[dpdk-dev] [PATCH v4 0/9] Improve cast alignment for strict aligned machines

[Cyril Chemparathy <cchemparathy@ezchip.com>]

This series contains a few improvements that allow the DPDK code base
to build properly on machines that enforce strict pointer cast
alignment constraints.

When dealing with packet data which could be arbitrarily aligned, we
get the compiler to do the right thing by (a) making sure that header
types are packed, and (b) introducing and using
unaligned_uint(16|32|64)_t types when upcasting from byte pointers.

In a few other instances, we know apriori that the pointer cast cannot
possibly break alignment.  This applies to the changes in mempool,
hash, mbuf, and the ethdev stats code.  Here, we simply silence the
compiler by casting through (void *) using the RTE_PTR_(ADD|SUB)
macros.

Finally, we introduce a new rte_pktmbuf_mtod_offset() helper to return
a type casted pointer to an offset within the packet data.  This
replaces the following commonly used pattern:
	(struct foo *)(rte_pktmbuf_mtod(m, char *) + offset)
with:
	rte_pktmbuf_mtod_offset(m, struct foo *, offset)

To ensure consistency, the above transform was applied throughout the
code base using the coccinelle semantic patching tool.

Changes in this series:
  v2: Fixes based on Olivier's comments.
  v3: Extends unaligned fixes to new code introduced on master.
  v4: Fixes based on Thomas' comments.
      Extends unaligned fixes to new code introduced on master.

Cyril Chemparathy (9):
  mempool: silence -Wcast-align on pointer arithmetic
  mbuf: silence -Wcast-align on pointer arithmetic
  ethdev: silence -Wcast-align on pointer arithmetic
  hash: silence -Wcast-align on pointer arithmetic
  eal: add and use unaligned integer types
  app/test-pmd: pack simple_gre_hdr
  librte_mbuf: Add rte_pktmbuf_mtod_offset()
  librte_mbuf: Add transform for rte_pktmbuf_mtod_offset()
  librte_mbuf: Apply mtod-offset.cocci transform

 app/test-pmd/csumonly.c                    |  2 +-
 app/test-pmd/flowgen.c                     |  4 +-
 app/test-pmd/icmpecho.c                    |  2 +-
 app/test-pmd/ieee1588fwd.c                 |  4 +-
 app/test-pmd/rxonly.c                      | 21 +++++----
 app/test-pmd/txonly.c                      |  6 +--
 app/test/packet_burst_generator.c          |  9 ++--
 app/test/test_hash_functions.c             |  2 +-
 app/test/test_mbuf.c                       | 16 +++----
 config/common_bsdapp                       |  5 ++
 config/common_linuxapp                     |  5 ++
 drivers/net/bonding/rte_eth_bond_pmd.c     | 12 +++--
 drivers/net/mlx4/mlx4.c                    |  9 ++--
 examples/dpdk_qat/crypto.c                 |  8 ++--
 examples/dpdk_qat/main.c                   |  5 +-
 examples/l3fwd-acl/main.c                  | 20 ++++----
 examples/l3fwd-power/main.c                |  8 ++--
 examples/l3fwd-vf/main.c                   |  4 +-
 examples/l3fwd/main.c                      | 71 ++++++++++++----------------
 examples/load_balancer/runtime.c           |  4 +-
 examples/vhost_xen/main.c                  |  4 +-
 lib/librte_eal/common/include/rte_common.h | 10 ++++
 lib/librte_ether/rte_ethdev.c              | 24 +++++-----
 lib/librte_ether/rte_ether.h               |  2 +-
 lib/librte_hash/rte_hash.c                 | 10 ++--
 lib/librte_ip_frag/rte_ipv4_reassembly.c   |  7 ++-
 lib/librte_ip_frag/rte_ipv6_reassembly.c   |  5 +-
 lib/librte_mbuf/rte_mbuf.h                 | 32 +++++++++----
 lib/librte_mempool/rte_mempool.c           |  2 +-
 lib/librte_mempool/rte_mempool.h           |  6 +--
 lib/librte_port/rte_port_ras.c             |  6 +--
 lib/librte_vhost/vhost_rxtx.c              |  6 +--
 scripts/cocci.sh                           | 64 +++++++++++++++++++++++++
 scripts/cocci/mtod-offset.cocci            | 76 ++++++++++++++++++++++++++++++
 34 files changed, 319 insertions(+), 152 deletions(-)
 create mode 100755 scripts/cocci.sh
 create mode 100644 scripts/cocci/mtod-offset.cocci

-- 
2.1.2