannes Frederic Sowa wrote:
> Currently we have 2 pkt_type_offset functions doing the same thing and
> spread across the architecture files. Remove those and replace them
> with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
> zero sized sk_buff member right in front of the bitfield with offsetof.
> This new offset marker does not change size of struct sk_buff.
> 
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: Markos Chandras <markos.chandras@imgtec.com>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> ---
> 
> v2) Incorporated Daniel's feedback. I first misinterpreted the feedback
>     as something not related to pkt_type_offset.

Thanks! It's a nice cleanup.

Acked-by: Alexei Starovoitov <ast@plumgrid.com>

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Cong Wang]

On Fri, Sep 12, 2014 at 9:06 AM, Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
> On Fri, Sep 12, 2014 at 02:04:43PM +0200, Hannes Frederic Sowa wrote:
>> Currently we have 2 pkt_type_offset functions doing the same thing and
>> spread across the architecture files. Remove those and replace them
>> with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
>> zero sized sk_buff member right in front of the bitfield with offsetof.
>> This new offset marker does not change size of struct sk_buff.
>>
>> Cc: Eric Dumazet <eric.dumazet@gmail.com>
>> Cc: Markos Chandras <markos.chandras@imgtec.com>
>> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
>> Cc: Daniel Borkmann <dborkman@redhat.com>
>> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
>> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
>> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
>> ---
>>
>> v2) Incorporated Daniel's feedback. I first misinterpreted the feedback
>>     as something not related to pkt_type_offset.
>
> Thanks! It's a nice cleanup.
>
> Acked-by: Alexei Starovoitov <ast@plumgrid.com>

Wait... Isn't there a same patch before?

http://www.spinics.net/lists/netdev/msg294839.html

Maybe not exactly the same, but roughly same from the stats....

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Hannes Frederic Sowa]

On Fr, 2014-09-12 at 10:06 -0700, Cong Wang wrote:
> On Fri, Sep 12, 2014 at 9:06 AM, Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
> > On Fri, Sep 12, 2014 at 02:04:43PM +0200, Hannes Frederic Sowa wrote:
> >> Currently we have 2 pkt_type_offset functions doing the same thing and
> >> spread across the architecture files. Remove those and replace them
> >> with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
> >> zero sized sk_buff member right in front of the bitfield with offsetof.
> >> This new offset marker does not change size of struct sk_buff.
> >>
> >> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> >> Cc: Markos Chandras <markos.chandras@imgtec.com>
> >> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> >> Cc: Daniel Borkmann <dborkman@redhat.com>
> >> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
> >> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
> >> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> >> ---
> >>
> >> v2) Incorporated Daniel's feedback. I first misinterpreted the feedback
> >>     as something not related to pkt_type_offset.
> >
> > Thanks! It's a nice cleanup.
> >
> > Acked-by: Alexei Starovoitov <ast@plumgrid.com>
> 
> Wait... Isn't there a same patch before?
> 
> http://www.spinics.net/lists/netdev/msg294839.html
> 
> Maybe not exactly the same, but roughly same from the stats....

Sure, he asked me to send it and I included his signed-off. I think I
did that correctly?

Bye,
Hannes

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Cong Wang]

On Fri, Sep 12, 2014 at 10:09 AM, Hannes Frederic Sowa
<hannes@stressinduktion.org> wrote:
>
> Sure, he asked me to send it and I included his signed-off. I think I
> did that correctly?
>

Maybe you should add v3 in case people like me get confused. :)

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Hannes Frederic Sowa]

On Fr, 2014-09-12 at 10:12 -0700, Cong Wang wrote:
> On Fri, Sep 12, 2014 at 10:09 AM, Hannes Frederic Sowa
> <hannes@stressinduktion.org> wrote:
> >
> > Sure, he asked me to send it and I included his signed-off. I think I
> > did that correctly?
> >
> 
> Maybe you should add v3 in case people like me get confused. :)

Oh, sorry. I looked in patchworks for the next version number and missed
the v2 submission. My bad, this should be submission v3. I think it is
ok, since the other versions already went out of review state.

Thanks for spotting,
Hannes

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Cong Wang]

On Fri, Sep 12, 2014 at 10:17 AM, Hannes Frederic Sowa
<hannes@stressinduktion.org> wrote:
> On Fr, 2014-09-12 at 10:12 -0700, Cong Wang wrote:
>> On Fri, Sep 12, 2014 at 10:09 AM, Hannes Frederic Sowa
>> <hannes@stressinduktion.org> wrote:
>> >
>> > Sure, he asked me to send it and I included his signed-off. I think I
>> > did that correctly?
>> >
>>
>> Maybe you should add v3 in case people like me get confused. :)
>
> Oh, sorry. I looked in patchworks for the next version number and missed
> the v2 submission. My bad, this should be submission v3. I think it is
> ok, since the other versions already went out of review state.
>

Don't worry, it is not a big deal at all, unless DaveM gets confused too.

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[David Miller]

From: Cong Wang <cwang@twopensource.com>
Date: Fri, 12 Sep 2014 10:47:54 -0700

> Don't worry, it is not a big deal at all, unless DaveM gets confused too.

DaveM is always confused.

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Daniel Borkmann]

On 09/12/2014 07:06 PM, Cong Wang wrote:
> On Fri, Sep 12, 2014 at 9:06 AM, Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
>> On Fri, Sep 12, 2014 at 02:04:43PM +0200, Hannes Frederic Sowa wrote:
>>> Currently we have 2 pkt_type_offset functions doing the same thing and
>>> spread across the architecture files. Remove those and replace them
>>> with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
>>> zero sized sk_buff member right in front of the bitfield with offsetof.
>>> This new offset marker does not change size of struct sk_buff.
>>>
>>> Cc: Eric Dumazet <eric.dumazet@gmail.com>
>>> Cc: Markos Chandras <markos.chandras@imgtec.com>
>>> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
>>> Cc: Daniel Borkmann <dborkman@redhat.com>
>>> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
>>> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
>>> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
>>> ---
>>>
>>> v2) Incorporated Daniel's feedback. I first misinterpreted the feedback
>>>      as something not related to pkt_type_offset.
>>
>> Thanks! It's a nice cleanup.
>>
>> Acked-by: Alexei Starovoitov <ast@plumgrid.com>
>
> Wait... Isn't there a same patch before?
>
> http://www.spinics.net/lists/netdev/msg294839.html
>
> Maybe not exactly the same, but roughly same from the stats....

Yes, this is what the whole discussion is about, to unify it to a
central place.

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[Daniel Borkmann]

On 09/12/2014 02:04 PM, Hannes Frederic Sowa wrote:
> Currently we have 2 pkt_type_offset functions doing the same thing and
> spread across the architecture files. Remove those and replace them
> with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
> zero sized sk_buff member right in front of the bitfield with offsetof.
> This new offset marker does not change size of struct sk_buff.
>
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: Markos Chandras <markos.chandras@imgtec.com>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>

Looks good to me, thanks!

Acked-by: Daniel Borkmann <dborkman@redhat.com>

Re: [PATCH net-next v2] net: filter: constify detection of pkt_type_offset

[David Miller]

From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Fri, 12 Sep 2014 14:04:43 +0200

> Currently we have 2 pkt_type_offset functions doing the same thing and
> spread across the architecture files. Remove those and replace them
> with a PKT_TYPE_OFFSET macro helper which gets the constant value from a
> zero sized sk_buff member right in front of the bitfield with offsetof.
> This new offset marker does not change size of struct sk_buff.
> 
> Cc: Eric Dumazet <eric.dumazet@gmail.com>
> Cc: Markos Chandras <markos.chandras@imgtec.com>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
> Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
> ---
> 
> v2) Incorporated Daniel's feedback. I first misinterpreted the feedback
>     as something not related to pkt_type_offset.

Applied, thanks.