This is a note to let you know that I've just added the patch titled
IB/core: Fix calculation of maximum RoCE MTU
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: ib-core-fix-calculation-of-maximum-roce-mtu.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Dec 18 14:12:35 CET 2017
From: Parav Pandit parav@mellanox.com Date: Mon, 16 Oct 2017 08:45:16 +0300 Subject: IB/core: Fix calculation of maximum RoCE MTU
From: Parav Pandit parav@mellanox.com
[ Upstream commit 99260132fde7bddc6e0132ce53da94d1c9ccabcb ]
The original code only took into consideration the largest header possible after the IB_BTH_BYTES. This was incorrect, as the largest possible header size is the largest possible combination of headers we might run into. The new code accounts for all possible headers in the largest possible combination and subtracts that from the MTU to make sure that all packets will fit on the wire.
Link: https://www.spinics.net/lists/linux-rdma/msg54558.html Fixes: 3c86aa70bf67 ("RDMA/cm: Add RDMA CM support for IBoE devices") Signed-off-by: Parav Pandit parav@mellanox.com Reviewed-by: Daniel Jurgens danielj@mellanox.com Reported-by: Roland Dreier roland@purestorage.com Signed-off-by: Leon Romanovsky leon@kernel.org Signed-off-by: Doug Ledford dledford@redhat.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/rdma/ib_addr.h | 7 ++++--- include/rdma/ib_pack.h | 19 +++++++++++-------- 2 files changed, 15 insertions(+), 11 deletions(-)
--- a/include/rdma/ib_addr.h +++ b/include/rdma/ib_addr.h @@ -243,10 +243,11 @@ static inline void rdma_addr_set_dgid(st static inline enum ib_mtu iboe_get_mtu(int mtu) { /* - * reduce IB headers from effective IBoE MTU. 28 stands for - * atomic header which is the biggest possible header after BTH + * Reduce IB headers from effective IBoE MTU. */ - mtu = mtu - IB_GRH_BYTES - IB_BTH_BYTES - 28; + mtu = mtu - (IB_GRH_BYTES + IB_UDP_BYTES + IB_BTH_BYTES + + IB_EXT_XRC_BYTES + IB_EXT_ATOMICETH_BYTES + + IB_ICRC_BYTES);
if (mtu >= ib_mtu_enum_to_int(IB_MTU_4096)) return IB_MTU_4096; --- a/include/rdma/ib_pack.h +++ b/include/rdma/ib_pack.h @@ -37,14 +37,17 @@ #include <uapi/linux/if_ether.h>
enum { - IB_LRH_BYTES = 8, - IB_ETH_BYTES = 14, - IB_VLAN_BYTES = 4, - IB_GRH_BYTES = 40, - IB_IP4_BYTES = 20, - IB_UDP_BYTES = 8, - IB_BTH_BYTES = 12, - IB_DETH_BYTES = 8 + IB_LRH_BYTES = 8, + IB_ETH_BYTES = 14, + IB_VLAN_BYTES = 4, + IB_GRH_BYTES = 40, + IB_IP4_BYTES = 20, + IB_UDP_BYTES = 8, + IB_BTH_BYTES = 12, + IB_DETH_BYTES = 8, + IB_EXT_ATOMICETH_BYTES = 28, + IB_EXT_XRC_BYTES = 4, + IB_ICRC_BYTES = 4 };
struct ib_field {
Patches currently in stable-queue which might be from parav@mellanox.com are
queue-4.9/ib-core-fix-calculation-of-maximum-roce-mtu.patch