diff mbox series

[net-next] net: Move skb decrypted field, avoid explicity copy

Message ID d277733a2eb3b5ffa2cbdbe4bd2a261d8fb60a0f.1531811764.git.sbrivio@redhat.com
State Changes Requested, archived
Delegated to: David Miller
Headers show
Series [net-next] net: Move skb decrypted field, avoid explicity copy | expand

Commit Message

Stefano Brivio July 17, 2018, 7:18 a.m. UTC
Commit 784abe24c903 ("net: Add decrypted field to skb")
introduced a 'decrypted' field that is explicitly copied on skb
copy and clone.

Move it between headers_start[0] and headers_end[0], so that we
don't need to copy it explicitly as it's copied by the memcpy()
in __copy_skb_header().

While at it, drop the assignment in __skb_clone(), it was
already redundant.

This doesn't change the size of sk_buff or cacheline boundaries.

The 15-bits hole before tc_index becomes a 14-bits hole, and
will be again a 15-bits hole when this change is merged with
commit 8b7008620b84 ("net: Don't copy pfmemalloc flag in
__copy_skb_header()").

Fixes: 784abe24c903 ("net: Add decrypted field to skb")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
 include/linux/skbuff.h | 9 ++++-----
 net/core/skbuff.c      | 9 +++------
 2 files changed, 7 insertions(+), 11 deletions(-)

Comments

kernel test robot July 17, 2018, 8:18 a.m. UTC | #1
Hi Stefano,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Stefano-Brivio/net-Move-skb-decrypted-field-avoid-explicity-copy/20180717-152125
config: ia64-allmodconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 8.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=8.1.0 make.cross ARCH=ia64 

All errors (new ones prefixed by >>):

   In file included from include/linux/kernel.h:10,
                    from include/linux/list.h:9,
                    from include/linux/module.h:9,
                    from net//core/skbuff.c:41:
   net//core/skbuff.c: In function '__copy_skb_header':
>> net//core/skbuff.c:787:31: error: attempt to take address of bit-field structure member 'decrypted'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) <  \
                                  ^~~~~~~
   include/linux/compiler.h:316:19: note: in definition of macro '__compiletime_assert'
      bool __cond = !(condition);    \
                      ^~~~~~~~~
   include/linux/compiler.h:339:2: note: in expansion of macro '_compiletime_assert'
     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
     ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:45:37: note: in expansion of macro 'compiletime_assert'
    #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                        ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:69:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
     BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
     ^~~~~~~~~~~~~~~~
   net//core/skbuff.c:787:2: note: in expansion of macro 'BUILD_BUG_ON'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) <  \
     ^~~~~~~~~~~~
   include/linux/stddef.h:17:32: note: in expansion of macro '__compiler_offsetof'
    #define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE, MEMBER)
                                   ^~~~~~~~~~~~~~~~~~~
   net//core/skbuff.c:787:15: note: in expansion of macro 'offsetof'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) <  \
                  ^~~~~~~~
   net//core/skbuff.c:837:2: note: in expansion of macro 'CHECK_SKB_FIELD'
     CHECK_SKB_FIELD(decrypted);
     ^~~~~~~~~~~~~~~
   net//core/skbuff.c:789:31: error: attempt to take address of bit-field structure member 'decrypted'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) >  \
                                  ^~~~~~~
   include/linux/compiler.h:316:19: note: in definition of macro '__compiletime_assert'
      bool __cond = !(condition);    \
                      ^~~~~~~~~
   include/linux/compiler.h:339:2: note: in expansion of macro '_compiletime_assert'
     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
     ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:45:37: note: in expansion of macro 'compiletime_assert'
    #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                        ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:69:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
     BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
     ^~~~~~~~~~~~~~~~
   net//core/skbuff.c:789:2: note: in expansion of macro 'BUILD_BUG_ON'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) >  \
     ^~~~~~~~~~~~
   include/linux/stddef.h:17:32: note: in expansion of macro '__compiler_offsetof'
    #define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE, MEMBER)
                                   ^~~~~~~~~~~~~~~~~~~
   net//core/skbuff.c:789:15: note: in expansion of macro 'offsetof'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) >  \
                  ^~~~~~~~
   net//core/skbuff.c:837:2: note: in expansion of macro 'CHECK_SKB_FIELD'
     CHECK_SKB_FIELD(decrypted);
     ^~~~~~~~~~~~~~~

vim +/decrypted +787 net//core/skbuff.c

795bb1c0 Jesper Dangaard Brouer 2016-02-08  784  
b1937227 Eric Dumazet           2014-09-28  785  /* Make sure a field is enclosed inside headers_start/headers_end section */
b1937227 Eric Dumazet           2014-09-28  786  #define CHECK_SKB_FIELD(field) \
b1937227 Eric Dumazet           2014-09-28 @787  	BUILD_BUG_ON(offsetof(struct sk_buff, field) <		\
b1937227 Eric Dumazet           2014-09-28  788  		     offsetof(struct sk_buff, headers_start));	\
b1937227 Eric Dumazet           2014-09-28  789  	BUILD_BUG_ON(offsetof(struct sk_buff, field) >		\
b1937227 Eric Dumazet           2014-09-28  790  		     offsetof(struct sk_buff, headers_end));	\
b1937227 Eric Dumazet           2014-09-28  791  

:::::: The code at line 787 was first introduced by commit
:::::: b1937227316417aa7568d01e6fa1f272e98fb890 net: reorganize sk_buff for faster __copy_skb_header()

:::::: TO: Eric Dumazet <edumazet@google.com>
:::::: CC: David S. Miller <davem@davemloft.net>

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kernel test robot July 17, 2018, 9:25 a.m. UTC | #2
Hi Stefano,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Stefano-Brivio/net-Move-skb-decrypted-field-avoid-explicity-copy/20180717-152125
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-16) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   In file included from include/linux/kernel.h:10:0,
                    from include/linux/list.h:9,
                    from include/linux/module.h:9,
                    from net//core/skbuff.c:41:
   net//core/skbuff.c: In function '__copy_skb_header':
   net//core/skbuff.c:787:31: error: attempt to take address of bit-field structure member 'decrypted'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) <  \
                                  ^
   include/linux/compiler.h:316:19: note: in definition of macro '__compiletime_assert'
      bool __cond = !(condition);    \
                      ^~~~~~~~~
   include/linux/compiler.h:339:2: note: in expansion of macro '_compiletime_assert'
     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
     ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:45:37: note: in expansion of macro 'compiletime_assert'
    #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                        ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:69:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
     BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
     ^~~~~~~~~~~~~~~~
>> net//core/skbuff.c:787:2: note: in expansion of macro 'BUILD_BUG_ON'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) <  \
     ^~~~~~~~~~~~
   include/linux/stddef.h:17:32: note: in expansion of macro '__compiler_offsetof'
    #define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE, MEMBER)
                                   ^~~~~~~~~~~~~~~~~~~
>> net//core/skbuff.c:787:15: note: in expansion of macro 'offsetof'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) <  \
                  ^~~~~~~~
>> net//core/skbuff.c:837:2: note: in expansion of macro 'CHECK_SKB_FIELD'
     CHECK_SKB_FIELD(decrypted);
     ^~~~~~~~~~~~~~~
   net//core/skbuff.c:789:31: error: attempt to take address of bit-field structure member 'decrypted'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) >  \
                                  ^
   include/linux/compiler.h:316:19: note: in definition of macro '__compiletime_assert'
      bool __cond = !(condition);    \
                      ^~~~~~~~~
   include/linux/compiler.h:339:2: note: in expansion of macro '_compiletime_assert'
     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
     ^~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:45:37: note: in expansion of macro 'compiletime_assert'
    #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                        ^~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:69:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
     BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
     ^~~~~~~~~~~~~~~~
   net//core/skbuff.c:789:2: note: in expansion of macro 'BUILD_BUG_ON'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) >  \
     ^~~~~~~~~~~~
   include/linux/stddef.h:17:32: note: in expansion of macro '__compiler_offsetof'
    #define offsetof(TYPE, MEMBER) __compiler_offsetof(TYPE, MEMBER)
                                   ^~~~~~~~~~~~~~~~~~~
   net//core/skbuff.c:789:15: note: in expansion of macro 'offsetof'
     BUILD_BUG_ON(offsetof(struct sk_buff, field) >  \
                  ^~~~~~~~
>> net//core/skbuff.c:837:2: note: in expansion of macro 'CHECK_SKB_FIELD'
     CHECK_SKB_FIELD(decrypted);
     ^~~~~~~~~~~~~~~

vim +/CHECK_SKB_FIELD +837 net//core/skbuff.c

   784	
   785	/* Make sure a field is enclosed inside headers_start/headers_end section */
   786	#define CHECK_SKB_FIELD(field) \
 > 787		BUILD_BUG_ON(offsetof(struct sk_buff, field) <		\
   788			     offsetof(struct sk_buff, headers_start));	\
   789		BUILD_BUG_ON(offsetof(struct sk_buff, field) >		\
   790			     offsetof(struct sk_buff, headers_end));	\
   791	
   792	static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
   793	{
   794		new->tstamp		= old->tstamp;
   795		/* We do not copy old->sk */
   796		new->dev		= old->dev;
   797		memcpy(new->cb, old->cb, sizeof(old->cb));
   798		skb_dst_copy(new, old);
   799	#ifdef CONFIG_XFRM
   800		new->sp			= secpath_get(old->sp);
   801	#endif
   802		__nf_copy(new, old, false);
   803	
   804		/* Note : this field could be in headers_start/headers_end section
   805		 * It is not yet because we do not want to have a 16 bit hole
   806		 */
   807		new->queue_mapping = old->queue_mapping;
   808	
   809		memcpy(&new->headers_start, &old->headers_start,
   810		       offsetof(struct sk_buff, headers_end) -
   811		       offsetof(struct sk_buff, headers_start));
   812		CHECK_SKB_FIELD(protocol);
   813		CHECK_SKB_FIELD(csum);
   814		CHECK_SKB_FIELD(hash);
   815		CHECK_SKB_FIELD(priority);
   816		CHECK_SKB_FIELD(skb_iif);
   817		CHECK_SKB_FIELD(vlan_proto);
   818		CHECK_SKB_FIELD(vlan_tci);
   819		CHECK_SKB_FIELD(transport_header);
   820		CHECK_SKB_FIELD(network_header);
   821		CHECK_SKB_FIELD(mac_header);
   822		CHECK_SKB_FIELD(inner_protocol);
   823		CHECK_SKB_FIELD(inner_transport_header);
   824		CHECK_SKB_FIELD(inner_network_header);
   825		CHECK_SKB_FIELD(inner_mac_header);
   826		CHECK_SKB_FIELD(mark);
   827	#ifdef CONFIG_NETWORK_SECMARK
   828		CHECK_SKB_FIELD(secmark);
   829	#endif
   830	#ifdef CONFIG_NET_RX_BUSY_POLL
   831		CHECK_SKB_FIELD(napi_id);
   832	#endif
   833	#ifdef CONFIG_XPS
   834		CHECK_SKB_FIELD(sender_cpu);
   835	#endif
   836	#ifdef CONFIG_TLS_DEVICE
 > 837		CHECK_SKB_FIELD(decrypted);
   838	#endif
   839	#ifdef CONFIG_NET_SCHED
   840		CHECK_SKB_FIELD(tc_index);
   841	#endif
   842	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
diff mbox series

Patch

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 3ceb8dcc54da..14bc9ebe30f2 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -630,7 +630,6 @@  typedef unsigned char *sk_buff_data_t;
  *	@hash: the packet hash
  *	@queue_mapping: Queue mapping for multiqueue devices
  *	@xmit_more: More SKBs are pending for this queue
- *	@decrypted: Decrypted SKB
  *	@ndisc_nodetype: router type (from link layer)
  *	@ooo_okay: allow the mapping of a socket to a queue to be changed
  *	@l4_hash: indicate hash is a canonical 4-tuple hash over transport
@@ -641,6 +640,7 @@  typedef unsigned char *sk_buff_data_t;
  *	@no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS
  *	@csum_not_inet: use CRC32c to resolve CHECKSUM_PARTIAL
  *	@dst_pending_confirm: need to confirm neighbour
+ *	@decrypted: Decrypted SKB
   *	@napi_id: id of the NAPI struct this skb came from
  *	@secmark: security marking
  *	@mark: Generic packet mark
@@ -737,11 +737,7 @@  struct sk_buff {
 				peeked:1,
 				head_frag:1,
 				xmit_more:1,
-#ifdef CONFIG_TLS_DEVICE
-				decrypted:1;
-#else
 				__unused:1;
-#endif
 
 	/* fields enclosed in headers_start/headers_end are copied
 	 * using a single memcpy() in __copy_skb_header()
@@ -797,6 +793,9 @@  struct sk_buff {
 	__u8			tc_redirected:1;
 	__u8			tc_from_ingress:1;
 #endif
+#ifdef CONFIG_TLS_DEVICE
+	__u8			decrypted:1;
+#endif
 
 #ifdef CONFIG_NET_SCHED
 	__u16			tc_index;	/* traffic control index */
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index cfd6c6f35f9c..b8a563b2d2df 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -805,9 +805,6 @@  static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 	 * It is not yet because we do not want to have a 16 bit hole
 	 */
 	new->queue_mapping = old->queue_mapping;
-#ifdef CONFIG_TLS_DEVICE
-	new->decrypted = old->decrypted;
-#endif
 
 	memcpy(&new->headers_start, &old->headers_start,
 	       offsetof(struct sk_buff, headers_end) -
@@ -836,6 +833,9 @@  static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 #ifdef CONFIG_XPS
 	CHECK_SKB_FIELD(sender_cpu);
 #endif
+#ifdef CONFIG_TLS_DEVICE
+	CHECK_SKB_FIELD(decrypted);
+#endif
 #ifdef CONFIG_NET_SCHED
 	CHECK_SKB_FIELD(tc_index);
 #endif
@@ -868,9 +868,6 @@  static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb)
 	C(head_frag);
 	C(data);
 	C(truesize);
-#ifdef CONFIG_TLS_DEVICE
-	C(decrypted);
-#endif
 	refcount_set(&n->users, 1);
 
 	atomic_inc(&(skb_shinfo(skb)->dataref));