svn commit: r282847 - in stable/9/sys: dev/ixgbe sys

[Garrett Cooper]

Author: ngie
Date: Wed May 13 10:43:49 2015
New Revision: 282847
URL: https://svnweb.freebsd.org/changeset/base/282847

Log:
  MFstable/10 r281951,r281954:
  
  r281951:
  
  Backport MHSIZE/MPKTHSIZE equivalents from head
  
  These macros are equivalent to the ones on head, except they are only exposed
  when _KERNEL is defined, i.e. to kernel code, whereas the code on head is exposed
  to userland as well
  
  This is for improved forwards compatibility with mbuf(9) macros in head at r277203+,
  and is required for a clean MFC of r279393
  
  This is a direct commit to stable/10
  
  Differential Revision: https://reviews.freebsd.org/D2126
  Reviewed by: glebius, rwatson
  Sponsored by: EMC / Isilon Storage Division
  
  r281954:
  
  MFC r279393:
  
  Pad RX copy alignment calculation to avoid illegal memory accesses
  
  The optimization made in r239940 is valid for struct mbuf's current structure
  and size in FreeBSD, but hardcodes assumptions about sizes of struct mbuf,
  which are unfortunately broken if additional data is added to the beginning of
  struct mbuf
  
  X-MFC note (discussed with rwatson):
  
  This change requires the MPKTHSIZE definition, which is only available after
  head at r277203 and will not be MFCed as it breaks mbuf(9) KPI.
  
  A direct commit to stable/10 and merges to other branches to add the necessary
  definitions to work with the code as-is will be done to facilitate this MFC
  
  PR: 194314
  Approved/Reviewed by: erj, jfv
  Sponsored by: EMC / Isilon Storage Division

Modified:
  stable/9/sys/dev/ixgbe/ixgbe.h
  stable/9/sys/sys/mbuf.h
Directory Properties:
  stable/9/   (props changed)
  stable/9/sys/   (props changed)
  stable/9/sys/dev/   (props changed)
  stable/9/sys/dev/ixgbe/   (props changed)
  stable/9/sys/sys/   (props changed)

Modified: stable/9/sys/dev/ixgbe/ixgbe.h
==============================================================================
--- stable/9/sys/dev/ixgbe/ixgbe.h	Wed May 13 10:35:34 2015	(r282846)
+++ stable/9/sys/dev/ixgbe/ixgbe.h	Wed May 13 10:43:49 2015	(r282847)
@@ -160,8 +160,9 @@
  * modern Intel CPUs, results in 40 bytes wasted and a significant drop
  * in observed efficiency of the optimization, 97.9% -> 81.8%.
  */
-#define IXGBE_RX_COPY_LEN	160
-#define IXGBE_RX_COPY_ALIGN	(MHLEN - IXGBE_RX_COPY_LEN)
+#define IXGBE_RX_COPY_HDR_PADDED	((((MPKTHSIZE - 1) / 32) + 1) * 32)
+#define IXGBE_RX_COPY_LEN		(MSIZE - IXGBE_RX_COPY_HDR_PADDED)
+#define IXGBE_RX_COPY_ALIGN		(IXGBE_RX_COPY_HDR_PADDED - MPKTHSIZE)
 
 /* Keep older OS drivers building... */
 #if !defined(SYSCTL_ADD_UQUAD)

Modified: stable/9/sys/sys/mbuf.h
==============================================================================
--- stable/9/sys/sys/mbuf.h	Wed May 13 10:35:34 2015	(r282846)
+++ stable/9/sys/sys/mbuf.h	Wed May 13 10:43:49 2015	(r282847)
@@ -174,6 +174,16 @@ struct mbuf {
 #define	m_pktdat	M_dat.MH.MH_dat.MH_databuf
 #define	m_dat		M_dat.M_databuf
 
+/* 
+ * NOTE: forwards compatibility definitions for mbuf(9)
+ *
+ * These aren't 1:1 with the macros in r277203; in particular they're exposed
+ * to both userland and kernel, whereas this is exposed to just _KERNEL -- to
+ * avoid disruption with existing KBI/KPIs
+ */
+#define	MHSIZE		offsetof(struct mbuf, m_dat)
+#define	MPKTHSIZE	offsetof(struct mbuf, m_pktdat)
+
 /*
  * mbuf flags.
  */